tag:theconversation.com,2011:/global/topics/insects-1160/articlesInsects – The Conversation2024-03-28T12:21:15Ztag:theconversation.com,2011:article/2265412024-03-28T12:21:15Z2024-03-28T12:21:15ZEarly spring brings a ‘hungry gap’ for bees – here’s how you can help<figure><img src="https://images.theconversation.com/files/584795/original/file-20240327-20-lqgl8m.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4430%2C2951&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/flight-flying-bumblebee-spring-on-fruit-1390687526">Daniel Pahmeier/Shutterstock</a></span></figcaption></figure><p>Wild bees pollinate the crops and wild plants that feed us and sustain entire ecosystems, but many of the world’s 20,000 bee species are in decline. <a href="https://academic.oup.com/ee/article/50/3/732/6119323">Loss of habitat</a> is chiefly to blame, especially the loss of plants that provide pollen and nectar for bees to feed themselves and their brood (their eggs, larvae and pupae).</p>
<p>Falling numbers of bees and other insect pollinators have prompted governments to respond. In the UK, Europe and US, “pollinator planting” initiatives have taken root, yet species continue to decline. At least part of the problem seems to be that these schemes, which offer guidance to farmers, gardeners and landowners, recommend planting flowers to feed bees that start blooming much too late.</p>
<p>In <a href="https://resjournals.onlinelibrary.wiley.com/doi/full/10.1111/icad.12736">a new study</a>, we modelled the quantity of food available to bees in a computer simulation of a real farm. We found that the plant species recommended for pollinator planting in national initiatives tend to flower up to a month too late for the bees that emerge in the early spring – that’s right now, in March and April. </p>
<p>This “hungry gap” means fewer bee colonies survive to the end of the summer and not enough new queens are produced for the following year. The good news is that expanding these schemes to include plants that bloom very early in the spring could throw a lifeline to struggling bees. </p>
<h2>Why is the early spring so important?</h2>
<p>We wanted to find out when, during a typical season, limited food most threatens the fitness of bumblebees and which plant species are most helpful for remedying this. Our computer model simulations included multiple colonies of the buff-tailed bumblebee (<em>Bombus terrestris</em>) and the common carder bee (<em>Bombus pascuorum</em>), two UK species which emerge in spring. </p>
<p>The computer model simulates the life cycle of bumblebees. In it, digital bees explore a realistic landscape, collecting nectar and pollen, forming colonies and caring for their brood. At the end of a season, males and daughter queens are produced, and over a number of years the population may prosper or decline.</p>
<p>The landscape of a real farm was digitised to make the simulation, and the different areas (hedgerows, meadows, paddocks) marked in a digital map. We could adjust the variety of flowering plants in these areas for different test runs.</p>
<p>Adding plant species to the model that flower between March and April, like ground ivy, red dead-nettle, maple, cherry, hawthorn or willow, improved the survival rate of these bee populations from 35% to 100% over ten years. This meant that all colonies of both species survived each year a decade after these early flowering plants had been introduced.</p>
<figure class="align-center ">
<img alt="Fuzzy yellow catkins on slender branches." src="https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584797/original/file-20240327-30-tgwz47.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Willow tends to flower early in the season when we rarely see many bees.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/willow-salix-caprea-branch-coats-fluffy-2244717269">Irina Boldina/Shutterstock</a></span>
</figcaption>
</figure>
<p>These plants can fit into existing hedgerows without reducing the area used for crop production, ensuring farmers can continue to grow food and make a living while nourishing pollinators.</p>
<p>We were surprised to find that the bee colony’s demand for nectar and pollen at the start of the spring was driven mainly by the number of larvae rather than the number of adult workers. But if we look at the life cycle of a typical social bee colony, this finding makes sense. </p>
<p>In the spring, a queen emerges from hibernation, finds a suitable nest site, collects nectar and pollen and raises a first generation of brood. This founding stage of the colony is followed by the social phase, when enough pupae have matured into adult workers that they can take over foraging and brood care for the colony. The founding stage can last several weeks, and during this time, there are very few adult bees foraging to meet the needs of a large number of brood. This explains why, for our spring-emerging species, we observed high food demand in March and April, before we normally see large numbers of adult worker bees foraging outside the colony.</p>
<h2>Filling the hungry gap</h2>
<p>Some bee species emerge in the early spring and some emerge later; in the northern hemisphere, a species can emerge any time between March and July. Across <a href="https://www.nature.com/articles/s41559-019-1062-4">Europe</a> and <a href="https://www.pnas.org/doi/full/10.1073/pnas.1115559108">North America</a> there are plenty of early-spring bees which appear at the beginning of this range. In fact, somewhere between a third and a quarter of bee species in temperate regions may appear around the start of spring.</p>
<p>But government guidance in the UK and the EU misses this critical March-April hungry gap. EU guidance is to allow wild plants to flower during the summer, when most pollinators are on the wing, by cutting grass or grazing in early spring and autumn. In the US, land managers are encouraged (depending on the state) to plant a minimum of three species that bloom between April and June 15. These recommendations overlook the need for early spring forage. </p>
<p>Our critical finding is that bees need flowers for food up to a month before we even see the adults flying around. If different species of bee are active from April through October, then we need flowers blooming from March onward. </p>
<p>Providing flowers across the whole season, with an emphasis on early spring flowers, would make pro-pollinator schemes more effective. To supplement the <a href="https://www.plantlife.org.uk/campaigns/nomowmay/">“No Mow May”</a> campaign, we need a “plant early spring flowers” drive. Or even better: make sure you have flowers blooming every month from March through October.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/226541/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthias Becher works for RIFCON GmbH, Germany. He received funding from UKRI NERC for supporting the development of BEESTEWARD (project NE/P016731/1).</span></em></p><p class="fine-print"><em><span>Tonya Lander does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Check that something is blooming every week, March through October, to help bees.Tonya Lander, Stipendiary Lecturer in Biology, University of OxfordMatthias Becher, Affiliate, Environment and Sustainability Institute, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2241522024-03-25T12:39:22Z2024-03-25T12:39:22ZWhat is dirt? There’s a whole wriggling world alive in the ground beneath our feet, as a soil scientist explains<figure><img src="https://images.theconversation.com/files/582688/original/file-20240318-24-77z9su.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C3110%2C2057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dig into soil and you'll find rock dust but also thousands of living species.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/little-childs-hands-digging-in-the-mud-royalty-free-image/619539728">ChristinLola/iStock/Getty Images Plus</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What is dirt? – Belle and Ryatt, ages 7 and 5, Keystone, South Dakota</strong></p>
</blockquote>
<hr>
<p>When you think about dirt, you’re probably picturing soil. There’s so much more going on under our feet than the rock dust, or “dirt,” that gets on your pants.</p>
<p>When <a href="https://arts-sciences.und.edu/academics/biology/brian-darby/index.html">I began studying soil</a>, I was amazed at how much of it is actually alive. Soil is teeming with life, and not just the earthworms that you see on rainy days.</p>
<p>Keeping this vibrant world healthy is <a href="https://www.youtube.com/watch?v=Qas9tPQKd8w">crucial for food, forests and flowers to grow</a> and for the animals that live in the ground to thrive. Here’s a closer look at what’s down there and how it all works together.</p>
<figure class="align-center ">
<img alt="Cupped hands holds soil against a dark background with a tendril of plant root dangling through the fingers." src="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Soil is a vibrant ecosystem.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/bokeh-photography-of-person-carrying-soil-jin4W1HqgL4">Gabriel Jimenez via Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The rocky part of soils</h2>
<p>If you scoop up a handful of dry soil, the basic dirt that you feel in your hand is actually very small pieces of <a href="https://passel2.unl.edu/view/lesson/c62dc027ae56/1">weathered rock</a>. These tiny bits eroded from larger rocks over millions of years.</p>
<p>The <a href="https://www.soils4teachers.org/physical-properties/">balance of these particles</a> is important for how well soil can hold water and nutrients that plants need to thrive. </p>
<p>For example, <a href="https://www.masterclass.com/articles/sandy-soil-guide">sandy soil</a> has larger rock grains, so it will be loose and can easily wash away. It won’t hold very much water. <a href="https://www.thespruce.com/understanding-and-improving-clay-soil-2539857">Soil with mostly clay</a> is finer and more compact, making it difficult for plants to access its moisture. In between the two in size is <a href="https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/what-is-silt.htm">silt, a mix of rock dust and minerals</a> often found in fertile flood plains.</p>
<p>Some of the most productive soils have a good balance of sand, clay and silt. <a href="https://www.masterclass.com/articles/how-to-create-loam-soil-for-your-garden">That combination</a>, along with the remnants of plants and animals that have died, helps the soil to retain water, allows plants to access that water and minimizes erosion from wind or rain.</p>
<figure class="align-center ">
<img alt="Three tipped over pots spill different types of soil – sandy is heavier grain, clay is finer grain and thicker, and loamy is darker." src="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Loamy soil, ideal for gardens, is a mix of sand, clay and silt.</span>
<span class="attribution"><a class="source" href="https://www.nesdis.noaa.gov/learn-about-soil-types">NOAA</a></span>
</figcaption>
</figure>
<h2>The wriggling, munching parts of soil</h2>
<p>Among all those rock particles is a <a href="https://doi.org/10.3390/app10113717">whole world of living things</a>, each busy doing its job.</p>
<p>To get a sense of just how many creatures are there, picture this: The zoo in Omaha, Nebraska, boasts <a href="https://www.omahazoo.com/">over 1,000 animal species</a>. But if you scooped up a small spoonful of soil in your backyard, it would likely contain <a href="https://www.ceh.ac.uk/our-science/case-studies/case-study-why-do-soil-microbes-matter">at least 10,000 species</a> and around a billion living microscopic cells.</p>
<p>Most of those species are <a href="https://www.westernsydney.edu.au/newscentre/news_centre/story_archive/2018/first_soil_atlas">still largely a mystery</a>. Scientists don’t know much about them or what they do in soil. In fact, most species in soil don’t even have a formal scientific name. But each plays some kind of role in the vast soil ecosystem, including generating the <a href="https://www.aces.edu/blog/topics/farming/essential-plant-elements/">nutrients that plants need to grow</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two centipede-like creatures caught on camera immediately after a rock is lifted." src="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lifting a rock reveals a symphylan, or garden centipede, left, and a poduromorph, or plump springtail, munching through the soil.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Symphylan_%26_poduromorph_springtail_(3406419924).jpg">Marshal Hedin via Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Imagine a leaf falling from a tree in late autumn.</p>
<p>Inside that leaf are a lot of nutrients that plants need, such as nitrogen, potassium and phosphorus. There is also a lot of <a href="https://scied.ucar.edu/learning-zone/earth-system/biogeochemical-cycles">carbon in that leaf</a>, which holds energy that can be used by other organisms such as bacteria and fungi.</p>
<p>The leaf itself is too large for a plant to take up through its roots, of course. But that leaf can be broken down into smaller and smaller pieces. This process of breaking down plant and animal tissue is <a href="https://youtu.be/IBvKKMzXYtY?feature=shared">known as decomposition</a>.</p>
<p>When the leaf first falls to the ground, <a href="https://doi.org/10.3390%2Finsects11010054">arthropods</a> – such as insects, mites and <a href="https://www.chaosofdelight.org/collembola-springtails">collembolans</a> – break the leaf down into smaller chunks by shredding the tissue. Then, an <a href="https://youtu.be/n3wsUYg3XV0?feature=shared">earthworm might come along</a> and eat one of the smaller chunks and break it down even more in <a href="https://www.pbs.org/video/how-do-worms-turn-garbage-into-compost-jwj6cm/">its digestive tract</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2Pa1FwmKZcQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">PBS explores how earthworms help turn dead plants into fertile soil.</span></figcaption>
</figure>
<p>Now the broken-up leaf is small enough for microbes to come in. <a href="https://ohioline.osu.edu/factsheet/anr-36">Bacteria</a> and <a href="https://ohioline.osu.edu/factsheet/anr-37">fungi secrete enzymes</a> into the soil that further break down organic material into even smaller pieces. If enough microbes are active, eventually this organic material will be broken down enough that it can dissolve in water and be taken up by plants that need it.</p>
<p>To aid in this process, there are many small animals, such as <a href="https://www.canr.msu.edu/news/are_soil_nematodes_beneficial_or_harmful">nematodes</a> and <a href="https://www.livingsoil.net/protozoa">amoebae</a>, that consume bacteria and fungi. There are also predatory nematodes that feed on other nematodes to make sure they don’t become too abundant, so everything remains in balance as much as possible. </p>
<p>It’s quite a complicated food web of interacting species in a delicate balance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IBvKKMzXYtY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A time-lapse video filmed about 4 inches underground shows a leaf decomposing over 21 days in July. At the end, radish roots make their way down into the soil. Video by Josh Williams.</span></figcaption>
</figure>
<p>While some fungi and bacteria <a href="https://www.growingagreenerworld.com/bacteria-fungus-and-viruses-an-overview/">can harm plants</a>, there are many species that are considered beneficial. In fact, they <a href="https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soils/soil-health">may be the key</a> to figuring out how to grow enough crops to feed everyone without degrading and overburdening the soil.</p>
<h2>Figuring out your soil type</h2>
<p>Scientists have named <a href="https://www.nrcs.usda.gov/resources/education-and-teaching-materials/soil-facts">over 20,000 different types</a> of unique soils. If you’re curious about the <a href="https://www.nesdis.noaa.gov/learn-about-soil-types">soil and dirt in your area</a>, the University of California, Davis has a <a href="https://casoilresource.lawr.ucdavis.edu/gmap/">website where you can learn</a> more about local soils and their chemical and physical attributes.</p>
<p><a href="https://www.farmers.gov/conservation/soil-health">Caring for soil</a> to promote its living creatures’ benefits and minimize their harm takes work, but it’s essential for keeping the land healthy and growing food for the future.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/224152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Darby receives funding from the United States Department of Agriculture. </span></em></p>Rock dust is only part of the story of soil. Living creatures, many of them too tiny to see, keep that soil healthy for growing everything from food to forests.Brian Darby, Associate Professor of Biology, University of North DakotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221082024-03-22T12:34:47Z2024-03-22T12:34:47ZClimate change is shifting the zones where plants grow – here’s what that could mean for your garden<figure><img src="https://images.theconversation.com/files/583569/original/file-20240321-20-wkg9tp.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C2474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change complicates plant choices and care. Early flowering and late freezes can kill flowers like these magnolia blossoms.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>With the <a href="https://www.pbs.org/newshour/science/the-vernal-equinox-marks-the-first-day-of-spring-what-does-that-mean">arrival of spring</a> in North America, many people are gravitating to the gardening and landscaping section of home improvement stores, where displays are overstocked with eye-catching seed packs and benches are filled with potted annuals and perennials. </p>
<p>But some plants that once thrived in your yard may not flourish there now. To understand why, look to the U.S. Department of Agriculture’s recent update of its <a href="https://planthardiness.ars.usda.gov/">plant hardiness zone map</a>, which has long helped gardeners and growers figure out which plants are most likely to thrive in a given location. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A U.S. map divided into colored geographic zones with a numbered key." src="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 2023 USDA plant hardiness zone map shows the areas where plants can be expected to grow, based on extreme winter temperatures. Darker shades (purple to blue) denote colder zones, phasing southward into temperate (green) and warm zones (yellow and orange).</span>
<span class="attribution"><a class="source" href="https://planthardiness.ars.usda.gov/">USDA</a></span>
</figcaption>
</figure>
<p>Comparing the 2023 map to the previous version from 2012 clearly shows that as climate change warms the Earth, plant hardiness zones are shifting northward. On average, the coldest days of winter in our current climate, based on temperature records from 1991 through 2020, are 5 degrees Fahrenheit (2.8 Celsius) warmer than they were between 1976 and 2005. </p>
<p>In some areas, including the central Appalachians, northern New England and north central Idaho, winter temperatures have warmed by 1.5 hardiness zones – 15 degrees F (8.3 C) – over the same 30-year window. This warming changes the zones in which plants, whether annual or perennial, will ultimately succeed in a climate on the move.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing large areas colored tan, denoting a 5-degree increase in average winter minimum temperatures." src="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows how plant hardiness zones have shifted northward from the 2012 to the 2023 USDA maps. A half-zone change corresponds to a tan area. Areas in white indicate zones that experienced minimal change.</span>
<span class="attribution"><a class="source" href="https://site.extension.uga.edu/climate/2023/11/new-usda-plant-hardiness-zone-map-shows-most-of-southeast-has-gotten-one-half-zone-warmer/">Prism Climate Group, Oregon State University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As a <a href="https://scholar.google.com/citations?user=frEPl6IAAAAJ&hl=en">plant pathologist</a>, I have devoted my career to understanding and addressing plant health issues. Many stresses not only shorten the lives of plants, but also affect their growth and productivity. </p>
<p>I am also a gardener who has seen firsthand how warming temperatures, pests and disease affect my annual harvest. By understanding climate change impacts on plant communities, you can help your garden reach its full potential in a warming world.</p>
<h2>Hotter summers, warmer winters</h2>
<p>There’s no question that the temperature trend is upward. From 2014 through 2023, the world experienced the <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">10 hottest summers ever recorded</a> in 174 years of climate data. Just a few months of sweltering, unrelenting heat can significantly affect plant health, especially <a href="https://extension.psu.edu/cool-season-vs-warm-season-vegetables">cool-season garden crops</a> like broccoli, carrots, radishes and kale. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radishes sprouting in a garden bed." src="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radishes are cool-season garden crops that cannot withstand the hottest days of summer.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Winters are also warming, and this matters for plants. The USDA defines plant hardiness zones based on the coldest average annual temperature in winter at a given location. Each zone represents a 10-degree F range, with zones numbered from 1 (coldest) to 13 (warmest). Zones are divided into 5-degree F half zones, which are lettered “a” (northern) or “b” (southern). </p>
<p>For example, the coldest hardiness zone in the lower 48 states on <a href="https://planthardiness.ars.usda.gov/">the new map</a>, 3a, covers small pockets in the northernmost parts of Minnesota and has winter extreme temperatures of -40 F to -35 F. The warmest zone, 11b, is in Key West, Florida, where the coldest annual lows range from 45 F to 50 F. </p>
<p>On the <a href="https://planthardiness.ars.usda.gov/system/files/US_Map_2012.jpg">2012 map</a>, northern Minnesota had a much more extensive and continuous zone 3a. North Dakota also had areas designated in this same zone, but those regions now have shifted completely into Canada. Zone 10b once covered the southern tip of mainland Florida, including Miami and Fort Lauderdale, but has now been pushed northward by a rapidly encroaching zone 11a. </p>
<p>Many people buy seeds or seedlings without thinking about hardiness zones, planting dates or disease risks. But when plants have to contend with temperature shifts, heat stress and disease, they will eventually struggle to survive in areas where they once thrived. </p>
<p>Successful gardening is still possible, though. Here are some things to consider before you plant:</p>
<h2>Annuals versus perennials</h2>
<p>Hardiness zones matter far less for <a href="https://www.britannica.com/science/annual">annual plants</a>, which germinate, flower and die in a single growing season, than for <a href="https://www.britannica.com/science/perennial">perennial plants</a> that last for several years. Annuals typically avoid the lethal winter temperatures that define plant hardiness zones. </p>
<p>In fact, most annual seed packs don’t even list the plants’ hardiness zones. Instead, they provide sowing date guidelines by geographic region. It’s still important to follow those dates, which help ensure that frost-tender crops are not planted too early and that cool-season crops are not harvested too late in the year.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange flowers blooming with other plants and grasses." src="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">California poppies are typically grown as annuals in cool areas, but can survive for several years in hardiness zones 8-10.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/FWtHc">The Marmot/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>User-friendly perennials have broad hardiness zones</h2>
<p>Many perennials can grow across wide temperature ranges. For example, hardy fig and hardy kiwifruit grow well in zones 4-8, an area that includes most of the Northeast, Midwest and Plains states. Raspberries are hardy in zones 3-9, and blackberries are hardy in zones 5-9. This eliminates a lot of guesswork for most gardeners, since a majority of U.S. states are dominated by two or more of these zones. </p>
<p>Nevertheless, it’s important to pay attention to plant tags to avoid selecting a variety or cultivar with a restricted hardiness zone over another with greater flexibility. Also, pay attention to instructions about proper sun exposure and planting dates after the last frost in your area. </p>
<h2>Fruit trees are sensitive to temperature fluctuations</h2>
<p>Fruit trees have two parts, the rootstock and the scion wood, that are <a href="https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource003733_Rep5323.pdf">grafted together to form a single tree</a>. Rootstocks, which consist mainly of a root system, determine the tree’s size, timing of flowering and tolerance of soil-dwelling pests and pathogens. Scion wood, which supports the flowers and fruit, determines the fruit variety. </p>
<p>Most commercially available fruit trees can tolerate a wide range of hardiness zones. However, stone fruits like peaches, plums and cherries are more sensitive to temperature fluctuations within those zones – particularly abrupt swings in winter temperatures that create unpredictable freeze-thaw events. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Packages for hardy fig and kiwi seedlings." src="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following planting instructions carefully can maximize plants’ chances of success.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These seesaw weather episodes affect all types of fruit trees, but stone fruits appear to be more susceptible, possibly because they flower earlier in spring, have fewer hardy rootstock options, or have bark characteristics that make them more vulnerable to winter injury. </p>
<p>Perennial plants’ hardiness increases through the seasons in a process called <a href="https://extension.umd.edu/resource/hardening-vegetable-seedlings-home-garden/">hardening off</a>, which conditions them for harsher temperatures, moisture loss in sun and wind, and full sun exposure. But a too-sudden autumn temperature drop can cause plants to die back in winter, an event known as <a href="https://extension.psu.edu/winterkill-of-turfgrasses">winter kill</a>. Similarly, a sudden spring temperature spike can lead to premature flowering and subsequent frost kill.</p>
<h2>Pests are moving north too</h2>
<p>Plants aren’t the only organisms constrained by temperature. With milder winters, southern insect pests and plant pathogens are expanding their ranges northward. </p>
<p>One example is <a href="https://www.britannica.com/science/blight">Southern blight</a>, a stem and root rot disease that affects 500 plant species and is caused by a fungus, <em>Agroathelia rolfsii</em>. It’s often thought of as affecting hot Southern gardens, but has become more commonplace recently in the Northeast U.S. on tomatoes, <a href="https://theconversation.com/how-to-keep-your-jack-o-lantern-from-turning-into-moldy-maggoty-mush-before-halloween-190526">pumpkins and squash</a>, and other crops, including <a href="https://extension.psu.edu/apple-disease-southern-blight">apples in Pennsylvania</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A stem dotted with small round growths." src="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Southern blight (small round fungal structures) at the base of a tomato plant.</span>
<span class="attribution"><a class="source" href="https://ag.purdue.edu/department/arge/swpap/southern-blight-tomato.html">Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Other plant pathogens may take advantage of milder winter temperatures, which leads to prolonged saturation of soils instead of freezing. Both plants and microbes are less active when soil is frozen, but in wet soil, microbes have an opportunity to colonize dormant perennial plant roots, leading to more disease.</p>
<p>It can be challenging to accept that climate change is stressing some of your garden favorites, but there are thousands of varieties of plants to suit both your interests and your hardiness zone. Growing plants is an opportunity to <a href="https://theconversation.com/take-a-break-from-your-screen-and-look-at-plants-botanizing-is-a-great-way-to-engage-with-life-around-you-210616">admire their flexibility</a> and the features that enable many of them to thrive in a world of change.</p><img src="https://counter.theconversation.com/content/222108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the US Department of Agriculture.</span></em></p>The US Department of Agriculture has updated its plant hardiness zone map, which shows where various plants will grow across the country. Gardeners should take note.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2262062024-03-20T01:25:27Z2024-03-20T01:25:27ZNZ’s summer insects are packing up for autumn – here’s how our gardens can help them through the cold months<p>Chillier mornings and higher heating bills aren’t the only signs of the changing seasons. Common insects, too, are having to adapt. One day we see them in our gardens and parks, the next they appear to have disappeared. </p>
<p>But most are still here – they’re just harder to find.</p>
<p>Overwintering is an adaptation that many plants, insects and other invertebrates undergo in temperate climates. It’s how they survive cold times of the year when food sources are scarce. </p>
<p>It’s similar to the way some mammals, such as bears, hibernate. But while hibernation involves an extended and deep dormancy akin to sleep, overwintering organisms are still active, just to a lesser extent. </p>
<p>Some alpine insects, such as wētapunga, can even tolerate being <a href="https://predatorfreenz.org/stories/mountain-stone-weta/">frozen solid</a> for days at a time, slowing down their metabolism until conditions become favourable again.</p>
<h2>The stay-at-home monarch</h2>
<p>New Zealand’s monarch butterflies demonstrate how insects can adapt to new environments. In North America, they disappear for the northern winter, <a href="https://www.fs.usda.gov/wildflowers/pollinators/Monarch_Butterfly/migration/index.shtml">migrating up to 5,000 kilometres</a> from around the Great Lakes to the central Mexican volcanic mountains. </p>
<p>They arrive in huge swarms, with population estimates one year of around <a href="https://monarchconservation.org/monarch-status/monarch-population-status">380 million butterflies</a>, clustering together to conserve energy. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/insects-and-spiders-make-up-more-than-half-nzs-animal-biodiversity-time-to-celebrate-these-spineless-creatures-195450">Insects and spiders make up more than half NZ's animal biodiversity – time to celebrate these spineless creatures</a>
</strong>
</em>
</p>
<hr>
<p>In New Zealand, however, the monarch has adapted to island life and does not migrate. We know this because, for 15 years, the Moths and Butterflies of NZ Trust tagged monarch butterflies in autumn and winter to track where they were overwintering. </p>
<p>The data collected showed <a href="https://www.nzbutterflies.org.nz/project/tagging-monarchs/">no pattern of migration</a> or any common destination. Most recovered tags were still within the general area in which the butterflies were released. </p>
<p>New Zealand monarchs do show some similar behaviours to their North American counterparts, though. You might be fortunate to see a tree with a swarm of monarchs, usually on the tree’s northern side. </p>
<p>The butterflies stay active during winter, as temperatures allow. On a sunny day you will see them flying around, looking for nectar from flowers to top up their energy.</p>
<h2>Leave the leaf litter</h2>
<p>Overwintering in large numbers, however, is not typical of the way most insects survive the winter. Aotearoa’s <a href="https://jandtlab.com/how-can-i-help-save-the-bees/">native bees</a> are active only in the summer, when females forage to collect a nutritious “pollen ball” to sustain their dozen or so offspring underground during development. </p>
<p>Bee larvae will remain underground during winter, long after their parents have perished. They will emerge the following summer as the new generation of adults, never having met their caregivers.</p>
<p>While flowers rich in nectar and pollen are crucial for insects to forage when they emerge from overwintering, dead and decaying plant matter is the <a href="https://xerces.org/blog/leave-leaves-to-benefit-wildlife">lifeblood of the invertebrate world</a> during autumn and winter. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nz-votes-the-red-admiral-butterfly-bug-of-the-year-how-to-make-your-garden-its-home-223083">NZ votes the red admiral butterfly ‘bug of the year’ – how to make your garden its home</a>
</strong>
</em>
</p>
<hr>
<p>Leaf litter provides cover and nutrition for millions of insects and other microorganisms that cycle nutrients and soil, pollinate ecosystems and sustain larger organisms such as birds and fish.</p>
<p>You can help butterflies and other invertebrates survive winter by raking dead leaves onto the garden, rather than into the rubbish, and leaving seed heads on plants. Not only will this give these amazing ecosystem engineers somewhere to shelter, it will also help them return precious nutrients to the soil. </p>
<p>Plants such as <a href="https://www.nzbutterflies.org.nz/wp-content/uploads/List-of-some-nectar-species.pdf">Leucanthemum and Alyssum</a>, which produce nectar-filled flowers in autumn and winter, can provide a top-up feed for butterflies and other pollinators during warm spells. </p>
<p>Native winter-flowering whauwhau, or five-finger (<em>Pseudopanax arboreus</em>), provides vital overwintering energy for insects. And kotukutuku (<em>Fuchsia excorticata</em>), though mainly bird-pollinated, is also <a href="https://thisnzlife.co.nz/top-17-trees-feed-bees-new-zealand-year-round/">popular with bees</a>.</p>
<h2>Flight of the bumble bee</h2>
<p>Not all insects overwinter. Colony and social insects such as bumble bees and honey bees follow <a href="https://www.nzbct.org.nz/bee-informed/">characteristic phenological cycles</a>, intricately and inseparably linked to floral blooming seasons. </p>
<p>Bumble bee queens initiate a colony underground and begin to produce workers that typically live for an average of 28 days. </p>
<p>As the colony deteriorates with age at the end of summer, the queen will shift from producing sterile workers to producing reproductive individuals. These male <a href="https://www.perfectbee.com/beekeeping-articles/role-of-the-drone-bee">drones</a> and female <a href="https://www.amentsoc.org/insects/glossary/terms/gyne/">gynes</a> will leave the nest to mate, while workers consume the remaining resources.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-bees-have-queens-2-biologists-explain-this-insects-social-structure-and-why-some-bees-dont-have-a-queen-at-all-213208">Why do bees have queens? 2 biologists explain this insect's social structure – and why some bees don't have a queen at all</a>
</strong>
</em>
</p>
<hr>
<p>Around March and April you may see many <a href="https://www.bumblebeeconservation.org/bee-faqs/finding-dead-bees/">dead bumble bees</a> on the ground. This isn’t necessarily cause for alarm – they have simply worked hard pollinating and have reached their natural life expectancy. </p>
<p>Meanwhile, newly mated queen bumble bees will now seek out new spots in which to begin colonies, such as vacant rodent and rabbit burrows. The queens benefit from the retained heat provided by undisturbed leaf litter, which also protects them from predators.</p>
<p>Eventually, our overwintering insects will emerge, often coinciding with the start of flowering and pollen production. But a changing climate can <a href="https://www.beeculture.com/pollination-its-all-about-timing/">disrupt key plant-animal interactions</a> such as pollination. In the meantime, they will appreciate all the help we can give them as temperatures drop and the cycle of life turns again.</p>
<hr>
<p><em>The authors gratefully acknowledge the help of the <a href="https://www.nzbutterflies.org.nz/">Moths and Butterflies of New Zealand Trust</a> in the preparation of this article.</em></p>
<hr><img src="https://counter.theconversation.com/content/226206/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janice Lord has received funding for invertebrate-related research from the Miss E.L. Hellaby Indigenous Grasslands Research Trust, Royal Society of New Zealand, Department of Conservation, and University of Otago. She is a member of the Entomological Society of New Zealand and an honorary associate of Plant and Food Research Ltd.</span></em></p><p class="fine-print"><em><span>Connal McLean is a member of The Entomological Society of New Zealand and The Moths and Butterflies of New Zealand Trust.</span></em></p>Many common insects seem to disappear during autumn and winter – but they are still around. Making your garden a good winter habitat can help these vital pollinators survive and thrive.Janice Lord, Associate Professor in Botany, University of OtagoConnal McLean, Natural History Technician – Invertebrates, Te Papa TongarewaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2237062024-03-19T12:23:24Z2024-03-19T12:23:24ZFemale mosquitoes rely on one another to choose the best breeding sites − and with the arrival of spring, they’re already on the hunt<figure><img src="https://images.theconversation.com/files/582309/original/file-20240315-26-7bf0sq.jpg?ixlib=rb-1.1.0&rect=30%2C0%2C6789%2C4468&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Aedes aegypti_, found across much of the U.S., spread Zika, dengue, chikungunya and other viruses.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/aedes-aegypti-mosquito-pernilongo-with-white-spots-royalty-free-image/1282216815">Mailson Pignata/iStock via Getty Images</a></span></figcaption></figure><p><em>Aedes aegypti</em> mosquitoes, one of the <a href="https://www.cdc.gov/mosquitoes/mosquito-control/professionals/range.html">most common species in the U.S.</a>, love everything about humans. They love our <a href="http://dx.doi.org/10.1126/science.adi8213">body heat and odors</a>, which enable them to find us. They love to feed on our blood to make their eggs mature. They even love all the standing water that we create. Uncovered containers, old tires and junk piles collect water and are perfect for breeding. </p>
<p>And with the advent of warm weather across the southern U.S., <a href="https://www.mosquitomagnet.com/articles/mosquito-season">mosquito breeding season is already underway</a>.</p>
<p>Given all the options that <em>Aedes</em> females have in urban areas, how do these cosmopolitan mosquitoes find the perfect site to lay their eggs? Scientists previously thought this was a solitary act, but now research shows that female <em>Aedes aegypti</em> mosquitoes – the main vector in the U.S. for diseases such as <a href="https://theconversation.com/explainer-where-did-zika-virus-come-from-and-why-is-it-a-problem-in-brazil-53425">Zika, dengue, chikungunya</a> and other viruses – can rely on one another for good reviews of breeding sites. </p>
<p>Our <a href="https://www.degennarolab.org/">Laboratory of Tropical Genetics</a> at Florida International University discovered a new behavior in which these mosquitoes <a href="https://doi.org/10.1038/s42003-024-05830-5">work together to find suitable egg-laying sites</a>. These findings, recently published in Communications Biology, show that mosquitoes regulate their own population density at breeding sites – an insight that could inform future mosquito control efforts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A half-dozen mosquitoes spread along the inside of a container." src="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581972/original/file-20240314-30-jxgzpm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Aedes aegypti</em> female mosquitoes laying their eggs in a laboratory breeding container.</span>
<span class="attribution"><span class="source">Kaylee Marrero</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Where and why female mosquitoes cluster</h2>
<p>Scientists know that female mosquitoes can be picky when it comes to where they lay their eggs. <em>Aedes aegypti</em> look for human-made breeding sites with relatively clean water, such as birdbaths, tires or even water-filled trash. But given two equal choices, you might expect them to spread evenly between the two. </p>
<p>On the contrary, when we released females in a two-choice test where both breeding site options were equivalent, we repeatedly found more mosquitoes in one chamber than in the other. Furthermore, this occurred irrespective of where the preferred chamber was positioned, whether the mosquitoes could touch water or whether mosquito eggs were already present at the breeding sites. </p>
<p>Female mosquitoes clearly were following one another in small groups to one breeding site rather than another – a newly discovered behavior in <em>Aedes aegypti</em> that we call aggregation. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two ramekins, one with a few black spots in it, the other with many spots." src="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=319&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=319&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=319&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=401&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=401&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581971/original/file-20240314-26-70qvqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=401&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The black spots in the container on the right indicate that <em>Aedes aegypti</em> females have chosen it as a place to lay their eggs over the identical site on the left.</span>
<span class="attribution"><span class="source">Kaylee Marrero</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The insects evidently preferred not to lay their eggs alone. When we tested 30 mosquitoes in our trials, they chose one site over another by a 2-to-1 margin. However, this changed as the test population increased beyond 30 mosquitoes. When we tested 60 or 90 females, the aggregation disappeared.</p>
<p>This tells us that females can regulate their own density at breeding sites – a response that likely is a mechanism to limit larval competition.</p>
<h2>Mosquitoes are smelling each other</h2>
<p>Mosquitoes largely sense the world through smell, using three families of <a href="https://www.britannica.com/science/olfactory-receptor">olfactory receptors</a>. These receptors detect odors when females are choosing where to lay eggs. But how do females sense each other to regulate their densities at breeding sites? </p>
<p>We explored this question by first placing 15 mosquitoes at one of our two test breeding sites. Other females seeking a place to lay preferred the unoccupied site over the one that was already occupied, even though we had already observed that the mosquitoes preferred not to lay their eggs alone. Something was directing them away from the occupied breeding site; we speculated that it might be carbon dioxide, which is an important cue for mosquitoes in all stages of their life cycle. </p>
<p>When female mosquitoes are looking for a blood meal, they fly toward the odor of CO₂, which all vertebrate animals <a href="https://theconversation.com/why-are-some-people-mosquito-magnets-and-others-unbothered-a-medical-entomologist-points-to-metabolism-body-odor-and-mindset-187957">exhale and release through their skin</a>. After feeding, they fly away from it, likely to avoid the risk of being killed by the host. </p>
<p>Mosquitoes also emit CO₂, and normally other mosquitoes can smell it, thanks to a receptor component called Gr3 in their olfactory organs. But when we released mutant females that lacked a functional Gr3 receptor to seek a place to lay eggs in our two-site test, we found that these insects, which could not detect CO₂, were willing to lay their eggs at preoccupied breeding sites. This suggested that normal mosquitoes might be avoiding the preoccupied laying site because they smelled CO₂ emitted by mosquitoes that were already there.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EUrOcquy8IU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Female mosquitoes lay eggs on or near still bodies of water.</span></figcaption>
</figure>
<p>To confirm this, we offered two unoccupied breeding sites to females seeking a place to lay. However, we increased CO₂ levels around one of the sites to between 600 and 750 parts per million, compared with the normal level of about 450 to 500 ppm at the other site. We found that <em>Aedes aegypti</em> females avoided the unoccupied sites with elevated CO₂. This behavior appears designed to keep occupied breeding sites from becoming too crowded. </p>
<p>Overall, we found that two families of receptors play a role in the interactions between <em>Aedes aegypti</em> females when they seek breeding sites. Odorant receptors detect an unknown odor, which draws females toward a site; gustatory receptors detect CO₂, which deters females from breeding sites when the carbon dioxide level is high. The balance between these attractive and repellent odors will ultimately determine whether a female chooses or avoids a particular site. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic showing common mosquito breeding sites around home, including gutters and pet dishes." src="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582583/original/file-20240318-20-i9yyck.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mosquitoes breed in many wet spots, large and small.</span>
<span class="attribution"><a class="source" href="https://www.cabq.gov/environmentalhealth/urban-biology/mosquitoes">City of Albuquerque</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Implications for mosquito control</h2>
<p>Suppressing mosquito populations in urban areas using <a href="https://www.cdc.gov/mosquitoes/mosquito-control/community/larvicides.html">biolarvicides</a> – pesticides made from live bacteria that are toxic to mosquito larvae – is a primary control strategy to limit the spread of deadly diseases such as West Nile virus and Zika virus. This is especially true for <em>Aedes aegypti</em>, which is the most common urban mosquito species that reproduces in artificial breeding sites that humans create. Other control tactics, such as <a href="https://undark.org/2019/10/25/when-residents-say-no-to-aerial-mosquito-spraying/">spraying pesticides over large areas</a>, target beneficial insects as well as mosquitoes and can be controversial. </p>
<p>Knowing that female <em>Aedes aegypti</em> use social cues to pick the best breeding grounds for their young and will move on from a breeding site when it becomes too crowded could lead to new control measures. Interrupting the female mosquito reproductive cycle would reduce the spread of mosquitoes and the spread of diseases that these insects carry.</p><img src="https://counter.theconversation.com/content/223706/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kaylee Marrero receives funding from the National Institutes of Health.</span></em></p><p class="fine-print"><em><span>Andre Luis Costa-da-Silva receives funding from the Centers for Disease Control and Prevention, the Southeastern Center of Excellence in Vector-borne Disease and the National Institutes of Health. Views expressed in this article are his own. </span></em></p><p class="fine-print"><em><span>Matthew DeGennaro receives funding from the Centers for Disease Control and Prevention (CDC), the Southeastern Center of Excellence in Vector-borne Disease and the National Institutes of Health. Views expressed in this article are his own.</span></em></p>Female mosquitoes don’t want to lay their eggs alone, but they don’t want sites that are too crowded either. Understanding what guides their choice could inform new control strategies.Kaylee Marrero, Ph.D. Student and Transdisiplinary Biomolecular and Biomedical Sciences Fellow, Florida International UniversityAndre Luis da Costa da Silva, Research Assistant Professor of Biological Sciences, Florida International UniversityMatthew DeGennaro, Associate Professor of Biological Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132002024-03-05T13:59:52Z2024-03-05T13:59:52ZRobber flies track their beetle prey using tiny microbursts of movement<figure><img src="https://images.theconversation.com/files/553851/original/file-20231015-26-ku2y0f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Robber flies visually track their prey before spearing it with their proboscis.</span> <span class="attribution"><span class="source">Paloma Gonzalez-Bellido</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>April in the Florida Panhandle. It was hot, humid, and a thunderstorm was lurking. But as a fresh graduate student, I was relieved for the escape from my first brutal Minnesota winter. I was accompanying my adviser, <a href="https://scholar.google.com/citations?user=OpaFwzoAAAAJ&hl=en&oi=ao">Paloma Gonzalez-Bellido</a>, on a project that would end up dominating <a href="https://scholar.google.com/citations?user=oux0RxAAAAAJ&hl=en">my Ph.D. work</a>. Out in the scrubland, my eyes darted at every movement, on the alert for an insect that likes shiny beads. </p>
<p><a href="https://doi.org/10.1093/aesa/43.2.227"><em>Laphria saffrana</em></a>, also known as robber flies, are chunky black and yellow flies. Most of a laphria’s head is made up of its large eyes, between which sits a formidable proboscis – a long, tubular mouthpart that can deliver a potent venom capable of incapacitating prey in a heartbeat.</p>
<p>The photos Paloma showed me before we got there, though stunning, were of no help in looking for the fly. There were insects flying in every direction, their movements a blur, making it impossible to pick out any details. I only had a split second to figure out whether the thing I was seeing was a laphria, a similarly colored yellowjacket wasp, or something else entirely. </p>
<p>Despite their <a href="https://doi.org/10.1016/j.cub.2017.02.032">relatively crude vision</a>, the flies I was looking for are far more adept than I am at picking out the insects they’re targeting. Somehow they’re able to zero in on their prey of choice: beetles. Based on her field observations the previous year, Paloma thought they did this by looking for the flash of beetle wings.</p>
<p>If she was right, laphria have hit upon an ingenious trick that balances the need for speed, accuracy and specificity. Here are some of the clues we’ve found to <a href="https://doi.org/10.1016/j.cub.2023.06.019">the secrets of their success</a>. </p>
<h2>Following the flash</h2>
<p>Paloma had previously studied other predator insects such as dragonflies and killer flies. Their <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/compound-eye">compound eyes</a> don’t provide a lot of detail about the visual world, making it possible to trick them into chasing simple beads as if they were their prey insects.</p>
<p>But when Paloma tried the same sleight of hand on laphria, they wouldn’t go for the regular black beads. They chased only clear beads. </p>
<p>The one important difference between laphria and the other predators Paloma had studied is that they’re picky eaters. Their prey of choice are beetles. So, Paloma and our collaborator, Jennifer Talley, speculated that the reason laphria are attracted to shiny beads is because they reflected light and flashed like the clear wings of a beetle.</p>
<p>In Florida, we tested this idea by swapping out the plain black beads for a panel of LED lights that we could program to flash in sequence at a frequency that matched the wing beats of beetles, which can be anywhere from 80 to 120 beats per second. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/m5gQ1Bhmag4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The experimental setup, with a robber fly sitting on a log facing the LED light panel.</span></figcaption>
</figure>
<p>In an outdoor enclosure, Paloma placed previously caught robber flies one after the other on a log. Outside, Jennifer and I controlled the LED panel in front of the log and the high-speed cameras that captured the action.</p>
<p>The LED pixels flashed in sequence, simulating a moving target. Laphria tracked the lights with keen interest only when they flashed at the same frequency at which beetles flapped their wings.</p>
<p>But even as our initial experiments began confirming the hypothesis, a new puzzle presented itself. How do the flies accurately track their prey?</p>
<h2>Unique strategy to track and identify</h2>
<p>Before they give chase, all visual predators, including laphria, need to accurately track their prey’s movements. Although many animals have this ability, what we found in laphria was, to our surprise, a slightly tweaked formula compared with other predators. Their strategy allows them not only to accurately track but also count those flashes from their prey’s wing movements.</p>
<p>When I looked at the high-speed videos of laphria tracking the flashing LEDs and actual beetles, I noticed that they primarily moved their head in short bursts, called <a href="https://eyewiki.aao.org/Saccade">saccades</a>, interspersed with little or no other movements. These saccades are extremely quick, lasting less than 40 milliseconds, and the time between them is only slightly longer. To the naked eye, this looks like continuous motion, but our high-speed videos show otherwise. The degree to which the flies moved their heads during each burst depended on the speed of the target and how far off center it was from the direction of the fly’s gaze.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ZnuEHGsGz9k?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Watch a robber fly watching moving lights it perceives as a prey beetle.</span></figcaption>
</figure>
<p><a href="https://doi.org/10.1016/j.cub.2023.06.019">What our findings told us</a> is that instead of continuously moving their heads to maintain the position of the target within the most sensitive parts of their eyes, laphria allow it to pass over their retina, moving only when it slips out of focus. We think this strategy helps them count the flashes of the prey’s beating wings, which determines their continued interest.</p>
<p>That is, the laphria know the wingbeat frequency of their most tasty prey and so pay attention to flashes that match. If the flash count matches their expectations, they will continue to track the target after it slips out of the sensitive zone of their eyes.</p>
<p>To bring it back into focus, though, they have to account for its speed and the position where they last saw it. Because the size of the saccade matches the speed of the prey, we think the laphria are keeping track of how fast the prey moves while at the same time counting the flashes from its wingbeats. So once a beetle slips out of focus, the predator knows how much to move its head to refocus.</p>
<p>Even though people track moving objects all the time – like while playing sports such as baseball or tennis or even just while watching a bird fly by – <a href="https://www.freethink.com/series/the-edge/eye-tracking">it’s a complex process</a>. It involves dynamic cross-talk between the visual and muscular systems.</p>
<p>Regardless of the motivation, the goal while visually tracking a target is the same – to train the most sensitive zone of the eyes, <a href="https://www.ncbi.nlm.nih.gov/books/NBK554706/">known as the fovea</a>, onto the item of interest. <em>Laphria saffrana</em> have seemingly tweaked that rule so they can learn more about the target. Their customized prediction strategy allows them to accurately locate and quickly chase down their very specific dietary needs.</p><img src="https://counter.theconversation.com/content/213200/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Siddhant Pusdekar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Not much is known about the predator fly Laphria saffrana. New research identified how they count the wingbeats of their favored prey, letting it slip out of focus before adjusting their heads.Siddhant Pusdekar, Graduate Researcher in Ecology, Evolution and Behavior, University of MinnesotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132082024-03-04T13:35:40Z2024-03-04T13:35:40ZWhy do bees have queens? 2 biologists explain this insect’s social structure – and why some bees don’t have a queen at all<figure><img src="https://images.theconversation.com/files/578405/original/file-20240227-30-jjne39.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C3019%2C1971&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The queen, on the right with a larger, darker body, is bigger than the worker bees in the colony and lives several times longer.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/bees-from-a-bee-colony-with-a-queen-are-seen-on-a-honeycomb-news-photo/1233050929">Jens Kalaene/picture alliance via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Why do bees have queens? – Rhylie, age 8, Rosburg, Washington</strong></p>
</blockquote>
<hr>
<p>When you think “bee,” you likely picture one species that lives all over the world: the <a href="https://www.natgeokids.com/au/discover/animals/insects/honey-bees/">honey bee</a>. And honey bees have queens, a female who lays essentially all of the eggs for the colony.</p>
<p>But most bees don’t have queens. With about <a href="https://www.usgs.gov/faqs/how-many-species-native-bees-are-united-states#:%7E">20,000 species of bees worldwide</a> – that’s about 2 trillion bees – the majority of them don’t even live in groups. They do just fine <a href="https://tpwd.texas.gov/huntwild/wild/wildlife_diversity/nongame/native-pollinators/solitary-social.phtml#:%7E">without queens or colonies</a>. </p>
<p>Instead, a single female lays eggs in a simple nest, either inside a plant stem or an underground tunnel. She provides each egg with a ball of pollen mixed with nectar that she collected from flowers, and she leaves the eggs to hatch and develop on their own. She doesn’t have anyone to help with this process. </p>
<p>These bee species, often spectacularly beautiful, are <a href="https://www.fs.usda.gov/wildflowers/pollinators/animals/bees.shtml">important pollinators of many crops and plants</a>, though most people aren’t even aware of them. </p>
<p>Since lots of bees successfully live without a queen, what is it that queens provide for the bee species that do have them? <a href="https://scholar.google.com/citations?user=KF4sBDIAAAAJ&hl=en&oi=ao">We are behavioral ecologists</a> <a href="https://scholar.google.com/citations?user=r9Wuv18AAAAJ&hl=en&oi=ao">who study social insects</a>, and this question is at the heart of our research. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="handful of bees flying toward a busy hive" src="https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578406/original/file-20240227-26-jefrkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A bee colony may have many thousands of workers who support the single queen.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/bees-flying-royalty-free-image/172457089">bo1982/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>A queen, workers and drones</h2>
<p>Along with honey bees, two other kinds of bees also have queens: <a href="https://www.treehugger.com/bumblebee-facts-5119379">bumble bees</a>, which are found on all continents except Australia and Antarctica, and <a href="https://beeswiki.com/stingless-bees/">stingless bees</a>, which are found primarily in tropical areas. </p>
<p>One honey bee colony – also called a hive – may have <a href="https://www.buzzaboutbees.net/honey-bee-facts.html">more than 50,000 bees</a>, while bumble bee colonies usually have just a few hundred bees. Stingless bee colonies are often small, but some are as large as the biggest honey bee hives. </p>
<p>These bees’ social structures have two more things in common besides the egg-laying queen: the female workers who care for the colony, and the males, <a href="https://www.buzzaboutbees.net/dronebee.html">sometimes called “drones</a>.” </p>
<p>Notice the males are not included in the “worker” group. Males generally don’t help collect nectar or pollen, protect and maintain the hive, or care for the young larvae. The females do all of those jobs. </p>
<p>Instead, the males have one task: to find and then mate with a female who may become a future queen. After building their strength, males leave the hive to join thousands of other drones to wait for new queens that are also looking for mates. If males are lucky enough to mate, they die soon afterward. In contrast, females typically mate with many different males before starting their lives as egg-laying queens. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/9ePic3dtykk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Female worker bees do pretty much all the work.</span></figcaption>
</figure>
<h2>The isolated queen</h2>
<p>Maybe you imagine a queen as the one in charge, ordering everyone around. But that’s a case of language being misleading. Unlike human queens who lead their people, bee queens don’t rule over their workers. </p>
<p>Instead, particularly for honey bees, the queen is rather isolated from what’s happening in the hive. Remember, she just lays eggs, up to 2,000 in a day. The workers surround and take care of her while managing the colony. The queen bee might <a href="https://www.buzzaboutbees.net/how-long-do-bees-live.html">live for a few years</a>, much longer than female worker bees and drones.</p>
<p>Other animals also live in social groups with a division of labor between those who reproduce and those who maintain the colony. <a href="https://www.natgeokids.com/uk/discover/animals/insects/ant-facts/">Ants</a>, <a href="https://kids.britannica.com/kids/article/termite/353849#:%7E">termites</a> and <a href="https://kids.britannica.com/kids/article/wasp/353914#:%7E">some wasps</a> – like yellow jackets and hornets – have a similar kind of colony structure. So does the <a href="https://nationalzoo.si.edu/animals/naked-mole-rat">naked mole rat</a>. Why did these groups evolve to have queens? </p>
<h2>Family ties</h2>
<p>One way for an organism to pass on genes is by having offspring. </p>
<p>Another way is to help close relatives, who are likely to share many of your same genes, to produce more offspring than they would if they were on their own. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="dozens of hexagonal cells, each containing a tiny white egg or slightly larger white worm" src="https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578408/original/file-20240227-28-3bsd6f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Honey bee eggs and larvae develop one to a cell.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/honey-bee-eggs-and-larva-in-comb-with-black-royalty-free-image/1455295651">Megan Kobe/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>This option is pretty much what happens in a bee colony. Those thousands of female worker bees may not themselves reproduce, but the queen is their mother. They help her produce another generation of siblings who will one day be their sisters. In this way, the female worker bees are passing their genes on to the next generation, just not directly. </p>
<p>Something else to consider: A honey bee hive is a <a href="https://www.beebasket.in/stories/nature/hive-architecture-the-engineering-marvel-of-beehives/#:%7E">wonderfully complex structure</a>. The layers of wax combs built to store honey and raise offspring are a marvel of architecture and require a large workforce for construction, ongoing repairs and protection from intruders or predators. </p>
<p>So you might ask: Which came first? Social groups with queens and workers producing large numbers of related offspring that required more elaborate nest structures? Or did the complex nest arise first, which led to greater success for groups that evolved to divide tasks among queens and workers? </p>
<p>These are fascinating questions that biologists have been exploring for decades. But both of these factors – the division of labor and the complex hive structures – help explain why there are bees with queens. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/213208/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A queen’s main job in the hive is to lay eggs and pass genes on to offspring. But many bee species do just fine without queens or big colonies.Phil Starks, Associate Professor of Biology, Tufts UniversityAviva Liebert, Professor of Biology, Framingham State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225592024-02-29T17:37:30Z2024-02-29T17:37:30ZThree ways climate change is pushing butterflies and moths to their limits<figure><img src="https://images.theconversation.com/files/573808/original/file-20240206-27-tmjdur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Like half of UK butterflies and moths, the high brown fritillary is a specialist feeder. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/high-brown-fritillary-butterfly-on-pink-460865704">Roman Malanchuk/Shutterstock</a></span></figcaption></figure><p>In any competition, there are winners and losers. In the race to adjust to a changing climate, some butterflies seem to be doing well. But others, less so. </p>
<p>The brown hairstreak has been reported to be doing well <a href="https://www.theguardian.com/environment/2024/jan/31/brown-hairstreak-rare-butterfly-quietly-retaking-london">around London</a> and the UK population has been stable <a href="https://butterfly-conservation.org/butterflies/the-state-of-britains-butterflies">since the 1980s</a>. Meanwhile, the comma butterfly boasts a <a href="https://butterfly-conservation.org/state-of-uk-butterflies-2022">94% range expansion since the 1970s</a>, and is now a familiar sight across England, Scotland and southern Wales. </p>
<p>This uplifting news is masking the plight of the UK’s other 57 breeding butterfly species. Butterfly Conservation’s <a href="https://butterfly-conservation.org/butterflies/the-state-of-britains-butterflies">2022 report</a> painted a grim picture. Since the 1980s, 80% of butterfly species have decreased in abundance, distribution or both. </p>
<p>The situation isn’t looking much better for moths, close cousins of the butterflies, with a 33% decrease in abundance of macromoths (larger moths) over the <a href="https://butterfly-conservation.org/sites/default/files/2021-03/StateofMothsReport2021.pdf">last 50 years</a>. Eight UK butterfly species are listed as endangered and a further 16 are vulnerable. </p>
<p>Only 29 species are classed as <a href="https://doi.org/10.1111/icad.12582">least concern</a>. So, while there are some winners, there are also many types of butterflies and moths that are clearly struggling to survive in our changing climate. </p>
<p><a href="https://butterfly-conservation.org/butterflies/recording-and-monitoring">Citizen science</a> tells us a lot about how butterfly numbers and distributions have changed since the 1970s, and sheds light on what drives some butterfly species to decline while others thrive. </p>
<h2>1. Butterflies are picky eaters</h2>
<p>Like half of the UK’s butterfly species, the high brown fritillary is a specialist. As a caterpillar, it depends on only one or a few plants to power its growth. The high brown fritillary relies on violets, which are mostly found in coppiced woodland and on sun-drenched slopes. Coppicing is a traditional method of woodland management, involving cutting trees down to stumps to maintain the woodland and encourage new growth.</p>
<hr>
<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
<hr>
<p>Changes in land management, like the decline in coppicing, intensified agriculture and urbanisation, have diminished these habitats and their host plants. This endangered butterfly was once found throughout the UK, but is now restricted to only a handful of sites and conservationists are working hard to <a href="https://butterfly-conservation.org/butterflies/high-brown-fritillary">conserve this species</a>. </p>
<h2>2. Some don’t like it hot or cold</h2>
<p>The wall brown, like <a href="https://catalogue.ceh.ac.uk/documents/5b5a13b6-2304-47e3-9c9d-35237d1232c6">most of the UK’s butterflies</a>, should spend winter as a caterpillar, or in a cocoon it will emerge from after April. But mild weather in autumn and winter means that wall brown adults are emerging from their cocoons in September and October. </p>
<p>At this time, it’s likely too cold for the adults, there aren’t other wall browns to mate with or there aren’t enough suitable plants for their caterpillars to eat before winter. Because these adults aren’t able to reproduce successfully, fewer caterpillars survive to become butterflies the following spring – a phenomenon researchers have called a <a href="https://doi.org/10.1111/oik.02066">developmental trap</a>. This is contributing to the decline of wall brown. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Small brown butterflu with orange and black spots on wings, wings open as it rests on grass" src="https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573810/original/file-20240206-22-2k6odo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The rare mountain ringlet butterfly.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rare-mountain-ringlet-butterfly-erebia-epiphron-600627353">Sandra Standbridge/Shutterstock</a></span>
</figcaption>
</figure>
<p>Warmer summers also pose a problem, with temperatures in the UK soaring last <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2023/2023-was-second-warmest-year-on-record-for-uk">September</a>. Unlike us, butterflies and other insects have <a href="https://doi.org/10.1111/1365-2656.13319">limited ways to keep cool</a>. </p>
<p>To cool down they angle their wings to not catch the direct sun and can also choose shady spots where it is often cooler. But butterflies and moths are very <a href="https://doi.org/10.1111/1365-2656.12594">sensitive to the weather</a> and extreme temperatures can cause <a href="https://doi.org/10.1002/ece3.3588">early death in butterflies</a>. </p>
<p>There are also more subtle effects of these bursts of high temperatures. In <a href="https://www.nature.com/articles/s41558-021-01047-0">fruit flies</a> and <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1002/2688-8319.12303">other insects</a>, fertility is often reduced at temperatures lower than the lethal limit. This means that while butterflies may survive heat waves, their fertility could be reduced and this could lead to longterm population declines. </p>
<p>Understanding the effects of temperature on fertility in butterflies and moths is clearly a key priority and is at the forefront of ecological research. </p>
<h2>3. Small ranges make survival tricky</h2>
<p>The mountain ringlet is a <a href="https://www.iucnredlist.org/">near-threatened</a> species that faces a different challenge. Currently only found in the Scottish Highlands and the Lake District, it lives at altitudes above 350 meters, where the air is cooler and the grass it depends on, <em>Nardus stricta</em>, flourishes. </p>
<p>Over time, these mountainous refuges will become less hospitable. Without cooler climes to retreat to, the mountain ringlet and other range-restricted butterflies may find themselves without a home. </p>
<p>The adonis blue (currently listed as vulnerable) is currently only seen in the south of England. As our climate warms the species may shift northwards, increasing its population. It thrives on horseshoe vetch, a plant that’s common on chalk and limestone grasslands. </p>
<p>But this butterfly is a real home body. It’s very <a href="https://www.eje.cz/pdfs/eje/2014/04/12.pdf">sedentary and has a low tendency to disperse</a> so it might not move north as the climate changes. Only time will tell. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bright blue butterfly on grassy plant, burry green background" src="https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573816/original/file-20240206-29-u3frse.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The rare adonis blue has a limited range and is only found in the south of England.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/adonis-blue-lysandra-bellargus-known-polyommatus-2418138073">Creative image dealer/Shutterstock</a></span>
</figcaption>
</figure>
<h2>What do these trends tell us?</h2>
<p>Because butterflies and moths are sensitive to environmental fluctuations, they act as excellent bioindicators for assessing the health of ecosystems. Declines in butterfly and moth populations have serious implications.</p>
<p>There are noticeably fewer butterflies and moths for you and I to watch in our gardens, parks and the beautiful countryside. Butterflies and moths play a vital role in pollinating wild and crop plants including <a href="https://doi.org/10.1002/ppp3.10376">strawberries, cucumbers and apples</a>. </p>
<p>Many animals, including bats, birds and other insects rely on butterflies, moths and their caterpillars as a food source. The abundance and timing of caterpillars determine when some songbirds lay their eggs, so these changing trends may alter <a href="https://pubmed.ncbi.nlm.nih.gov/29152888/">longterm bird populations</a>. </p>
<p>That said, it’s not all doom and gloom. <a href="https://butterfly-conservation.org/our-work">Butterfly Conservation</a> runs a UK-wide conservation programme, targeting 200 priority landscapes for threatened butterflies and moths. Citizen science surveys, including the <a href="https://bigbutterflycount.butterfly-conservation.org/">big butterfly count</a>, help scientists understand longterm trends in butterfly populations. </p>
<p>And you, as gardeners and nature lovers, can get involved with citizen science activities, cultivate shady butterfly-friendly habitats and help preserve urban green spaces that act as havens for these insects.</p><img src="https://counter.theconversation.com/content/222559/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elizabeth Duncan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Climate change puts pressure on British butterflies and moths - sometimes pushing them to the edges of their geographical range or shifting the timing of their life cycle so they can’t feed.Elizabeth Duncan, Associate Professor of Zoology, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239302024-02-29T17:37:28Z2024-02-29T17:37:28ZPlants are flowering earlier than ever – here’s how they sense the seasons<p>Hedgerows in mid-February might have traditionally appeared white with snow; this year the white was the work of blackthorn blossoms – a harbinger of spring. Although a welcome sign after a wet and gloomy winter, the early flowering brings unease for experienced season watchers. Has this plant always flowered in mid-February, I wondered, or is something changing?</p>
<p>Fortunately, the science of recording and understanding seasonal events, phenology, has a long history in Britain. <a href="https://www.robertmarsham.co.uk/">Robert Marsham</a>, an 18th-century naturalist, kept records of the appearance of the flowers, birds and insects in his Norfolk village as far back as 1736. Marsham’s descendants continued the recording until 1958. The Woodland Trust maintains the tradition with <a href="https://naturescalendar.woodlandtrust.org.uk/">Nature’s Calendar</a>, a scheme in which members of the public are invited to record various seasonal events.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2456">Detailed analysis</a> of almost half a million plant records by scientists in 2022 showed that when all species were considered together the average flowering time in the UK had advanced by a month over the last 40 years. There was variation between species. Hawthorn, the common hedgerow plant, is generally flowering 13 days earlier than it did in the early 1980s while the flowers of the horse chestnut tree appear ten days earlier.</p>
<p>The climate has warmed rapidly since the 1980s. By flowering earlier, plants recognise that winters are becoming shorter and milder. They sense the days getting warmer and alter their spring development in a manner akin to humans feeling warmth on their skin and so stepping out with fewer layers of clothing. The precise mechanisms for detecting these cues differ between plants and animals, but both are responding to the climate as it changes. </p>
<h2>Detecting light and heat without eyes and skin</h2>
<p>Plants detect the shortening days of autumn with a pigment called phytochrome that is particularly sensitive to wavelengths in the red region of the electromagnetic spectrum. The longer autumn nights alter the quality of this red light. While this subtle shift escapes humans (our eyes are not sensitive to this part of the spectrum) a plant can detect this transition and start to change.</p>
<figure class="align-center ">
<img alt="A bench next to a woodland at sunset." src="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants detect subtle changes in red light and instigate dormancy as autumn descends.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/romantic-autumn-mood-sunset-lake-ammersee-690569119">Art180/Shutterstock</a></span>
</figcaption>
</figure>
<p>Just as the autumn can engineer a drop in the level of the hormone serotonin in our blood, a plant that has sensed winter’s approach will increase the production of a hormone called abscisic acid. This has multiple effects. In deciduous trees, twigs stop growing and develop tough winter buds capable of surviving frost and snow and leaves fall off.</p>
<p>Growth in spring is determined by similar triggers of light length and temperature, but temperature typically has the more significant role. If plants only paid attention to light, they’d run the risk of starting growth when fatal frosts are still a threat or of missing good growing time in mild early spring days. Temperature detection determines when spring flowers appear. This is why global heating is evident in the earlier appearance of these flowers.</p>
<hr>
<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
<hr>
<p>It isn’t fully understood how plants detect temperature. Some of it may be due to a growth-stalling hormone in its cells breaking down when the air falls below a certain temperature, which in turn allows a growth hormone to increase. </p>
<p>While humans have nerves in their skin to detect temperature, plants probably rely on pigments, though the mechanism isn’t fully understood. Heat is part of the same electromagnetic spectrum that phytochrome is sensitive to, so possibly this pigment is involved. Whatever mechanisms are responsible for initiating growth, temperature also determines how fast plants grow.</p>
<h2>Flowers and pollinators out of sync</h2>
<p>Insect pollinators like bees must synchronise their life cycles so that they are on the wing when the blossoms on which they feed emerge. The timing of their emergence from winter is also determined by the effects of temperature and day length and mediated by hormones. </p>
<p>Evolution working on many generations of pollinators has generated a tight link between the emergence of flowers and that of their pollinators. If the appearance of flowers and pollinators isn’t synchronised, the insects have no nectar and the plants aren’t fertilised. </p>
<p>A similar link exists between the emergence of leaves and the insect herbivores that graze on them. The rapidity of climate change and slight differences in how the two groups respond risk breaking this synchrony with serious consequences for both sides.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2142">A large study</a> by German scientists looking at when flowers and their pollinators emerged between 1980 and 2020 found a complex picture. Both responded to climate change with earlier flowering and appearances, but the plants had made a greater shift. </p>
<p>There was variation between insect groups, bees and butterflies had shifted in synchrony with the plants, but this wasn’t observed in hoverflies. There was also variation between species of these insects.</p>
<figure class="align-center ">
<img alt="A white butterfly on a purple flower." src="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants and insects co-evolved to emerge at roughly the same time in Spring.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blackveined-white-butterfly-aporia-crataegi-perfect-79443766">Marek Mierzejewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Even when plants and their dependent insects change timings in synchrony, the next stage of the food chain may not be so flexible. Oak leaves are fed upon by the oak moth caterpillar. This, in turn, is the primary food of the chicks of birds such as blue tits and pied flycatchers <a href="https://www.nature.com/articles/s41559-018-0543-1">link text</a>. Chicks have hatched at roughly the same time, while oak leaves and caterpillars have appeared earlier and so far remain in synchrony. But for how long?</p>
<p>Blackthorn blossoms remain a welcome relief from winter and a sign that spring is on its way. But they are also a sign of climate change: an unfolding experiment on the timing and synchrony of plants and animals – and the intricate food chains that they are part of.</p><img src="https://counter.theconversation.com/content/223930/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Ashton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Rising air temperatures mean shorter winters and earlier springs.Paul Ashton, Professor of Botany, Edge Hill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2232042024-02-26T23:23:17Z2024-02-26T23:23:17ZAs Varroa spreads, now is the time to fight for Australia’s honey bees – and you can help<figure><img src="https://images.theconversation.com/files/577517/original/file-20240223-26-eqvxkz.jpg?ixlib=rb-1.1.0&rect=855%2C409%2C3693%2C2687&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Nic Vevers/ANU</span></span></figcaption></figure><p>A tiny foe threatens Australian beekeepers’ livelihood, our food supply and the national economy. First detected in New South Wales in 2022, <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response">the Varroa mite is now established in Australia</a>.</p>
<p>The parasitic mite, which feeds on honey bees and transmits bee viruses, has since spread across New South Wales.</p>
<p>It is expected to kill virtually all unmanaged honey bees living in the bush (also known as “feral” honey bees), which provide ecosystem-wide pollination. Honey bees managed by beekeepers will survive only with constant and costly use of pesticides.</p>
<p>As the last holdout against Varroa, Australia has a key advantage – we can still take action that was impossible elsewhere. We know <a href="https://agrifutures.com.au/wp-content/uploads/2024/01/23-226-Resilient-Beekeeping-In-The-Face-Of-Varroa.pdf">Varroa-resistant bees would be the silver bullet</a>.
Despite decades of research, no fully resistant strains exist, largely because the genetics of Varroa resistance are complex and remain poorly understood.</p>
<p>A recently released national <a href="https://www.abc.net.au/news/2024-02-13/plan-slow-varroa-mite-spread-australia-focuses-beekeepers/103458434">management plan places a heavy focus on beekeeper education</a>, aiming to transition the industry to self-management in two years. This leaves research gaps that need to be urgently filled – and we can all work together to help tackle these.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-has-officially-given-up-on-eradicating-the-varroa-mite-now-what-214002">Australia has officially given up on eradicating the Varroa mite. Now what?</a>
</strong>
</em>
</p>
<hr>
<h2>Unlocking the genetic key to resistance</h2>
<p>Without human intervention, Varroa <a href="https://www.ars.usda.gov/research/publications/publication/?seqNo115=191987">kills around 95% of the honey bees</a> it infects, but the survivors can evolve resistance. However, losing almost all bees would decimate Australia’s agriculture.</p>
<p>Our feral honey bees will have no choice but to evolve resistance, <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1375">as they have in other countries</a>. However, feral honey bees are not suited for beekeeping as they are too aggressive, don’t stay with the hive and don’t produce enough honey.</p>
<p>In principle, we could breed for a combination of feral resistance and domestic docility. But figuring out the genetics of how feral bees resist Varroa has been a challenge. As most bees exposed to the parasite will die, the <a href="https://news.cornell.edu/stories/2015/08/some-honeybee-colonies-adapt-wake-deadly-mites">survivors will be genetically different</a>. </p>
<p>Some of these differences will be due to natural selection, but most will be due to chance. Identifying the genes responsible for resistance in this scenario is difficult. The best way to find them is to measure genetic changes before and after Varroa infestation. But to do that, we need bee populations largely unaffected by Varroa.</p>
<p>This is where our unique Australian opportunity comes in. We have a small and vanishing window to collect bees before the inevitable rapid spread of the mites, and the mass die-offs, occur.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of the octagonal cells of a beehive with a small red-brown speck visible" src="https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577521/original/file-20240223-30-q12r27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Varroa mite visible in a beehive – they mainly reproduce on bee larvae.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mite-beehive-638331532">Igor Chus/Shutterstock</a></span>
</figcaption>
</figure>
<h2>We are collecting information… and bees</h2>
<p>My lab at the Australian National University’s <a href="https://biology.anu.edu.au/research/research-groups/mikheyev-group-evolutionary-genomics#acton-tabs-link--tabs-group_tabs_biology-middle-1">Research School of Biology</a> has started collecting data on feral bee populations around New South Wales to identify pre-Varroa genetic diversity.</p>
<p>We will also monitor changes in bee population size and the spread of viruses and mites.</p>
<p>The most efficient way to collect bees is to go to a local clearing, such as a sports oval surrounded by forest. Unbeknownst to the cricket players, honey bee males (that is, drones) congregate at these sites by the thousands on sunny afternoons looking for mates.</p>
<p>You can lure them with some queen pheromone suspended from a balloon, and sweep them up with a butterfly net. Bee drones have no stinger and only come out for a couple of hours when the weather is fantastic, making collecting them literally a walk in the park, suitable for nature enthusiasts of all ages.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man with a beard and glasses holding a small honey bee on his fingertips" src="https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577519/original/file-20240223-26-kqtlgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author pictured with a stingless male honey bee (a drone) collected for genetic research into Varroa resistance.</span>
<span class="attribution"><span class="source">Nic Vevers/ANU</span></span>
</figcaption>
</figure>
<h2>Anyone can help</h2>
<p>You can help this effort by collecting some drones in your local area – this would save us time and carbon emissions from driving all over the country. We will provide pheromone lures, instructions, and materials for sending the bees back via mail. By sacrificing a few drones for the research now, we might save millions of bees in the future. </p>
<p>If you can spare just a couple of summer afternoons, this would give two timepoints at your location, and we can monitor any changes as the Varroa infestation progresses. More information can be <a href="https://science.anu.edu.au/australian-bee-observation-network">found on our website</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ho94e_SFAFE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Apart from our project, there are also other urgent research questions. For example, how will native forests respond to the loss of their dominant pollinators? Will honey bee viruses spread into other insects?</p>
<p>Work on these and other projects also requires pre-Varroa data. Unfortunately, Varroa falls through our research infrastructure net. Most of Australia’s agricultural funding is industry-led, however, the beekeeping industry is small and lacks the resources to tackle Varroa research while also reeling from its impacts.</p>
<p>Other industries that rely on honey bees for pollination, <a href="https://agrifutures.com.au/product/pollination-aware-the-real-value-of-pollination-in-australia-fact-sheet/">including most fruit, nut and berry growers</a>, have diverse research needs and are one step removed from the actual problem.</p>
<p>Together, we can take action to save Australia’s honey bees and assure security for our key pollinators.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hear-me-out-we-could-use-the-varroa-mite-to-wipe-out-feral-honey-bees-and-help-australias-environment-185959">Hear me out – we could use the varroa mite to wipe out feral honey bees, and help Australia's environment</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/223204/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Mikheyev receives funding from the Australian Research Council. </span></em></p>Australia could still take action in the fight against Varroa that wasn’t possible elsewhere. But to do so, we need to fill urgent gaps in bee research.Alexander Mikheyev, Professor, ANU Bee lab, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230832024-02-14T00:50:26Z2024-02-14T00:50:26ZNZ votes the red admiral butterfly ‘bug of the year’ – how to make your garden its home<p>New Zealanders traditionally show their love for a special other on Valentine’s Day, so what better time to reveal which insect they feel the most affection for?</p>
<p>The second annual <a href="https://bugoftheyear.ento.org.nz/">Bug of the Year</a> contest has been won by the red admiral butterfly. It received a total of 2,275 votes from the nearly 17,000 votes cast by New Zealanders at home and abroad.</p>
<p>One of our most spectacular butterflies, the red admiral inherits the crown from last year’s inaugural winner, the native bee, or ngaro huruhuru (<em>Leioproctus fulvescens</em>). </p>
<p>While a butterfly beat the other bugs, the <a href="https://bugoftheyear.ento.org.nz/2024-bug-of-the-year-nominees/mt-arthur-giant-weta/">Mt Arthur giant wētā</a>, the ngāokeoke (velvet worm) and the titiwai (glowworm) were close behind, with thousands of votes each.</p>
<p>The <a href="https://ento.org.nz/">Entomological Society of New Zealand</a> began the competition to shed light on the underrepresented and stunningly unique bugs of Aotearoa New Zealand. As interest grows, it is hoped more people will be inspired to create and maintain habitats for these often-endangered species.</p>
<p>Aotearoa is home to over 20,000 different species of bugs – more correctly known as terrestrial invertebrates. They range from vibrant butterflies and iconic wētā to secretive velvet worms and carnivorous land snails. And those are just the species described so far.</p>
<p>There are ten times as many bug species in New Zealand than there are native plants, and over a hundred times more than native bird species. Yet most people don’t know much about them.</p>
<h2>Moths and butterflies aren’t so different</h2>
<p>The red admiral is easily recognisable by its vibrant red and black wings. Its Māori name, kahukura, translates directly as “red cloak or garment”, but can also refer to the atua (deity) represented by the top bow of a double rainbow.</p>
<p>The closely related kahukōwhai, or yellow admiral, has similar colouring, except the underside of its upper wings is creamy yellow. Red admirals are endemic – only found in New Zealand – whereas yellow admirals are also native to Australia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/unveiling-the-enigmatic-world-of-moths-from-ancient-pollinators-to-whistling-wonders-209590">Unveiling the enigmatic world of moths: from ancient pollinators to whistling wonders</a>
</strong>
</em>
</p>
<hr>
<p>Aotearoa has over 2,000 species of lepidoptera – butterflies and moths – and roughly 90% of these are endemic. You might be surprised to know there are no clear differences between what are commonly called butterflies and those called moths.</p>
<p>Only 17 of our lepidoptera species are popularly referred to as butterflies. But many of the other 98% – so-called moths – are active during the day and can also be beautifully patterned and coloured.</p>
<p>Because they feed from floral nectar sources and transfer pollen in the process, moths and butterflies are important pollinators. They are also staples in the food chain, forming a large portion of native bird diets.</p>
<h2>Gardens as butterfly habitats</h2>
<p>Like many butterflies worldwide, red admirals are less common than they used to be. While <a href="https://tuigarden.co.nz/inspiration-hub/ideas-and-inspiration/bee-aware-and-bee-friendly/">recent gardening advice</a> has begun to include bee-friendly planting, it is also important to think of other invertebrates, like butterflies, when we plan and cultivate our backyards.</p>
<p>In general, a diversity of simple nectar-rich flowers is <a href="https://nodglobal.com/pollinators-biodiversity-and-healthy-ecosystems/">positively related to pollinator health</a>. And resilient and diverse pollinator populations benefit both natural and created ecosystems like gardens. In turn, they support <a href="https://www.sciencedirect.com/science/article/pii/S2468265922000166">biodiversity and overall environmental health</a> – which all benefits human welfare.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-butterflies-conquered-the-world-a-new-family-tree-traces-their-100-million-year-journey-across-the-globe-205487">How butterflies conquered the world: a new 'family tree' traces their 100-million-year journey across the globe</a>
</strong>
</em>
</p>
<hr>
<p>The Moths and Butterflies of New Zealand Trust conducts an <a href="https://www.nzbutterflies.org.nz/project/habitat-creation/">online course</a> on how to assess, create and maintain butterfly habitats.</p>
<p>Lepidoptera differ from some other invertebrates in that females prefer to (or exclusively) lay their eggs on specific host plants. If preferred host plants are not available, caterpillar survival can be low. </p>
<p>So, while having a variety of flowering plants for adults to feed from is important, providing host plants for caterpillars to develop on is crucial.</p>
<p>It is well known that monarch butterfly caterpillars need to feed on milkweed (swan plant). Similarly, <a href="https://www.nzpcn.org.nz/flora/species/muehlenbeckia-astonii/"><em>Muehlenbeckia</em> species</a> such as climbing pohuehue and shrubby tororaro are important host plants for many native butterflies, as well as many native moths. </p>
<p>Lack of suitable hosts may be one reason red admirals are becoming increasingly uncommon. <a href="https://ourarchive.otago.ac.nz/handle/10523/15709">Recent research</a> has shown the females prefer laying eggs on native nettles, and larvae raised on native nettles outperform those raised on introduced nettles.</p>
<p>Experiments show that the tree nettle ongaonga (<em>Urtica ferox</em>) is an ideal host for red admiral caterpillars. But ongaonga is often removed due to its extremely painful stinging hairs.</p>
<h2>Pollinator protection</h2>
<p>Besides planting with butterflies and moths in mind, there are many other actions you can take in the garden to help make it suitable for thriving pollinator populations.</p>
<p>Some of the <a href="https://www.pnas.org/doi/full/10.1073/pnas.2023989118">biggest threats</a> to insect populations in Aotearoa and the world are related to urbanisation, deforestation and agricultural intensification: loss of habitat and food sources, and pesticide use. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/next-time-you-see-a-butterfly-treasure-the-memory-scientists-raise-alarm-on-these-26-species-159798">Next time you see a butterfly, treasure the memory: scientists raise alarm on these 26 species</a>
</strong>
</em>
</p>
<hr>
<p>Introduced predators also threaten our unique bugs. Invasive <a href="https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/invasive-invertebrates/vespula-wasps/wasp-impacts-on-biodiversity/">vespula wasps</a> and rodents are a menace to native butterflies and moths. But <a href="https://predatorfreenz.org/get-involved/backyards-and-neighbourhoods/backyard-trapping/">predator control systems</a> such as backyard trapping can make a difference.</p>
<p>Future articles will offer seasonal advice on gardening and lifestyle practices to help bugs in your backyard. This will include the best times to spot native and introduced bugs, and other ways to promote invertebrate conservation and biodiversity.</p>
<p>Whether you’re already a bug lover or still a bit bug-tentative, it’s important we all help invertebrate populations in Aotearoa survive and thrive.</p>
<hr>
<p><em>The authors gratefully acknowledge the help of the <a href="https://www.nzbutterflies.org.nz/">Moths and Butterflies of New Zealand Trust</a> in the preparation of this article.</em> </p>
<hr><img src="https://counter.theconversation.com/content/223083/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janice Lord is a member of the Entomological Society of New Zealand.</span></em></p><p class="fine-print"><em><span>Connal McLean is a volunteer with The Moths and Butterflies of New Zealand Trust. </span></em></p>The native red admiral is less common than it used to be, but we can all help threatened bug species by ensuring they have the right habitats to thrive in.Janice Lord, Associate Professor in Botany, University of OtagoConnal McLean, Natural History Technician – Invertebrates, Te Papa TongarewaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2227672024-02-06T16:34:20Z2024-02-06T16:34:20ZWe’ve found out how earless moths use sound to defend themselves against bats – and it could give engineers new ideas<figure><img src="https://images.theconversation.com/files/573732/original/file-20240206-20-zrb59g.jpg?ixlib=rb-1.1.0&rect=26%2C40%2C4466%2C2950&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ermine moths are deaf, but have an intricate wing structure that protects them from bats by producing warning clicks when they fly.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/detailed-closeup-on-white-speckled-yponomeuta-2169581991">HWall/Shutterstock</a></span></figcaption></figure><p>An acoustic battle between <a href="https://www.annualreviews.org/doi/10.1146/annurev-ento-121510-133537">bats and their insect prey</a> has been raging in the night skies for over 65 million years. Many different techniques are used, and <a href="https://www.pnas.org/doi/10.1073/pnas.2313549121">our new study</a> reveals the fascinating strategy of the small, deaf ermine moth, which has evolved a tiny wing structure that produces warning sounds. We hope this insight could inspire engineers to create new technology.</p>
<p>Bats count on their secret weapon, <a href="https://www.bats.org.uk/about-bats/flight-food-and-echolocation">echolocation</a>, to find and catch their flying prey, and in response, nocturnal insects have evolved interesting defences. Many silk moths, for instance, rely on a kind of <a href="https://doi.org/10.1073/pnas.2014531117">sound-absorbing stealth cloak</a> that makes them “disappear” from bat sonar. Some large moth species have <a href="https://doi.org/10.1016/j.cub.2021.08.038">evolved reflective decoys</a> that draw bat attacks away from their body and towards the tips of their wings.</p>
<p>The next level of defence is <a href="https://www.annualreviews.org/doi/10.1146/annurev-ento-121510-133537">ears</a> that allow insects, including many moths, to pick up bat echolocation calls and fly out of harm’s way. They can also use their sensory awareness of location to blast an attacking bat with ultrasonic sounds that deter or confuse their biosonar. </p>
<p>However, scientists have long been puzzled about the many earless moths that cannot detect their predators and are too small for decoys. How do they protect themselves? </p>
<p>We recently discovered that <a href="https://research-information.bris.ac.uk/ws/portalfiles/portal/185355664/tymbals.pdf">even earless moths</a>, such as <a href="https://butterfly-conservation.org/moths/white-ermine">ermine moths</a> (<em>Yponomeuta</em>), use acoustic signals as a defence against bat attacks. These moths have a tiny structure in their hind wings which creates a powerful ultrasonic signal that jams the echolocating sonar of bats.</p>
<p>Because these moths don’t have hearing organs, they are not aware of their unique defence mechanism, and nor can they control it. Instead, the sound production mechanism is coupled to the flapping of their wings.</p>
<h2>Protective wing beats</h2>
<p>When we studied the ermine moth’s wing under a microscope, it became clear that one part of the wing stands out from the rest. While most of it is covered by small hairs and scales, one patch of wing is clear and located adjacent to a corrugated structure of ridges and valleys. In our new study, we found this structure produces sound perfectly tuned to confuse bats. </p>
<figure class="align-center ">
<img alt="Pipistrelle bat flying on wooden ceiling of house in darkness" src="https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573422/original/file-20240205-21-ssex63.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bats such as this pipistrelle use echolocation to hunt.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pipistrelle-bat-pipistrellus-flying-on-wooden-1018158514">Rudmer Zwerver/Shutterstock</a></span>
</figcaption>
</figure>
<p><a href="https://dosits.org/science/sound/what-is-sound/">Sound is a pressure wave</a> that travels through a fluid or solid and requires a displacement of this medium, usually a vibration, to produce noise. Large vibrating surfaces over cavities are <a href="https://cmtext.indiana.edu/acoustics/chapter1_resonance.php">good for amplifying sound</a> – a good example is a tymbal drum, which has a taught skin stretched over a cavity. As the drum skin is struck by a drumstick, the skin vibrates at its natural frequencies and transmits these vibrations into the surrounding air as sound.</p>
<p>In ermine moths, the clear patch in the hind wing serves as the drum skin, while the corrugated structure of valleys and ridges act as drumsticks. During flight, the moth’s wing makes the ridges snap one after the other in a sequence. Each snap makes the clear patch, known as an <a href="https://research-information.bris.ac.uk/en/publications/a-bioinspired-mechanical-model-of-the-ultrasonic-clicks-produced-">aeroelastic tymbal</a>, vibrate and amplifies the sound volume.</p>
<p>Recordings we made of ermine moths found their wings make clicking noises during flight, which we could detect using a bat detector that converts ultrasound into sound audible to humans.</p>
<p>Using 3D X-ray and a sophisticated microscope technique called <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961134/#:%7E:text=The%20primary%20functions%20of%20a,3D%20reconstructions%20of%20imaged%20samples.">confocal microscopy</a>, our study’s lead author, Hernaldo Mendoza Nava, mapped out the intricate properties of the materials that make these moths’ aeroelastic tymbals. We then used computer simulations to test our hypothesis that the deformations of the corrugations stimulate the wing’s membrane in a way that produces sound. These simulations produced a sound that matched our recordings of the moths’ clicks in frequency, structure, amplitude and direction.</p>
<p>Some eared moths can make similar warning sounds, but none of them (so far) have been shown to do this with an aeroelastic tymbal. </p>
<p>To our team of biologists and engineers, these wing structures are fascinating because they rely on a mechanism that we teach our engineering students to avoid. “Snap through” is an example of a <a href="https://www.egr.msu.edu/classes/me471/thompson/handout/class07_2005S_Buckling.pdf">buckling instability</a> – when a structure loses stability when loaded, and suddenly snaps into a different state.</p>
<p>In a buckling instability, the material doesn’t break but the structure usually loses stiffness and can even collapse. This can have catastrophic consequences for any structure that carries load, such as buildings, bridges and aeroplanes.</p>
<h2>Inspired by nature</h2>
<p>Historically, structures were made to be rigid enough to withstand external forces. Over the last decade, researchers and engineers have started to question this default position, and have begun to use buckling instabilities to create structures with new capabilities. </p>
<p>One example is engineers designing <a href="https://www.nature.com/collections/aabiaicgej#:%7E:text=Traditionally%2C%20structures%20were%20constructed%20to,and%20maintain%20its%20desired%20form.">morphing structures</a> <a href="https://www.cambridge.org/core/journals/aeronautical-journal/article/abs/morphing-skins/912AB6CFD2C2075099CC5D362D8BCB60">for future aircraft wings</a> that autonomously adapt their shape to perform better when the environment changes. The aeroelastic tymbal of ermine moths embodies this concept and demonstrates how nature can be an inspiration for new technology.</p>
<p>Our hope is that these deaf moths’ aeroelastic tymbals will encourage new developments in engineering domains such as acoustic structural monitoring, where structures give off sound when overloaded. This is often used to check the safety of infrastructure. It could also lead to innovations in <a href="https://en.wikipedia.org/wiki/Soft_robotics">soft robotics</a>, where the robots are made of fluids and gels instead of metal and plastics.</p><img src="https://counter.theconversation.com/content/222767/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marc Holderied receives funding from the Biotechnology and Biological Sciences Research Council (grant no. BB/N009991/1) and the Engineering and Physical Sciences Research Council (grant no. EP/T002654/1). We thank Diamond Light Source for access
to beamline I13 (proposal MT17616) and to Dr. Shashi Marathe and Kaz Wanelik for their assistance at the facility. We thank Daniel Robert for access to and support with Laser Doppler vibrometry.</span></em></p><p class="fine-print"><em><span>Alberto Pirrera has received funding for this research from the Engineering and Physical Sciences Research Council (grant no. EP/M013170/1).</span></em></p><p class="fine-print"><em><span>Rainer Groh has received funding from the Royal Academy of Engineering (grant no. RF/201718/17178) for this research. Hernaldo Mendoza Nava, a PhD student who worked on this project for his thesis, was funded by the Science and Technology National Council (CONACYT-Mexico, CVU/studentship no. 530777/472285) and the Engineering and Physical Sciences Research Council through the EPSRC Centre for Doctoral Training in Advanced Composites for Innovation and Science (grant no. EP/L0160208/1).</span></em></p>The ermine moth’s wing structures are fascinating because they rely on a mechanism we teach our engineering students to avoidMarc Holderied, Professor in Sensory Biology, University of BristolAlberto Pirrera, Professor of Nonlinear Structural Mechanics, University of BristolRainer Groh, Senior Lecturer in Digital Engineering of Structures, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2213872024-01-30T16:01:27Z2024-01-30T16:01:27ZThe surprising reason why insects circle lights at night: They lose track of the sky<figure><img src="https://images.theconversation.com/files/571170/original/file-20240124-21-ynct7x.png?ixlib=rb-1.1.0&rect=30%2C20%2C6679%2C4446&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A multiple-exposure photograph of insects circling a light at night.</span> <span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>It’s an observation as old as humans gathering around campfires: Light at night can draw an erratically circling crowd of insects. In art, music and literature, this spectacle is an enduring metaphor for <a href="https://roundglasssustain.com/wildvaults/moths">dangerous but irresistible attractions</a>. And watching their frenetic movements really gives the sense that something is wrong – that instead of finding food and evading predators, these nocturnal pilots are trapped by a light.</p>
<p>Sadly, centuries of witnessing what happens have produced little certainty about why it happens. How does a simple light change fast, precise navigators into helpless, flittering captives? We are researchers examining <a href="https://scholar.google.co.uk/citations?user=wG5HGs8AAAAJ&hl=en">flight</a>, <a href="https://scholar.google.com/citations?user=4i4wRGgAAAAJ&hl=en">vision</a> and <a href="https://scholar.google.co.in/citations?user=X-j5RnwAAAAJ&hl=en">evolution</a>, and we have used high-speed tracking techniques in <a href="https://www.nature.com/articles/s41467-024-44785-3">newly published research</a> to provide an answer.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FxNRDxlVyxk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The reason insects fly around light will surprise you.</span></figcaption>
</figure>
<h2>Moths to a flame?</h2>
<p>Many old explanations for this hypnotic behavior have not fully panned out. An early notion was that the insects might be attracted to the heat of a flame. This was interesting, as some insects really <a href="https://doi.org/10.1016/j.foreco.2022.120629">are pyrophilic</a>: They are attracted to fire and have evolved to take advantage of conditions in recently burned areas. But most insects around a light are not in this category, and cool lights attract them quite well. </p>
<p>Another thought was that insects were just directly attracted to light, a <a href="https://doi.org/10.1007/s13355-013-0219-x">response called phototaxis</a>. Many insects move toward light, perhaps as a way to escape dark or entrapping surroundings. But if this were the explanation for the clusters around a light, you might expect them to bump straight into the source. This theory does little to explain the wild circling behavior.</p>
<p>Still another idea was that insects might mistake a nearby light for the Moon, as they attempted to use <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">celestial navigation</a>. Many insects reference the Moon to keep their course at night.</p>
<p>This strategy relies on how objects at great distance seem to hover in place as you move along a straight path. A steady Moon indicates that you have not made any unintentional turns, as you might if you were buffeted by a gust of wind. Nearer objects, however, don’t appear to follow you in the sky but drift behind as you move past.</p>
<p>The celestial navigation theory held that insects worked to keep this light source steady, turning sharply in a failed attempt to fly straight. An elegant idea, but this model predicts that many flights will spiral inward to a collision, which doesn’t usually match the orbits we see. So what’s really going on?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several cameras face a bright light on a stand in a forest setting at night." src="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists used high-speed stereo motion capture to document how the presence of artificial light at night affects insects’ flight behavior.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Turning their backs to the light</h2>
<p>To examine this question in detail, we and our colleagues captured high-speed videos of insects around different light sources to precisely determine flight paths and body postures, both in the lab at <a href="https://www.imperial.ac.uk">Imperial College London</a> and at two field sites in Costa Rica, <a href="https://www.ciee.org/go-abroad/college-study-abroad/locations/costa-rica/monteverde">CIEE</a> and the <a href="https://www.estacionbiologica.com/">Estación Biológica</a>. We found that their flight patterns weren’t a close match for any existing model. </p>
<p>Rather, a broad swath of insects consistently pointed their backs toward the lights. This is a known behavior called the <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">dorsal light response</a>. In nature, assuming that more light comes down from the sky than up from the ground, this response helps keep insects in the proper orientation to fly.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qECYfEN70qs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Artificial light at night interrupts the normal flight patterns of insects. This compilation video shows an orbiting behavioral motif in which insects circle the light.</span></figcaption>
</figure>
<p>But pointing their backs toward nearby artificial lights alters their flight paths. Just as airplanes bank to turn, sometimes rolling until the ground seems nearly straight out your window, banking insects turn as well. When their backs orient to a nearby light, the resulting bank loops them around the light, circling but rarely colliding. </p>
<p>These orbiting paths were only one of the behaviors we observed. When insects flew directly under a light, they often arched upward as it passed behind them, keeping their backs to the bulb until, eventually flying straight up, they stalled and fell out of the air. And even more compelling, when flying directly over a light, insects tended to flip upside down, again turning their backs to the light but then abruptly crashing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagrams show insects rolling vertically or horizontally or inverting in the presence of artificial light." src="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three different observed turning behaviors in which flying insects turn their backs to artificial light.</span>
<span class="attribution"><span class="source">Jamie Theobald</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why have a dorsal light response?</h2>
<p>Although light at night can harm <a href="https://www.jstor.org/stable/43597777">other animals</a> – for example, by <a href="https://doi.org/10.1073/pnas.1708574114">diverting migrating birds into urban areas</a> – larger animals don’t seem to lose their vertical orientation. So why do insects, the oldest and most species-rich group of flyers, rely on a response that leaves them so vulnerable?</p>
<p>It may have to do with their small size. Larger animals can sense gravity directly with sensory organs pulled by its acceleration, or any acceleration. Humans, for example, use the <a href="https://www.ncbi.nlm.nih.gov/books/NBK279394/">vestibular system of our inner ear</a>, which regulates our sense of balance and usually gives us a good sense of which way is down.</p>
<p>But insects have only small sensory structures. And especially as they perform rapid flight maneuvers, acceleration offers only a poor indication of which way is down. Instead, they seem to bet on the brightness of the sky. </p>
<p>Before modern lighting, the sky was usually brighter than the ground, day or night, so it provided a fairly reliable cue for a small active flyer hoping to keep a steady orientation. The artificial lights that sabotage this ability, by cueing insects to fly in circles, are relatively recent. </p>
<h2>The growing problem of nighttime lighting</h2>
<p>As new technology spreads, lights that pervade the night are <a href="https://doi.org/10.3390/rs13163311">proliferating faster then ever</a>. With the introduction of cheap, bright, <a href="https://www.energy.gov/eere/ssl/led-basics">broad-spectrum LEDs</a>, many areas, such as large cities, never see a dark night.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A view upward through treetops to a starry dark sky, with a bright light at the top of the screen from a light bulb near the ground." src="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This upward view at the authors’ field research site in Monteverde, Costa Rica, shows how artificial light competes with the night sky.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Insects aren’t the only creatures affected. Light pollution disrupts circadian rhythms and physiological processes in other <a href="https://darksky.org/resources/what-is-light-pollution/effects/wildlife-ecosystems/">animals, plants</a> and <a href="https://darksky.org/resources/what-is-light-pollution/effects/human-health/">humans</a>, often with <a href="https://theconversation.com/new-atlas-shows-extent-of-light-pollution-what-does-it-mean-for-our-health-60836">serious health consequences</a></p>
<p>But insects trapped around a light seem to get the worst of it. Unable to secure food, easily spotted by predators and prone to exhaustion, many die before the morning comes.</p>
<p>In principle, light pollution is one of the easiest things to fix, often by just <a href="https://www.youtube.com/watch?v=EfhuU5Ceo_w">flipping a switch</a>. <a href="https://darksky.org/what-we-do/advancing-responsible-outdoor-lighting/">Restricting outdoor lighting</a> to useful, targeted warm light, no brighter than necessary, and for no longer than necessary, can greatly improve the health of nocturnal ecosystems. And the same practices that are good for insects help restore views of the night sky: Over one-third of the world population lives in areas where the <a href="http://dx.doi.org/10.1126/sciadv.1600377">Milky Way is never visible</a>. </p>
<p>Although insects circling around a light are a fascinating spectacle, it is certainly better for the insects and the <a href="https://www.si.edu/spotlight/buginfo/benefits">benefits they provide to humans</a> when we leave the night unlit and let them go about the activities they so masterfully perform under the night sky.</p><img src="https://counter.theconversation.com/content/221387/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samuel Fabian receives funding from the European Research Council and a National Geographic Explorer Grant.</span></em></p><p class="fine-print"><em><span>Jamie Theobald receives funding from the National Science Foundation and the U.S. Air Force Office of Scientific Research.</span></em></p><p class="fine-print"><em><span>Yash Sondhi receives funding from the Florida International University Graduate School, the Susan Levine Foundation, a National Geographic Explorer Grant, the American Philosophical Society, and the Kimberly-Green Latin-American and Caribbean Center.</span></em></p>A new study shows how artificial light at night scrambles insects’ normal flight patterns, pulling them off course into orbit around the light.Samuel Fabian, Postdoctoral Research Associate in Bioengineering, Imperial College LondonJamie Theobald, Associate Professor of Biological Sciences, Florida International UniversityYash Sondhi, Postdoctoral Research Associate in Entomology, Mcguire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2212182024-01-25T20:46:04Z2024-01-25T20:46:04ZThe first flowers evolved before bees – so how did they become so dazzling?<figure><img src="https://images.theconversation.com/files/571111/original/file-20240124-17-j4irzv.jpg?ixlib=rb-1.1.0&rect=60%2C25%2C5596%2C3802&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/red-pink-and-yellow-flowering-plants-v-3NQ3pmWkY">Nature Uninterrupted Photography/Unsplash</a></span></figcaption></figure><p>Colourful flowers, and the insects and birds that fly among their dazzling displays, are a joy of nature. But how did early relationships between flower colour and animal pollinators emerge?</p>
<p>In a study published in <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2023.2018">Proceedings of the Royal Society</a>, we have unravelled this mystery by analysing the visual environments in which the ancestors of today’s bees foraged from flowers.</p>
<p>We measured and analysed the light reflected from today’s flowers, as well as the rocks, soil, sticks, bark and leaves that form their natural backgrounds.</p>
<p>From this data we built computer simulations that recreate the ancient visual environment when the first flowers emerged.</p>
<h2>Insect colour vision came before flowers</h2>
<p>Today, bees are prolific pollinators of flowering plants, including <a href="https://theconversation.com/our-bee-eye-camera-helps-us-support-bees-grow-food-and-protect-the-environment-110022">food crops</a>. Bees use <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2010.2412">colour vision</a> based on ultraviolet, blue and green sensitive photoreceptors (light-sensing cells) to detect and discriminate the most rewarding flowers. In comparison, most humans perceive colour using blue, green and red sensitive photoreceptors.</p>
<p>When the first flowers evolved during the Mesozoic era, between 252 million and 66 million years ago, the ancestors of bees had to orientate themselves, maintain stable flight, avoid collisions, and find food among natural backgrounds. We suspect their visual systems may have been influenced by evolution to efficiently operate in that environment.</p>
<p>By the time the first flowering plants appeared, bees’ ancestors had already evolved colour vision – and we know it <a href="https://link.springer.com/article/10.1007/BF01142181">has stuck around throughout the evolutionary history of bees</a>.</p>
<p>So, while bees weren’t initially around, their ancestors were. Flower colours likely evolved the vivid colours we see today to suit this ancient visual system. At the same time, the first bees emerged as the most efficient pollinators. </p>
<h2>What colour were flower backgrounds on the ancient Earth?</h2>
<p>Australia is an ideal place to collect data on natural background materials that early insects would have seen, as it is a <a href="https://www.publish.csiro.au/bt/BT00023">geologically ancient continent</a>.</p>
<p>We collected background samples from across Australia and measured their reflective properties using a tool called a <a href="https://en.wikipedia.org/wiki/Spectrophotometry">spectrophotometer</a>.</p>
<p>We used this data to create a database of materials that would have been present in the visual environment of flying insects more than 100 million years ago – when the first flowers appeared.</p>
<h2>Flower colour evolved in response to bee colour vision</h2>
<p>For our collection of natural backgrounds, insect and bird pollinated flowers, we calculated <a href="https://www.sciencedirect.com/science/article/pii/S2215016120300479">marker points</a> – rapid changes in the intensity of light reflected from a surface, within a small wavelength band.</p>
<p>These marker points identify the key visual features of coloured surfaces, and we can use them for statistical testing of the evolutionary process. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-the-electromagnetic-spectrum-8046">Explainer: what is the electromagnetic spectrum?</a>
</strong>
</em>
</p>
<hr>
<p>We then wrote computer simulations to generate possible flower backgrounds. By analysing their marker points, we tested the visibility of today’s flowers against the simulated backgrounds.</p>
<p>Interestingly, we showed that the distribution of marker points on petals from plants pollinated by bees clearly indicates these flowers are “salient” – that is, they stand out as stronger signals from natural backgrounds.</p>
<p>This finding matches with previous studies suggesting that in the <a href="https://link.springer.com/article/10.1007/BF00188925">Northern Hemisphere</a> and <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2012.0827">Australia</a>, flowering plants evolved colour signals to facilitate colour perception by bees.</p>
<p>The very first flowers were likely a <a href="https://theconversation.com/flies-like-yellow-bees-like-blue-how-flower-colours-cater-to-the-taste-of-pollinating-insects-167111">dull greenish-yellow colour and initially pollinated by flies</a>. However, as the first bees – with their tuned vision systems – started pollinating flowers, the flowers likely evolved new colours to match the bees’ visual capabilities.</p>
<p>The process of natural selection seems to have driven flower colours to stand out from their backgrounds in the eyes of pollinators.</p>
<h2>Birds were involved, too</h2>
<p>Birds became established as flower visitors <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.17822">millions of years after insect pollination evolved</a>. Bird vision uses <a href="https://www.journals.uchicago.edu/doi/abs/10.1086/510141">four types of colour photoreceptors</a>, and they can see long-wavelength red colours that bees cannot easily process against natural backgrounds.</p>
<p>Our analysis confirmed that bird-pollinated flowers evolved marker points towards <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.12135">longer wavelengths than bee-pollinated flowers</a>. Our new discovery also showed that these flowers systematically differ from natural backgrounds.</p>
<p>As Earth’s climate changes, it is important to consider what might happen to ecosystems and our food production systems <a href="https://www.publish.csiro.au/RS/RS23003">in a world without bees</a>. It is vital that we understand how pollination and plant reproduction may be altered.</p>
<p>Our research shows that bees are a major driver of floral evolution. Unless we protect these insects and their habitat, we will lose fundamental and beautiful aspects of life we all enjoy and need.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bees-can-do-so-much-more-than-you-think-from-dancing-to-being-little-art-critics-204039">Bees can do so much more than you think – from dancing to being little art critics</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/221218/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adrian Dyer receives funding from the Alexander von Humboldt Foundation, the Air Force Office of Scientific Research and the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Alan Dorin receives or has received funding and/or support from the Australian Research Council, Microsoft, National Geographic Society, AgriFutures Australia, Costa Group, Australian Blueberry Grower's Association, Sunny Ridge Berries.</span></em></p><p class="fine-print"><em><span>Mani Shrestha worked under the German Federal Ministry of Education (BMBF) funded project, Professor Anke Jentsch, Disturbance Ecology Lab, University of Bayreuth, Germany and also wok in the Department of Life Science, National Taiwan University, Taipei, Taiwan </span></em></p><p class="fine-print"><em><span>Jair Garcia does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Flowers tend to stand out against a natural background. A new study shows this contrast evolved in a key relationship with their most famous pollinators – bees.Adrian Dyer, Associate Professor, Department of Physiology, Monash UniversityAlan Dorin, Associate Professor, Faculty of Information Technology, Monash UniversityJair Garcia, Researcher and analyst, Monash UniversityMani Shrestha, Senior Researcher and International Fellow, Disturbance Ecology, University of Bayreuth, Germany, Bayreuth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2212842024-01-22T20:05:54Z2024-01-22T20:05:54ZTiny water-walking bugs provide scientists with insights on how microplastics are pushed underwater<figure><img src="https://images.theconversation.com/files/570372/original/file-20240119-29-p4evyd.jpg?ixlib=rb-1.1.0&rect=242%2C9%2C5985%2C4146&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You may hardly feel a raindrop, but for some tiny insects, one drop can have an intense impact. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/raindrop-royalty-free-image/682204834?phrase=raindrop+falling&adppopup=true">Mendowong Photography/Moment via Getty Images</a></span></figcaption></figure><p><a href="https://doi.org/10.1016/j.envpol.2016.06.074">Microplastics are tiny plastic particles</a> that can cause <a href="https://doi.org/10.3390/su151410821">big problems</a> when they enter the water supply. One way my <a href="https://www.dickersonlab.com/">fluid dynamics lab</a> explores microplastic movement is by studying how tiny water-walking insects are pushed underwater by raindrops.</p>
<p>Exposure to microplastic pollution can pose health risks, such as <a href="https://doi.org/10.3390/nano11020496">respiratory and digestive problems</a>, increased <a href="https://doi.org/10.5334/aogh.4056">risk of diabetes</a> and <a href="https://doi.org/10.3390/ijerph17041212">disrupted sleep</a>. But <a href="https://mabe.utk.edu/people/andrew-dickerson/">physicists like me</a> can study how they move through water to learn how to clean them up. </p>
<p><a href="https://www.britannica.com/animal/water-strider">Water striders</a> are tiny insects that can <a href="https://doi.org/10.1038/nature01793">walk on water</a>. They’re abundant in humid, rainy areas, and some species go their entire lives without ever touching land. Raindrops can weigh more than 40 times a water strider, and during storms they occasionally strike striders directly. The drops form a tiny crater under the surface of the water that envelops the strider before jettisoning it out as the crater collapses back to the surface. </p>
<p>The water striders have strong exoskeletons that allow them to survive being hit by a raindrop. Because these insects are <a href="https://doi.org/10.1016/j.matpr.2022.04.901">water-repellent</a> and very lightweight, they usually bounce right back. But sometimes the raindrops will form a second, smaller crater right below the surface. The second crater usually forms from a large, fast drop.</p>
<p>If the water strider finds itself inside this second crater, it could get trapped under the water. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four photos showing a raindrop colliding with the surface of the water, the first showing a dip below the surface in which a small, long-legged insect floats, the second showing the insect meeting the surface, and the third showing another small sip with the insect inside, and the fourth showing the insect submerged under the water." src="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=606&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=606&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=606&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=761&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=761&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=761&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Raindrops form two craters, the second of which can submerge striders.</span>
<span class="attribution"><span class="source">Daren A. Watson and Andrew K. Dickerson, from the Proceedings of the National Academy of Sciences</span></span>
</figcaption>
</figure>
<p>In my lab’s <a href="https://doi.org/10.1073/pnas.2315667121">latest study</a>, we captured water striders from local ponds and released falling drops above their tanks. We used high-speed videography and image analysis to see how fast the insects submerged when the raindrops hit them.</p>
<p>My colleagues and I also measured the acceleration of the second, smaller crater. This crater retracts quickly – according <a href="https://doi.org/10.1073/pnas.2315667121">to our measurements</a>, 50 times the acceleration due to gravity. Water striders cannot support themselves inside this second bubble, as the surface they’re on moves upward so quickly, and they might fall underwater and become submerged. If that happens, the water striders make powerful swimming strokes to try to resurface.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two illustrations show the process of a strider underwater using its legs to kick up to the water's surface." src="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=121&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=121&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=121&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=153&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=153&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=153&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Striders can often kick back up to the surface if they get submerged, unlike plastic particles.</span>
<span class="attribution"><span class="source">Daren A. Watson and Andrew K. Dickerson, from the Proceedings of the National Academy of Sciences</span></span>
</figcaption>
</figure>
<h2>Why it matters</h2>
<p>Like water striders, microplastics are very light and often water-repellent. They tend to move on top of the water in a similar way, and raindrops can submerge them. When pollutants get submerged, they’re <a href="https://doi.org/10.1007/s10311-020-00983-1">harder to clean up</a>, and <a href="https://journals.openedition.org/factsreports/5257">marine life might consume</a> them.</p>
<p>Our research tells us that the second crater’s quick acceleration toward the water’s surface plays a big part in sinking tiny particles – water striders and microplastics alike.</p>
<p>Studying how small particles and organisms disperse in water could help scientists figure out how to prevent and mediate microplastic pollution. </p>
<h2>What still isn’t known</h2>
<p>Water striders are so water-repellent that they carry a bubble around them <a href="https://doi.org/10.1017/S0022112008002048">called a plastron</a> when pushed underwater.</p>
<p>In the lab, the more times they are struck by drops before repelling away the water, the more likely water striders are to remain submerged <a href="https://doi.org/10.1073/pnas.2315667121">for extended periods</a>.</p>
<p>Raindrop impacts seem to deplete the plastron. We don’t yet know how many repeated impacts striders can tolerate and how chemical pollutants in waterways affect their resistance to submersion. </p>
<h2>What’s next</h2>
<p>Future work will replace the water striders in our experiments with floating particles that mimic microplastics, with a range of size, density and water-repellency. We expect larger particles to make the drops break apart upon contact, while the smaller particles will likely get carried into the air, or <a href="https://doi.org/10.1186/s43591-021-00018-8">aerosolized</a>, by the splash.</p>
<p>And the striders aren’t just good models for microplastic movement. Studying water striders’ legs as they swim could also help researchers design underwater robots.</p><img src="https://counter.theconversation.com/content/221284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Dickerson receives funding from the National Science Foundation. </span></em></p>Microplastic pollution is a growing problem − one lab is looking at tiny insects as inspiration for how these pollutants might move through water.Andrew Dickerson, Assistant Professor of Mechanical, Aerospace and Biomedical Engineering, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2195772024-01-14T19:05:59Z2024-01-14T19:05:59ZDo they see what we see? Bees and wasps join humans in being tricked by illusions of quantity<figure><img src="https://images.theconversation.com/files/565690/original/file-20231214-18-xu49z8.jpg?ixlib=rb-1.1.0&rect=404%2C0%2C2068%2C1213&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Scarlett Howard</span></span></figcaption></figure><p>If you’ve ever been tricked by a visual illusion, you know the feeling of disconnect between what your eyes perceive and what is actually there. Visual illusions occur due to errors in our perception, causing us to misperceive certain characteristics of objects or scenes.</p>
<p>As it turns out, many non-human animals also experience these effects, including illusions of item size, brightness, colour, shape, orientation, motion or quantity. We study these illusions and the differences between animals as it can tell us how visual systems evolved.</p>
<p>Our latest study, published in <a href="https://www.cell.com/iscience/fulltext/S2589-0042(23)02774-8">iScience</a>, shows that European honeybees and European wasps see illusions of quantity in a similar way to humans.</p>
<figure class="align-center ">
<img alt="Muller-Lyer illusion; Vertical-horizontal illusion; Ponzo illusion; Illusory contour; Delboeuf illusion; Ebbinghaus illusion" src="https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Examples of different visual illusions where the eye is tricked to perceive incorrect proportions of objects.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>An illusion perceived by several species</h2>
<p>The study of visual illusions provides interesting windows into how brains operate. Visual illusions are perceptual errors, which likely enable us to process complex natural information efficiently.</p>
<p>The Solitaire illusion causes a misperception of quantity based on the configuration of dots in an image. Those who perceive the illusion will overestimate the quantity of dots when they are clustered together and/or underestimate the number of dots when unclustered.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two images containing a cross shape made up of yellow and blue dots" src="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=393&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=393&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=393&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An example of the Solitaire illusion. The yellow elements generally appear more numerous on the right than the left, despite both images having an identical quantity of yellow and blue elements.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<p>We know the Solitaire illusion is perceived by <a href="https://psycnet.apa.org/record/2014-33482-001">humans, capuchin monkeys</a>, <a href="https://psycnet.apa.org/record/2017-55920-001">guppies</a> and <a href="https://www.biorxiv.org/content/10.1101/2023.08.22.554303v1.abstract">bumblebees</a>. <a href="https://psycnet.apa.org/record/2014-33482-001">Chimpanzees, rhesus monkeys</a> and <a href="https://www.mdpi.com/2076-2615/10/12/2304">domestic dogs</a> do not appear to perceive the illusion. Interestingly, in humans age appears to impact the perception of the Solitaire illusion – younger children are less susceptible than <a href="https://www.sciencedirect.com/science/article/pii/S0022096515002258">older children</a>.</p>
<p>A possible evolutionary reason humans and other species may experience this misperception of quantities is it may allow us to process and compare large numbers of items more efficiently and quickly.</p>
<p>For quantities greater than about five, fast decisions may be more important than absolute accuracy, which would require manual, sequential counting.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/one-then-some-how-to-count-like-a-bee-138815">One, then some: how to count like a bee</a>
</strong>
</em>
</p>
<hr>
<h2>Testing honeybees</h2>
<p>Some insects, including bees and wasps, are very “motivated” to participate in behavioural experiments. European honeybees and wasps are central-place foragers: they will return to the location of a high-quality food source.</p>
<p>We provided freely flying bees and wasps with a reward of sugar water for participating in experiments. This allows us to train and test individually colour-marked insects throughout a day, with them returning by their own choice.</p>
<p>We have used this method to show honeybees can perform a variety of numerical tasks such as <a href="https://theconversation.com/bees-join-an-elite-group-of-species-that-understands-the-concept-of-zero-as-a-number-97316">understanding the concept of zero</a>, <a href="https://theconversation.com/bees-can-learn-higher-numbers-than-we-thought-if-we-train-them-the-right-way-124887">discriminating between quantities</a>, <a href="https://theconversation.com/can-bees-do-maths-yes-new-research-shows-they-can-add-and-subtract-108074">performing simple addition and subtraction</a>, <a href="https://theconversation.com/we-taught-bees-a-simple-number-language-and-they-got-it-117816">matching symbols with quantities</a>, and <a href="https://theconversation.com/honeybees-join-humans-as-the-only-known-animals-that-can-tell-the-difference-between-odd-and-even-numbers-181040">categorising quantities as odd or even</a>.</p>
<p>Honeybees are also known to perceive some <a href="https://theconversation.com/which-square-is-bigger-honeybees-see-visual-illusions-like-humans-do-87673">spatial</a>, movement and colour illusions. These past skills make them an ideal candidate to study and see if they are fooled by illusions of quantity.</p>
<p>Wasps are far less tested than honeybees for their behaviour and cognition, but recent <a href="https://theconversation.com/many-people-hate-wasps-but-theyre-smarter-than-you-might-think-and-ecologically-important-212706">studies</a> show they are also capable of advanced learning. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A grey circular screen displaying stimuli to insects" src="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=706&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=706&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=706&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=888&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=888&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=888&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The circular rotating screen used to present stimuli to insects during training and testing. Insects were trained one at a time and rewarded with a sugar water drop for landing on the correct stimulus option during training.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>Bees, wasps and the Solitaire illusion</h2>
<p>We tested the European honeybee (<em>Apis mellifera</em>) and the European wasp (<em>Vespula vulgaris</em>) using an identical method for both species.</p>
<p>We presented each insect with images containing blue and yellow dots. For 70 trials, the insects were trained with a sugar reward to visit an image with a higher quantity of yellow dots versus blue.</p>
<p>We then presented them with the Solitaire illusion – one image with the yellow dots clustered in the middle and the blue dots unclustered, versus one image of the opposite. </p>
<p>The images actually contained an identical number of blue and yellow dots. So, if the insects perceived the illusion, they would choose the option with the yellow dots clustered in the centre, revealing an overestimation of the quantity of yellow dots.</p>
<p>We found both honeybees and wasps perceived the illusion in a similar way to humans, capuchin monkeys and guppies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A wasp sits on a platform in front of an image of yellow and blue dots. A honeybee is approaching to land" src="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A bee and wasp in front of one of the training images.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>Is there an evolutionary clue here?</h2>
<p>We now know the perception of the Solitaire illusion occurs across a range of species including humans, non-human primates, fish and insects. There are also primates and other mammals that appear not to perceive the illusion.</p>
<p>This could suggest two potential evolutionary pathways of experiencing the illusion. </p>
<p>One is <em>convergent</em> evolution, where different species separately developed the ability to perceive this illusion due to the requirements of their environment.</p>
<p>The other pathway is that the perception occurred through <em>conserved</em> evolution, where a common ancestor perceived the illusion, and subsequently some species either retained or lost the illusion perception.</p>
<p>One important consideration is that while the Solitaire illusion is considered an illusion of quantity, it could also be perceived as an illusion of colour area, size, line length, or perimeter. More research will be needed to determine whether the illusion induces the misperception of quantity or other cues that correlate with quantity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/which-square-is-bigger-honeybees-see-visual-illusions-like-humans-do-87673">Which square is bigger? Honeybees see visual illusions like humans do</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/219577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scarlett Howard receives funding from the Australian Research Council, Monash University, Australian Academy of Sciences, and the Hermon Slade Foundation. She is affiliated with Triple R.</span></em></p><p class="fine-print"><em><span>Adrian Dyer receives funding from the Alexander von Humboldt Foundation, the Air Force Office of Scientific Research and the Australian Research Council.</span></em></p>Being susceptible to visual illusions is part and parcel of life not just for humans, but many other species – including bees.Scarlett Howard, Lecturer, School of Biological Sciences, Monash UniversityAdrian Dyer, Associate Professor, Department of Physiology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2173582023-12-11T23:29:05Z2023-12-11T23:29:05ZPeople worry Christmas beetles are disappearing. We’re gathering citizen data to see the full picture<figure><img src="https://images.theconversation.com/files/564735/original/file-20231211-25-tm8qr4.jpg?ixlib=rb-1.1.0&rect=156%2C287%2C3621%2C2614&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/christmas-beetle-feeding-on-scrub-apple-1566097558">Ken Griffiths/Shutterstock</a></span></figcaption></figure><p>In eastern Australia, the arrival of the summer holidays has traditionally been heralded by big iridescent beetles known as <a href="https://australian.museum/learn/animals/insects/christmas-beetle/">Christmas beetles</a> due to their appearance during the Christmas season.</p>
<p>In recent years, public perception seems to suggest these lovely insects may no longer be arriving in high numbers.</p>
<p>Each year insect scientists like us field questions from the press and public about <a href="https://australian.museum/learn/animals/insects/christmas-beetles/">Christmas beetle populations</a>: where have they gone? Why have their populations shrunk? Is it climate change?</p>
<p>So have Christmas beetles really declined? With the help of people around Australia, we’re working to figure this out.</p>
<h2>What are Christmas beetles?</h2>
<p>In most of Australia, the term “Christmas beetle” refers to large beetles in the genus <em>Anoplognathus</em>. There are 36 Christmas beetle species, almost all of which are only found in Australia.</p>
<p>Christmas beetles are most common along the east coast and are found over most of the continent, except for a <a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/c0b25da0-a8f0-4be8-a2c3-72cb64918aba">curious absence in the south west</a>.</p>
<p>They emerge in early summer and seek out mates, sometimes pausing to munch on eucalyptus leaves. Females lay their eggs in the soil. After a few weeks, these eggs hatch into chunky white or cream coloured larvae often known as “curl grubs”.</p>
<p>Larvae live in the soil for 1–2 years until forming a pupa and transforming into their final adult form. They then dig their way out of the ground and take to the air, starting the cycle again.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/TolRQ4pXDjI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Commonly observed species like the washerwoman (<em><a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/01a8652e-6a29-47ef-ae90-9c87bdb5e04d">Anoplognathus porosus</a></em>) and <em><a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/09b5e6e4-4818-45b0-821e-960c2c41f9bf">A. olivieri</a></em> have classic Christmas beetle colouring, with flecks of iridescence across their tawny brown bodies.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a beige beetle with orange-green iridescence on its front part" src="https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564407/original/file-20231207-23-96i7xh.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The washerwoman (<em>Anoplognathus porosus</em>) Christmas beetle.</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<p>But not all Christmas beetles are iridescent. Some, like the Granny Smith beetle (<em><a href="https://australian.museum/learn/collections/natural-science/entomology/christmas-beetles/Anoplognathus-prasinus/">A. prasinus</a></em>), are a vibrant green, while others look golden (<a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/f68e243d-2353-4f7c-90e5-4c9d8a256e43"><em>A. aureus</em></a> and <em><a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/9460fbc2-3b3d-4bff-b3e2-e5d6e4a96493">A. parvulus</a></em>).</p>
<p>To make things more complicated, people in Tasmania tend to use the term “Christmas beetle” to refer to the glorious golden stag beetle (<em><a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/59fede41-4359-40c9-bff7-c0cbcab02440">Lamprima aurata</a></em>). A lovely beetle to be sure – but not the kind we’re talking about.</p>
<p>Christmas beetles are also frequently <a href="https://www.youtube.com/watch?v=ECEHmBibyAY">confused with other scarab beetles</a>, especially Argentinian lawn scarabs (<em><a href="https://inaturalist.ala.org.au/taxa/517487-Cyclocephala-signaticollis">Cyclocephala signaticollis</a></em>) which are very common in the summer, particularly in cities. Argentinian lawn scarabs are smaller than most Christmas beetles and lack the distinct thickened back legs and scoop-shaped snout.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a brown beetle with dark specks on its wings" src="https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564444/original/file-20231208-25-v6wlih.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An Argentinian lawn scarab (<em>Cyclocephala signaticollis</em>) is not a Christmas beetle.</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<p>Native flower chafers such as <a href="https://australian.museum/learn/animals/insects/fiddler-beetle/">fiddler beetles</a> (<em>Eupoecila australasiae</em>), <a href="https://australian.museum/learn/animals/insects/punctate-flower-chafer-beetle/">punctate flower chafers</a> (<em>Neorrhina punctata</em>) and <a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/c88d4abd-4262-429b-b70a-428d1fb2cd8d">cowboy beetles</a> (<em>Chondropyga dorsalis</em>) are also commonly mistaken for Christmas beetles. These beautiful summer-active beetles are pollinators of native flowers.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black beetle with neon green stripes in a cool pattern on its back" src="https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564453/original/file-20231208-23-2uftxu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A native fiddler beetle (<em>Eupoecila australasiae</em>) is striking, but isn’t a Christmas beetle.</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<h2>Have Christmas beetles declined?</h2>
<p>Unfortunately, we don’t have long term population data for any Christmas beetle species, so we cannot conclusively say if there’s been a decline. However, many people (including some of the authors) remember there being more Christmas beetles in the past. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a small beige beetle with black spots all over it" src="https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=678&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=678&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=678&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=852&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=852&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564447/original/file-20231208-21-tciit6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=852&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A native punctate flower chafer (<em>Neorrhina punctatum</em>).</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<p>But memory alone is not strong enough evidence, so we’ve designed a project to help us determine the health of Christmas beetle populations. The <a href="https://invertebratesaustralia.org/christmasbeetles">Christmas Beetle Count</a> is a community science project led by conservation organisation Invertebrates Australia in collaboration with the University of Sydney.</p>
<p>We are asking the public to submit their sightings of Christmas beetles to the online database <a href="https://www.inaturalist.org/">iNaturalist</a>. We can then use the data to determine which Christmas beetle species are likely to be at risk of decline or extinction. </p>
<p>So far, the project has been a roaring success. As of December 2023, over <a href="https://www.inaturalist.org/projects/christmas-beetle-count">8,000 sightings</a> have been submitted by over 4,000 people across Australia, including photos of four very rare species last sighted decades ago.</p>
<p>For one species (<em><a href="https://www.inaturalist.org/taxa/1443806-Anoplognathus-vietor">A. vietor</a></em>), our observers took the first known picture of a living individual – it had previously been known only from a single, dead beetle. This record was 300km away from the only site previously known for this species, suggesting it occupies a larger range than thought. </p>
<p>Sightings like these help us better understand the distribution and population health of Christmas beetles, and anyone can help.</p>
<h2>Are Christmas beetles coming back in 2023?</h2>
<p>It’s too early to determine if Christmas beetles have made a comeback this year. Between November 1 and December 8 2023, 532 “research grade” sightings of Christmas beetles have been reported, more than double from the same period last year.</p>
<p>Although the rise in reported sightings seems promising, it’s possible this increase is not due to a growing beetle population, but rather because more people are aware of the project and are actively searching for Christmas beetles.</p>
<p>We will need a few more years of data before we can say anything conclusive about Christmas beetle population trends.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The face of a beetle with red legs, big black eyes and green-yellow iridescent sheen" src="https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564448/original/file-20231208-21-za277f.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Close up, you can really appreciate the iridescent shine of a true Christmas beetle.</span>
<span class="attribution"><span class="source">Tanya Latty</span></span>
</figcaption>
</figure>
<h2>Why are Christmas beetles important?</h2>
<p>Like many insects, Christmas beetles are likely threatened by habitat loss. We can help by conserving our native bushland – Australia’s pledge to <a href="https://theconversation.com/weve-committed-to-protect-30-of-australias-land-by-2030-heres-how-we-could-actually-do-it-217795">preserve 30% of land</a> is welcome news.</p>
<p>These insects play an important ecological role. Since they emerge at a predictable time of the year when many reptiles, mammals and birds are producing and raising their young, adult Christmas beetles may be an important food source for many animals. </p>
<p>The larvae of Christmas beetles tunnel through the soil helping to aerate it and to recycle organic matter. They likely serve as a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684676/">protein and fat-rich</a> meal for hungry birds, reptiles and mammals. </p>
<p>Christmas beetles are an iconic part of Australia’s natural heritage, as uniquely Australian as koalas, platypuses and kangaroos.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/dont-kill-the-curl-grubs-in-your-garden-they-could-be-native-beetle-babies-191771">Don’t kill the curl grubs in your garden – they could be native beetle babies</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/217358/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tanya Latty co-founded and works for conservation organisation Invertebrates Australia, is former president of the Australasian Society for the Study of Animal Behaviour and is on the Education committee for the Australian Entomological Society. She receives funding from the Australian Research Council, NSW Saving our Species, and Agrifutures. </span></em></p><p class="fine-print"><em><span>Chris Reid received funding from the Australian Biological Resources Study (ABRS), federal Department of Environment (2016) to produce the Xmas Beetle ID app.</span></em></p><p class="fine-print"><em><span>Hauke Koch volunteers as outreach officer for the conservation organization Invertebrates Australia. </span></em></p><p class="fine-print"><em><span>Thomas Mesaglio volunteers as outreach officer for the conservation organization Invertebrates Australia.</span></em></p>Each year insect scientists like us field questions from the press and public about Christmas beetle populations: where have they gone?Tanya Latty, Associate professor, University of SydneyChris Reid, Adjunct Associate Professor in Zoology, UNSW SydneyHauke Koch, Research Scientist, Environment, CSIROThomas Mesaglio, PhD candidate, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170822023-12-07T19:19:04Z2023-12-07T19:19:04ZWe thought we’d find 200 species living in our house and yard. We were very wrong<figure><img src="https://images.theconversation.com/files/559530/original/file-20231115-19-q1g80l.jpeg?ixlib=rb-1.1.0&rect=0%2C42%2C4025%2C2685&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dot-underwing moth (_Eudocima materna_) found in the researchers' yard.</span> <span class="attribution"><span class="source">Matthew Holden</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>We are biodiversity researchers – an ecologist, a mathematician and a taxonomist – who were locked down together during the COVID pandemic. Being restricted to the house, it didn’t take long before we began to wonder how many species of plants and animals we were sharing the space with. So we set to work counting them all.</p>
<p>We guessed we would find around 200–300, and many of our colleagues guessed the same. </p>
<p>There was nothing extraordinary about our 400 square metre block of land in Annerley, a suburb of Brisbane in Queensland, Australia. Roughly half the block was occupied by a three-bedroom house.</p>
<p>What was extraordinary was the number of species we discovered there. As revealed in our just-published study, starting on the first day of lockdown and continuing over the course of a year, we catalogued <a href="https://doi.org/10.1002/ecy.4225">1,150 species</a> on our inner-city property.</p>
<h2>Familiar faces and rare recluses</h2>
<p>Many of the species were what any east coast suburban Australian would expect: ibises, brush turkeys, kookaburras, possums and flying foxes. But, surprisingly, others had rarely been recorded. </p>
<p>In fact, three of the 1,150 species had never been documented in Australia’s leading biodiversity database at that point. This included a rare mosquito, a sandfly and an <a href="https://en.wikipedia.org/wiki/Platydemus_manokwari">invasive flatworm</a> that can cause populations of native snails to decline. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-39-endangered-species-in-melbourne-sydney-adelaide-and-other-australian-cities-114741">The 39 endangered species in Melbourne, Sydney, Adelaide and other Australian cities</a>
</strong>
</em>
</p>
<hr>
<p>We found common foes, but also many friends. That rare mosquito was just one of 13 mosquito species we found. The cupboards accommodated pantry moths and grain weevils, but also spiders to prey on them (we recorded 56 species). </p>
<p>Our lack of assiduous garden-tending meant weeds were prolific; of the 103 plant species we documented on the property, 100 were non-native. </p>
<p>Apart from weeds, however, the vast majority of species were actually native. Our two massive lilly-pilly trees provided shade, shelter and food, magnets for numerous pollinators and other species. </p>
<h2>Bees and butterflies</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of sleeping bees hanging on a plant stem." src="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=889&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=889&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=889&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1117&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1117&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1117&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blue-banded bees sleep grasping plant stems with their mandibles.</span>
<span class="attribution"><span class="source">Andrew Rogers</span></span>
</figcaption>
</figure>
<p>The yard was filled with pollinators. For example, there were hoverflies which, at a quick glance, you’d think were wasps. We had ten species of those, a fraction of the more than 109 species of flies we found. </p>
<p>Native blue-banded bees and fluffy teddybear bees roosted in the hedges under our windows at night. They were just two of more than 70 bee and wasp species we observed. </p>
<p>We also counted a mindblowing 436 species of butterflies and moths. A few were as large as a human hand, but most were tiny and barely noticeable. Some were brightly coloured, while others – like the vampire moth <em>Calyptra minuticornis</em> – seemed boring until we began to study their behaviour. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1252048652337479681"}"></div></p>
<p>The moth <em>Scatochresis innumera</em> is another interesting one: as a caterpillar, it lives inside a single possum poop before emerging as an adult. </p>
<p>The caterpillars of <em>Parilyrgis concolor</em>, yet another moth, live in spiderwebs, surviving on the spider’s food waste, while the adults can be found hanging bat-like from the spiderwebs. It is not known how they avoid getting eaten by the spiders.</p>
<figure class="align-center ">
<img alt="A photo of a brown moth hanging from a spiderweb." src="https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=423&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=423&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=423&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=532&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=532&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=532&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The caterpillars of the moth Parilyrgis concolor live in spiderwebs, and adults often hang from webs like bats.</span>
<span class="attribution"><span class="source">Russell Yong</span></span>
</figcaption>
</figure>
<h2>Wasps and beetles</h2>
<p>We recorded ten species of lycaenid “blue” butterflies, many of which use ants to protect their caterpillars from predators, including certain wasp species which would lay eggs in them if they got a chance.</p>
<p>These wasps are called parasitoids – meaning their young develop in other organisms, eventually killing them. Some of these wasps even parasitise other parasitoid wasps. Our urban homes are clearly complex ecosystems.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a small orange and black bug on a thin tree branch." src="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=828&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=828&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=828&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A tiny Braconid wasp that parasitises other insects.</span>
<span class="attribution"><span class="source">Matthew Holden</span></span>
</figcaption>
</figure>
<p>We were surprised to only find just under 100 beetle species (the fourth most common group of organisms in our study). Beetles are widely believed to be the most diverse order of insects on the planet. </p>
<p>Our finding may be a sign of declining beetle populations, which has been observed around the world. On the other hand, it may just have been a bad year for beetles in our neighbourhood.</p>
<h2>An urban environment teeming with life</h2>
<p>Overall, we found far more species than we expected, and we showed that even urban environments can be teeming with wildlife. </p>
<p>A big reason for that was surely the vegetation: the shrubs, trees and weeds in the yard. The monotony of perfectly tended lawn and heavily sprayed and manicured flowerbeds may be nice to look at and for the kids to play on but, as habitat for urban wildlife, it is lacking. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/heres-how-to-design-cities-where-people-and-nature-can-both-flourish-102849">Here's how to design cities where people and nature can both flourish</a>
</strong>
</em>
</p>
<hr>
<p>Our own laziness meant we did little work in the garden. However, by giving the mower and pesticides a break, and by sacrificing some lawn for native trees, shrubs and flowering weeds, we ended up with something much more valuable.</p>
<p>But no matter what you do to maintain your home, definitely check your porch or balcony light tonight, and keep your eye out for urban wildlife around your home. You too can experience some pretty amazing nature, no matter how urban the environment you live in.</p><img src="https://counter.theconversation.com/content/217082/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew H. Holden receives funding from the Australian Research Council and the Department of Environment and Science, Queensland</span></em></p><p class="fine-print"><em><span>Andrew Rogers and Russell Q-Y Yong do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An ecologist, a mathematician and a taxonomist were locked down together in a suburban house. So they counted all the species of plants and animals they could find.Matthew H. Holden, Lecturer, School of Mathematics and Physics, The University of QueenslandAndrew Rogers, PhD student, The University of QueenslandRussell Q-Y Yong, PhD candidate, Marine Parasitology, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2180662023-11-24T17:18:25Z2023-11-24T17:18:25ZHoneybees cluster together when it’s cold – but we’ve been completely wrong about why<figure><img src="https://images.theconversation.com/files/561274/original/file-20231123-20-liu4xf.jpg?ixlib=rb-1.1.0&rect=0%2C11%2C2456%2C1624&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/yong-bee-inside-honeycomb-closeup-76369804">Smit/Shutterstock</a></span></figcaption></figure><p>Honeybees in man-made hives may have been suffering the cold unnecessarily for over a century because commercial hive designs are based on erroneous science, <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsif.2023.0488">my new research shows</a>.</p>
<p>For <a href="https://doi.org/10.5962/bhl.title.64465">119 years</a>, a belief that the way honeybees cluster together gives them a kind of evolutionary insulation has been fundamental for beekeeping practice, hive design and <a href="https://doi.org/10.1242/jeb.00082">honeybee study</a>. More recently, California beekeepers have even been putting <a href="https://www.projectapism.org/indoor-storage-of-honey-bees-blog/using-cold-storage-for-a-brood-break-in-one-of-the-hottest-places-on-earth">bee colonies into cold storage</a> during summer because they think it is good for brood health. </p>
<p>But my study shows that clustering is a distress behaviour, rather than a benign reaction to falling temperatures. Deliberately inducing clustering by practice or poor hive design may be considered poor welfare or even cruelty, in light of these findings. </p>
<p>Honeybee (<em>Apis mellifera</em>) colonies don’t hibernate. In the wild they overwinter in tree cavities that keep at least some of their numbers above 18°C in a wide range of climates, including -40°C winters. But popular understanding of their overwintering behaviour is dominated by observation of their behaviour in thin (19mm) wooden hives. These man-made hives have <a href="https://books.google.co.uk/books?hl=en&lr=&id=tc6MDwAAQBAJ&oi=fnd&pg=PP9&ots=jpkgmY9Kz6&sig=BmNbAxlrv2tfGhPLtkkczJxK3VY&redir_esc=y#v=onepage&q&f=false">very different</a> thermal properties compared with their natural habitat of thick-walled (150mm) tree hollows. </p>
<h2>Getting through winter</h2>
<p>On cold days in these thin-walled hives, colonies form dense disks of bees, called a cluster, between the honeycombs. The centre of these disks (the core) is less dense and warmer (up to 18°C). This is where the honeybees produce most of the heat by eating and metabolising the sugar from honey. The cooler outer layers (mantle) produce very little heat as the bees’ body temperatures are too low. If the temperature falls much below 10°C, the bees there will die.</p>
<p><a href="https://doi.org/10.5962/bhl.title.64465">Since 1914</a>, beekeeping texts and academic papers have said the mantle “insulates” the inner core of the hive. This meant beekeepers saw clustering as natural or even necessary. This belief was used <a href="https://doi.org/10.1093/jee/45.3.445">in the 1930s</a> to justify keeping honey bees in thin-walled hives even in -30°C climates. This led, <a href="https://doi.org/10.1080/0005772X.1984.11098768">in the late 1960s in Canada</a>, to a practice of keeping honeybees in cold storage (4°C) to keep them clustered over the winter.</p>
<p><a href="https://www.youtube.com/watch?v=oHRgmZGRcic">In the 2020s</a>, keepers are refrigerating honeybees <a href="https://www.youtube.com/watch?v=RJDnqQNcd34">in summer</a> to facilitate the chemical treatment of parasites. This is happening across the US – for example in <a href="https://www.projectapism.org/demographics-of-indoor-bee-storage.html">Idaho, Washington and Southern California</a>. Outside of a cold winter, if beekeepers want to treat mite infestations, they normally have to locate and cage the queen. But cold storage means beekeepers can skip this labour-intensive step, making their commercial pollination services more profitable. </p>
<h2>Struggling for warmth</h2>
<p>However, <a href="https://doi.org/10.1098/rsif.2023.0488">my study</a> found cluster mantles act more like a <a href="https://en.wikipedia.org/wiki/Heat_sink">heatsink</a>, decreasing insulation. Clustering is not a wrapping of a thick blanket to keep warm, but more like a desperate struggle to crowd closer to the “fire” or die. The only upside is that the mantle helps keep the bees near the outside alive. </p>
<p>As the temperature outside the hive falls, bees around the mantle go into hypothermic shutdown and stop producing heat. The mantle compresses as the bees try to stay above 10°C. </p>
<p>The mantle bees getting closer together increases the thermal conductivity between them and decreases the insulation. Heat will always try to move from a warmer region <a href="https://www.physics.ox.ac.uk/system/files/file_attachments/basic_thermo.pdf">to a colder one</a>. The rate of heat flow from the core bees to the mantle bees increases, keeping those bees on the outside of the mantle at 10°C (hopefully).</p>
<p>Think of <a href="https://baselayer.co.uk/pages/feather-down-rating-explained">a down jacket</a> – it’s the air gap between the feathers that help keeps the wearer warm. Honeybee clusters are similar to the action of compressing a down jacket, whereby the thermal conductivity eventually increases to that of a dense solid of feathers, more like a leather jacket.</p>
<p>In contrast, when penguins are huddling in the Antarctic winter, they all keep their body core hot at similar temperatures, and therefore there is <a href="https://www.youtube.com/watch?v=UA43xr2zR-A">little or no heat transfer</a> between the penguins. Unlike the bees in the mantle, there aren’t any penguins in a hypothermic shutdown. </p>
<p><a href="https://doi.org/10.1016/0300-9629(71)90282-9">Academics</a> and <a href="https://americanbeejournal.com/the-greatest-generation-winter-bees/">beekeepers</a> have overlooked the part played by the invisible air gap between the hive and the cluster. The thin wooden walls of commercial hives act as little more than a boundary between the air gap and the outside world. This means that for hive walls to be effective, they have to be substantially insulating, such as 30mm of polystyrene.</p>
<p>This misunderstanding of the complex interaction between the colony enclosure, thermofluids (heat, radiation, water vapour, air) and honeybee behaviour and physiology are a result of people not recognising the hive as the <a href="https://global.oup.com/academic/product/the-extended-phenotype-9780198788911?cc=gb&lang=en&">extended phenotype</a> of the honey bee. Other examples of extended phenotype include a spider’s web and a beaver’s dam. </p>
<p>There are almost no ethics standards for insects. But there is growing evidence that <a href="https://theconversation.com/insects-may-feel-pain-says-growing-evidence-heres-what-this-means-for-animal-welfare-laws-195328">insects feel pain</a>. A 2022 study found that bumblebees react to potentially harmful stimuli in a way that is similar to pain responses in humans. We urgently need to change beekeeping practice to reduce the frequency and duration of clustering.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/218066/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Derek Mitchell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research shows honeybee hive clusters are a sign of desperation, not insulation.Derek Mitchell, PhD Candidate in Mechanical Engineering, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2152222023-11-21T13:27:15Z2023-11-21T13:27:15ZClimate change is already forcing lizards, insects and other species to evolve – and most can’t keep up<figure><img src="https://images.theconversation.com/files/558259/original/file-20231108-29-upppm0.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C1615%2C1069&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Temperature sensitivity makes western fence lizards vulnerable to climate change.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/blmoregon/47961427128">Greg Shine/BLM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Climate change is threatening the survival of plants and animals around the globe as temperatures rise and habitats change.</p>
<p>Some species have been able to meet the challenge with rapid evolutionary adaptation and other changes in behavior or physiology. Dark-colored dragonflies are <a href="https://doi.org/10.1073/pnas.2101458118">getting paler</a> in order to reduce the amount of heat they absorb from the sun. Mustard plants are <a href="https://doi.org/10.1098/rspb.2012.1051">flowering earlier</a> to take advantage of earlier snowmelt. Lizards are <a href="https://doi.org/10.1098/rsbl.2020.0625">becoming more cold-tolerant</a> to handle the extreme variability of our new climate.</p>
<p>However, scientific studies show that climate change is occurring much faster than species are changing.</p>
<figure class="align-center ">
<img alt="A tiny, royal blue fish with gold stripes looks into the camera. The downward slant of its mouth and shadow at the top of its eye give it an annoyed look." src="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5599%2C3724&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zebrafish have evolved to thrive in water a degree or so warmer than normal, but they struggle to survive at higher temperatures.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brachydanio-rerio-royalty-free-image/154930602?adppopup=true">isoft/E+ Getty Images</a></span>
</figcaption>
</figure>
<h2>What is evolutionary adaptation?</h2>
<p>The word “adaptation” is used in many ways by climate scientists, but it has a very specific meaning to biologists: It refers to genetic changes that are passed on from one generation to the next and improve a species’ ability to survive in its environment.</p>
<p>These genetic modifications make evolutionary adaptation different from “acclimation” or “acclimatization,” which involve advantages that are not passed on to offspring. For example, when people move to high-altitude cities, they <a href="http://dx.doi.org/10.1136/bjsports-2013-092840">start producing more red blood cells</a> as they acclimate to the low oxygen.</p>
<p>All over the world, plants and animals have adapted to many different warm and dry habitats, prompting scientists to <a href="https://doi.org/10.1098/rstb.2018.0176">question</a> <a href="https://doi.org/10.1038/s41586-019-1520-9">whether</a> <a href="https://doi.org/10.1111/gcb.14881">species</a> <a href="https://doi.org/10.1073/pnas.1406314111">might</a> <a href="https://doi.org/10.1111/evo.13862">also</a> <a href="https://doi.org/10.1126/science.1063656">adapt</a> <a href="https://doi.org/10.1073/pnas.0608379104">to</a> <a href="https://doi.org/10.1111/ele.14072">our</a> <a href="https://doi.org/10.1126/science.aba9287">rapidly</a> <a href="https://doi.org/10.1126/science.abj7484">changing</a> <a href="https://doi.org/10.1126/science.aaf3343">climate</a>, <a href="https://doi.org/10.1038/nclimate2628">too</a>.</p>
<p>Thus far, the answer <a href="https://doi.org/10.1002/wcc.852">seems to be no</a> for most species.</p>
<h2>Evolving, fast and slow</h2>
<p>A <a href="https://doi.org/10.1038/s41467-019-10924-4">recent study</a> of the populations of 19 bird and mammal species, including owls and deer, shows one potential barrier to adaptation. </p>
<p>In animals that take several years to reach breeding age, the climate has already shifted by the time their offspring are born. Genes that gave the parents an advantage – like hatching at exactly the right time or growing to the best size – are no longer as beneficial for the offspring.</p>
<p>Populations of these slow-maturing animals are adapting to climate change, but not enough during each generation to thrive in the changing conditions. In fact, the rate of evolution is so mismatched to the rate of global warming that the study’s authors estimate that nearly 70% of the local populations they studied are already vulnerable to climate-driven extinction over the coming decades.</p>
<figure class="align-center ">
<img alt="A dragonfly with dark bands on its wings." src="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Black bands on dragonflies heat up their bodies. Research shows some dragonflies have evolved smaller black bands as the climate warms.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A heat map clearly shows that the dark bands on the wings absorb more heat." src="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In this heat map of the same dragonfly, white areas are the warmest and purple areas are cooler. The dark bands on the wings stand out.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>Small-bodied animals, such as many fish, insects and plankton, typically mature quickly. Yet, recent research on <a href="https://doi.org/10.1073/pnas.2011419117">small fish</a> and a type of <a href="https://doi.org/10.1098/rspb.2011.0542">fast-maturing plankton called a copepod</a> revealed another hurdle for rapid genetic adaptation to climate change.</p>
<p>Many species possess genes that permit them to live in environments that are 1 to 2 degrees Celsius (about 2 to 4 Fahrenheit) warmer than today, but new genetic mutations must arise to enable survival if climates reach 4 to 5 C (about 7 to 9 F) warmer, as is possible in some regions, particularly if greenhouse gas emissions continue at a high rate.</p>
<p>To test species’ resilience, scientists warmed populations of these fast-maturing species over many generations to observe their genetic changes. They found that both the copepods and the small fish were able to adapt to the first couple degrees of warming, but populations soon went extinct above that. This was because genetic mutations that increased their ability to live in hotter conditions occurred at a slower rate than the temperatures rose.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tiny nearly translucent oval creature with a tail and egg sacks trailing behind it." src="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A live copepod with egg sacs at 10 times magnification. These ocean creatures produce new generations quickly, allowing for speedier evolution.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/copepod-micrograph-royalty-free-image/170025374?adppopup=true">NNehring/E+ Getty Images</a></span>
</figcaption>
</figure>
<p>Cold-blooded species, such as lizards, frogs and fish, are especially vulnerable to climate change because they have a limited capacity to regulate their own body temperatures. Their ability to evolve in response to climate change is expected to be critical for their survival.</p>
<p>However, rapid adaptation to climate change often comes <a href="https://doi.org/10.1007/BF02984069">at a cost</a>: Populations get smaller due to the deaths of individuals that cannot tolerate new, hotter temperatures. Therefore, even if species do evolve to survive with climate change, their smaller populations may still go extinct due to problems such as inbreeding, harmful new mutations or plain old bad luck, such as a disease epidemic.</p>
<p><a href="https://doi.org/10.1126/science.1184695">In a now-classic study</a>, researchers studying lizards in Mexico discovered that the high death rates of just the heat-sensitive individuals – representing only a subset of the entire population – caused 12% of all lizard populations in Mexico to go extinct between 1975 and 2009. Even with some heat-tolerant adult lizards surviving in each population under the warmer conditions, the researchers estimated climate change would kill so many heat-sensitive adults within each population that 54% of all populations would go extinct by 2080.</p>
<h2>Evolutionary adaptation isn’t species’ only option</h2>
<p>Another way species adjust to rising temperatures is acclimation, sometimes called “phenotypic plasticity.” For example, <a href="https://doi.org/10.1126/science.1157174">great tits in the U.K.</a> – small birds that are common in yards and forests – lay their eggs earlier in warmer years so that their nestlings hatch right as the winter weather ends, no matter when that happens.</p>
<figure class="align-center ">
<img alt="A small bird with a yellow body and black head with white cheeks sits on a branch." src="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A great tit – <em>Parus major</em>. In the U.K., these common birds have been laying their eggs earlier in warm years.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/hedera_baltica/49433487712/in">Hedera.Baltica via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>However, a <a href="https://www.nature.com/articles/s41467-022-32953-2">recent analysis</a> of more than 100 beetle, grasshopper and other insect species all over the world found that acclimation may not help those species enough. The study’s authors found that the species they reviewed gained an average of only 0.1 C (about 0.2 F) greater heat tolerance when acclimating to 1 C (about 2 F) warmer air temperatures during their development. Thus, the rate of global warming seems to be outstripping species’ abilities to acclimate, too.</p>
<p>Plants and animals could also escape the impacts of global warming by migrating to cooler habitats. A <a href="https://doi.org/10.1038/s41559-020-1198-2">global analysis</a> of more than 12,000 different plants and animal species recently showed that many species are migrating toward the poles fast enough to keep pace with rising temperatures, and many <a href="https://doi.org/10.1111/ele.13762">tropical species are moving upslope</a> to higher elevations as well.</p>
<p>Nonetheless, migration has its limits. Research shows that <a href="https://doi.org/10.1073/pnas.1804224115">tropical birds that already live high in the mountains could be doomed</a> because there is no room for them to migrate any farther upward. Tropical species, therefore, may be on what the authors call an “escalator to extinction.”</p>
<figure class="align-center ">
<img alt="A yellow-and-black moth sits on a yellow flower in an alpine field with snow-covered mountains in the background." src="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=789&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=789&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=789&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=992&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=992&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=992&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Police car moths living at high elevations have little room to migrate to escape increasing heat.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>High-latitude and high-elevation habitats also present numerous challenges for species to overcome besides temperature. Our own research across 800 species of insects all over the Earth shows that butterflies, bees and other flying insects are <a href="https://doi.org/10.1038/s41558-023-01794-2">especially hindered from migrating to higher elevations</a> because there is not enough oxygen for them to survive. </p>
<h2>Many species lack obvious climate strategies</h2>
<p>Overall, evolutionary adaptation appears to help lessen the impacts of global warming, but the evidence thus far shows that it is insufficient to overcome current rates of climate change. Acclimation and migration provide faster solutions, but research shows that those may not be enough, either.</p>
<p>Of course, not all evolution is driven by warming temperatures. Plant and animal species appear to be also gradually adapting to other kinds of environments, including <a href="https://doi.org/10.1111/evo.14191">human-created ones like cities</a>. But the fast pace of global warming makes it <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">one of the major threats</a> that species must respond to immediately.</p>
<p>The <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">evidence indicates</a> that humanity cannot simply assume that plants and animals will be able to save themselves from climate change. To protect these species, humans will have to stop the activities that are fueling climate change.</p><img src="https://counter.theconversation.com/content/215222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From dark dragonflies becoming paler to plants flowering earlier, some species are slowly evolving with the climate. Evolutionary biologists explain why few will evolve fast enough.Michael P. Moore, Assistant Professor of Biology, University of Colorado DenverJames T. Stroud, Assistant Professor of Ecology and Evolution, Georgia Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163722023-11-16T10:12:57Z2023-11-16T10:12:57ZInsects are spreading a devastating plant disease in Italy – Britain must keep it out<figure><img src="https://images.theconversation.com/files/559575/original/file-20231115-27-9hc0jy.jpg?ixlib=rb-1.1.0&rect=0%2C486%2C3954%2C2134&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Olive trees that have died after becoming infected with _Xylella fastidiosa_.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dead-olive-trees-xylella-fastidiosa-1471805759">Fabio Michele Capelli/Shutterstock</a></span></figcaption></figure><p>Since 2013, over 20 million olive trees in Italy have succumbed to a <a href="https://www.bbc.com/future/article/20230111-the-super-sniffer-dogs-saving-italys-dying-olive-trees#:%7E:text=With%20its%2060%20million%20olive,which%20were%20several%20centuries%20old">devastating plant disease</a>. The same disease now threatens many more plant species, across several countries, with the same fate. </p>
<p>Our recent <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0291734">research</a> shows that the insect responsible for inadvertently transmitting the bacteria that cause this disease can feed on a vast number of different plant species. These include many herbaceous plants and trees that are commonly grown in gardens, parks and across the wider countryside in Britain.</p>
<p>During spring, gardeners will often wonder why blobs of spit-like foam have suddenly appeared on their favourite plants. Many will think them unsightly, perhaps even taking time to wash them off, only for the foam to appear again the next day. </p>
<p>This “spittle” is produced by an insect, unimaginatively called a spittlebug, whose juvenile stages immerse themselves in the foam in order to stop drying out and to protect themselves from predators.</p>
<figure class="align-center ">
<img alt="Meadow spittlebug spittle on the branches of Salix." src="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spittle produced by a spittlebug.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aphrophoridae-spittlebugs-family-insects-belonging-order-2000372249">Ihor Hvozdetskyi/Shutterstock</a></span>
</figcaption>
</figure>
<p>There are several species of spittlebug. But one in particular has been shown to smash several entomological records.</p>
<p>The <a href="https://en.wikipedia.org/wiki/Philaenus_spumarius">meadow spittlebug</a> (<em>Philaenus spumarius</em>) can jump with such force that it accelerates faster than any other animal, equivalent to an extraordinary <a href="https://journals.biologists.com/jeb/article/209/23/4607/16474/Jumping-performance-of-froghopper-insects">550 times</a> that of the Earth’s gravity. Even the toughest astronaut will die if faced with an acceleration <a href="https://www.sciencefocus.com/science/whats-the-maximum-speed-a-human-can-withstand">more than eight times</a> that of gravity.</p>
<p>These insects feed by sucking the sap out of plants. A typical adult meadow spittlebug will drink in and then excrete up to <a href="https://www.nytimes.com/2019/02/19/science/spittlebugs-bubble-home.html">200 times its body weight</a> of fluid per day: another record, and the equivalent of an average human excreting 13,000 litres each day. </p>
<p>Most recently, our research has found that this insect has far broader tastes than any other insect known to science; it can feed on over 1,300 species of plant.</p>
<h2>Why does this matter?</h2>
<p>The meadow spittlebug can transmit a bacterium called <em>Xylella fastidiosa</em> that is potentially deadly for the plants on which it feeds. When the spittlebug uses its syringe-like mouthparts to suck out the plant’s sap, the bacteria can get into the tubes that draw fluids up from the roots. Once there, the bacteria proliferate and block these tubes, starving the plant of water. </p>
<p>The symptoms of infection include scorched or stunted leaves. But, as these symptoms can be confused with several other plant problems, such as dehydration, a definitive diagnosis is difficult. To complicate matters further, some infected plants do not show any symptoms, at least not immediately, making them undetected reservoirs of the bacteria.</p>
<p>The bacteria have caused problems on an epic scale in <a href="https://apsjournals.apsnet.org/doi/epdf/10.1094/PHYTO-08-18-0319-FI">Apulia</a>, Italy’s premier olive-growing region. Entire groves of ancient olive trees have died or have been deliberately destroyed to stop the spread of this devastating plant disease.</p>
<p>The <a href="https://food.ec.europa.eu/plants/plant-health-and-biosecurity/legislation/control-measures/xylella-fastidiosa/database-susceptible-host-plants_en">list of plant species</a> that are known to be susceptible to this disease is long and growing. It already includes 690 species across 88 plant families, encompassing not just trees, but many popular garden plants, important horticultural crops and even some arable crops.</p>
<h2>Spittlebugs in Britain</h2>
<p>As part of our research, we asked members of the British public to send us their sightings of spittle. We received over 17,000 responses. Our results suggest that the insect is widespread in almost all British habitats, including gardens, and on an enormously diverse range of plants.</p>
<p>Fortunately, Britain and most of northern Europe are not yet in the grip of this plant disease. But the ubiquitous distribution of the spittlebug vector and its fondness for such a variety of different plants means that if the bacteria were ever accidentally introduced to Britain, it would be able to spread rapidly with potentially devastating consequences.</p>
<p>Scientists in Britain are anxiously watching for signs of any northward spread of the disease on the European continent. It originated in the Americas and was first detected in Apulia, Italy, in 2013, but it has since been <a href="https://www.efsa.europa.eu/en/topics/topic/xylella-fastidiosa#:%7E:text=Official%20surveys%20carried%20out%20by,How%20do%20plants%20become%20infected%3F">reported</a> in southern France, Spain and Portugal. Certain strains of the disease could certainly tolerate cooler northern temperatures, and their spread may be facilitated by our warming climate. </p>
<p><strong>The global distribution of <em>Xylella fastidiosa</em></strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A world map showing the distribution of xylella fastidiosa bacteria." src="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Xylella fastidiosa has not yet been detected in Britain.</span>
<span class="attribution"><a class="source" href="https://gd.eppo.int/taxon/XYLEFA/distribution">EPPO Global Database</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Stopping the spread</h2>
<p>Spittlebugs don’t fly very far so are unlikely to bring the disease into Britain themselves. The most likely entry route would be through plants brought in via the horticultural trade. </p>
<p>Historically, Britain has imported both lavender and olive trees from Italy. However, these plants now have to go through strict importation and quarantine <a href="https://planthealthportal.defra.gov.uk/assets/uploads/UK-Trade-Letter-Feb21-.pdf">controls</a>.</p>
<p>It is critically important that British holidaymakers in Mediterranean countries do not bring home live plant material of any kind. <em>Xylella fastidiosa</em> has not been detected in Britain so far, but the spittlebug’s extraordinarily broad taste in food shows that it would be extremely hard to control if it ever did arrive.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/216372/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Stewart received funding from the UK Biotechnology and Biological Sciences Research Council.</span></em></p><p class="fine-print"><em><span>Claire Harkin received funding from the UK Biotechnology and Biological Sciences Research Council</span></em></p><p class="fine-print"><em><span>Vinton Thompson receives funding from the Biotechnology and Biological Sciences Research Council. </span></em></p>The meadow spittlebug can transmit a deadly bacterium – many plants in Britain could be at risk.Alan Stewart, Professor of Ecology, University of SussexClaire Harkin, Research Associate in the Department of Evolution, Behaviour and Environment, University of SussexVinton Thompson, Research Associate in the Division of Invertebrate Zoology, American Museum of Natural HistoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2165442023-11-08T15:48:59Z2023-11-08T15:48:59ZFewer insects hitting your car windscreen? Here’s why<figure><img src="https://images.theconversation.com/files/556273/original/file-20231025-29-1hf6cd.jpg?ixlib=rb-1.1.0&rect=0%2C147%2C5463%2C3489&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/bugs-on-windshields-464974862">Leo Quintero / Shutterstock</a></span></figcaption></figure><p>Every summer for almost the last 20 years, volunteers from the <a href="https://www.kentwildlifetrust.org.uk/">Kent Wildlife Trust</a> and <a href="https://www.buglife.org.uk/">Buglife</a>, both in the UK, have been tracking car number plates. But not in the the way you might think. Their inspections aim to register the numbers of flying insects hit by vehicles. </p>
<p>Though this may seem insignificant, the scale of this citizen science project makes it important. With nearly 700 participants, the 2023 Bugs Matter campaign has taken data from 6,358 journeys, which can help to draw much wider conclusions.</p>
<p>The results of the <a href="https://cdn.buglife.org.uk/2022/12/Bugs-Matter-Summary-Report-2022-A4.pdf">2022</a> campaign showed a reduction, over fewer than 20 years, of 64% in the number of insects hit by cars. These results back up a thesis that is worrying scientists: this massive loss of insect life demonstrates that we are moving ever closer to the <a href="https://theconversation.com/climate-change-is-killing-off-earths-little-creatures-109719">sixth mass extinction</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1504427349017825280"}"></div></p>
<h2>The sixth mass extinction</h2>
<p>Unfortunately, studies show that the UK is not the only place where insect populations are declining; studies have been done across Europe that draw similar conclusions. In order to gain realistic measurements, the most rigorous research uses historical studies that track insect populations over decades. </p>
<p>In Germany, a <a href="https://doi.org/10.1371/journal.pone.0185809">27 year-long study was published in 2017</a> showing that 76% of flying insect biomass has been lost within a wide network of natural spaces. </p>
<p>In Denmark, <a href="https://doi.org/10.1002/ece3.5236">a reduction in the number of insects has been documented</a> alongside shrinking numbers of birds, such as the barn swallow, who feed on them. </p>
<p>The Spanish and Portuguese scientific societies of entomologists met in June of this year in Alicante for the <a href="https://xxcongresoie.entomologica.es/">Twentieth Iberian Congress of Entomology</a>. Alarmed by the decline of insect populations, they published a <a href="https://xxcongresoie.entomologica.es/cont/docs/ManifiestoXXCIE.pdf">manifesto</a> that aims to raise social awareness of this unprecedented situation, and to put a stop to it. </p>
<p>However, the situation is not only causing alarm in Europe, which is very densely populated and exposed to the pressures of human activity. Studies <a href="https://www.pnas.org/doi/epdf/10.1073/pnas.1722477115">from tropical forests in Puerto Rico</a> have compared current insect numbers with those of 36 years ago, with similarly catastrophic results: a reduction of over 78% in ground-dwelling insect biomass. This study also showed a parallel decline in animals that eat insects, such as lizards, frogs and birds. </p>
<h2>Why are there fewer insects?</h2>
<p>There are many causes, all stemming from the continuous, increasing deterioration of soil, vegetation, water and air due to human activities. </p>
<p>Insects have various needs. They need the ground that we cover with cement, the increasingly scarce water that we pollute or divert, and the plants that we treat with pesticides. What is more, we interrupt the means of communication that insects need to survive: light, chemical and air pollution all cause insects to become disoriented. Among other things, the number of airborne microscopic particles, which <a href="https://doi.org/10.1038/s41467-023-39469-3">block their sensory organs and ways of communicating</a>, are on the rise.</p>
<p>These are all occurring alongside <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecm.1553">climate change</a>, which is considered to be an important factor in declining insect populations in and of itself.</p>
<p>The loss of insect biodiversity leads to homogenisation. This weakens the vital biological relationships between all living things, and in turn threatens our very existence as a species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=412&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=412&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=412&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=517&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=517&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555870/original/file-20231025-23-36udad.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=517&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wasps play an essential role as pollinators.</span>
<span class="attribution"><a class="source" href="https://es.wikipedia.org/wiki/Archivo:Vespula_rufa_on_bupleurum_falcatum_Richard_Bartz.jpg">Richard Bartz / Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Why are they so important?</h2>
<p>Insects make up over 80% of the known animals in the world. It is therefore clear that they play many essential roles in sustaining life on Earth, most importantly that of pollinating plants. </p>
<p>35% of the world’s food supply <a href="https://doi.org/10.1016/j.cosust.2020.08.012">comes from plants that are pollinated by insects</a>. <a href="https://www.unep.org/resources/emerging-issues/we-are-losing-little-things-run-world">The UN Food and Agriculture Organsiation warns</a> that if they were to disappear, food security would be at risk.</p>
<p>Another irreplaceable role that insects play in ecology is that of decomposing organic matter and recycling nutrients. Insects act as natural garbage collectors and gardeners. In this way, they contribute to soil health and formation, a process essential to maintaining food chains and life cycles. </p>
<p>Another ecological function of insects – which often goes unnoticed – is their contribution to pest control in natural ecosystems, as they prevent or reduce pest damage. </p>
<p>Pest control by predators and parasitic insects in natural environments can actually teach us how to <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">improve biological control in agriculture</a>.</p>
<hr>
<p>
<em>
<strong>
Leer más:
<a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">The battle against bugs: it's time to end chemical warfare</a>
</strong>
</em>
</p>
<hr>
<h2>What can we do to protect them?</h2>
<p>Large scale environmental problems cannot be solved by the actions of individuals. However, experience shows us that lots of small gestures can add up to achieve big results. Some of the things we can do are:</p>
<ul>
<li><p>Support or work with projects that aim to raise awareness and protections for insects both in rural and urban areas. The aforementioned Kent Wildlife Trust and Buglife are good examples in the UK. In Spain we have the <a href="https://aeaelbosqueanimado.org/en/homepage/">SPIPOLL project</a>, the <a href="https://ubms.creaf.cat/en/the-observatory/">uBMS Citizens’ Butterfly Observatory</a> and the <a href="http://rerb.oapn.es/SF/">Spanish Network of Biosphere Reserves’ Phenological Monitoring Programme</a>.</p></li>
<li><p>Ensure that urban green spaces – as well as verges, roundabouts and other undeveloped areas – contain animal habitats and native flora which can provide breeding sites and refuge for insect species. </p></li>
<li><p>Refrain from using pesticides in private gardens or vegetable patches, and where possible in public green spaces. Limit the removal of “weeds” growing around ornamental plants, especially during flowering periods.</p></li>
<li><p>Consume food products made following good agricultural practices that value and promote organic farming and biological or integrated pest control.</p></li>
<li><p>Replace livestock pest control treatments with products that are not harmful to insects that help in the decomposition process. </p></li>
<li><p>Avoid introducing invasive plant or animal species, both in agriculture and gardening.</p></li>
</ul>
<p>All of us, in particular educators, have an important responsibility to show both children and adults that insects are noble, vital and beautiful. Their declining numbers are an unprecedented problem, and our very survival as a species is at stake if we cannot reverse this trend.</p><img src="https://counter.theconversation.com/content/216544/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Saioa Legarrea Imizcoz carries out her research at the University of La Rioja thanks to the European Union's Next Generation funding, articulated in the María Zambrano Call (Royal Decree 289/2021 of 20 April).</span></em></p><p class="fine-print"><em><span>María Ángeles Marcos García receives funding to carry out Scientific Projects from the Spanish Government, Autonomous Communities and Europe in which insects are studied from different conservationist themes (pollination, pest control, decomposers...).</span></em></p>The number of bugs on our windscreens has plummeted in recent years. Are we driving faster? Or are there fewer of them?Saioa Legarrea Imizcoz, Investigadora en Entomología Agrícola, Universidad de La RiojaMaría Ángeles Marcos García, Entomóloga, Catedrática de Universidad, Universidad de AlicanteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2160292023-10-25T16:02:13Z2023-10-25T16:02:13ZBed bugs are a global problem, yet we still know so little about how they spread<figure><img src="https://images.theconversation.com/files/555558/original/file-20231024-23-yod6s8.jpg?ixlib=rb-1.1.0&rect=26%2C5%2C3472%2C2323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sleep tight...</span> <span class="attribution"><span class="source">Dr Richard Naylor</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Bed bugs have recently <a href="https://www.cntraveller.com/article/paris-bed-bugs-everything-you-need-to-know">exploded into the limelight</a> amid widespread reports of a major outbreak in Paris. The more people share photos of bed bug bites on social media, the more concerned we feel. That’s understandable, but the really worrying thing is the missing information – there is still no publicly available data about the infestations in Paris. </p>
<p>Indeed, data that confirms or denies the location and date of <em>any</em> bed bug cases is notoriously hard to find. The vast majority of people around the world go to the private sector for pest control, but data from this sector is often classed as “commercially sensitive” and not usually shared for research purposes.</p>
<p>Although it is not clear if the scale of the problem in Paris is real or social media hype, one thing is true: bed bugs are not just in the French capital. In fact, they are present in <a href="https://digitalmedia.sheffield.ac.uk/media/Bedbugs/1_fk8ko3mw/69389871">almost all human settlements</a> – there have been reports of bed bugs living with humans since our history began, with remains found in <a href="https://www.researchgate.net/publication/234040076_Cimex_lectularius_L_the_common_bed_bug_from_Pharaonic_Egypt">ancient Egypt</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/15RGqICSrGA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Unlike a lot of other countries, the UK does at least have some data about bed bug infestations, as most local authorities <a href="https://www.gov.uk/report-pest-problem">do some bed bug control</a> for commercial and domestic infestations. They are a good source of data due to the powers of the UK’s <a href="https://ico.org.uk/for-organisations/foi-eir-and-access-to-information/guide-to-freedom-of-information/what-is-the-foi-act/#:%7E:text=The%20Freedom%20of%20Information%20Act%202000%20provides%20public%20access%20to,request%20information%20from%20public%20authorities.">Freedom of Information Act</a>.</p>
<h2>A seasonal spike</h2>
<p>I have researched the number of confirmed bed bug cases treated by local authorities in three major UK cities: Birmingham, Manchester and Sheffield. I used data on confirmed bed bug cases per month between 2009 and 2015, and ran this through a statistical model called a <a href="https://thedatalab.com/tech-blog/using-generalised-additive-mixed-models-gamms-to-predict-visitors-to-edinburgh-and-craigmillar-castles/">generalised additive mixed-effect model</a> (GAMM), which accounted for the size of each city and random variation between years. </p>
<p>The results showed a significant peak in bed bug cases around August and September each year (Figure 1), and also that bed bug numbers were steadily increasing (Figure 2). The same seasonal pattern and year-on-year increase was seen in the US city of Philadelphia between <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3955002/">2009 and 2011</a>, and <a href="https://academic.oup.com/jme/article/52/1/76/873440?login=true">in two Chinese cities in 2012/13</a>. In New York between 2010 and 2020, the seasonal pattern was the same but the numbers <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0268798">did not increase</a>.</p>
<p>More recent studies have looked at a region’s internet search history as a proxy for the prevalence of bed bug cases. When you find what you think is a bed bug, the first thing most people do is search the internet for answers. Studies <a href="https://academic.oup.com/jme/article/53/1/116/2459664?login=true">from the US</a> and <a href="https://www.jaad.org/article/S0190-9622(16)30092-5/fulltext">Australia</a> both found the same seasonal pattern in internet searches for bed bugs, although the pattern in Australia was the opposite to the northern hemisphere. </p>
<p>However, in order to tackle infestations, we need to understand more about these creatures. </p>
<h2>What we know about bed bugs</h2>
<p>Bed bugs are small, flightless insects that feed on human blood. There are several species, but the one most people know is called <em><a href="https://www.nhm.ac.uk/take-part/identify-nature/common-insect-pest-species-in-homes/bed-bug-cimex-lectularius-identification-guide.html">Cimex lectularius</a></em>. The Romans called them <em>Cimex</em>, which means bug. It was much later in 1758 that the natural historian Carl Linnaeus added “lectularius” to their name, meaning bed or couch. </p>
<p>Our blood is their main source of nutrition, but they will <a href="https://www.nhbs.com/monograph-of-cimicidae-hemiptera-heteroptera-book#:%7E:text=book%20Related%20titles-,About%20this%20book,which%20includes%20human%20bed%20bugs">feed on other animals</a> if they have to, including birds, pets and bats. Bed bugs have a complex gut microbiota, which helps them extract all the nutrients they need from our blood. </p>
<p>Juveniles require a blood meal in order to develop from one life stage to another – so, to become adult, each bed bug will need <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119171539.ch16">at least five blood meals</a>. Adult bed bugs, though, <a href="https://www.vdacs.virginia.gov/pdf/bb-biology1.pdf">can survive an entire year</a> without a meal. </p>
<p>They can’t fly. As you can imagine, walking doesn’t get them very far, but it does allow them to spread around apartment blocks. And bed bugs hitch-hike on humans to move greater distances, although scientists can’t agree about exactly how they do this – it’s one of the unanswered questions about their ecology. People assume they travel on luggage, but it’s never been proven. </p>
<p>My <a href="https://www.nature.com/articles/s41598-017-11850-5">previous work in 2017</a> proved for the first time that they aggregate in dirty clothes in the absence of humans. My team put bed bugs in corrugated filter paper in the centre of a room, with clean and dirty clothes evenly spaced around them. The bed bugs all left the filter paper, and made a beeline for the dirty clothes nearly every time. This might explain how they get into our suitcases when we are travelling. </p>
<h2>How to stop their spread</h2>
<p>If we could understand more about bed bug dispersal and spatial distribution, we would stand a better chance of stopping their spread. </p>
<p>New York, which suffered a major outbreak <a href="https://www.theguardian.com/world/2010/oct/21/bedbugs-invaded-new-york">in the 2010s</a>, has shown it’s possible to tackle bed bug numbers if the public and private sectors work together. Pest control agencies <a href="https://www.npmapestworld.org/default/assets/file/newsroom/magazine/2015/nov-dec_2015.pdf">published data showing the scale of the problem</a> and <a href="https://www.nyc.gov/html/om/pdf/2010/dm_07-28-10.pdf">submitted a report</a> to officials with their recommendations for dealing with the outbreak. </p>
<p>According to the same <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0268798">report that confirmed the 2010 outbreak</a>, bed bug numbers in New York are declining. The researchers believe this is because of the pest management policies New York officials introduced from 2010. </p>
<p>First, they launched a <a href="https://www.nyc.gov/site/doh/health/health-topics/bedbugs.page">non-emergency helpline</a> for the public to call if they found bed bugs. The city also passed a policy where, from 2010, landlords were required to <a href="https://www.nyc.gov/site/doh/health/health-topics/bedbugs-information-for-landlords-and-building-managers.page#:%7E:text=New%20York%20City%20lists%20bedbugs,units%20from%20getting%20infested%20again.">report bed bug infestations</a> to prospective tenants. Since 2017, landlords must report all units that have bed bug infestations both to the local authorities and any residents sharing the same building as the infestation. </p>
<p>The future for bed bugs is unclear. Those we see today <a href="https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2232-3">are resistant</a> to most pesticides, are <a href="https://www.terminix.com/bed-bugs/behavior/where-do-bed-bugs-live/#:%7E:text=Due%20to%20their%20small%20size,aid%20of%20a%20credit%20card.">masters of subterfuge</a>, and are not going anywhere. They have <a href="https://www.sciencedirect.com/science/article/pii/S0960982219304804">co-evolved with humans</a> – so our best option for reducing their impact on our lives is for researchers and pest control professionals to spend less time trying to kill them, and more time trying to understand how they function within our world. Maybe then, we will work out a way to limit or even remove them from our homes for good.</p><img src="https://counter.theconversation.com/content/216029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>William Hentley is affiliated with the University of Sheffield. He receives funding from the University of Sheffield.</span></em></p>The trouble is most countries don’t make bed bug infestation data available to researchers.William Hentley, Teaching Associate in Ecology, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2153352023-10-16T02:49:22Z2023-10-16T02:49:22ZFly season: what to know about Australia’s most common flies and how to keep them away<figure><img src="https://images.theconversation.com/files/553893/original/file-20231016-29-hgfpk6.jpg?ixlib=rb-1.1.0&rect=7%2C22%2C4987%2C3302&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-housefly-musca-domestica-2264882059">Shutterstock</a></span></figcaption></figure><p>As the days grow longer and temperatures climb, we’re greeted by a familiar chorus of buzzing. It’s fly season again. </p>
<p>This year is off to a bumper start, with <a href="https://www.9news.com.au/national/flies-sydney-influx-insects/ecb6696a-2aea-4da9-bc32-5f194ce2ea00">bush flies swarming beach-goers</a>, <a href="https://www.ashburton.wa.gov.au/news/residents-alerted-to-increased-march-fly-activity/1542">March flies on the march</a>, and <a href="https://www.portnews.com.au/story/8045459/virus-warning-as-mosquito-numbers-explode/">mosquitoes taking to the skies</a> en masse.</p>
<p>But with almost a million species worldwide and some 30,000 calling Australia home, the (<a href="https://media.bom.gov.au/releases/1177/warmer-and-drier-spring-forecast-after-warmest-winter-on-record/">unusually</a>) warm weather also presents an opportunity to appreciate these remarkable and essential insects with whom we share our world.</p>
<p>Despite their sheer diversity, we’re likely to encounter only a select few flies daily. So who are these curious insects, and how should we think about their presence in our lives?</p>
<h2>Familiar faces</h2>
<p><a href="https://en.wikipedia.org/wiki/Musca_vetustissima">Bush flies</a> (<em>Musca vetustissima</em>) are the iconic Australian fly, and are found country-wide. They slake their thirst on the sweat and tears of mammals and so linger around our heads, shoulders and faces in search of a refreshing drink. </p>
<p>They’re so persistent that they’re credited with inspiring the “<a href="https://en.wikipedia.org/wiki/Aussie_salute">Aussie salute</a>”. These small explorers are otherwise harmless, and pose no serious threat to health or home beyond being a mild nuisance. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a man in an Australian flag hat waving his hand in front of his face." src="https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553878/original/file-20231015-19-1l4j90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The ‘Aussie salute’ is a characteristic gesture of waving flies – specifically the persistent Australian bush flies – away from the face.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Aussie_salute#/media/File:Aussie_salute.jpg">Mick and Rortles / Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Similar in appearance are <a href="https://en.wikipedia.org/wiki/Housefly">house flies</a> (<em>Musca domestica</em>), which frequent our homes. Unlike bush flies, however, they’re more interested in scraps of food and waste left unprotected. They regurgitate digestive juices to break solids into a mush more amenable to their straw-like mouths, and can pose a minor hygiene concern as a consequence.</p>
<p><a href="https://en.wikipedia.org/wiki/Calliphoridae">Blowflies</a> bring some sparkle to the fly world, and are easily recognised by their often large, shiny bodies. Although sometimes a pest, they’re also voracious scavengers and effective pollinators. In this way they do their bit to break down organic matter, recycle nutrients, and transport pollen to support plant life.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a sparkly, metallic blue fly perched on a green leaf or stem." src="https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553895/original/file-20231016-21-m2xrcy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The golden bluebottle (Chrysomya incisuralis) is one of many species of Australian blowfly.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/australian-golden-bluebottle-blowfly-known-chrysomya-1676775739">Shutterstock</a></span>
</figcaption>
</figure>
<p>The sheer size of <a href="https://en.wikipedia.org/wiki/Tabanidae">horseflies</a> makes them powerful fliers, which can often be heard and seen at a distance. Females demand a blood meal and so pack a hearty bite to mammals, including us, and can be a nuisance to livestock. They are also, however, excellent pollinators, with <a href="https://doi.org/10.1016/j.sajb.2009.06.015">some orchids</a> relying on their hard work and specialised mouthparts for survival.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/does-zika-virus-pose-a-threat-to-australia-53557">Does Zika virus pose a threat to Australia?</a>
</strong>
</em>
</p>
<hr>
<p>Finally, and famously, are <a href="https://en.wikipedia.org/wiki/Mosquito">mosquitoes</a>. (Yes, they are a type of fly.) Many summer evenings are spent swatting females as they sip our blood. </p>
<p>More serious is their role as vectors for diseases that have <a href="https://doi.org/10.1641/B580812">helped to topple empires</a>, and which remain a significant health burden, especially in the Global South. <a href="https://doi.org/10.1016/S0140-6736(12)60034-8">Malaria</a> is among the farthest-reaching, while <a href="https://www.cdc.gov/ross-river-virus/healthcareproviders/">Ross River Virus</a>, <a href="http://www.cdc.gov/chikungunya/">chikungunya</a>, <a href="https://theconversation.com/does-zika-virus-pose-a-threat-to-australia-53557">zika</a> and <a href="http://www.cdc.gov/dengue/">dengue</a> all circulate with help from mosquitoes.</p>
<h2>Shoo fly?</h2>
<p>For the minority of flies that prove a recurring annoyance, the primary goal is to deter rather than kill them. In this case, the remedies are simple:</p>
<ul>
<li>use topical repellents containing DEET or Picaridin, and wear loose-fitting clothing when outside</li>
<li>install flyscreens in the house, and check them regularly for holes</li>
<li>keep your food covered, both at home and when out enjoying the warm weather</li>
<li>empty your bins regularly and minimise standing water, both of which can attract unwanted attention.</li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">The battle against bugs: it's time to end chemical warfare</a>
</strong>
</em>
</p>
<hr>
<p>Avoid <a href="https://theconversation.com/the-battle-against-bugs-its-time-to-end-chemical-warfare-111629">reaching for the bug-bombs and sprays</a>, which have devastating impacts on beneficial insects. If a chemical last resort is required, choose selective sprays rather than broad-spectrum options such as pyrethroids and neonicotinoids, which kill the many good bugs with the few bad ones. </p>
<p>Similarly, those noise-emitting, electrified or smelly gadgets that promise a fly-free existence are best avoided, as most are either <a href="https://theconversation.com/the-buzz-from-your-smartphone-wont-stop-mosquito-bites-92611">ineffective</a>, or harm far more than their intended targets.</p>
<h2>From pesky to paramount</h2>
<p>While our daily encounters with a handful of fly species may taint our perception of the group as a whole, such a view is both unwarranted and unjustified. Flies are among the most diverse animals on the planet, and are utterly crucial for the healthy function of our ecosystems.</p>
<p>Many, like <a href="https://en.wikipedia.org/wiki/Hover_fly">hover flies</a>, are important pollinators. In an era of pollinator declines and <a href="https://www.fao.org/documents/card/en/c/cc3017en">heightened food insecurity</a>, their ongoing work is <a href="https://doi.org/10.1080/14888386.2008.9712892">key to supporting agricultural production</a>, and plant life more generally. </p>
<figure class="align-center ">
<img alt="A photo of a skinny black fly sitting in the middle of a yellow and pink flower." src="https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553897/original/file-20231016-23-cxxzcl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The larvae of the black soldier fly (Hermetia illucens) are highly effective decomposers, eating twice their own bodyweight every day.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Hermetia_illucens#/media/File:Hermetia_illucens_MHNT_Fronton.jpg">Didier Descouens / Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>On the other side of the circle of life are outstanding decomposers, such as <a href="https://en.wikipedia.org/wiki/Hermetia_illucens">black soldier flies</a>. Each individual larva can eat twice its bodyweight daily, which at the scale of tens of thousands of grubs presents a promising pathway towards sustainable waste management. They are also a rich source of protein for livestock, <a href="https://theconversation.com/food-for-thought-feeding-our-growing-population-with-flies-64374">or even humans</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/food-for-thought-feeding-our-growing-population-with-flies-64374">Food for thought: feeding our growing population with flies</a>
</strong>
</em>
</p>
<hr>
<p>Just as a very few flies are pests, many serve as remedies in their role as biological controls. The 10,000-odd species of <a href="https://en.wikipedia.org/wiki/Tachinidae">tachinid</a>, or example, make a living as parasitoids of other insects. That is, they lay their eggs inside, and eventually kill, the developing young of others, which include pest caterpillars, flies and bugs.</p>
<p>Moreover, flies have proven invaluable in <a href="https://theconversation.com/trust-me-im-an-expert-forensic-entomology-or-what-bugs-can-tell-police-about-when-someone-died-124416">forensics</a>, <a href="https://doi.org/10.1038/35042080">medicine and scientific research</a>, and <a href="https://doi.org/10.3389/fenvs.2023.1146052">environmental monitoring</a>, underscoring how deeply our lives intertwine with theirs. </p>
<h2>Fly on</h2>
<p>As the warm weather rolls around, then, take the opportunity to look a little closer at our nimble neighbours, and consider both their <a href="https://dx.doi.org/10.1111/j.1469-185X.2007.00018.x">staggering diversity</a> and the vital roles they humbly fill. The natural world – us included – would not be the same without them.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trust-me-im-an-expert-forensic-entomology-or-what-bugs-can-tell-police-about-when-someone-died-124416">Trust Me, I'm An Expert: forensic entomology, or what bugs can tell police about when someone died</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/215335/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas White receives funding from The Australian Research Council, Agrifutures, and the Hermon Slade Foundation. He is also affiliated with the conservation charity Invertebrates Australia. </span></em></p><p class="fine-print"><em><span>Tanya Latty receives funding from the Australian Research Council and AgriFutures Australia. She is affiliated with conservation organisation Invertebrates Australia and is president of the Australasian Society for the Study of Animal Behaviour. </span></em></p>Early warm weather has triggered a bumper season for Australia’s 30,000 fly species.Thomas White, Senior lecturer, University of SydneyTanya Latty, Associate professor, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2150622023-10-10T19:04:09Z2023-10-10T19:04:09ZEarly heat and insect strike are stressing urban trees – even as canopy cover drops<figure><img src="https://images.theconversation.com/files/552275/original/file-20231005-17-de8trl.jpg?ixlib=rb-1.1.0&rect=27%2C0%2C4573%2C3449&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Have you noticed street trees looking oddly sad? You’re not alone. Normally, spring means fresh green leaves and flowers. But this year, the heat has come early, stressing some trees. </p>
<p>But there’s more going on – insects are on the march. Many eucalypts are showing signs of lerp or <a href="https://ipm.ucanr.edu/PMG/PESTNOTES/pn7423.html">psyllid</a> attack. These insects hide underneath leaves and build little waxy houses for themselves. But as they feed on the sap, they can give the leaves a stressed, pinkish look. When they appear in numbers – as they are this year – they can defoliate a whole tree with a serious infestation. </p>
<p>How did we get here? Milder, wetter summers during three successive La Niña years mean boomtime for insects. This year, we’ve had a warm winter and a warm spring, meaning insects are up and about early and in large numbers.</p>
<p>This summer <a href="http://www.bom.gov.au/climate/enso">will be an El Niño</a>, which usually means drier and hotter weather for most of Australia. For those of us interested in urban trees, these conditions are troubling. </p>
<p>But it’s more than that. The fact our urban trees are in danger should tell us something – we need to value and protect them better. As the world heats up, our urban forests will be <a href="https://theconversation.com/we-need-urban-trees-more-than-ever-heres-how-to-save-them-from-extreme-heat-211414">even more at risk</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="lerp insects sucking sap gum tree" src="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lerps and psyllid sap-sucking insects can stress or even kill a tree.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What’s different this year?</h2>
<p>In most years, insect infestations arrive later. That gives trees time to produce a flush of new growth. As a result, they’re rarely lethal. Trees can put out more leaves and recover. </p>
<p>But this year, they’re attacking early and in numbers. It also makes it more likely we’ll see more and more infestations over a long summer. End result: stressed trees, and even deaths from sap-sucking and other insect damage.</p>
<p>That’s not ideal for us either. In an El Niño summer, we’ll likely face hotter days. This year is unusually hot, due to unchecked climate change. The heatwaves to come could make us sick, hospitalise us, or even kill. </p>
<p>Urban trees are <a href="https://www.epa.gov/heatislands/using-trees-and-vegetation-reduce-heat-islands">one of our best methods</a> of protecting ourselves. Suburbs with greater tree canopy cover are significantly cooler. Trees shade the ground and their foliage emits water, which cools the air. Good canopy cover can cut temperatures by up to 6°C. </p>
<p>So, it’s not good news for us that our urban trees are looking stressed. Worse is the fact that our urban tree canopy is actually declining, due to bad urban planning of new suburbs with no space for canopy trees coupled with tree loss from subdivisions or apartment builds. Our state governments <a href="https://vpa.vic.gov.au/project-subpage/key-ideas-review-of-guidelines/greener-and-cooler-environments/">talk about this</a> in their planning documents, but efforts to correct the problem don’t seem to be working. </p>
<p>What happens in hot summers with fewer trees? More air conditioner use, sending energy demand and electricity bills soaring. </p>
<p>We can hope this summer <a href="https://theconversation.com/here-are-5-practical-ways-trees-can-help-us-survive-climate-change-129753">acts as a wake up call</a> about the importance of healthy urban trees as we head into ever-hotter years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/here-are-5-practical-ways-trees-can-help-us-survive-climate-change-129753">Here are 5 practical ways trees can help us survive climate change</a>
</strong>
</em>
</p>
<hr>
<h2>What can you do for your trees?</h2>
<p>It’s worth <a href="https://theconversation.com/running-out-of-things-to-do-in-isolation-get-back-in-the-garden-with-these-ideas-from-4-experts-134229">looking after your own trees</a> in anticipation of the tough summer ahead. </p>
<p>As soils are already drying out, keep up the moisture and add quality mulch under trees to a good depth. </p>
<p>The longer you can keep them healthy and stress free, the more likely trees are to be able to cope with the summer stress and insect attacks. </p>
<p>If water restrictions are imposed in your town or city, it’s likely irrigating trees and gardens will be the first activity restricted. </p>
<p>If your plants have been kept stress free as long as possible, they are more likely to survive. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-urban-trees-more-than-ever-heres-how-to-save-them-from-extreme-heat-211414">We need urban trees more than ever – here's how to save them from extreme heat</a>
</strong>
</em>
</p>
<hr>
<p>An irony here is that if trees are water-stressed, many species will start to defoliate by shedding leaves. That means we lose both shade and transpirational cooling when we could use them most. </p>
<p>Councils, state governments and water authorities face a dilemma in these situations. Save the water for human use? Or keep urban trees alive and reduce the risk of heat illness and death? </p>
<h2>Time to value our urban trees</h2>
<p>What this summer will show is the need for local and state governments to place greater value on their urban forests and canopy cover. </p>
<p>In many places, urban canopy cover is dropping by <a href="https://treenet.org/resource/taking-it-to-the-streets-celebrating-a-twenty-year-history-of-treenet-responding-to-the-urban-forest-challenge/">about 1-1.5% per year</a>. Many tree removals are <a href="https://treenet.org/resource/defending-and-expanding-the-urban-forest-opposing-unnecessary-tree-removal-requests/">thoughtless and unnecessary</a>. </p>
<p>Sometimes, these losses provoke outcry. Adelaide, for instance, <a href="https://www.abc.net.au/news/2022-12-02/adelaide-tree-canopy-subject-of-new-parliamentary-inquiry/101723682">has been losing</a> an estimated 75,000 trees a year in recent years. That prompted a <a href="https://www.jaynestinson.com.au/news/2022/12/4/media-release-parliamentary-inquiry-into-the-urban-forest#:%7E:text=A%20Parliamentary%20inquiry%20has%20been,severe%20in%20Adelaide's%20inner%20suburbs">parliamentary inquiry</a> into how to better protect urban forests. </p>
<p>For things to change for the better, our local governments need the ability to protect mature trees in the front and back yards of developed sites and to set out minimum areas of green space and numbers of canopy trees for new developments. </p>
<p>In most states, giving councils these powers would require changes to state planning laws. But without them, the urban forest and canopy cover of most major cities, regional centres and country towns will continue to decline. </p>
<p>With proper planning, we can have both new housing and canopy trees. If we simply aim to maximise housing, our towns and suburbs will be economically and environmentally unsustainable. </p>
<p>So when you see sick trees on our streets this spring, see them as a symptom. We need to value them. We would most certainly notice if they were gone. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/urban-patchwork-is-losing-its-green-making-our-cities-and-all-who-live-in-them-vulnerable-187161">Urban patchwork is losing its green, making our cities and all who live in them vulnerable</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/215062/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s spring, but many street trees look stressed and sick. Heat and insect attack are arriving early. But our cities are also steadily losing canopy cover.Gregory Moore, Senior Research Associate, School of Ecosystem and Forest Sciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.