tag:theconversation.com,2011:/au/topics/pollen-7388/articlesPollen – The Conversation2024-03-27T13:27:00Ztag:theconversation.com,2011:article/2257282024-03-27T13:27:00Z2024-03-27T13:27:00ZHoney is said to help with hay fever symptoms – here’s what the research says about this claim<figure><img src="https://images.theconversation.com/files/584039/original/file-20240325-22-41zped.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5742%2C3828&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Recent investigations into honey's allergy-alleviating potential have yielded intriguing results.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/positive-young-woman-honey-kitchen-1009425373">Africa Studio/ Shutterstock</a></span></figcaption></figure><p>Honey has a long history as a revered natural remedy across many cultures. Ancient civilisations recognised its therapeutic potential, employing it for various medicinal purposes. The ancient Egyptians, Assyrians, Chinese, Greeks and Romans, for instance, used it to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758027/#:%7E:text=of%20natural%20honey-,Human%20use%20of%20honey%20is%20traced%20to%20some%208000%20years,of%20the%20gut%20(12).">heal wounds</a>. And many cultures today continue to use it as a remedy for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5424551/">sore throats and coughs</a>.</p>
<p>Some people also assert that honey can alleviate hay fever symptoms. Advocates of this method claim honey can help thanks to its purported <a href="https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2020.599080/full">anti-inflammatory and anti-allergic properties</a> (though empirical evidence for this is lacking).</p>
<p>But what does science actually say about this <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758027/">age-old remedy</a>? Recent investigations into honey’s potential for <a href="https://core.ac.uk/download/pdf/48853226.pdf">alleviating hay fever</a> symptoms have yielded <a href="https://www.annsaudimed.net/doi/full/10.5144/0256-4947.2013.469">intriguing findings</a> that certainly warrant further exploration. </p>
<p>One fascinating aspect being investigated is honey’s ability to act as a form of <a href="https://core.ac.uk/download/pdf/48853226.pdf">immunotherapy</a> – a treatment strategy that aims to modify the immune system’s response to allergens.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/books/NBK279487/">Immunotherapy</a> involves exposing the immune system to gradually increasing doses of allergens, such as pollen, in a controlled manner. This exposure helps <a href="https://www.sciencedirect.com/science/article/pii/S108112062031214X">desensitise the immune system over time</a>, reducing its hypersensitivity and lessening allergic reactions. </p>
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Read more:
<a href="https://theconversation.com/hay-fever-how-immunotherapy-can-help-sufferers-not-getting-relief-from-the-usual-treatments-204945">Hay fever: how immunotherapy can help sufferers not getting relief from the usual treatments</a>
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<p>For instance, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6074882/">one study</a> found that people who consumed local honey daily for four weeks alongside an allergy tablet had significant improvements in their hay fever symptoms compared to those who only took an allergy tablet.</p>
<p>Honey’s <a href="https://link.springer.com/article/10.1186/s12906-020-03170-5">anti-inflammatory properties</a> are of considerable interest when it comes to hay fever. Honey contains various bioactive compounds, including <a href="https://www.sciencedirect.com/science/article/pii/S0271531710001715?casa_token=SA2rSuXhWicAAAAA:SfwGGe6S1RS4zsbSzWtiTwqLkvVzJMxKDYyRiGyHKTIrEfSvQz7mrO1VjfILxhXZvWOiwyXUHyc">flavonoids and phenolic acids</a>, which exhibit anti-inflammatory effects. These compounds work by preventing inflammation in the body, which may help reduce many of the symptoms caused by an allergic reaction (such as a stuffy or runny nose).</p>
<p>Honey also boasts a <a href="https://www.sciencedirect.com/science/article/pii/S096399692031111X?casa_token=lkdrP9Isd7cAAAAA:GGAlThdW4PL0Uhe9tHgvqoxxtqWaYDYgprpW-g6yVJT-U-_tceJEV3dF_sLpim8eeEIzMesN_M8">rich array of antioxidants</a>, such as polyphenols. These antioxidants scavenge harmful free radicals – unstable molecules that may damage cells and trigger inflammation. By neutralising free radicals, honey may help protect cells and tissues from damage, reducing allergic inflammation (and allergy symptoms).</p>
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<img alt="A young girl standing outside in a field of flowers holds a jar and a spoonful of honey." src="https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584041/original/file-20240325-16-zvddmg.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">
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<span class="caption">Certain types of honey may be more beneficial than others.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/child-eats-honey-summer-photo-selective-1786699142">Tatevosian Yana/ Shutterstock</a></span>
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<p>Honey also has prebiotic characteristics, which may further explain their potential in managing hay fever symptoms. Prebiotics are substances that promote the growth and activity of beneficial gut bacteria, enhancing gut health. Emerging evidence suggests that <a href="https://www.frontiersin.org/articles/10.3389/fnut.2022.957932/full">honey’s prebiotic properties</a> may change the composition and function of the gut microbiota.</p>
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Read more:
<a href="https://theconversation.com/hay-fever-could-be-linked-to-our-gut-and-nose-bacteria-and-probiotics-may-help-symptoms-203855">Hay fever could be linked to our gut and nose bacteria – and probiotics may help symptoms</a>
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<p>A healthy gut microbiota is essential for <a href="https://www.mdpi.com/2304-8158/11/14/2102">maintaining a balanced immune system</a> and preventing aberrant immune responses – including allergic reactions. By promoting the growth of beneficial gut bacteria and bolstering gut function, honey may indirectly influence how severely we react to seasonal pollen.</p>
<h2>What to consider</h2>
<p>Not all honey is created equal. Where it’s sourced and how it’s processed may affect its <a href="https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.642836/full">therapeutic potential</a>. </p>
<p>Raw honey, which undergoes minimal processing and retains more of its natural compounds, is often favoured for its potential health benefits.</p>
<p>Honey’s composition can also vary depending on the types of plants visited by the bees. Monofloral honey, derived primarily from the nectar of a single plant species, may contain <a href="https://www.sciencedirect.com/science/article/pii/S0271531702004062?casa_token=BkuFSyKQ8fQAAAAA:IkGedKDhNQpx03zchlKjkbvIjEacHhCyqC_H-7BarkV_VMnyBKq2rpOI1_RQH0q8GXfL0ux_SrA">specific compounds</a> that offer therapeutic advantages over polyfloral varieties (derived from multiple plant species). </p>
<p>If you’re thinking about using honey to help with your hay fever symptoms, it’s important to take into account certain practical considerations and exercise caution.</p>
<p><a href="https://www.annsaudimed.net/doi/full/10.5144/0256-4947.2013.469">Research recommends</a> consuming 1g of honey per kilogram of body weight each day in order to have any affect. For a person weighing 80kg, this would translate to four tablespoons of honey daily. Studies also recommend taking honey <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870997/">before and throughout</a> hay fever season in order to have the most benefit on symptoms.</p>
<p>It’s important to note that honey may not be suitable for everyone. Children under the age of one should not consume honey due to the <a href="https://accpjournals.onlinelibrary.wiley.com/doi/abs/10.1592/phco.22.16.1479.33696?casa_token=YuEegd3p17MAAAAA:JW_bI1PQQsVXBClNRnrl9VHrxXDLlgVDUMmhMeaE2zixEkgEuF-C7AQxLPVg0DvVFPA6xGCij-4HdGvy">risk of botulism</a>, a rare but serious illness. People with severe hay fever or asthma should speak with their GP before using honey, as <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1398-9995.1992.tb02248.x">allergic reactions</a> to bee products can be severe.</p>
<p>While honey shows promise in managing hay fever symptoms, it should complement, rather than replace, <a href="https://www.nhs.uk/conditions/hay-fever/">conventional therapies</a> prescribed by your doctor since it may not work equally well for everyone. If you’re experiencing severe hay fever symptoms, it’s unlikely honey will provide sufficient relief.</p><img src="https://counter.theconversation.com/content/225728/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 organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Honey has long been used as a natural remedy for many ailments.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2184072023-12-05T12:39:03Z2023-12-05T12:39:03ZChristmas tree syndrome: why the festive evergreen can make your nose run – and what you can do about it<figure><img src="https://images.theconversation.com/files/563330/original/file-20231204-29-cia24o.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5760%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These health issues are trigged by the allergens that normally reside in live Christmas trees.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/ruined-christmas-holidays-young-handsome-man-2221562955">voronaman/ Shutterstock</a></span></figcaption></figure><p>Decorating the Christmas tree is a beloved tradition for many of us during the festive season. While some people prefer using and reusing an artificial tree as an environmentally friendly way to enjoy the holiday spirit, others hunt instead for the perfect real tree to adorn with ornaments and cluster presents around.</p>
<p>But some people who decide to get a real tree may find that after it has been decorated they begin to experience cold-like symptoms. While many may simply chalk these symptoms up to having caught a cold – or even COVID – the culprit may actually be a little-known condition called <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">Christmas tree syndrome</a>. </p>
<p>Christmas tree syndrome encompasses a spectrum of health issues triggered by exposure to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">allergens residing on live Christmas trees</a>. For those who are sensitive to allergens, prolonged exposure to live Christmas trees can lead to <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780128045435000075">respiratory</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930903/">skin health issues</a>.</p>
<p>The <a href="https://www.thermofisher.com/allergy/gb/en/living-with-allergies/understanding-allergies/is-christmas-tree-allergy-making-you-sick.html">main symptoms</a> of Christmas tree syndrome include a stuffy or runny nose, sneezing, irritated eyes, coughing, wheezing and itchy throat. Asthma symptoms may also worsen. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0105-1873.2005.00495.x">Skin-related symptoms</a> may include redness, swelling, and itching.</p>
<p>This phenomenon happens thanks to the ecology of live trees, which carry microscopic entities – including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">pollen and fungi</a>. Pollen, a notorious outdoor allergen, may hitch a ride into our homes, while fungi find a cosy haven in cold, damp Christmas tree farms and garden centres.</p>
<p>Live Christmas trees can also carry mould. Notably, a single Christmas tree can host more than <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">50 species of mould</a>, creating a habitat for these tiny yet potentially troublesome organisms. Many of the mould varieties found on trees are those <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">most likely to trigger allergies</a>, including <em>Aspergillus</em>, <em>Penicillium</em>, and <em>Cladosporium</em>.</p>
<p>Researchers have also <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext#back-bib3">closely measured mould counts</a> in rooms containing live Christmas trees. During the first three days the tree is indoors, mould spore counts measure about 800 spores per cubic meter of air. On the fourth day, however, spore counts begin rising – eventually reaching 5,000 spores per cubic meter within two weeks.</p>
<p>Mould grows best in <a href="https://health.uconn.edu/occupational-environmental/wp-content/uploads/sites/25/2015/12/mold_guide.pdf">warm, wet and humid conditions</a>. So when the tree is brought indoors, the warmer climate <a href="https://medcraveonline.com/MOJI/MOJI-02-00045.pdf">significantly increases</a> mould production. </p>
<p>Pine pollen is not a major issue for allergy-sufferers when it comes to Christmas trees. But Christmas trees can come into contact with <a href="https://www.sciencedirect.com/science/article/abs/pii/S0021870730901050">other known allergens</a> while they’re growing, which can then be carried into the house. For example, grass pollen can stick to the sap in a Christmas tree during the spring. Then, when the tree is harvested and brought indoors, the sap dries out, and the trapped pollen particles are released into the air.</p>
<h2>Managing symptoms</h2>
<p>Certain people are at higher risk of experiencing Christmas tree syndrome. People with asthma or chronic obstructive pulmonary syndrome (COPD) may be more sensitive to allergens – and these allergens may also exacerbate symptoms such as coughing and wheezing.</p>
<p>People who suffer from allergies are also at greater risk – with research showing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">7% of allergy-sufferers</a> experienced a spike in symptoms when they had a Christmas tree in their home. People with skin issues (such as contact dermatitis and itching) may also find that their symptoms worsen around fresh Christmas trees.</p>
<p>Timely recognition of symptoms is crucial to mitigate the impact of Christmas tree syndrome. So if you do suffer from allergies, here’s what you can do:</p>
<ol>
<li><p><strong>Select your tree carefully:</strong> Opt for varieties with lower allergenic potential. Fir trees, such as Douglas and Fraser, are known for producing fewer allergens compared to <a href="https://www.cabdirect.org/cabdirect/abstract/19700607118">spruce or pine</a>. </p></li>
<li><p><strong>Inspect your tree:</strong> Conduct a <a href="https://www.annallergy.org/article/S1081-1206(10)60670-9/fulltext">meticulous inspection for signs of fungi</a> before bringing the tree indoors. Focus on areas where moisture may accumulate, as damp conditions foster mould growth. The most common mould found on Christmas trees is <em>Aspergillus</em>, which will look black on the surface and usually white-ish or yellow underneath.</p></li>
<li><p><strong>Proper maintenence:</strong> <a href="https://www.entandallergyspecialists.com/uncategorized/can-christmas-trees-cause-allergy-symptoms/">Regularly water live trees</a> to prevent dehydration, as this can lead to mould growth. A well-hydrated tree is also less likely to harbour fungus. And since warm, moist environments increase mould growth, try to keep your house ventilated while it’s up. You might even consider using a dehumidifier to decrease moisture levels in your home.</p></li>
<li><p><strong>Minimise direct contact:</strong> Try to avoid too much direct contact when decorating the tree. Wearing gloves might be one may of reducing the risk of skin-related reactions.</p></li>
<li><p><strong>Go artificial:</strong> Consider artificial trees as a <a href="https://jamanetwork.com/journals/jama/article-abstract/662569">practical alternative</a>. These eliminate the risk of allergens and can be reused – reducing their environmental impact. </p></li>
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<p>Christmas tree syndrome can be a nuisance. But by considering the science and taking precautions, you can ensure an enjoyable and allergen-free festive season.</p><img src="https://counter.theconversation.com/content/218407/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 organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People who usually suffer from allergies are most at risk.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2157932023-10-30T06:08:22Z2023-10-30T06:08:22ZWe could see thunderstorm asthma in south-eastern Australia this season – here’s how to prepare<figure><img src="https://images.theconversation.com/files/556014/original/file-20231026-21-hqekmc.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5982%2C3997&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/lighting-strikes-over-melbourne-victoria-2278570109">Ruben Fino/Shutterstock</a></span></figcaption></figure><p>Victorians <a href="https://www.9news.com.au/national/victorians-warned-to-prepare-for-thunderstorm-asthma-season/e4fc9389-32d6-4bfc-a105-8e9d450d9097">have been warned</a> to prepare for the possibility of thunderstorm asthma again this season. </p>
<p>In temperate regions of Australia, thunderstorm asthma occurs when levels of grass pollen in the air are high, and when thunderstorm fronts pass over grass pollen sources. The weather conditions we see with a thunderstorm, including stormy winds and moisture, can break up pollen into particles small enough to enter the airways. </p>
<p>Thunderstorm asthma events have been noted all over the world, but the most severe ever reported was <a href="https://pubmed.ncbi.nlm.nih.gov/29880157/">in Melbourne on November 21, 2016</a>. In one night almost 3,500 people sought emergency care and ten people died.</p>
<p>While we don’t have reason to expect we’ll see another emergency at this scale, a longer than usual <a href="https://www.canberratimes.com.au/story/8382447/long-pollen-season-prompts-thunderstorm-asthma-warning/">grass pollen season</a> suggests a risk of thunderstorm asthma in southern Australia this year. </p>
<p>At the time of writing, on <a href="https://www.miragenews.com/high-thunderstorm-asthma-forecast-for-west-1113262/">Monday October 30</a>, west and south Gippsland was classified as being <a href="https://www.melbournepollen.com.au/">at high risk</a> of thunderstorm asthma. </p>
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<p>So who is at highest risk, and what’s the best way to prepare?</p>
<h2>A changing climate</h2>
<p>In Australia, most thunderstorm asthma events have occurred during <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194929">the peak grass pollen season</a> from the end of October through to early December. </p>
<p>With climate change we’re seeing significant increases in <a href="https://www.frontiersin.org/articles/10.3389/falgy.2021.705313/full">seasonal loads of airborne grass pollen</a>. Pollen production depends partly on rainfall. Rain preceding the pollen season generally makes grasses grow more, driving up airborne <a href="https://www.sciencedirect.com/science/article/pii/S0013935122010891">grass pollen levels</a> over the season. </p>
<p>Despite this El Niño year, <a href="http://www.bom.gov.au/climate/enso/">when rainfall is typically lower</a>, paradoxically, grass pollen levels in <a href="https://www.canberrapollen.com.au/news-events/how-grass-pollen-season-going-canberra/">Canberra</a> have been high early in the season. </p>
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Read more:
<a href="https://theconversation.com/pollen-does-more-than-make-you-sneeze-it-can-cause-thunderstorm-asthma-even-if-youre-not-asthmatic-190235">Pollen does more than make you sneeze. It can cause thunderstorm asthma, even if you're not asthmatic</a>
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<p>With <a href="https://www.sciencedirect.com/science/article/pii/S0034425722000979?via%3Dihub#f0005">shifts over time in the distribution</a> of the sorts of grasses that flower in cool season (temperate) and those that flower in warmer season (subtropical), grass pollen seasons may continue to change, potentially extending the timing and magnifying exposure.</p>
<p>However, these patterns aren’t necessarily predictable, so we need long-term, year-round pollen monitoring to track ongoing changes in Australian grass pollen seasons.</p>
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<img alt="Grass in a meadow." src="https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556015/original/file-20231026-24-hqekmc.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">
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<span class="caption">Grass pollen can trigger thunderstorm asthma.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blooming-grass-summer-meadow-macro-pollen-2314006571">Fire-n/Shutterstock</a></span>
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<h2>Who is most at risk?</h2>
<p>The <a href="https://www.sciencedirect.com/science/article/pii/S0954611117303517?via%3Dihub">main risk factor for thunderstorm asthma</a> is hay fever, a condition usually due to grass pollen allergy. Hay fever is common, affecting as many as <a href="https://www.aihw.gov.au/reports/chronic-respiratory-conditions/allergic-rhinitis-hay-fever/contents/allergic-rhinitis">one in five people</a> in Australia and causing symptoms including an itchy, runny and blocked nose and itchy eyes over the course of the pollen season. </p>
<p>Asthma is more common in people with hay fever and its symptoms include cough, wheeze, chest tightness and shortness of breath. Symptoms of <a href="https://asthma.org.au/triggers/thunderstorm-asthma/">thunderstorm asthma</a> are the same as for other asthma attacks.</p>
<p>However, many people who develop thunderstorm asthma won’t have <a href="https://www.sciencedirect.com/science/article/pii/S0954611117303517?via%3Dihub">had asthma before</a>.</p>
<p>That said, people with asthma and hay fever are at higher risk of thunderstorm asthma, particularly if they’re not taking asthma preventer medication regularly. </p>
<p>Our research indicates that people with hay fever with <a href="https://www.jacionline.org/article/S0091-6749(21)01689-4/fulltext">high levels of allergic antibodies</a> (allergen-specific IgE) to ryegrass pollen, one of the most common temperate grasses in the southern regions of Australia, are particularly at risk of thunderstorm asthma.</p>
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Read more:
<a href="https://theconversation.com/its-not-just-about-melbourne-why-we-need-a-national-approach-to-thunderstorm-asthma-69426">It's not just about Melbourne: why we need a national approach to 'thunderstorm asthma'</a>
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<h2>How to prepare</h2>
<p>People who are affected by hay fever, asthma or both should be particularly vigilant for thunderstorm asthma warnings.</p>
<p>Thunderstorm asthma alerts are available from the <a href="https://www.health.vic.gov.au/environmental-health/epidemic-thunderstorm-asthma-risk-forecast">Victorian Department of Health</a> or the <a href="https://www.melbournepollen.com.au/">Melbourne Pollen Count and Forecast</a>, and you can register for alerts <a href="https://www.health.nsw.gov.au/environment/factsheets/Pages/thunderstorm-asthma.aspx">in the Wagga Wagga region</a> in New South Wales. Local grass pollen information is also available for <a href="https://auspollen.edu.au/brisbane/">Brisbane</a>, <a href="https://www.melbournepollen.com.au/">Perth</a>, <a href="https://www.canberrapollen.com.au/">Canberra</a> and <a href="https://www.sydneypollen.com.au/">Sydney</a>. </p>
<p>If faced with a thunderstorm asthma warning, the first thing to do if you think you may be susceptible is to stay out of the weather. Remain indoors with the doors and windows closed, particularly during the windy period that precedes the actual storm. Don’t use air conditioners that bring air in from outside. </p>
<figure class="align-center ">
<img alt="A man sitting on a couch at home using an inhaler." src="https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556016/original/file-20231026-27-39d2cn.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">The symptoms of thunderstorm asthma are generally the same as regular asthma.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-asthma-asian-home-sitting-on-2132727539">voronaman/Shutterstock</a></span>
</figcaption>
</figure>
<p>The second thing – and you don’t need to wait for a warning to do this – is to ensure you have a plan to prevent and manage symptoms. This is something you can work out during a visit with your GP.</p>
<p>People with asthma should have a management plan which will usually include a prescribed preventer inhaler. It’s important to take preventer medications regularly as prescribed (even if you’re feeling well) and have reliever medication available at all times. </p>
<p>If you have <a href="https://www.allergy.org.au/patients/allergic-rhinitis-hay-fever-and-sinusitis">hay fever</a>, it’s similarly important to keep it well-managed. Regular use of a nasal steroid spray can help control underlying allergy processes.</p>
<p>Having a plan and treatment on hand is especially important for people who suffer from both hay fever and asthma.</p>
<p>Knowing the steps of asthma first aid and <a href="https://asthma.org.au/treatment-diagnosis/asthma-first-aid/">how to manage an asthma attack</a> is also important for patients and families. People experiencing severe symptoms such as difficulty breathing should call an ambulance or attend the nearest emergency department.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/3-ways-to-prepare-for-bushfire-season-if-you-have-asthma-or-another-lung-condition-214065">3 ways to prepare for bushfire season if you have asthma or another lung condition</a>
</strong>
</em>
</p>
<hr>
<p>On a broader scale, we need sustained, standardised pollen monitoring, forecasting and reporting at daily and seasonal time scales across Australia to document and predict changes in airborne pollen loads. </p>
<p>Currently, only Victoria has <a href="https://www.health.vic.gov.au/environmental-health/epidemic-thunderstorm-asthma-risk-forecast">a supported thunderstorm asthma warning system</a> in place. But New South Wales has also experienced <a href="https://erj.ersjournals.com/content/16/1/3">thunderstorm asthma events</a>, and outside of temperate regions, grass pollen exposure is associated with increased asthma presentations. A thunderstorm asthma event can overwhelm health-care resources, supporting the need for widespread pollen monitoring and alerts.</p><img src="https://counter.theconversation.com/content/215793/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janet Davies receives funding from the Australian Research Council (DP210100347; LP190100216) and the Department of Health and Aging for the National Allergy Centre of Excellence, and has received grants in the last five years from the National Foundation of Medical Research Innovation, Abionic SA Switzerland, NHMRC (GNT1116107), with co-contributions from Asthma Australia and Stallergenes Greer Australia Pty Ltd, and in kind support from Australian Society for Clinical Immunology and Allergy, Asthma Australia, Bureau of Meteorology, Commonwealth Scientific and Industrial Research Organisation, Stallergenes Greer Australia Pty Ltd, and Federal Office of Meteorology and Climatology MeteoSwiss, ARC (DP190100376; DP170101630), and Queensland Chief Scientist Citizen Science Grant. QUT owns relevant patents US PTO 14/311944 and AU2008/316301 issued. </span></em></p><p class="fine-print"><em><span>Jo Douglass has received funding from the MRFF to support research in Thunderstorm Asthma. She is employed as Director of Research at the Royal Melbourne Hospital and is Head, Department of Medicine at the University of Melbourne. In the past 5 years, she has received honoraria for educational presentations from Astra-Zeneca, GSK, Novartis & CSL. She has served on advisory boards for Sanofi-Aventis, Novartis, GSK, Astra-Zeneca, Immunosis and CSL. She has undertaken contracted or investigator-initiated research on behalf of: GSK, Novartis, Immunosis, AstraZeneca, Sanofi-Aventis, Grifols, CSL, BioCryst & Equilium. She has a personal shareholding in CSL in her superannuation. She is affiliated with the National Allergy Centre of Excellence. </span></em></p><p class="fine-print"><em><span>Joy Lee has received funding from Centre of Research Excellence in Treatable traits, Sanofi and GSK for presenting at educational meetings and travel grants. She is affiliated with the National Allergy Centre of Excellence.</span></em></p>If you’ve got hay fever, or asthma, or both, it’s important to make sure they’re well managed.Janet Davies, Respiratory Allergy Stream Co-chair, National Allergy Centre of Excellence; Professor and Head, Allergy Research Group, Queensland University of TechnologyJo Douglass, Respiratory Allergy Stream Co-chair, National Allergy Centre of Excellence; Professor of Medicine, The University of MelbourneJoy Lee, Respiratory Allergy Stream member, National Allergy Centre of Excellence; Associate Professor, School of Public Health and Preventive Medicine, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132692023-09-14T11:59:04Z2023-09-14T11:59:04ZPollen in pee: fossilised urine from a small African mammal helps us understand past environments<figure><img src="https://images.theconversation.com/files/547771/original/file-20230912-27-za8r9z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The lessons pollen can teach us are not to be sneezed at.</span> <span class="attribution"><span class="source">Elisa Manzati</span></span></figcaption></figure><p>If you are allergic to pollen, you are likely to curse the existence of these microscopic particles. You’re not alone: <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829390/#:%7E:text=Allergies%20on%20the%20Rise,people%20worldwide%20affected%20by%20asthma">up to 30%</a> of the world’s population suffers from hay fever, which is often driven by pollen allergies. Shifting global climates are likely to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829390/">push that figure even higher</a>.</p>
<p>However, pollen represents one of the most powerful tools to uncover the nature of past environmental change. </p>
<p>I am the head of the <a href="https://drlynnequick.com/nelson-mandela-palaeolab/">Palaeoecology Laboratory</a> at <a href="https://www.mandela.ac.za/">Nelson Mandela University</a> in South Africa. My research focuses on unravelling the secrets of ancient environments and ecosystems by examining fossil pollen grains. These tiny time capsules hold a wealth of information about the earth’s past. They help scientists to reconstruct ecosystems, track climate change and understand the evolution of plant life.</p>
<p>But it can be difficult to source pollen deposits in arid regions. That’s because such deposits are often found in large lakes, which are in short supply in southern Africa. That’s where an unlikely scientific ally enters the picture: the fossilised urine of a small mammal, the <a href="https://www.awf.org/wildlife-conservation/hyrax">rock hyrax</a> (South Africans call them “dassies”). </p>
<h2>Looking back</h2>
<p>Pollen grains are incredibly durable because they are made of an organic substance (called sporopollenin) that is very resistant to decay. Pollen is released into the air, often in large quantities, and can settle on surfaces like lakes, and become preserved in sediment deposits over thousands, or even millions, of years.</p>
<p>In the lab, we examine the pollen found in these deposits using a microscope. By identifying the different types of pollen grains found within the different layers (representing different time slices) we can reconstruct the area’s vegetation history. Plants grow under specific climatic conditions: for instance, desert plants can grow under low rainfall conditions whereas forest plants need high amounts of rainfall. So we can make inferences about the climate at the time that the pollen was incorporated into the deposit.</p>
<figure class="align-center ">
<img alt="A rather chubby small rodent with dark brown fur and protruding front teeth regards the photographer." src="https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547484/original/file-20230911-23-arxq3p.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">The fossilised urine of rock hyraxes helps in the study of pollen.</span>
<span class="attribution"><span class="source">Kiev Victor</span></span>
</figcaption>
</figure>
<p>As I’ve said, southern Africa’s arid climates mean there are very few large lakes in the region. This makes it a challenge to source deposits that adequately preserve pollen within them over long periods of time. That’s where <a href="https://www.sciencedirect.com/science/article/abs/pii/S0277379112003319">fossilised dassie urine</a> comes in. </p>
<p>These sticky deposits called “middens” accumulate in rock crevices in mountainous areas over thousands to tens of thousands of years and contain beautifully preserved pollen grains. As they also contain various other types of evidence (such as geochemical data) and can be accurately dated, they represent the most valuable archive of past climate data in southern Africa. The oldest middens we’ve worked with date back 50,000 years.</p>
<h2>Ancient sites</h2>
<p>The research my lab conducts, focusing on harnessing the power of the humble pollen grain and utilising unique archives such as hyrax middens, is strongly multidisciplinary. It draws together elements from botany, geography, geology, climatology and archaeology. </p>
<p>We are currently generating fossil pollen records from several sites within the Cape Fold Belt mountains of South Africa. For example, we have a midden sequence that covers the last 6,000 years from the Baviaanskloof in the Eastern Cape province. The fossil pollen from this sequence shows that there was a dramatic shift in vegetation about 3,300 years ago, driven by a large fire event and increased temperatures. We’re hoping to publish this research soon.</p>
<p>This information provides baselines of variability in natural systems and can help inform current conservation efforts within the Baviaanskloof, which is a biodiversity hotspot. </p>
<p><a href="https://www.africanpaleoscienceslab.org/fieldwork/capp">Another project</a> that we are involved in is centred on the archaeological excavation within South Africa’s southern Cape region at a site called Boomplaas Cave. By using the fossil pollen within hyrax middens found within the vicinity of Boomplaas Cave, we hope to provide the environmental context to the archaeological record which can help to decipher how early humans responded to climate change.</p>
<h2>And looking forward</h2>
<p>We are not only working within the realm of the past: as pollen is one of the main sources of allergies it is important to monitor the types and amounts of pollen currently present in the air we breathe. My lab is part of the <a href="https://pollencount.co.za/">South African Pollen Monitoring network</a> and we generate pollen data for the city of Gqeberha in the Eastern Cape province. </p>
<p>This initiative focuses on analysing pollen captured in the air across several different parts of South Africa and ensuring that this information is publicly available. This project is particularly important as, <a href="https://journals.co.za/doi/abs/10.10520/EJC21714">due to climate change</a>, pollen seasons are lengthening and <a href="https://www.immunology.theclinics.com/article/S0889-8561(20)30061-8/fulltext">allergenic pollen is increasing</a>.</p><img src="https://counter.theconversation.com/content/213269/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lynne Quick receives funding from the National Research Foundation of South Africa: African Origins Platform and
GENUS: DSI-NRF Centre of Excellence in Palaeosciences
</span></em></p>Pollen can become preserved in sediment deposits over thousands, or even millions, of years.Lynne Quick, Senior Research Fellow, Nelson Mandela UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2038372023-05-17T12:39:23Z2023-05-17T12:39:23ZBees can learn, remember, think and make decisions – here’s a look at how they navigate the world<figure><img src="https://images.theconversation.com/files/526312/original/file-20230515-24407-1yxhj8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2286%2C1560&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A bumblebee lands on the flowers of a white sloe bush. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/april-2022-saxony-anhalt-kathendorf-a-bumblebee-lands-on-news-photo/1240227459">Soeren Stache/picture alliance via Getty Images</a></span></figcaption></figure><p>As trees and flowers blossom in spring, bees emerge from their winter nests and burrows. For many species it’s <a href="https://theconversation.com/spring-signals-female-bees-to-lay-the-next-generation-of-pollinators-134852">time to mate</a>, and some will start new solitary nests or colonies. </p>
<p>Bees and other pollinators are essential to human society. They provide about one-third of the <a href="https://theconversation.com/a-bee-economist-explains-honey-bees-vital-role-in-growing-tasty-almonds-101421">food we eat</a>, a service with a global value estimated at <a href="https://doi.org/10.1038/nature20588">up to $US577 billion annually</a>.</p>
<p>But bees are interesting in many other ways that are less widely known. In my new book, “<a href="https://islandpress.org/books/what-bee-knows">What a Bee Knows: Exploring the Thoughts, Memories, and Personalities of Bees</a>,” I draw on my experience <a href="https://scholar.google.com/citations?user=tqms8REAAAAJ&hl=en">studying bees for almost 50 years</a> to explore how these creatures perceive the world and their amazing abilities to navigate, learn, communicate and remember. Here’s some of what I’ve learned.</p>
<h2>It’s not all about hives and honey</h2>
<p>Because people are widely familiar with honeybees, many assume that all bees are social and live in hives or colonies with a queen. In fact, only about 10% of bees are social, and most types don’t make honey.</p>
<p>Most bees lead solitary lives, digging nests in the ground or finding abandoned beetle burrows in dead wood to call home. Some bees are cleptoparasites, <a href="https://www.sciencefriday.com/articles/death-and-thievery-in-the-colony/">sneaking into unoccupied nests to lay eggs</a>, in the same way that cowbirds lay their eggs in other birds’ nests and let the unknowing foster parents <a href="https://madisonaudubon.org/blog/2018/8/9/into-the-nest-cowbirds-everybodys-favorite-villain">rear their chicks</a>.</p>
<p>A few species of tropical bees, known as vulture bees, survive by <a href="https://doi.org/10.1128/mBio.02317-21">eating carrion</a>. Their guts contain acid-loving bacteria that enable the bees to digest rotting meat. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CGWgbHdgmBB/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Busy brains</h2>
<p>The world looks very different to a bee than it does to a human, but bees’ perceptions are hardly simple. Bees are intelligent animals that <a href="https://doi.org/10.1016/j.anbehav.2016.05.005">likely feel pain</a>, remember patterns and odors and even <a href="https://doi.org/10.1242/jeb.01929">recognize human faces</a>. They <a href="https://doi.org/10.1006/nlme.1996.0069">can solve mazes</a> and other problems and use simple tools. </p>
<p>Research shows that bees <a href="https://doi.org/10.1016/j.cub.2020.12.027">are self-aware</a> and may even have a <a href="https://doi.org/10.1016/j.cub.2017.08.008">primitive form of consciousness</a>. During the six to 10 hours bees spend <a href="https://doi.org/10.7717/peerj.9583">sleeping daily</a>, <a href="https://doi.org/10.1016/j.neubiorev.2014.09.020">memories are consolidated</a> within their amazing brains – organs the size of a poppy seed that contain 1 million nerve cells. There are some indications that <a href="https://doi.org/10.1016/j.cub.2015.09.001">bees might even dream</a>. I’d like to think so. </p>
<h2>An alien sensory world</h2>
<p>Bees’ sensory experience of the world is markedly different from ours. For example, humans see the world through the primary colors of <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html">red, green and blue</a>. Primary colors for bees are <a href="https://doi.org/10.1007/978-3-642-71496-2_15">green, blue and ultraviolet</a>.</p>
<p>Bees’ vision is <a href="https://doi.org/10.1146/annurev.ento.010908.164537">60 times less sharp than that of humans</a>: A flying bee can’t see the details of a flower until it is about 10 inches away. However, bees can see hidden ultraviolet floral patterns that are invisible to us, and those patterns lead the bees to flowers’ nectar.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/kQ8GRJp8bVg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Naturalist David Attenborough uses ultraviolet light to show how flowers may appear different to bees than to humans.</span></figcaption>
</figure>
<p>Bees also can spot flowers by detecting color changes at a distance. When humans watch film projected at 24 frames per second, the individual images appear to blur into motion. This phenomenon, which is called the <a href="https://www.britannica.com/science/movement-perception/Apparent-movement#ref488126">flicker-fusion frequency</a>, indicates how capable our visual systems are at resolving moving images. Bees have a much higher flicker-fusion frequency – you would have to play the film 10 times faster for it to look like a blur to them – so they can fly over a flowering meadow and <a href="https://doi.org/10.1007/BF00610583">see bright spots of floral color</a> that wouldn’t stand out to humans.</p>
<p>From a distance, bees detect flowers by scent. A honeybee’s sense of smell is <a href="https://doi.org/10.1371/journal.pone.0009110">100 times more sensitive</a> than ours. Scientists have used bees to sniff out chemicals <a href="https://entomologytoday.org/2013/11/25/can-trained-bees-detect-cancer-in-patients/">associated with cancer</a> and <a href="https://www.cbsnews.com/boston/news/boston-researchers-train-bees-to-detect-diabetes/">with diabetes</a> on patients’ breath and to detect the presence of <a href="https://www.technologyreview.com/2006/12/07/227361/using-bees-to-detect-bombs/">high explosives</a>. </p>
<p>Bees’ sense of touch is also highly developed: They can feel tiny fingerprint-like ridges <a href="https://doi.org/10.1073/pnas.82.14.4750">on the petals of some flowers</a>. Bees are <a href="https://doi.org/10.1080/0005772X.1995.11099233">nearly deaf</a> to most airborne sounds, unless they are very close to the source, but are sensitive if they are standing on a vibrating surface. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1348645052134944771"}"></div></p>
<h2>Problem solvers</h2>
<p>Bees <a href="https://doi.org/10.1080/0005772X.1995.11099233">can navigate mazes</a> as well as mice can, and studies show that they are self-aware of their body dimensions. For example, when fat bumblebees were trained to fly and then walk through a slit in a board to get to food on the other side, the bees <a href="https://doi.org/10.1073/pnas.2016872117">turned their bodies sideways and tucked in their legs</a>. </p>
<p>Experiments by Canadian researcher Peter Kevan and Lars Chittka in England demonstrated remarkable feats of bee learning. Bumblebees were trained to pull a string – in other words, to use a tool – connected to a plastic disk with hidden depressions filled with sugar water. They could see the sugar wells but couldn’t get the reward <a href="https://doi.org/10.1371/journal.pbio.1002564">except by tugging at the string</a> until the disk was uncovered.</p>
<p>Other worker bees were placed nearby in a screen cage where they could see what their trained hive mates did. Once released, this second group also pulled the string for the sweet treats. This study demonstrated what scientists term <a href="https://www.britannica.com/science/social-learning">social learning</a> – acting in ways that reflect the behavior of others.</p>
<h2>Pollinating with vibrations</h2>
<p>Even pollination, one of bees’ best-known behaviors, can be much more complicated than it seems. </p>
<p>The basic process is similar for all types of bees: Females carry pollen grains, the sex cells of plants, on their bodies from flower to flower as they collect pollen and nectar to feed themselves and their developing grubs. When pollen rubs off onto <a href="https://www.amnh.org/learn-teach/curriculum-collections/biodiversity-counts/plant-identification/plant-morphology/parts-of-a-flower">a flower’s stigma</a>, the result is pollination. </p>
<p>My favorite area of bee research examines a method called <a href="https://doi.org/10.1016/j.pbi.2013.05.002">buzz pollination</a>. Bees use it on about 10% of the world’s 350,000 kinds of flowering plants that have special <a href="https://www.amnh.org/learn-teach/curriculum-collections/biodiversity-counts/plant-identification/plant-morphology/parts-of-a-flower">anthers</a> – structures that produce pollen. </p>
<p>For example, a tomato blossom’s five anthers are pinched together, like the closed fingers of one hand. Pollen is released through one or two small pores at the end of each anther. </p>
<p>When a female bumblebee lands on a tomato flower, she bites one anther at the middle and contracts her flight muscles from <a href="https://doi.org/10.1093/jxb/erab428">100 to 400 times per second</a>. These powerful vibrations eject pollen from the anther pores in the form of a cloud that strikes the bee. It all happens in just a few tenths of a second. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/SZrTndD1H10?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Bumblebees demonstrate buzz pollination on a Persian violet blossom.</span></figcaption>
</figure>
<p>The bee hangs by one leg and scrapes the pollen into “baskets” – structures on her hind legs. Then she repeats the buzzing on the remaining anthers before moving to different flowers.</p>
<p>Bees also use buzz pollination on the flowers of blueberries, cranberries, eggplant and kiwi fruits. My colleagues and I are conducting experiments to determine the biomechanics of <a href="https://doi.org/10.1098/rsif.2022.0040">how bee vibrations eject pollen from anthers</a>. </p>
<h2>Planting for bees</h2>
<p>Many species of bees are <a href="https://theconversation.com/bees-face-many-challenges-and-climate-change-is-ratcheting-up-the-pressure-190296">declining worldwide</a>, thanks to stresses including <a href="http://dx.doi.org/%2010.1126/science.1255957">parasites, pesticides and habitat loss</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wood cubes filled with twigs and bricks." src="https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526311/original/file-20230515-18664-v796la.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 backyard ‘insect hotel’ for solitary bees and other nesting insects, made from stems, bricks and wood blocks.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/insect-hotel-for-solitary-bees-and-artificial-nesting-place-news-photo/601067110">Arterra/Universal Images Group vis Getty Images</a></span>
</figcaption>
</figure>
<p>Whether you have an apartment window box or several acres of land, you can do a few <a href="https://theconversation.com/to-help-insects-make-them-welcome-in-your-garden-heres-how-153609">simple things to help bees</a>. </p>
<p>First, plant native wildflowers so that blooms are available in every season. Second, try to avoid using insecticides or herbicides. Third, provide open ground where burrowing bees can nest. With luck, soon you’ll have some buzzing new neighbors.</p><img src="https://counter.theconversation.com/content/203837/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Buchmann 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>Scientists are learning amazing things about bees’ sensory perception and mental capabilities.Stephen Buchmann, Adjunct Professor of Entomology and of Ecology and Evolutionary Biology, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2038812023-04-20T12:40:04Z2023-04-20T12:40:04ZAllergy season is getting more intense with climate change – we’re creating better pollen forecasts to help<figure><img src="https://images.theconversation.com/files/521940/original/file-20230419-28-qacnzc.jpg?ixlib=rb-1.1.0&rect=308%2C37%2C7230%2C4622&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Allergy season is here.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/teenage-girl-with-allergy-blowing-nose-royalty-free-image/1198047425">Imgorthand/E+ via Getty Images</a></span></figcaption></figure><p>If you’re feeling the misery of allergy season in your sinuses and throat, you’re probably wondering what nature has in store for you this time – and in the future.</p>
<p>Pollen allergies affect over <a href="https://doi.org/10.1016/j.anai.2010.10.014">30% of the global population</a>, making them a significant <a href="https://doi.org/10.1016/j.anai.2010.10.014">public health</a> and <a href="https://doi.org/10.1016/j.rmed.2010.05.006">economic issue</a> as people feel ill and miss work. Our research shows that, as greenhouse gases warm the planet, their effects are driving longer and more intense pollen seasons.</p>
<p>To help allergy sufferers manage their symptoms in our changing climate, we’re building better pollen forecasts for the future.</p>
<p>As <a href="https://scholar.google.com/citations?user=3dWPwz8AAAAJ&hl=en">atmospheric</a> <a href="https://clasp.engin.umich.edu/people/zhang-yingxiao/">scientists</a>, we study how the atmosphere and climate affect trees and plants. In a 2022 study, we found that the U.S. will face <a href="https://www.nature.com/articles/s41467-022-28764-0">up to a 200% increase</a> in total pollen this century if the world continues producing carbon dioxide emissions at a high rate. Pollen season in general will start up to 40 days earlier in the spring and last up to 19 days longer than today under that scenario.</p>
<figure class="align-center ">
<img alt="6 maps showing differences in how types of plant pollen seasons will change. _Ambrosia_, better known as ragweed, has the greatest increase." src="https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=604&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=604&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=604&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=759&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=759&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=759&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The maps on the left show the recent average pollen season length in days for three types of plants: <em>Platanus</em>, or plane trees, such as sycamores; <em>Betula</em>, or birch; and <em>Ambrosia</em>, or ragweed. The maps on the right show the expected changes in total days by the end of the century if carbon dioxide emissions continue at a high rate.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41467-022-28764-0">Zhang and Steiner, 2022</a></span>
</figcaption>
</figure>
<p>While most studies focus on pollen overall, we zoomed in on more than a <a href="https://www.nature.com/articles/s41467-022-28764-0">dozen different types of grasses and trees</a> and how their pollen will affect regions across the U.S. in different ways. For example, species like oak and cypress will give the Northeast the biggest increase, but allergens will be on the rise just about everywhere, with consequences for human health and the economy.</p>
<h2>Why pollen is increasing</h2>
<p>Let’s start with the basics. Pollen – the dustlike grains produced by grasses and plants – contains the male genetic material for a plant’s reproduction.</p>
<p>How much pollen is produced depends on how the plant grows. Rising global temperatures will boost plant growth in many areas, and that, in turn, will affect pollen production. </p>
<p>Warmer temperatures will extend the growing season, allowing plants to grow and emit pollen for longer periods. But temperature is only part of the equation. We found that <a href="https://www.nature.com/articles/s41467-022-28764-0">a potentially greater driver of the future pollen increase</a> will be rising carbon dioxide emissions from sources such as vehicles and power plants. Carbon dioxide fuels photosynthesis, leading to increased growth and the potential for more pollen production. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Dust-like pollen falls from pine cones" src="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.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">Cones on a Norway spruce in Virginia release pollen.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:2021-04-17_10_43_13A_Pollen_cones_releasing_pollen_on_a_Norway_Spruce_along_Tranquility_Court_in_the_Franklin_Farm_section_of_Oak_Hill,_Fairfax_County,_Virginia.jpg">Famartin/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Pollen changes will vary by region</h2>
<p>We looked at 15 different pollen types, rather than treating all pollen the same as many past studies have. Our study found that the amount of pollen increase in a specific region depends on the types of vegetation.</p>
<p>Typically, pollination starts with leafy deciduous trees in late winter and spring. Alder, birch and oak are the three top deciduous trees for causing allergies, though there are others, like mulberry. Grass pollen becomes more prevalent in the summer, followed by ragweed in late summer. In the Southeast, evergreen trees like mountain cedar and juniper (in the cypress family) start in January. In Texas, “cedar fever” is the equivalent of hay fever.</p>
<p>We found that in the Northeast, pollen seasons for a lot of allergenic trees will <a href="https://www.nature.com/articles/s41467-022-28764-0">increasingly overlap</a> as temperatures and carbon dioxide emissions rise. For example, it used to be that maple trees would release pollen first, and then birch would pollinate. Now we see more overlap of their pollen seasons.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2OsicNwv9jE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How pollen season spreads across the U.S. over one year. Yingxiao Zhang and Allison Steiner.</span></figcaption>
</figure>
<p>In general, pollen season changes are greater in the northern United States than in the South, because of larger temperature increases in northern areas in future climate projections.</p>
<p>Southeastern regions, including Florida, Georgia and South Carolina, can expect large grass and weed pollen increases in the future. The Pacific Northwest is likely to see peak pollen season a month earlier because of the early pollen season of alder. </p>
<p>Allergy problems are already on the rise. A study in 2021 found that the <a href="https://theconversation.com/pollen-can-raise-your-risk-of-covid-19-and-the-season-is-getting-longer-thanks-to-climate-change-156754">overall pollen season</a> was already about <a href="https://doi.org/10.1073/pnas.2013284118">20 days longer in North America</a> than it was in 1990 and pollen concentrations were up about 21%.</p>
<h2>Silver lining: We can improve pollen forecasting</h2>
<p>Most pollen forecasts right now provide a very broad estimate of where and when pollen counts will be high. Part of the problem is that there aren’t many <a href="https://pollen.aaaai.org/#/">observing stations</a> for pollen counts. Most are run by allergy clinics, and there are fewer than 200 of these stations distributed across the country. Michigan, where we live, doesn’t have any that are currently operating.</p>
<p>It’s a very labor-intensive process to measure different types of pollen. As a result, current forecasts have a lot of uncertainties. These likely are based in part on what a station has observed in the past and the weather forecast.</p>
<figure class="align-center ">
<img alt="A person's hands jostle a pine branch to collect pollen" src="https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pollen sampling for regional forecasts can be labor-intensive.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Pollen_collection.jpg">HelenaAnna/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our model, <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022MS003329">if integrated into a forecasting framework</a>, could provide more targeted pollen forecasts across the country.</p>
<p>We can estimate where the trees are from satellite data and on-the-ground surveys. We also know how temperature influences when pollen comes out – what scientists call the <a href="https://www.britannica.com/science/phenology">phenology</a> of the pollen. With that information, we can use meteorological factors like wind, relative humidity and precipitation to figure out how much pollen gets into the air, and atmospheric models can show how it moves and blows around, to create a real-time forecast.</p>
<p>We’re currently working with a <a href="https://www.noaa.gov/">National Oceanic and Atmospheric Administration</a> lab about ways to integrate that information into a tool for air quality forecasting. Our next step is to evaluate these forecast tools and make information available to the public.</p>
<figure class="align-center ">
<img alt="Dozens of round, spiky pollen grains attached to a plant" src="https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.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">Ragweed pollen grains, magnified and colorized.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/ragweed-pollen-royalty-free-image/529469522">Bob Sacha/Corbis Documentary via Getty Images</a></span>
</figcaption>
</figure>
<p>There are still some unknowns when it comes to long-term pollen projections. For example, scientists don’t fully understand why plants produce more pollen in some years than others, and currently we cannot include these changes in our models. It’s also not fully clear how plants will respond if carbon dioxide levels go through the roof. Ragweed and residential trees are also hard to capture. There are very few ragweed surveys showing where these plants are growing in the U.S., but that can be improved.</p>
<p><em>This is an update to <a href="https://theconversation.com/pollen-season-is-getting-longer-and-more-intense-with-climate-change-heres-what-allergy-sufferers-can-expect-in-the-future-179158">an article</a> originally published March 15, 2022.</em></p><img src="https://counter.theconversation.com/content/203881/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allison L. Steiner has received funding from NSF, NASA, DOE, and NOAA. She is currently the President of the Atmospheric Sciences section of the American Geophysical Union.</span></em></p><p class="fine-print"><em><span>Yingxiao Zhang 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>Rising temperatures mean longer, earlier pollen seasons, but a bigger problem is what more carbon dioxide will do to the amount of pollen being released.Yingxiao Zhang, Ph.D. Student in Atmospheric Science, University of MichiganAllison L. Steiner, Professor of Atmospheric Science, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1987242023-03-08T13:40:36Z2023-03-08T13:40:36ZOnce the Callery pear tree was landscapers’ favorite – now states are banning this invasive species and urging homeowners to cut it down<figure><img src="https://images.theconversation.com/files/513447/original/file-20230303-16-jjphd6.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C1933%2C1283&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bradford pear trees in bloom along a driveway in Sussex County, Del.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/9xfPoK">Lee Cannon/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>When people think of spring, they often picture flowers and trees blooming. And if you live in the U.S. Northeast, Midwest or South, you have probably seen a medium-sized tree with long branches, covered with small white blooms – the Callery pear (<em>Pyrus calleryana</em>). </p>
<p>For decades, Callery pear – which comes in many varieties, including “Bradford” pear, “Aristocrat” and “Cleveland Select” – was among the most popular trees in the U.S. for ornamental plantings. Today, however, it’s widely recognized as an <a href="https://www.govinfo.gov/content/pkg/FR-1999-02-08/pdf/99-3184.pdf">invasive species</a>. Land managers and plant ecologists <a href="https://scholar.google.com/citations?user=uRA-SZ0AAAAJ&hl=en&oi=sra">like me</a> are working to eradicate it to preserve biodiversity in natural habitats. </p>
<p>As of 2023, it is illegal to <a href="https://ohiodnr.gov/discover-and-learn/plants-trees/invasive-plants/callery-pear">sell, plant or grow Callery pear</a> in Ohio and <a href="https://www.agriculture.pa.gov/Plants_Land_Water/PlantIndustry/NIPPP/Pages/Callery-Pear.aspx">Pennsylvania</a>, and will become illegal in <a href="https://news.clemson.edu/invasive-bradford-pear-3-other-species-to-be-banned-for-sale-in-sc/">South Carolina</a> on October 1, 2024. <a href="https://news.ncsu.edu/2022/03/bounty-offered-on-bradford-pear-trees/">North Carolina</a> and <a href="https://www.lakeexpo.com/community/community_news/cut-down-your-bradford-pear-and-missouri-conservation-will-send-you-a-free-tree/article_df77978a-b51a-11ec-ab85-b39d20e73240.html">Missouri</a> will give residents free native trees if they cut down Callery pear trees on their property. </p>
<p>How did this tree, once in high demand, become designated by the U.S. Forest Service as “<a href="https://www.invasive.org/weedcd/pdfs/wow/callery_pear.pdf">Weed of the Week</a>”? The devil is in the biological details.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/txwrZ1CqzrE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A Kentucky extension specialist explains why Callery pears initially seemed like a solution, but have proved to be a major problem.</span></figcaption>
</figure>
<h2>A quasi-perfect tree</h2>
<p>Botanists brought the Callery pear to the U.S. from Asia <a href="https://arboretum.harvard.edu/stories/the-rise-and-fall-of-the-ornamental-callery-pear-tree/">in the early 1900s</a>. They intentionally bred the horticultural variety to enhance its ornamental qualities. In doing so, they created an arboricultural wunderkind. As The New York Times <a href="https://www.nytimes.com/1964/01/05/archives/bradford-pear-has-many-assets-new-ornamental-fruit-offers-sturdy.html">observed in 1964</a>: </p>
<blockquote>
<p>“Few trees possess every desired attribute, but the Bradford ornamental pear comes unusually to close to the ideal.”</p>
</blockquote>
<p>Modern varieties of Callery pear produce an explosion of white flowers in springtime, followed by deep green summer foliage that turns deep red and maroon in autumn. They also are very tolerant of urban soils, which can be <a href="https://arboretum.harvard.edu/stories/urban-soil-problems-and-promise/">highly compacted</a> and hard for roots to penetrate. The trees grow quickly and have a rounded shape, which made them suitable for planting in rows along driveways and roadsides.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Tree with leaves mostly shaded red." src="https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510742/original/file-20230216-22-hkyqya.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 Callery pear turning red in fall.</span>
<span class="attribution"><span class="source">Ryan McEwan</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>During the post-World War II suburban development boom, Callery pear trees became extremely popular in residential settings. In 2005 the Society of Municipal Arborists named the “Chanticleer” variety the <a href="https://www.concreteconstruction.net/projects/infrastructure/arborists-select-urban-tree-of-the-year_o">urban street tree of the year</a>. But the breeding process that created this and other varieties of Callery pear was producing unexpected results.</p>
<h2>Cloning to produce an American original</h2>
<p>To ensure that each Callery pear tree had bright blooms, red foliage and other desired traits, horticulturists created identical clones through <a href="https://www.britannica.com/topic/graft">a process known as grafting</a>: creating seedlings from cuttings of trees with the desired characteristics. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/LTqG8-OhElY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Grafting is a method for propagating new fruit trees using buds from existing trees and fusing them onto a branch or stem of another tree, which is called the rootstock.</span></figcaption>
</figure>
<p>This approach eliminated the messy complexity of mixing genes during sexual reproduction and ensured that when each tree matured, it would have the characteristics that homeowners desire. Every tree of a specific variety was a genetically identical clone.</p>
<p>Grafting also meant Callery pear trees could not make fruits. Some fruit trees, such as peaches and tart cherries, can <a href="https://extension.umaine.edu/fruit/growing-fruit-trees-in-maine/pollination-requirements/">fertilize their flowers with their own pollen</a>. In contrast, Callery pear is self-incompatible: pollen on an individual tree cannot fertilize flowers on that tree. And since all Callery pears of a specific variety planted in a neighborhood would be identical clones, they would effectively be the same tree. </p>
<p>If a tree can’t produce fruits, it can’t disperse into natural habitats. Gardeners and landscapers thought it was perfectly safe to plant Callery pear near natural habitats, such as prairies, because the species was trapped in place by its reproductive biology. But the tree would break free from its isolation and spread seeds far and wide.</p>
<h2>The great escape</h2>
<p>University of Cincinnati botanist <a href="https://culleylab.com/home-page/members-lab/theresa-culley-pi/">Theresa Culley</a> and colleagues have found that as horticulturalists tinkered with Callery pears to produce new versions, they made the individuals different enough <a href="https://doi.org/10.1007/s10530-008-9386-z">to escape the fertilization barrier</a>. If a neighborhood had only “Bradford” pear trees, then no fruits could be produced – but once someone added an “Aristocrat” pear to their yard, then these two varieties could fertilize each other and produce fruits. </p>
<p>When Callery pear trees in gardens and parks started depositing seeds in nearby areas, wild populations of the trees became established. Those wild trees could pollinate one another, as well as neighborhood trees. </p>
<p>In today’s landscape, Callery pear is astonishingly fertile. The prolific flowering that horticulturists intentionally bred into these varieties now yields tremendous crops of pears each year. Although these little pears are generally not edible by humans, birds feed on the fruit, then fly away and excrete the seeds into natural habitats. Callery pear has become one of the <a href="https://www.fws.gov/program/invasive-species">most problematic invasive species</a> in the eastern United States. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1628379085364957184"}"></div></p>
<h2>A thorny problem</h2>
<p>Like other invasives, Callery pears crowd out native species. Once Callery pear seedlings <a href="https://doi.org/10.1007/s10530-022-02861-z">spread from habitat edges into grasslands</a>, they have advantages that allow them to dominate the site. </p>
<p>In <a href="https://mcewanlab.org/">my research lab</a>, we have found that Callery pear leafs out very early in spring and drops its leaves late in fall. This enables it to <a href="https://doi.org/10.3159/TORREY-D-22-00008.1">soak up more sun than native species</a>. We also have discovered that during invasion, these trees <a href="https://doi.org/10.1016/j.apsoil.2021.103989">alter the soil</a> and release chemicals that suppress the germination of native plants. </p>
<p>Callery pear is highly resistant to natural disturbances. In fact, when <a href="https://www.linkedin.com/in/meg-maloney-51b22b112/">my graduate student Meg Maloney</a> tried to kill the trees by using <a href="https://www.youtube.com/shorts/AeaEsDTnMLw">prescribed fires</a> or applying <a href="https://www.youtube.com/shorts/wtkMey4IItE">liquid nitrogen</a> directly to stumps after cutting the trees down, her efforts failed. Instead, the trees sprouted aggressively and <a href="https://muse.jhu.edu/article/883911#info_wrap">seemingly gained strength</a>.</p>
<p>Once Callery pear has escaped into natural areas, its seedlings produce <a href="https://doi.org/10.21273/HORTTECH04892-21">very sharp, stiff thorns</a> that can puncture shoes or even tires. This makes the trees a menace to people working in the area, as well as to native plants. Another nuisance factor is that when Callery pears bloom, they produce a <a href="https://www.npr.org/2015/04/24/401943000/whats-that-smell-the-beautiful-tree-thats-causing-quite-a-stink">strong odor</a> that many people find unpleasant.</p>
<p>Currently, <a href="https://www.invasive.org/alien/pubs/midatlantic/pyca.htm">directly applying herbicides</a> is the only known control for a Callery pear invasion. But the trees are so successful at spreading that poisoning their seedlings may simply create space for other Callery pear seedlings to establish. It is unclear how habitat managers can escape a confounding ecological cycle of invasion, herbicide application and re-invasion.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An open space studded with Callery pear trees, with dead grasses between the trees." src="https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513473/original/file-20230304-14-ct0blo.jpeg?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 Callery pear invasion is crowding out native species on this agricultural land, converting it to woodland.</span>
<span class="attribution"><a class="source" href="https://extension.okstate.edu/fact-sheets/the-invasive-callery-pear.html">Oklahoma State University Extension</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Banned but not gone</h2>
<p>In response to work by the <a href="https://www.oipc.info/">Ohio Invasive Plants Council</a> and other experts, Ohio has taken the extraordinary step of <a href="https://codes.ohio.gov/ohio-administrative-code/rule-901:5-30-01">banning Callery pear</a> to thwart its ecological invasion into natural habitats. But the trees are common in residential areas across the state and have established vigorous populations in natural habitats. Ecologists will be working well into the future to maintain openness and biodiversity in areas where Callery pear is invading. </p>
<p>In the meantime, homeowners can help. Horticulturists recommend that people who have a Callery pear on their property should <a href="https://dyckarboretum.org/callery-pear-cut-them-down/">remove it and replace it</a> with something that is not an invasive species. Few trees possess every desired attribute, but many <a href="https://moinvasives.org/2018/03/29/plant-this-not-that-10-native-trees-to-plant-in-place-of-callery-pear/">native trees</a> have visually attractive features and will not threaten ecosystems in your region.</p>
<p><em>This article has been updated to reflect current state bans on Callery pear trees as of March 2024.</em></p><img src="https://counter.theconversation.com/content/198724/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan W. McEwan 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>They’re beautiful in bloom, but Callery pear trees crowd out native plants and turn productive open land into woody thickets.Ryan W. McEwan, Professor of Biology, University of DaytonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1902352022-10-05T23:41:02Z2022-10-05T23:41:02ZPollen does more than make you sneeze. It can cause thunderstorm asthma, even if you’re not asthmatic<figure><img src="https://images.theconversation.com/files/488192/original/file-20221004-23-z8yzc0.jpg?ixlib=rb-1.1.0&rect=204%2C548%2C5259%2C3088&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/woman-has-reflux-acids-park-551855089">Shutterstock</a></span></figcaption></figure><p>Climate change has caused melting icebergs, flooding, and landslides. It can also bring about an <a href="https://pubmed.ncbi.nlm.nih.gov/33228867/">increase</a> in pollen levels, prolong the duration of pollen season, and <a href="https://ehp.niehs.nih.gov/doi/10.1289/EHP173">cause more</a> pollen-related health problems.</p>
<p>Pollen grains landing on the moist membranes of the nose or eyes cause “hay fever” (allergic rhinitis) in <a href="https://www.aihw.gov.au/reports/chronic-respiratory-conditions/allergic-rhinitis-hay-fever/contents/allergic-rhinitis">one in five people</a>. This often leads to a runny or blocked nose and itchy eyes.</p>
<p>During the pollen season, people with asthma are at greater risk of a flare-up. </p>
<p>Pollen can also trigger <a href="https://pubmed.ncbi.nlm.nih.gov/31759647/">thunderstorm asthma</a>, even in those <a href="https://pubmed.ncbi.nlm.nih.gov/33996193/">who haven’t been diagnosed</a> with asthma and hay fever. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lush-grasslands-higher-allergy-risks-what-hay-fever-sufferers-can-expect-from-another-la-nina-season-189982">Lush grasslands, higher allergy risks – what hay fever sufferers can expect from another La Niña season</a>
</strong>
</em>
</p>
<hr>
<h2>What is thunderstorm asthma?</h2>
<p>Thunderstorms <a href="https://pubmed.ncbi.nlm.nih.gov/29880157/">cause</a> a drop in temperature and a sudden rise in humidity. This <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(18)30120-7/fulltext">can cause</a> whole grass pollen grains to rupture into particles that are tiny enough to penetrate deeper into the lungs, which causes thunderstorm asthma. </p>
<p>Because of this, a lot of people – even those with no known asthma – can be affected. </p>
<p>The largest thunderstorm asthma event occurred in Melbourne during the 2016 grass pollen season – some <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/resp.13410">10,000 people</a> were affected and hospital emergency departments were over-capacity by <a href="https://pubmed.ncbi.nlm.nih.gov/29880157/">at least 3,000</a> respiratory-related cases. Sadly, ten people also died from asthma that night. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/TMQxBZ9M8g8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">This short Better Health Channel video gives a quick overview of thunderstorm asthma.</span></figcaption>
</figure>
<h2>Who is at risk of thunderstorm asthma?</h2>
<p>Even people who do not have a history of asthma are at risk of thunderstorm asthma. However, research has shown some people can be more susceptible to pollen than others. This includes:</p>
<ul>
<li>those with <a href="https://pubmed.ncbi.nlm.nih.gov/29229087/">pollen allergy</a>, specifically <a href="https://pubmed.ncbi.nlm.nih.gov/34774618/">ryegrass pollen allergy</a></li>
<li>people who have respiratory conditions such as <a href="https://www.jacionline.org/article/S0091-6749(21)01689-4/fulltext">asthma</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29229087/">hay fever</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/26048665/">a cold</a>, and <a href="https://www.safercare.vic.gov.au/clinical-guidance/covid-19/epidemic-thunderstorm-asthma">COVID</a></li>
<li>being outdoors at <a href="https://pubmed.ncbi.nlm.nih.gov/29229087/">the time of the thunderstorm</a></li>
<li>people who are <a href="https://pubmed.ncbi.nlm.nih.gov/29573176/">of Asian ethnicity</a></li>
<li>people living in areas with <a href="https://pubmed.ncbi.nlm.nih.gov/33131877/">lots of plant life</a></li>
<li>children with <a href="https://pubmed.ncbi.nlm.nih.gov/35398553/">a food allergy or eczema</a></li>
<li>those with exposure to high levels of <a href="https://pubmed.ncbi.nlm.nih.gov/34116012/">air pollution</a></li>
<li>those with lower <a href="https://pubmed.ncbi.nlm.nih.gov/15723767/">socioeconomic status</a>, as reduced access to health care and poor quality housing can exacerbate symptoms. </li>
</ul>
<p>In our research, we found people with <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/all.14566">co-existing allergic conditions</a> (such as asthma and hay fever) to be more impacted by pollen compared to those with single allergic conditions (such as asthma only). </p>
<h2>How else can pollen cause harm?</h2>
<p>Even outside of thunderstorms, pollen alone can <a href="https://www.mdpi.com/1660-4601/19/12/7541">cause</a> asthma attacks requiring hospitalisations, respiratory symptoms such as wheezing and runny nose, and reduced lung function, making it harder to breath.</p>
<p>Despite a low mortality rate, allergic asthma and hay fever can cause further <a href="https://pubmed.ncbi.nlm.nih.gov/15698810/">burdens</a> such as additional <a href="https://erj.ersjournals.com/content/21/1/116">health-care costs</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/11029350/">poorer physical and mental health</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1577143799859535874"}"></div></p>
<p>Our yet-to-be-published research has shown grass pollen may trigger a general state of heightened immune responses, leading to increased risk of eczema flares in children. </p>
<p>Other <a href="https://www.sciencedirect.com/science/article/pii/S0022202X15321904">studies</a> have indicated children with eczema experience more symptoms such as a higher intensity of itchiness and rash on days with high levels of grass pollen.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sneezing-with-hay-fever-native-plants-arent-usually-the-culprit-190336">Sneezing with hay fever? Native plants aren't usually the culprit</a>
</strong>
</em>
</p>
<hr>
<h2>How can you prepare?</h2>
<p>So, what can you do to prepare for the grass pollen season and the threat of thunderstorm asthma?</p>
<ul>
<li>download your state’s emergency services app, such as the Victorian Emergency App, which can provide thunderstorm asthma alerts</li>
<li>keep an eye on pollen counts (see below for useful websites)</li>
<li>keep doors and windows closed on high pollen days</li>
<li>use air purifiers<br></li>
<li>stay indoors during high pollen counts or thunderstorm asthma alerts</li>
<li>plant non-allergenic flowers if you have a garden</li>
<li>keep wearing a face mask. <a href="https://pubmed.ncbi.nlm.nih.gov/34277327/">Masks</a> have shown to be very effective in reducing the risk of COVID-19 infection and pollen-induced respiratory symptoms</li>
<li>take anti-asthma medications. Reliever medications are available over-the-counter. Preventer medications offer much stronger protection but require a prescription from a doctor. They also need to be used preventatively in the setting of pollen-induced asthma, or in severe hay fever, to prevent thunderstorm asthma </li>
<li>take antihistamines such as Zyrtec, which can be used both on an as-needed basis or more regularly through the pollen season. However, it does not treat or prevent asthma. </li>
</ul>
<figure class="align-center ">
<img alt="Person uses an asthma inhaler" src="https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488189/original/file-20221004-12421-cqj3xb.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">People with diagnosed asthma should take their preventer medication regularly during the pollen season.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/health-medicine-young-girl-using-blue-1503422258">Shutterstock</a></span>
</figcaption>
</figure>
<p>If you know you suffer from asthma, hay fever or pollen allergy, you are at risk of thunderstorm asthma. Aside from taking advantage of warning systems and staying out of the storm, you should see your doctor and have an asthma puffer at hand through the pollen season to keep yourself safe. Your doctor can advise you on the correct treatment. </p>
<p>Research including our own has shown pollen exposure can have a <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/all.14566">lagged effect</a> on the lungs and airways. This means asthma attacks or respiratory symptoms can sometimes occur a few days after exposure. So, if you forget to take medications pre-emptively, it’s not too late. However, go to a hospital if it gets severe. </p>
<p>Refer to the following websites for useful daily pollen information in Australia: <a href="https://airrater.org/">AirRater</a> or <a href="https://www.pollenforecast.com.au/">AusPollen</a>.</p><img src="https://counter.theconversation.com/content/190235/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shyamali Dharmage receives funding from the Australian National Health and Medical Research Council (NHMRC). She currently holds investigator-initiated grants from GSK and AstraZeneca for unrelated work. </span></em></p><p class="fine-print"><em><span>Jo Douglass has received honoraria for educational presentations from Astra-Zeneca, GSK, Novartis, Shire, & CSL. She has served on advisory boards: Sanofi-Aventis, Novartis, GSK, Astra-Zeneca, Shire, Immunosis, Equilium and CSL. She has undertaken contracted or investigator-initiated research for unrelated work on behalf of: GSK, Novartis, Immunosis, AstraZeneca, Sanofi-Aventis, Grifols, CSL, BioCryst & Equilium. She has a personal superannuation shareholding in CSL.</span></em></p><p class="fine-print"><em><span>Sabrina Idrose receives funding from the NHMRC Centre for Food and Allergy Research and LifeCourse PhD scholarships.</span></em></p>Pollen can trigger thunderstorm asthma, even in those without diagnosed asthma.Shyamali Dharmage, NHMRC Professorial Fellow, The University of MelbourneJo Douglass, Professor of Medicine, The University of MelbourneSabrina Idrose, PhD Candidate, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1880302022-08-05T11:44:56Z2022-08-05T11:44:56ZDo I have COVID or hay fever? Here’s how to tell<figure><img src="https://images.theconversation.com/files/477411/original/file-20220803-14-u61x1y.jpg?ixlib=rb-1.1.0&rect=44%2C0%2C5000%2C3330&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/young-woman-blowing-her-nose-while-236652919">ShutterDivision/Shutterstock</a></span></figcaption></figure><p>With warm weather in the northern hemisphere, many people will be suffering from pollen allergies. Also called <a href="https://www.nhs.uk/conditions/hay-fever/">hay fever</a>, this common condition affects millions of people around the world during the spring, summer and autumn months.</p>
<p>Meanwhile, COVID cases are high. Although seasonal allergies are commonplace for many people, there’s significant overlap between COVID and hay fever symptoms. This could lead people to mistake COVID for allergies, in turn exacerbating the spread of COVID in the community.</p>
<p>Notably, we’re now often seeing <a href="https://www.bmj.com/content/373/bmj.n1088.full">milder COVID symptoms</a> compared with earlier in the pandemic. This is due to a combination of factors including increased immunity from vaccines and prior infections, and the evolution of new variants of the virus.</p>
<p>Of course, it’s a good thing that people generally aren’t getting as sick with COVID. At the same time, this could actually increase confusion between COVID and other illnesses or allergies. </p>
<p>The latest data from the UK’s <a href="https://www.youtube.com/watch?v=05_idwi66jM&t=547s">ZOE app</a>, which tracks people’s self-reported COVID symptoms, shows the most commonly reported symptoms of COVID are now a sore throat, followed by headache, cough, blocked nose and runny nose. These symptoms can all affect people with pollen allergies. So it’s very possible someone might dismiss COVID as the onset of their usual allergies.</p>
<h2>COVID symptoms vs hay fever symptoms</h2>
<iframe title="" aria-label="Table" id="datawrapper-chart-q44G6" src="https://datawrapper.dwcdn.net/q44G6/1/" scrolling="no" frameborder="0" style="border: none;" width="100%" height="512"></iframe>
<p>Although there are several overlapping symptoms, there are a few key symptoms that may help you distinguish between COVID and hay fever.</p>
<p><strong>Itchy eyes:</strong> Itchy, red, watery or puffy eyes are a common sign of pollen allergies, but are not associated with COVID.</p>
<p><strong>Fever or chills:</strong> A high temperature is not a sign of pollen allergies, but it’s a fairly common COVID symptom. So if you have a fever, in combination with other symptoms, you may have COVID or another respiratory infection. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-you-know-if-your-child-has-hay-fever-and-how-should-you-treat-it-122853">How do you know if your child has hay fever and how should you treat it?</a>
</strong>
</em>
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<p><strong>Diarrhoea, vomiting and nausea:</strong> Diarrhoea in particular can be <a href="https://health-study.joinzoe.com/post/covid-symptoms-diarrhoea">an early sign</a> of COVID, starting on the first day of infection and often getting worse from there. It’s not associated with pollen allergies.</p>
<p><strong>Muscle ache:</strong> COVID-related muscle pains can range from being mild to quite debilitating, especially when they occur alongside fatigue. Muscle aches and pains are not associated with pollen allergies.</p>
<p>Differences can also be seen within some symptoms of <a href="https://www.nhs.uk/conditions/hay-fever/">pollen allergies</a> and <a href="https://health-study.joinzoe.com/post/new-top-5-covid-symptoms">COVID</a>. For example, COVID-related coughing is commonly persistent and dry, whereas a cough associated with hay fever is more “tickly”, due to mucus from the nose presenting in the throat. Similarly, the loss of smell and taste in pollen allergies results from a blocked nose, so if you have this symptom without a blocked nose, it could be more likely to be COVID.</p>
<figure class="align-center ">
<img alt="A young man wrapped in a blanket feels his forehead." src="https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477413/original/file-20220803-9397-f1t6qf.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">A fever isn’t a symptom of hay fever, but could indicate COVID or another respiratory infection.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/health-cold-people-concept-sick-young-1715306050">Ground Picture/Shutterstock</a></span>
</figcaption>
</figure>
<p>If your pollen allergy symptoms seem worse than usual, or you have one or more of the distinguishing symptoms above, it’s advisable to take a rapid COVID test. </p>
<h2>Protecting yourself</h2>
<p>Controlling allergy symptoms can help to prevent absences from work and school, and potentially facilitate earlier identification of COVID symptoms, in combination with testing. Further, although there’s no link between allergies and increased risk of COVID, pollen exposure can actually <a href="https://www.pnas.org/doi/10.1073/pnas.2019034118">weaken the body’s immunity</a> against COVID.</p>
<p>If you have a history of pollen allergies, make sure your treatment plan is current and that you have medications on hand for when you need them. Pollen exposure <a href="https://www.nhs.uk/conditions/allergies/prevention/">can be reduced</a> by avoiding outdoor activities when the pollen count is high, keeping windows closed, changing clothes after being outside, and using an air purifier. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pollen-can-raise-your-risk-of-covid-19-and-the-season-is-getting-longer-thanks-to-climate-change-156754">Pollen can raise your risk of COVID-19 – and the season is getting longer thanks to climate change</a>
</strong>
</em>
</p>
<hr>
<p>The best ways to prevent <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public">COVID infection</a> continue to include vaccination, wearing appropriately-fitting face coverings, and physical distancing. If you’re looking for the best of both worlds, <a href="https://www.pnas.org/doi/10.1073/pnas.2019034118">a particle filter mask</a> can be protective against both pollen and COVID.</p><img src="https://counter.theconversation.com/content/188030/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philippe B. Wilson is Chief Scientific Officer of NHS Willows Health. </span></em></p><p class="fine-print"><em><span>Samuel J. White 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>COVID symptoms have become milder over the course of the pandemic. While this is a good thing, it might make them more easily confused with allergy symptoms.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1847302022-07-12T12:33:24Z2022-07-12T12:33:24ZLight pollution is disrupting the seasonal rhythms of plants and trees, lengthening pollen season in US cities<figure><img src="https://images.theconversation.com/files/473427/original/file-20220711-13-xmyjzd.jpg?ixlib=rb-1.1.0&rect=0%2C1772%2C3712%2C2160&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some cities never sleep.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/light-trails-on-city-street-against-sky-at-night-royalty-free-image/1311603238">Noam Cohen/EyeEm via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>City lights that blaze all night are profoundly disrupting urban plants’ phenology – shifting when their buds open in the spring and when their leaves change colors and drop in the fall. New research I coauthored shows how nighttime lights are <a href="https://doi.org/10.1093/pnasnexus/pgac046">lengthening the growing season in cities</a>, which can affect everything from <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">allergies</a> to local economies.</p>
<p>In our study, my colleagues and I analyzed trees and shrubs at about 3,000 sites in U.S. cities to see <a href="https://doi.org/10.1093/pnasnexus/pgac046">how they responded</a> under different lighting conditions over a five-year period. Plants use <a href="https://islandpress.org/books/ecological-consequences-artificial-night-lighting">the natural day-night cycle</a> as a signal of seasonal change along with <a href="https://doi.org/10.1073/pnas.1911117117">temperature</a>.</p>
<p>We found that artificial light alone <a href="https://doi.org/10.1093/pnasnexus/pgac046">advanced the date that leaf buds broke</a> in the spring by an average of about nine days compared to sites without nighttime lights. The timing of the fall color change in leaves was more complex, but the leaf change was still delayed on average by nearly six days across the lower 48 states. In general, we found that the more intense the light was, the greater the difference.</p>
<p><iframe id="gSKIJ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/gSKIJ/9/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>We also projected the future influence of nighttime lights for five U.S. cities – Minneapolis, Chicago, Washington, Atlanta and Houston – based on different scenarios for future global warming and up to a 1% annual increase in nighttime light intensity. We found that increasing nighttime light would likely continue to shift the start of the season earlier, though its influence on the fall color change timing was more complex.</p>
<h2>Why it matters</h2>
<p>This kind of shift in plants’ biological clocks has important implications for the <a href="https://doi.org/10.1016/j.tourman.2018.08.021">economic</a>, <a href="https://theconversation.com/satellites-zoom-in-on-cities-hottest-neighborhoods-to-help-combat-the-urban-heat-island-effect-182925">climate</a>, <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">health</a> and <a href="https://doi.org/10.1098/rsbl.2014.0586">ecological</a> services that urban plants provide.</p>
<p>On the positive side, longer growing seasons could allow urban farms to <a href="https://doi.org/10.2134/jeq2013.01.0031">be active over longer periods of time</a>. Plants could also provide shade to cool neighborhoods earlier in spring and later in fall as global temperatures rise.</p>
<p>But changes to the growing season could also increase plants’ <a href="https://doi.org/10.1038/s41586-018-0399-1">vulnerability to spring frost damage</a>. And it can create a mismatch with the timing of other organisms, <a href="https://doi.org/10.1042/ETLS20190139">such as pollinators</a>, that some urban plants rely on.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Charts show the intensity of urban light in seven representative cities" src="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Urban light intensity varies among cities, and among neighborhoods within cities.</span>
<span class="attribution"><span class="source">Yuyu Zhou</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>A longer active season for urban plants also suggests an earlier and longer pollen season, which can exacerbate asthma and other breathing problems. A study in Maryland found a <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">17% increase</a> in hospitalizations for asthma in years when plants bloomed very early.</p>
<h2>What still isn’t known</h2>
<p>How the fall color timing will change going forward as night lighting increases and temperatures rise is less clear. Temperature and artificial light together influence the fall color in a complex way, and our projections suggested that the delay of coloring date due to climate warming might stop midcentury and possibly reverse because of artificial light. This will require more research.</p>
<p>How urban artificial light will change in the future also remains to be seen.</p>
<p>One study found that urban light at night had increased <a href="https://doi.org/10.1126/sciadv.1701528">by about 1.8% per year</a> worldwide from 2012-2016. However, many cities and states are <a href="https://www.ncsl.org/research/environment-and-natural-resources/states-shut-out-light-pollution.aspx">trying to reduce light pollution</a>, including requiring shields to control where the light goes and shifting to LED street lights, which use less energy and have <a href="https://doi.org/10.1111/1365-2664.12927">less of an effect</a> on plants than traditional streetlights with <a href="https://doi.org/10.1038/35036500">longer wavelengths</a>.</p>
<figure class="align-center ">
<img alt="Cars are parked on an old brick residential street at dusk with street lights and trees lining the sidewalks." src="https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.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">Baltimore has been converting its streetlights to LED to save money on energy. LEDs also have less of an impact on plants.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cobblestone-street-and-fells-point-neighborhood-at-royalty-free-image/1179432549">Cyndi Monaghan via Getty Images</a></span>
</figcaption>
</figure>
<p>Urban plants’ phenology may also be influenced by other factors, such as carbon dioxide and soil moisture. Additionally, the faster increase of temperature at night compared to the daytime could lead to different day-night temperature patterns, which might <a href="https://doi.org/10.1016/j.agrformet.2019.107832">affect plant phenology in complex ways</a>.</p>
<p>Understanding these interactions between plants and artificial light and temperature will help scientists <a href="https://doi.org/10.1038/s41558-022-01331-7">predict changes in plant processes under a changing climate</a>. Cities are already serving as natural laboratories.</p><img src="https://counter.theconversation.com/content/184730/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yuyu Zhou receives funding from the College of Liberal Arts and Sciences at Iowa State University. </span></em></p>Artificial light is upending trees’ ability to use the natural day-night cycle as a signal of seasonal change.Yuyu Zhou, Associate Professor of Environmental Science, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1816722022-04-21T12:18:01Z2022-04-21T12:18:01ZAchoo! 5 essential reads for pollen season<figure><img src="https://images.theconversation.com/files/458973/original/file-20220420-14894-m6e6re.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6016%2C4007&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Common hazel dispersing pollen in early spring. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/common-hazel-close-up-of-male-catkins-dispersing-pollen-in-news-photo/971552142">Arterra/Universal Images Group via Getty Images</a></span></figcaption></figure><p>As spring expands across North America, trees, shrubs and flowers are releasing <a href="https://www.britannica.com/science/pollen">pollen</a>. This fine, powdery substance is produced by the male structures of cone-bearing and flowering plants. When it’s carried to the plants’ female structures by wind, water or pollinators, fertilization happens. </p>
<p>As pollen travels, it also triggers allergies in <a href="https://www.aafa.org/allergy-facts/#">some 25 million Americans</a>. Pollen exposure can cause sneezing, coughing, itchy eyes, runny nose and postnasal drip – unwelcome signs of spring for sufferers. This roundup of articles from our archives describes recent findings on protecting pollinators and coping with pollen season.</p>
<h2>1. Hey pollinators, over here</h2>
<p>Since pollen grains carry the cells that fertilize plants, it’s critical for them to get where they need to go. Often wind or gravity is all it takes, but for many plants, a pollinator has to carry the pollen grains. Some plants offer nectar or edible pollen to attract insects, bats or other animals, which carry pollen from plant to plant as they forage. Many flowers also <a href="https://theconversation.com/why-do-flowers-smell-151672">lure pollinators with scent</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bee flying, coated with bright yellow particles." src="https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=586&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=586&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458976/original/file-20220420-25-8bves7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=586&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 thistle long-horned bee (<em>Melissodes desponsa</em>) covered with flower pollen.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/D8E563">Dejen Mengis, USGS</a></span>
</figcaption>
</figure>
<p>“Similar to the perfumes at a department store counter, flower scents are made up from a large and diverse number of chemicals which evaporate easily and float through the air,” writes Mississippi State University horticulturalist <a href="https://scholar.google.com/citations?user=dJ8gD7MAAAAJ&hl=en">Richard L. Harkess</a>. “To differentiate itself from other flowers, each species’ flowers put out a unique scent to attract specific pollinators. … Once pollinated, the flower stops producing a floral scent and nectar and redirects its energy to the fertilized embryo that will become the seed.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-flowers-smell-151672">Why do flowers smell?</a>
</strong>
</em>
</p>
<hr>
<h2>2. Bees at the buffet</h2>
<p>It’s well known that many species of insects have <a href="https://theconversation.com/insect-apocalypse-not-so-fast-at-least-in-north-america-141107">declined in recent years</a>. One big focus is <a href="https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/honey-bees/honeybees">honeybees</a> and <a href="https://theconversation.com/beyond-honey-bees-wild-bees-are-also-key-pollinators-and-some-species-are-disappearing-89214">other species of bees</a>, which pollinate many important crops. </p>
<p>In a 2021 study, University of Florida agricultural extension specialist <a href="https://scholar.google.com/citations?user=I8IjAnIAAAAJ&hl=en">Hamutahl Cohen</a> found that when bees visited fields where sunflowers, grown as crops, were blooming over many acres, they <a href="https://theconversation.com/planting-mixes-of-flowers-around-farm-fields-helps-keep-bees-healthy-170527">picked up parasites at a high rate</a>. In contrast, bees that foraged in hedgerows around crop fields and could choose from diverse types of flowers to feed on spread out farther and had lower rates of infection. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diverse shrubs in a planted border with inset photos of beneficial insects that they attract." src="https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=561&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=561&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458979/original/file-20220420-18-33gaht.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=561&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hedgerows like this one in California have been shown to increase the number of beneficial insects like (left to right) lady beetles, syrphid flies and their larvae, shown feeding on aphids.</span>
<span class="attribution"><a class="source" href="https://ucanr.edu/sites/calagjournal/archive/?image=img6504p200.jpg">UCANR</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>“The more bees in sunflower fields, the more parasites,” Cohen observed. “Sunflower blooms were aggregating bees, which in turn was amplifying disease risk.” However, “in the presence of many flower types, bees disperse and spread across resources, reducing each individual bee’s likelihood of encountering an infected individual.” </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/planting-mixes-of-flowers-around-farm-fields-helps-keep-bees-healthy-170527">Planting mixes of flowers around farm fields helps keep bees healthy</a>
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</em>
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<h2>3. Warmer weather means more pollen</h2>
<p>As climate change raises average temperatures across the U.S., growing seasons are starting earlier and ending later in the year. That’s <a href="https://theconversation.com/pollen-season-is-getting-longer-and-more-intense-with-climate-change-heres-what-allergy-sufferers-can-expect-in-the-future-179158">bad news for allergy sufferers</a>. </p>
<p>“The higher temperature will extend the growing season, giving plants more time to emit pollen and reproduce,” write University of Michigan atmospheric scientists <a href="https://clasp.engin.umich.edu/people/zhang-yingxiao/">Yingxiao Zhang</a> and <a href="https://scholar.google.com/citations?user=3dWPwz8AAAAJ&hl=en">Allison L. Steiner</a>. And by increasing the concentration of carbon dioxide in Earth’s atmosphere, climate change will make it possible for plants to grow larger and generate more pollen. </p>
<p>“Southeastern regions, including Florida, Georgia and South Carolina, can expect large grass and weed pollen increases in the future. The Pacific Northwest is likely to see peak pollen season a month earlier because of the early pollen season of alder,” Zhang and Steiner report.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pollen-season-is-getting-longer-and-more-intense-with-climate-change-heres-what-allergy-sufferers-can-expect-in-the-future-179158">Pollen season is getting longer and more intense with climate change – here's what allergy sufferers can expect in the future</a>
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<h2>4. Providing better forecasts</h2>
<p>With all that pollen out there, how can allergy sufferers know when counts are high? Today the U.S. has only a rudimentary network of 90 pollen observation stations across the country, staffed by volunteers and run only during pollen season, so often there isn’t good information available when people need it.</p>
<p><a href="https://scholar.google.com/citations?user=sUwveOEAAAAJ&hl=en">Fiona Lo</a>, an environmental health scientist at the University of Washington, is working with colleagues to develop a model that can predict airborne pollen releases. “Our forecast can predict for specific pollen types because our model includes information about how each plant type interacts differently with the environment,” Lo reports.</p>
<p>So far, the model only predicts levels of four types of common pollen in areas where there are observation stations. Ultimately, though, Lo and her collaborators “want to provide a forecast every day during pollen season to give allergy sufferers the information they need to manage their symptoms. Allergies are often undertreated, and knowledge about self-care is limited, so a reliable pollen forecast that is easy to access – for example, via an app on your phone – along with education on allergy management, could really help allergy sufferers.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sunny-with-a-chance-of-sneezing-im-building-a-tool-to-forecast-pollen-levels-that-will-help-allergy-sufferers-know-when-its-safe-to-go-outside-162073">Sunny with a chance of sneezing – I'm building a tool to forecast pollen levels that will help allergy sufferers know when it's safe to go outside</a>
</strong>
</em>
</p>
<hr>
<h2>5. Support pollinators in your garden</h2>
<p>Pollen season is also gardening season, since it’s when plants are blooming. West Virginia University mycologist <a href="https://www.researchgate.net/profile/Brian-Lovett">Brian Lovett</a> offers advice for gardeners who want to <a href="https://theconversation.com/to-help-insects-make-them-welcome-in-your-garden-heres-how-153609">attract beneficial insects to their yards</a> for pollination and other purposes. </p>
<p>One step is to replace grass with native wildflowers, which will provide pollen and nectar for insects like ants, bees and butterflies. “Just as you may have a favorite local restaurant, insects that live around you have a taste for the flowers that are native to their areas,” Lovett notes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Striped black and yellow butterfly feeding on purple flower" src="https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458980/original/file-20220420-13790-30cq5q.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">Swallowtail butterflies, shown here on a liatris flower in Washington state, are efficient pollinators that can be attracted to home gardens.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/swallowtail-butterfly-on-a-liatris-spicata-flower-in-july-news-photo/624174230">Wolfgang Kaehler/LightRocket via Getty Images</a></span>
</figcaption>
</figure>
<p>Replacing white lightbulbs with yellow or warm-hued LED bulbs, and providing water in dishes or other containers, are also insect-friendly steps. Local university extension offices and gardening stores can offer other suggestions. </p>
<p>“In my view, humans all too often see ourselves as separate from nature, which leads us to relegate biodiversity to designated parks,” Lovett observes. “In fact, however, we are an important part of the natural world, and we need insects just as much as they need us.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/to-help-insects-make-them-welcome-in-your-garden-heres-how-153609">To help insects, make them welcome in your garden – here's how</a>
</strong>
</em>
</p>
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Pollen brings seasonal misery to millions of Americans, but it serves a critical purpose: fertilizing many kinds of plants, including food crops.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1791582022-03-15T16:08:24Z2022-03-15T16:08:24ZPollen season is getting longer and more intense with climate change – here’s what allergy sufferers can expect in the future<figure><img src="https://images.theconversation.com/files/452084/original/file-20220315-99009-sispwj.jpg?ixlib=rb-1.1.0&rect=0%2C15%2C1280%2C929&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ragweed pollen, instigator of headaches and itchy eyes across the U.S.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/ragweed-pollen-royalty-free-image/529469522">Bob Sacha/Corbis Documentary via Getty Images</a></span></figcaption></figure><p>Brace yourselves, allergy sufferers – research shows pollen season is going to get a lot longer and more intense with climate change.</p>
<p>Our study finds that the U.S. will face <a href="https://www.nature.com/articles/s41467-022-28764-0">up to a 200% increase</a> in total pollen this century if the world continues producing carbon dioxide emissions from vehicles, power plants and other sources at a high rate. Pollen season in general will start up to 40 days earlier in the spring and last up to 19 days longer than today under that scenario.</p>
<p>As <a href="https://scholar.google.com/citations?user=3dWPwz8AAAAJ&hl=en">atmospheric</a> <a href="https://clasp.engin.umich.edu/people/zhang-yingxiao/">scientists</a>, we study how the atmosphere and climate affect trees and plants. While most studies focus on pollen overall, we zoomed in on more than a <a href="https://www.nature.com/articles/s41467-022-28764-0">dozen different types of grasses and trees</a> and how their pollen will affect regions across the U.S. in different ways. For example, species like oak and cypress will give the Northeast the biggest increase, but allergens will be on the rise just about everywhere, with consequences for human health and the economy.</p>
<figure class="align-center ">
<img alt="6 maps showing differences in how types of plant pollen seasons will change. Ambrosia, better known as ragweed, has the greatest increase." src="https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=604&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=604&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=604&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=759&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=759&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451986/original/file-20220314-117573-11rcxij.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=759&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The maps on the left show the recent average pollen season length in days for three types of plants: platanus, or plane trees, such as sycamores; betula, or birch; and ambrosia, or ragweed. The maps on the right show the expected changes in total days by the end of the century if carbon dioxide emissions continue at a high rate.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41467-022-28764-0">Zhang and Steiner, 2022</a></span>
</figcaption>
</figure>
<p>If your head is pounding at just the thought of it, we also have some good news, at least for knowing in advance when pollen waves are coming. We’re working on using the model from this study to develop more accurate local pollen forecasts.</p>
<h2>Why pollen is increasing</h2>
<p>Let’s start with the basics. Pollen – the dust-like grains produced by grasses and plants – contains the male genetic material for a plant’s reproduction.</p>
<p>How much pollen is produced depends on how the plant grows. Rising global temperatures will boost plant growth in many areas, and that, in turn, will affect pollen production. But temperature is only part of the equation. We found that <a href="https://www.nature.com/articles/s41467-022-28764-0">the bigger driver of the future pollen increase</a> will be rising carbon dioxide emissions.</p>
<p>The higher temperature will extend the growing season, giving plants more time to emit pollen and reproduce. Carbon dioxide, meanwhile, fuels photosynthesis, so plants may grow larger and produce more pollen. We found that carbon dioxide levels may have a much larger impact on pollen increases than temperature in the future.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Dust-like pollen falls from pine cones" src="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451965/original/file-20220314-16-1h5t3qc.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">Cones on a Norway Spruce in Virginia release pollen.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:2021-04-17_10_43_13A_Pollen_cones_releasing_pollen_on_a_Norway_Spruce_along_Tranquility_Court_in_the_Franklin_Farm_section_of_Oak_Hill,_Fairfax_County,_Virginia.jpg">Famartin/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Pollen changes will vary by region</h2>
<p>We looked at 15 different pollen types, rather than treating all pollen the same as many past studies have.</p>
<p>Typically, pollination starts with leafy deciduous trees in late winter and spring. Alder, birch and oak are the three top deciduous trees for causing allergies, though there are others, like mulberry. Then grasses come out in the summer, followed by ragweed in late summer. In the Southeast, evergreen trees like mountain cedar and juniper (in the cypress family) start in January. In Texas, “cedar fever” is the equivalent of hay fever.</p>
<p>We found that in the Northeast, pollen seasons for a lot of allergenic trees will <a href="https://www.nature.com/articles/s41467-022-28764-0">increasingly overlap</a> as temperatures and carbon dioxide emissions rise. For example, it used to be that oak trees would release pollen first, and then birch would pollinate. Now we see more overlap of their pollen seasons.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2OsicNwv9jE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How pollen season spreads across the U.S. over one year. Yingxiao Zhang and Allison Steiner.</span></figcaption>
</figure>
<p>In general, pollen season will change more in the north than in the south, because of larger temperature increases in northern areas.</p>
<p>Southeastern regions, including Florida, Georgia and South Carolina, can expect large grass and weed pollen increases in the future. The Pacific Northwest is likely to see peak pollen season a month earlier because of the early pollen season of alder. </p>
<h2>Silver lining: We can improve pollen forecasting</h2>
<p>Most pollen forecasts right now provide a very broad estimate. Part of the problem is that there aren’t many <a href="https://pollen.aaaai.org/#/">observing stations</a> for pollen counts. Most are run by allergy clinics, and there are less than 100 of these stations distributed across the country. Michigan, where we live, doesn’t have any.</p>
<p>It’s a very labor-intensive process to actually measure different types of pollen. As a result, current forecasts have a lot of uncertainties. These likely are based in part on what a station has observed in the past and the weather forecast.</p>
<figure class="align-center ">
<img alt="A person's hands jostle a pine branch to collect pollen" src="https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451976/original/file-20220314-117573-o3yi1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pollen sampling for regional forecasts can be labor-intensive.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Pollen_collection.jpg">HelenaAnna/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our model, if integrated into a forecasting framework, could provide more targeted pollen forecasts across the country.</p>
<p>We can estimate where the trees are from satellite data and on-the-ground surveys. We also know how temperature influences when pollen comes out – what we call the phenology of the pollen. With that information, we can use meteorological factors like wind, relative humidity and precipitation to figure out how much pollen gets into the air, and atmospheric models can show how it moves and blows around, to create a real-time forecast.</p>
<p>All of that information allows us to look at where pollen might be in space and time, so people dealing with allergies will know what’s coming in their area.</p>
<p>We’re currently talking with a <a href="https://www.noaa.gov/">National Oceanic and Atmospheric Administration</a> lab about ways to integrate that information into a tool for air quality forecasting.</p>
<figure class="align-center ">
<img alt="Dozens of round, spiky pollen grains attached to a plant" src="https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/452085/original/file-20220315-19-guleto.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">Ragweed pollen grains, magnified and colorized.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/ragweed-pollen-royalty-free-image/529469522">Bob Sacha/Corbis Documentary via Getty Images</a></span>
</figcaption>
</figure>
<p>There are still some unknowns when it comes to long-term pollen projections. For example, scientists don’t fully understand why plants produce more pollen in some years than others. There’s not a good way to include that in models. It’s also not fully clear how plants will respond if carbon dioxide levels go through the roof. Ragweed and residential trees are also hard to capture. There are very few ragweed surveys showing where these plants are growing in the U.S., but that can be improved.</p>
<h2>Pollen levels are already on the rise</h2>
<p>A study in 2021 found that the <a href="https://theconversation.com/pollen-can-raise-your-risk-of-covid-19-and-the-season-is-getting-longer-thanks-to-climate-change-156754">overall pollen season</a> was already about <a href="https://doi.org/10.1073/pnas.2013284118">20 days longer in North America</a> than it was in 1990 and pollen concentrations were up about 21%.</p>
<p>Increasing pollen levels in the future will have a much broader impact than a few sniffles and headaches. Seasonal allergies affect <a href="https://doi.org/10.1016/j.anai.2010.10.014">about 30% of the population</a>, and they have economic impacts, from <a href="https://doi.org/10.1016/j.anai.2010.10.014">health costs</a> to <a href="https://doi.org/10.1016/j.rmed.2010.05.006">missed working days</a>.</p><img src="https://counter.theconversation.com/content/179158/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allison L. Steiner has received funding from NSF, NASA, DOE, and NOAA. She is currently a member of the NASEM Board on Atmospheric Sciences and Climate.</span></em></p><p class="fine-print"><em><span>Yingxiao Zhang 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>Rising temperatures mean longer, earlier pollen seasons, but the bigger problem is what carbon dioxide will do to the amount of pollen being released. A 200% increase is possible this century.Yingxiao Zhang, Ph.D. Student in Atmospheric Science, University of MichiganAllison L. Steiner, Professor of Atmospheric Science, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1745522022-01-24T17:12:52Z2022-01-24T17:12:52ZUrban gardens are crucial food sources for pollinators - here’s what to plant for every season<figure><img src="https://images.theconversation.com/files/441813/original/file-20220120-8260-1ujogi7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A bumblebee visits a blooming honeysuckle plant.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/honeysuckle-bloom-spring-garden-bumblebee-collects-1976580638">Sidorova Mariya | Shutterstock</a></span></figcaption></figure><p>Pollinators are <a href="https://www.science.org/doi/10.1126/science.1255957">struggling to survive</a> in the countryside, where flower-rich meadows, hedges and fields have been replaced by green <a href="https://theconversation.com/single-crop-farming-is-leaving-wildlife-with-no-room-to-turn-38991">monocultures</a>, the result of modern industrialised farming. Yet an unlikely refuge could come in the form of city gardens.</p>
<p>Research has shown how the havens that urban gardeners create provide <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13598">plentiful nectar</a>, the energy-rich sugar solution that <a href="https://theconversation.com/biodiversity-depends-on-pollinators-a-first-estimate-of-how-many-plants-rely-on-animals-166908">pollinators</a> harvest from flowers to keep themselves flying. </p>
<p>In a city, flying insects like bees, butterflies and hoverflies, can flit from one garden to the next and by doing so ensure they find food whenever they need it.
These urban gardens produce <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13598">some 85%</a> of the nectar found in a city. Countryside nectar supplies, by contrast, have <a href="https://www.nature.com/articles/nature16532">declined by one-third</a> in Britain since the 1930s. </p>
<p>Our new research has found that this urban food supply for pollinators is also more <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14094">diverse and continuous</a> throughout the year <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13403">than in farmland</a>. Everyone with a garden, allotment or even a window box can create their own haven for pollinators. Here are tips on what to plant for each season.</p>
<figure class="align-center ">
<img alt="Three people in wellington boots work on raised beds in a garden." src="https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441812/original/file-20220120-9372-1jpd6w3.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">Community gardens, allotments, even window boxes can sustain pollinators throughout the year.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/people-taking-care-plants-community-garden-2108650739">KOTOIMAGES | Shutterstock</a></span>
</figcaption>
</figure>
<h2>What to plant in spring</h2>
<p>The first queen bumblebees emerge from winter hibernation in February and March. They need food straight away. </p>
<p>At this time of year nectar-rich plants are vital energy sources for warming up cold flight muscles, with pollen providing the necessary protein for egg laying and larval growth. In early spring much of the countryside is still bleak and inhospitable. </p>
<p>Gardeners can help by planting borders of hellebore, <em>Pulmonaria</em> and grape hyacinth. Trees and shrubs such as willow, cherry and flowering currant are also fantastic for packing a lot of food into a small space.</p>
<figure class="align-right ">
<img alt="A bee on a willow flower" src="https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441983/original/file-20220121-17-14c2na9.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 in bloom.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/bee-on-branch-blooming-willow-617939870">Ira Kalinicheva | Shutterstock</a></span>
</figcaption>
</figure>
<h2>What to plant in summer</h2>
<p>In late spring and early summer, pollinators have more food available – but there is also more competition for it. So it is crucial to ensure you have a diverse array of different flowering plants. This will guarantee there is attractive and accessible food to suit a wide range of insects and provide them with nutritionally balanced diets. </p>
<p>A great assortment of plants, including honeysuckle, <em>Campanula</em> and lavender, can provide floral resources in summer. Mowing the lawn a little less often will help too, giving the chance for important so-called weeds, such as clover and dandelion, to bloom.</p>
<figure class="align-left ">
<img alt="Ivy in bloom with a red admiral." src="https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441984/original/file-20220121-13-h0nicm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ivy in bloom with a red admiral.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vanessa-atalanta-sitting-on-ivy-leaves-2084367058">Seepix | Shutterstock</a></span>
</figcaption>
</figure>
<h2>What to plant in autumn</h2>
<p>By late summer and autumn there are fewer species still flowering in gardens. A handful dominate the nectar supplies, particularly <em>Fuchsia</em>, <em>Salvia</em> and <em>Crocosmia</em>. </p>
<p>For many pollinators, however, these flowers are entirely useless. Their nectar is hidden away down a tube, only accessible to insects with long tongues, such as the garden bumblebee.</p>
<p>This means solitary bees and hoverflies may need to find other sources of food. The gardener can help by prioritising open and accessible flowers. Opt for species such as ivy, <em>Sedum</em>, <em>Echinacea</em> and oregano.</p>
<h2>What to plant in winter</h2>
<p>Few pollinators are still active in winter. Most species die off leaving the next generation behind as eggs, larvae or pupae. </p>
<p>But bumblebees and honeybees remain in flight, taking advantage of the warmer climate and winter flowers that cities can provide. By vibrating their wings, bumblebees can warm up to forage in temperatures barely exceeding freezing point, but they need a lot of energy-rich nectar to do so. If you want to attract bees into your garden during the winter some of the best options are <em>Mahonia</em>, sweet box, winter honeysuckle and the strawberry tree.</p>
<figure class="align-center ">
<img alt="Yellow Mahonia on a frosty morning." src="https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441809/original/file-20220120-9595-3p9v0p.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">Mahonia on a frosty morning.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/spray-colorful-mahonia-winter-cover-frost-42886990">Sally Wallis | Shutterstock</a></span>
</figcaption>
</figure>
<p>Urban gardens are small and numerous, with hundreds or even thousands packed into a single square kilometre of a residential neighbourhood. Each gardener is different, with individual preferences of what to plant, how regularly to mow the lawn and even how to decide what constitutes a weed. </p>
<p>This results in an enormous variation from garden to garden in the quantity of nectar, the timing of its production and the types of flowers producing it. But there is always room for improvement. Some gardens provide pollinators with hundreds of times less nectar than others.</p>
<p>So keep yours <a href="https://www.rhs.org.uk/science/conservation-biodiversity/wildlife/plants-for-pollinators">well stocked with nectar</a> and <a href="https://www.rhs.org.uk/about-the-rhs/policies/pesticide-statement">free from toxic pesticides</a>. You’ll be amazed by the impact you can have.</p><img src="https://counter.theconversation.com/content/174552/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Tew receives funding from The Natural Environment Research Council (NERC) and the Royal Horticultural Society (RHS). Nicholas, Katherine and Jane would like to acknowledge the valuable contributions of all co-authors to this study, and in particular, Dr. Stephanie Bird (RHS) for her help with this article.</span></em></p><p class="fine-print"><em><span>Jane Memmott currently receives funding from NERC and has received funding from BBSRC and the Leverhulme Trust in the past.</span></em></p><p class="fine-print"><em><span>Katherine Baldock receives funding from the Natural Environment Research Council (NERC). </span></em></p>Up to 85% of the nectar available to pollinating insects in a city comes from gardens. What we plant – whether in an allotment or a window box – can make a huge difference.Nicholas Tew, PhD Candidate in Community Ecology, University of BristolJane Memmott, Professor of Ecology, University of BristolKatherine Baldock, Senior Lecturer in Ecology, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1657302021-11-23T01:54:57Z2021-11-23T01:54:57ZWe expected people with asthma to fare worse during COVID. Turns out they’ve had a break<figure><img src="https://images.theconversation.com/files/431230/original/file-20211110-19-1bg65ie.jpg?ixlib=rb-1.1.0&rect=499%2C0%2C6229%2C2417&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>There were fears at the beginning of the COVID pandemic that people with asthma would fare much worse than those without it. Intuitively, a disease that attacks the lungs should put asthma sufferers at much greater risk.</p>
<p>But this hasn’t been borne out.</p>
<p>Firstly, it’s turned out people with asthma are at <a href="https://doi.org/10.1111/resp.14003">slightly lower</a> <a href="https://asthma.org.au/wp-content/uploads/2020/10/COVID-rapid-review_Summarised-report-for-technical-audience-VF-clean_v2.pdf">risk of acquiring COVID</a>, being <a href="https://www1.racgp.org.au/newsgp/clinical/why-are-patients-with-asthma-not-at-increased-susc">hospitalised with it</a> or indeed dying from it compared to people without asthma. Though, someone with asthma who is hospitalised with COVID is <a href="https://asthma.org.au/wp-content/uploads/2020/10/COVID-rapid-review_Summarised-report-for-technical-audience-VF-clean_v2.pdf">slightly more likely to require ICU admission</a>.</p>
<p>In addition, asthma attack rates have <a href="https://www.bmj.com/company/newsroom/fewer-people-sought-medical-help-for-severe-asthma-attacks-during-the-covid-19-pandemic/">substantially</a> <a href="https://doi.org/10.1016/j.jaip.2021.04.038">reduced</a> in many parts of the world.</p>
<p>What explains this?</p>
<h2>Asthma sufferers aren’t getting sicker from COVID</h2>
<p>Asthma is an umbrella term for a range of diseases of the airways, which have similar outcomes – constriction of the airways causing difficulty breathing. In some forms of asthma the constriction is a result of inflammation, or rash, within the lung.</p>
<p>Many people with asthma take asthma preventers, which are a type of steroid drug we lung experts call “inhaled corticosteroids”. These drugs reduce the amount of inflammation in the lungs.</p>
<p>Interestingly, another steroid, <a href="https://theconversation.com/dexamethasone-the-cheap-old-and-boring-drug-thats-a-potential-coronavirus-treatment-140932">dexamethasone</a>, is being used as a treatment for COVID for this same reason.</p>
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Read more:
<a href="https://theconversation.com/dexamethasone-the-cheap-old-and-boring-drug-thats-a-potential-coronavirus-treatment-140932">Dexamethasone: the cheap, old and boring drug that's a potential coronavirus treatment</a>
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<p>Asthmatics might be <a href="https://www1.racgp.org.au/newsgp/clinical/why-are-patients-with-asthma-not-at-increased-susc">inadvertently reducing the risk of severe COVID</a> if they contract it by regularly using their preventers, because they are “pre-treated” if you like.</p>
<p>Indeed some preventers are thought to be “anti SARS-CoV-2”, that is, they have <a href="https://www.thelancet.com/article/S2213-2600(21)00160-0/fulltext">some ability to kill the virus</a> that causes COVID. </p>
<p>What’s more, <a href="https://doi.org/10.1111/resp.14003">some good evidence from Australia</a> demonstrates that patients with asthma have decreased “ACE2 gene expression”. ACE2 is the point of entry for the SARS-CoV-2 virus to get into our cells.</p>
<p>If you have less ACE2 then there are fewer gateways for the virus to enter our cells, and there’s less opportunity for the infection to take hold.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-the-ace2-receptor-how-is-it-connected-to-coronavirus-and-why-might-it-be-key-to-treating-covid-19-the-experts-explain-136928">What is the ACE2 receptor, how is it connected to coronavirus and why might it be key to treating COVID-19? The experts explain</a>
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<h2>Why have asthma attacks declined?</h2>
<p>There a number of possible reasons why asthma attacks have declined.</p>
<p>Asthma is a chronic condition which can flare up when sufferers are exposed to their “triggers”. Common ones are pollens, chemicals, dust mites, pets, mould, smoke, or viruses.</p>
<p>Social distancing and locking down millions of people around the world has been a real time case study in what staying at home would do to asthma rates.</p>
<p>Because people in lockdown go outside a lot less, it could reduce their exposure to pollen and other allergens and irritants outdoors such as smoke, thereby reducing asthma attacks.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1413669341334224896"}"></div></p>
<p>What’s more, social distancing and lockdowns also significantly reduce the number of interactions between people, thereby reducing the spread of infectious diseases. We’ve been able to reduce COVID cases this way, and flu cases too. </p>
<p>In 2019, there were <a href="https://www.guild.org.au/__data/assets/pdf_file/0025/84229/Influenza-Report-30-October-2019.pdf">302,084 flu cases</a> notified to health departments in Australia. And that was with a significant proportion of the population vaccinated.</p>
<p>In 2021, up to November 7, there have been just <a href="https://www1.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-ozflu-flucurr.htm">598 flu cases</a>.</p>
<p>Along with this, we can presume there have been far fewer common colds and other types of infectious diseases.</p>
<p>Viruses can cause asthma flare ups, which is known by lung experts as “viral exacerbation of asthma”. So fewer people with colds and the flu could also <a href="https://doi.org/10.1136/bmj.m2806">contribute to lower asthma attack rates</a>.</p>
<p>There have also been reports of <a href="https://www.bmj.com/company/newsroom/fewer-people-sought-medical-help-for-severe-asthma-attacks-during-the-covid-19-pandemic/">fewer people seeking medical care</a> for fear of contracting COVID in health-care settings, which may be another reason for fewer people seeking care for asthma. </p>
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<h2>What will happen to asthma post-COVID?</h2>
<p>We’re used to tolerating a certain level of many infectious diseases in the community, particularly things like common colds, strep throat, even glandular fever and the flu.</p>
<p>For many of us, this is no big deal and the only effects are feeling not great for a few days or weeks of the year.</p>
<p>But for many others, these sorts of common infectious illnesses can be deadly. Think about someone with cystic fibrosis, which severely damages the lungs and digestive system. If they get a cold or the flu, it can seriously knock them around, or even kill them. Same with someone who takes medications to depress their immune system, for example people with rheumatoid arthritis.</p>
<p>These infections result in many hospitalisations, which puts pressure on the whole hospital system.</p>
<p>From COVID, we know there are simple measures we can take to substantially reduce the transmission of these seemingly “benign” diseases, including wearing masks, not going to work or socialising when you’re sick, and washing/sanitising your hands regularly.</p>
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<p>We’ve reached the milestone of having <a href="https://www.reuters.com/world/asia-pacific/australia-hits-magnificent-milestone-with-80-rate-vaccinations-2021-11-06/">more than 80% of Australians over 16 fully vaccinated</a> against COVID, and <a href="https://www.reuters.com/world/asia-pacific/australia-eases-international-border-ban-first-time-since-march-2020-2021-10-31/">international travel is resuming</a>. Returning travellers are likely to bring with them new flu strains that we’re totally unprepared for.</p>
<p>Usually flu vaccines for Australia are designed to tackle strains from the Northern Hemisphere winter so we’re prepared for when the new strain arrives in our winter.</p>
<p>But there has been such little flu overseas, and with the understandable focus on COVID, our vaccines for flu and other existing conditions may need to be revisited.</p>
<p>Not revisiting existing vaccines for flu and other previously common conditions may lead to a <a href="https://www.abc.net.au/news/2021-09-16/queensland-what-happened-to-the-flu-in-2021/100456616">wave of flu</a> and many other diseases, given we’ll have limited <a href="https://www.economist.com/britain/2021/08/19/out-of-lockdown-britons-are-discovering-other-viruses-still-exist">immunity to them</a>.</p>
<p>So we may soon see asthma attacks take off again, exacerbated by viruses.</p><img src="https://counter.theconversation.com/content/165730/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce Thompson receives research funding from the NHMRC, is immediate past president of the Thoracic Society of Australia and New Zealand and has received speaker fees from GSK, Mundipharma, Chiesi and Astra Zeneca.</span></em></p>Not only have asthma attack rates decreased during the pandemic, evidence suggests people with asthma are not at increased risk of severe outcomes from COVID.Bruce Thompson, Professor and Dean of the School of Health Sciences, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1669082021-10-14T09:43:04Z2021-10-14T09:43:04ZBiodiversity depends on pollinators: a first estimate of how many plants rely on animals<figure><img src="https://images.theconversation.com/files/424970/original/file-20211006-27-1wdyuzb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The daisy Dimorphotheca pluvialis depends on insects like the pictured horsefly for its pollination.</span> <span class="attribution"><span class="source">A.G. Ellis</span></span></figcaption></figure><p>The honeybee may be the best-known pollinator of plants, but there are <a href="https://discoverpollinators.org/author/dmartins/">thousands of pollinator species</a>, including other bees, butterflies, moths, beetles, flies and even some birds and mammals. Pollinators help to produce food – their contribution to crops is worth <a href="https://www.sciencedirect.com/science/article/pii/S0921800916301331?casa_token=3rcmlYVeJs4AAAAA:G3cnh60wk8RrmwO22P5eLzSVwZnFDhPUidRIf9ftHsvFU6BFDT7mYmZAELgcfqMD1YS6JxEuwN4">billions of dollars</a>. But they are also essential for the reproduction of plants generally, and thus for biodiversity.</p>
<p>This is why it’s a worry that certain pollinator species have <a href="https://www.pnas.org/content/108/2/662">fallen in numbers</a>, and in some places the <a href="https://www.sciencedirect.com/science/article/abs/pii/S2590332220306515">diversity of pollinators</a> has decreased. These declines are due to <a href="https://ipbes.net/assessment-reports/pollinators">the combined effects</a> of pesticide use, destruction and degradation of habitats, invasive species, pollinator diseases and climate change. </p>
<p>More and more pollinators are becoming <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12162">threatened with extinction</a>. For example, the Loveridge’s sunbird <a href="http://datazone.birdlife.org/species/factsheet/22717931">is endangered</a> by damage caused by people to the forest where it lives in Tanzania. Some species have already gone extinct, for example <em>Libythea cinyras</em>, a swallowtail butterfly from Mauritius. This species <a href="https://www.sbbt.org.uk/what-are-swallowtails-birdwings/threats-to-swallowtails/">has died out entirely</a>, probably due to the forests in which it lived being chopped down to make sugarcane plantations.</p>
<p>These declines motivated us to find out how important pollinators are for wild plants. Our <a href="https://www.science.org/doi/10.1126/sciadv.abd3524">paper</a> provides the first global estimate of how many plant species mostly or completely rely on animal pollinators to make seeds and thus to reproduce. We found that it’s about 175,000 plant species – <a href="https://onlinelibrary.wiley.com/doi/10.2307/25066027">half of all flowering plants</a>. This means declines in pollinators could cause major disruptions in natural ecosystems, including loss of biodiversity.</p>
<h2>DIY versus animal pollination</h2>
<p>We already knew that about 88% of flowering plants are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0706.2010.18644.x">pollinated by animals</a>, as opposed to being wind-pollinated. But most animal-pollinated plants are also a bit auto-fertile. That means they can produce some seeds <a href="https://www.nature.com/articles/ncomms13313">without pollinators</a>, for instance by self-fertilisation. To estimate the importance of pollinators to seed production, we therefore had to account for auto-fertility.</p>
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Read more:
<a href="https://theconversation.com/the-sex-organs-of-baobab-flowers-may-solve-the-puzzle-of-trees-that-bear-more-fruit-161926">The sex organs of baobab flowers may solve the puzzle of trees that bear more fruit</a>
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<p>We used the contribution of pollinators to seed production as an indicator of their importance to plants. We measured this by comparing seed production in the absence of pollinators to seed production with pollinators present.</p>
<p>There was already a lot of data, but it was spread out in hundreds of scientific papers, each focused on pollination of different plant species. Originally working in three separate groups, 21 scientists from five continents read these papers in languages including English, Spanish, Portuguese and Chinese to gather pollination information into databases. In <a href="https://www.science.org/doi/10.1126/sciadv.abd3524">our study</a>, we combined forces and consolidated the data into a single database including 1,174 species from all over the world. </p>
<p>We estimate that, without pollinators, a third of flowering plant species would produce no seeds and half would suffer an 80% or more reduction in fertility. This means most plants would produce fewer seeds if they were less well pollinated by animal pollinators. In most plants, auto-fertility is very much plan B. Overall, we estimate only about 21% of plants are not vulnerable to pollinator declines at all. This includes <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0706.2010.18644.x">12% that are wind-pollinated</a> and 9% that have very high auto-fertility. </p>
<p>We also found that in tropical areas, where there is a lack of information on trends in pollinator numbers, pollinators are especially important for plant reproduction.</p>
<h2>Consequences for plants</h2>
<p>As so many plants species are highly reliant on pollinators, if the numbers of pollinators decline, or different pollinators become the most numerous, reproduction of many plant species is likely to be affected. This would likely lead to declines in numbers of some of those plants. The endangered species <a href="https://mobi.operationwildflower.org.za/index.php/albums/genera-b-c/babiana/babiana-odorata-jack-1-8135"><em>Babiana odorata</em></a> from the Western Cape in South Africa is an example of one of these vulnerable plant species, as it is completely dependent on pollinating bees to make seeds.</p>
<p>Even though some plants might evolve to be more auto-fertile on the one hand, or more attractive to the remaining pollinators on the other hand, this <a href="https://www.researchgate.net/publication/349250260_Pollination_strategies_in_the_face_of_pollinator_decline">will not be possible</a> for all plant species. Some plants will be at risk of extinction. </p>
<p>For example, in South Africa, in locations where special oil-collecting bees have disappeared due to habitat destruction, the numbers of some of the plants they pollinate – like the endemic witch orchid <em>Disperis cucullata</em> – <a href="https://www.researchgate.net/publication/229545435_Reconstruction_of_historical_pollination_rates_reveals_linked_declines_of_pollinators_and_plants">have plummeted too</a>. </p>
<p>Our results also suggest that pollinator declines could change the competitive balance between plant species, changing which plant species are most common. For example, many weeds <a href="https://www.nature.com/articles/ncomms13313">are auto-fertile</a>, raising the concern that they would gain an advantage because they would have less competition from more desirable pollinator-dependent plants. </p>
<p>Also, if ecosystems become dominated by auto-fertile plants, this could lead to further reductions in pollinators because auto-fertile plants typically have <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16075">less of the pollen and nectar</a> that pollinators feed on. </p>
<p>Seeds aren’t only important for plant reproduction, but also as food sources for animals. If plants are less well pollinated in future, there will be fewer seeds for some seed-feeding animals, which could also then be threatened with extinction. </p>
<h2>What can be done</h2>
<p>Our study provides grounds to hope that if pollinator declines can be reversed, the worst consequences can be averted. Most plants are quite long-lived, so it will take some years for these plant populations to start to decline and go extinct, even if pollinator declines reduce their reproduction.</p>
<p>Aside from their importance in crop production, we hope our findings will add motivation to conserve and restore pollinators for biodiversity itself. More research is especially important in tropical areas. </p>
<p>But there are already many things we can do, such as <a href="https://ir.library.oregonstate.edu/concern/administrative_report_or_publications/vq27zn805">avoiding pesticide use</a> and conserving their habitats.</p>
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<strong>
Read more:
<a href="https://theconversation.com/what-honeybees-in-south-africa-need-from-people-better-managed-forage-166369">What honeybees in South Africa need from people: better managed forage</a>
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<p>Although pollinator decline has many potential knock-on effects, it is only one of <a href="https://ipbes.net/global-assessment">a range of threats</a> to biodiversity. Others are climate change, habitat destruction and invasive species. Our study shows that to mitigate the other threats to biodiversity, we must ensure that future ecosystems have enough of the pollinators they need.</p><img src="https://counter.theconversation.com/content/166908/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Rodger currently receives funding from the South African National Research Foundation (NRF) and Stellenbosch University. He was also supported by funding from the European Commission while carrying out this study.</span></em></p>Half of all flowering plants mostly or completely rely on animal pollinators to make seeds. A decline in pollinators could cause major disruptions in natural ecosystems.James Rodger, Postdoctoral Research Fellow in evolutionary ecology of plant reproduction, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1620732021-08-03T12:34:16Z2021-08-03T12:34:16ZSunny with a chance of sneezing – I’m building a tool to forecast pollen levels that will help allergy sufferers know when it’s safe to go outside<figure><img src="https://images.theconversation.com/files/414210/original/file-20210802-26-1mcpjqh.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5539%2C3820&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Advance warning of high pollen levels could help people plan their activities to avoid allergies.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/car-driver-using-asthma-inhaler-royalty-free-image/1304794626">Dobrila Vignjevic/E+ via Getty Images</a></span></figcaption></figure><p>Do flowers blossoming in spring make you miserable? Are you sworn enemies with fall bloomers like ragweed? If you suffer from pollen allergies, imagine the usefulness of a reliable pollen forecast that could help you manage your symptoms by providing an early warning when pollen conditions are bad.</p>
<p>We’re working on it! <a href="https://scholar.google.com/citations?user=sUwveOEAAAAJ&hl=en&oi=ao">As an atmospheric scientist, I study</a> the weather, climate and anything in our Earth’s atmosphere, including pollen. One in three people in the U.S. <a href="https://doi.org/10.1056/NEJMcp1412282">suffer from allergic rhinitis</a>, otherwise known as “allergies,” and pollen is the most common cause.</p>
<p>While allergic rhinitis is not curable, its symptoms can be successfully treated. Two main methods are medication and pollen avoidance. They both rely on knowing when, where and how much pollen is, and is expected to be, in the air. Many medications work best if taken before symptoms occur. Advance knowledge of pollen allows allergy sufferers to change plans in order to minimize their exposure to pollen. </p>
<p>My colleagues and I are pulling together what we know about how plant biology and meteorology affect the amount of pollen in the air, along with pollen count numbers, to build a reliable pollen forecast. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="magnified view of pollen grains" src="https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=445&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=445&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=445&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=559&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=559&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414211/original/file-20210802-24-1jmlm3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=559&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A view of pollen from various plants, magnified 586 times under the microscope.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/pollen-high-powered-photomicrographic-magnification-are-news-photo/179796938">BSIP/Universal Images Group via Getty Images</a></span>
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<h2>Counting pollen grain by grain</h2>
<p>Allergic symptoms tend to be more severe the higher the concentration of airborne pollen. The amount of pollen in the air is constantly changing, so it would be ideal to monitor pollen in populated areas at regular frequent intervals. In the U.S., <a href="https://pollen.aaaai.org/#/">the National Allergy Bureau</a> collects, processes and distributes daily pollen concentrations from stations around the country. </p>
<p>Unfortunately, there are fewer than 90 active stations. Of these, many do not count on weekends or outside of the main pollen season. Part of the reason is that these are volunteer-run stations, and pollen monitoring requires significant time and resources.</p>
<p>Pollen is collected using a machine that sucks in air and traps pollen on sticky tape. A trained technician then processes, identifies and counts the tiny pollen grains under a microscope. During the height of pollen season, it may take a few hours for a technician to count the day’s pollen. Automated pollen monitoring systems do exist and would greatly reduce the need for human resources. But for now, these systems are either extremely expensive or have not been evaluated for accuracy.</p>
<h2>Building a forecasting model</h2>
<p>Pollen that causes allergic reactions is from <a href="http://sweetgum.nybg.org/science/glossary/glossary-details/?irn=2953">anemophilous or wind-pollinated plants</a>. Pollen grains contain the <a href="http://pollen.utulsa.edu/whatispollen.html">male sperm from the plant</a>, an essential component of plant reproduction. Anemophilous plants produce a lot of pollen because they rely on the whims of the wind to carry it to reach the female counterparts of their species to reproduce and grow new plants. The amount of pollen in the air has been rising because <a href="https://doi.org/10.1073/pnas.2013284118">climate change is lengthening the pollen season</a> and increasing how much pollen gets produced. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="backlit pollen wafts in the air around a flowering tree branch" src="https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414212/original/file-20210802-26-18kit17.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Certain weather conditions make it more likely to be a heavy pollen day.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pollen-like-snow-royalty-free-image/91821142">Alkimson/iStock via Getty Images Plus</a></span>
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<p>Since we have access to only a limited amount of pollen count data, my colleagues and I leverage what we know about the environment to estimate the amount of pollen in the air. Generally warm, sunny, dry and windy days are correlated with high airborne pollen concentrations, and rainy and humid days with low concentrations. </p>
<p>Plants depend on water and sunlight to grow. The timing of precipitation, temperature and solar radiation can affect a plant’s development and its readiness to flower. Once the plant is ready to flower, environmental variables can determine when pollen is released, how far it travels and how long it remains in the air. </p>
<p>The <a href="https://doi.org/10.1016/j.scitotenv.2021.145590">pollen model my colleagues and I have developed</a> uses these known relationships between meteorology and pollen to estimate airborne pollen. We also include satellite images of vegetation in the model because satellites can detect greening and provide an estimate of the beginning of spring.</p>
<p>Our model can forecast pollen 1 to 14 days in advance for locations where there are pollen stations. But due to the sparsity of pollen stations, we are working on extending the model to forecast in locations with no pollen counts. In those places we use nearby pollen station data, along with localized meteorology, to estimate the pollen. </p>
<p>Although pollen reporting and forecasts do exist in the popular media, <a href="https://doi.org/10.1186/1710-1492-8-S1-A11">their pollen reports differ from observations</a>, and their forecasts are limited only to categories of trees, grasses and weeds. Our forecast can predict for specific pollen types because our model includes information about how each plant type interacts differently with the environment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman checks her phone against backdrop of windows at night" src="https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414213/original/file-20210802-18-11a1ai0.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">Checking the pollen forecast could help you plan when to take allergy medication and how much time you’d spend outside.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-businesswoman-checking-smartphone-in-the-royalty-free-image/969436696">Klaus Vedfelt/DigitalVision via Getty Images</a></span>
</figcaption>
</figure>
<h2>A fine-tuned forecast in your pocket</h2>
<p>We are collaborating with medical professionals and health scientists to understand the pollen levels associated with increasing severity of allergic symptoms. Our plan is to tailor the forecast to allow patients to better manage their symptoms.</p>
<p>So far, we can accurately forecast for four of the most abundant pollen types in the U.S. only in locations with pollen stations. We are seeking funding to expand to other pollen types and other locations, and we are working on creating a platform to automate the data processing and run the forecast.</p>
<p>Ultimately, we want to provide a forecast every day during pollen season to give allergy sufferers the information they need to manage their symptoms. <a href="https://doi.org/10.1016/j.rmed.2005.05.012">Allergies are often undertreated</a> and <a href="https://doi.org/10.1111/crj.12015">knowledge about self-care is limited</a>, so a reliable pollen forecast that is easy to access – for example via an app on your phone – along with education on allergy management, could really help allergy sufferers.</p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>.]</p><img src="https://counter.theconversation.com/content/162073/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fiona Lo 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>Scientists are building a pollen forecasting model using meteorology, botany, pollen count numbers and satellite imagery to help people plan ahead.Fiona Lo, Postdoctoral Researcher in Environmental and Occupational Health Sciences, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1585742021-05-05T18:06:48Z2021-05-05T18:06:48ZEarly humans used fire to permanently change the landscape tens of thousands of years ago in Stone Age Africa<figure><img src="https://images.theconversation.com/files/398430/original/file-20210503-13-nd6j8k.JPG?ixlib=rb-1.1.0&rect=0%2C179%2C4608%2C3269&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Today the shoreline of Lake Malawi is open, not forested the way it was before ancient humans started modifying the landscape.</span> <span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Fields of rust-colored soil, spindly cassava, small farms and villages dot the landscape. Dust and smoke blur the mountains visible beyond massive Lake Malawi. Here in tropical Africa, you can’t escape the signs of human presence.</p>
<p>How far back in time would you need to go in this place to discover an entirely natural environment?</p>
<p>Our work has shown that it would be a very long time indeed – <a href="https://advances.sciencemag.org/content/7/19/eabf9776">at least 85,000 years</a>, eight times earlier than the <a href="https://doi.org/10.1126/science.aax1192">world’s first land transformations via agriculture</a>.</p>
<p><a href="https://scholar.google.com/citations?user=MQkcYDYAAAAJ&hl=en&oi=ao">We</a> <a href="https://scholar.google.com/citations?user=kNBySP0AAAAJ&hl=en&oi=ao">are</a> <a href="https://scholar.google.com/citations?user=ZGB_9bQAAAAJ&hl=en&oi=ao">part</a> of an interdisciplinary collaboration between archaeologists who study past human behavior, geochronologists who study the timing of landscape change and paleoenvironmental scientists who study ancient environments. By combining evidence from these research specialities, we have identified an instance in the very distant past of early humans bending environments to suit their needs. In doing so, they transformed the landscape around them in ways still visible today.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="people excavate stone tools below the ground's surface" src="https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395547/original/file-20210417-17-gv4vry.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Crew members excavate artifacts at a site in Karonga, Malawi, where stone tools are buried more than 3 feet (1 meter) below the modern ground surface.</span>
<span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Digging for behavioral and environmental clues</h2>
<p>The dry season is the best time to do archaeological fieldwork here, and finding sites is easy. Most places we dig in these red soils, we find stone artifacts. They are evidence that someone sat and skillfully broke stones to create edges so sharp they can still draw blood. Many of these stone tools can be fit back together, reconstructing a single action by a single person, from tens of thousands of years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="stone tools paired together" src="https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=520&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=520&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395548/original/file-20210417-13-4zrut7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=520&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Middle Stone Age artifacts, some of which can be fit back together.</span>
<span class="attribution"><a class="source" href="https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.abf4098">Sheila Nightingale</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>So far we’ve recovered more than 45,000 stone artifacts here, buried many feet (1 to 7 meters) below the surface of the ground. The sites we are excavating date to a time ranging from about 315,000 to 30,000 years ago known as the Middle Stone Age. This was also a period in Africa when innovations in human behavior and creativity pop up frequently – and <a href="https://doi.org/10.1038/s41586-021-03419-0">earlier than anywhere else in the world</a>. </p>
<p>How did these artifacts get buried? Why are there so many of them? And what were these ancient hunter-gatherers doing as they made them? To answer these questions, we needed to figure out more about what was happening in this place during their time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="barge with drill floats in the distance on lake water" src="https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395549/original/file-20210417-13-90z5s9.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">The Viphya drill barge on Lake Malawi, where researchers braved waterspouts and lake fly swarms to obtain a long record of past environments.</span>
<span class="attribution"><span class="source">Andy Cohen</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For a clearer picture of the environments where these early humans lived, we turned to the fossil record preserved in layers of mud at the bottom of Lake Malawi. Over millennia, pollen blown into the water and tiny lake-dwelling organisms became trapped in <a href="http://lrc.geo.umn.edu/laccore/">layers of muck on the lake’s floor</a>. Members of our collaborative team extracted a <a href="https://doi.org/10.1016/j.palaeo.2010.10.030">1,250-foot (380-meter) drill core</a> of mud from a modified barge, then painstakingly tallied the microscopic fossils it contained, layer by layer. They then used them to reconstruct ancient environments across the entire basin.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Malawi landscape with patches of forest high in the hills" src="https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395893/original/file-20210420-21-1rylzf9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Today, the high plateaus of northern Malawi harbor most of the remaining forests that once extended all the way to the Lake Malawi shoreline.</span>
<span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Today, this region is characterized by bushy, <a href="https://doi.org/10.1016/j.actao.2020.103599">fire-tolerant open woodlands</a> that do not develop a thick and enclosed canopy. Forests that do develop these canopies harbor the richest diversity in vegetation; this ecosystem is now restricted to patches that occur at higher elevations. But these forests once stretched all the way to the lakeshore.</p>
<p>Based on the fossil plant evidence present at various times in the drill cores, we could see that the area around Lake Malawi repeatedly alternated between wet times of forest expansion and dry periods of forest contraction. </p>
<p>As the area underwent cycles of aridity, driven by natural climate change, the lake shrank at times to only 5% of its present volume. When lake levels eventually rose each time, forests <a href="https://doi.org/10.1111/gcb.14150">encroached on the shoreline</a>. This happened time and time again over the last 636,000 years.</p>
<h2>Harnessing fire to manage resources</h2>
<p>The mud in the core also contains a record of fire history, in the form of tiny fragments of charcoal. Those little flecks told us that around 85,000 years ago, something strange happened around Lake Malawi. Charcoal production spiked, erosion increased and, for the first time in more than half a million years, rainfall did not bring forest recovery.</p>
<p>At the same time this charcoal burst appears in the drill core record, our sites began to show up in the archaeological record – eventually becoming so numerous that they formed one continuous landscape littered with stone tools. Another drill core immediately offshore showed that as site numbers increased, more and more charcoal was washing into the lake. Early humans had begun to make their first permanent mark on the landscape.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="people silhouetted against bonfire at night" src="https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=266&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=266&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=266&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=334&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=334&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395891/original/file-20210420-23-1ucsfyb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=334&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many people around the world still rely on fire for warmth, cooking, ritual and socializing – including the research crew when doing fieldwork.</span>
<span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Fire use is a technology that stretches back <a href="https://doi.org/10.1098/rstb.2015.0164">at least a million years</a>. Using it in such a transformative way is human innovation at its most powerful. Modern hunter-gatherers use fire to warm themselves, cook food and socialize, but many also deploy it as an engineering tool. Based on the wide-scale and permanent transformation of vegetation into more fire-tolerant woodlands, we infer that this was what these ancient hunter-gatherers were doing.</p>
<p>By converting the natural seasonal rhythm of wildfire into something more controlled, people can encourage specific areas of vegetation to grow at different stages. This so-called “<a href="https://doi.org/10.1002/evan.21482">pyrodiversity</a>” establishes miniature habitat patches and diversifies opportunities for foraging, kind of like increasing product selection at a supermarket.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="people digging in red earth at an outdoor archaeological site" src="https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395552/original/file-20210417-15-5xlhfa.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 research team exposes ancient stone tools near Karonga, Malawi.</span>
<span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Just like today, changing any part of an ecosystem has consequences everywhere else. With the loss of closed forests in ancient Malawi, the vegetation became dominated by more open woodlands that are resilient to fire – but these did not contain the same species diversity. This combination of rainfall and reduced tree cover also increased opportunities for erosion, which spread sediments into a thick blanket known as an alluvial fan. It sealed away archaeological sites and created the landscape you can see here today.</p>
<h2>Human impacts can be sustainable</h2>
<p>Although the spread of farmers through Africa within the last few thousand years brought about more <a href="https://doi.org/10.1073/pnas.1802172115">landscape and vegetation transformations</a>, we have found that the legacy of human impacts was already in place tens of thousands of years before. This offers a chance to understand how such impacts can be sustained over very long timescales.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="aerial view of an excavation site in Malawi" src="https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395894/original/file-20210420-21-1ysfwud.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">Open woodlands have grown over alluvial fans that formed during the Middle Stone Age. Trenches such as this one at an excavation site show multiple layers of discarded artifacts over a period of tens of thousands of years.</span>
<span class="attribution"><span class="source">Jessica Thompson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Most people associate human impacts with a time after the Industrial Revolution, but paleo-scientists have a deeper perspective. With it, researchers like us can see that wherever and whenever humans lived, we must abandon the idea of “<a href="https://www.pnas.org/content/118/17/e2023483118">pristine nature</a>,” untouched by any human imprint. However, we can also see how humans shaped their environments in sustainable ways over very long periods, causing ecosystem transformation without collapse.</p>
<p>Seeing the long arc of human influence therefore gives us much to consider about not only our past, but also our future. By establishing long-term ecological patterns, conservation efforts related to fire control, species protection and human food security can be <a href="https://doi.org/10.1038/s41559-020-01361-4">more targeted and effective</a>. People living in the tropics, such as Malawi today, are especially vulnerable to the economic and social impacts of food insecurity brought about by <a href="https://www.un.org/press/en/2019/gaef3516.doc.htm">climate change</a>. By studying the deep past, we can establish connections between long-term human presence and the biodiversity that sustains it.</p>
<p>With this knowledge, people can be better equipped to do what humans had already innovated nearly 100,000 years ago in Africa: manage the world around us.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/HaO9UPvirQk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Paleoanthropologist Jessica Thompson explains the research.</span></figcaption>
</figure>
<p>[<em>The Conversation’s newsletter explains what’s going on with the coronavirus pandemic. <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=coronavirus-going-on">Subscribe now</a>.</em>]</p><img src="https://counter.theconversation.com/content/158574/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Thompson has received funding for this research from the Australian Research Council, Wenner-Gren Foundation, and National Geographic Society-Waitt Foundation. She is affiliated with Yale University and the Yale Peabody Museum of Natural History, Arizona State University, the Paleoanthropology Society, the Society of Africanist Archaeologists, and the Society for American Archaeology. </span></em></p><p class="fine-print"><em><span>David K. Wright has received funding from the Wenner-Gren Foundation, National Geographic Foundation, Nordforsk (Nordic Council of Ministers) fund and the National Research Foundation of Korea. He is affiliated with the University of Oslo and the State Key Laboratory of Loess and Quaternary Geology at the Chinese Academy of Sciences and is a member of the Society for American Archaeology and the Society of Africanist Archaeologists.</span></em></p><p class="fine-print"><em><span>Sarah Ivory receives funding from the US National Science Foundation and the Belmont Forum. </span></em></p>Combining evidence from archaeology, geochronology and paleoenvironmental science, researchers identified how ancient humans by Lake Malawi were the first to substantially modify their environment.Jessica Thompson, Assistant Professor of Anthropology, Yale UniversityDavid K. Wright, Professor of Archaeology, Conservation and History, University of OsloSarah Ivory, Assistant Professor of Geosciences, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1567542021-03-09T15:36:05Z2021-03-09T15:36:05ZPollen can raise your risk of COVID-19 – and the season is getting longer thanks to climate change<figure><img src="https://images.theconversation.com/files/388548/original/file-20210309-15-11kg3dw.jpg?ixlib=rb-1.1.0&rect=0%2C28%2C4818%2C3555&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pollen can suppress how the body's immune system responds to viruses.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/of-pollen-grains-royalty-free-image/1134490788">Callista Images via Getty Images</a></span></figcaption></figure><p><em>Exposure to pollen can make you more susceptible to COVID-19, and it isn’t just a problem for people with allergies, new research released March 9 shows. Plant physiologist <a href="https://scholar.google.com/citations?user=TkabY8wAAAAJ&hl=en&oi=sra">Lewis Ziska</a>, a co-author of the new peer-reviewed study and other recent research on pollen and climate change, explains the findings and why pollen seasons are getting longer and more intense.</em> </p>
<h2>What does pollen have to do with a virus?</h2>
<p>The <a href="https://doi.org/10.1073/pnas.2019034118">most important takeaway from our new study</a> is that pollen can be a factor in exacerbating COVID-19.</p>
<p>A couple years ago, my coauthors showed that <a href="https://doi.org/10.1111/all.14047">pollen can suppress how the human immune system</a> responds to viruses. By interfering with proteins that signal antiviral responses in cells lining the airways, it can leave people more susceptible to potentially a whole host of respiratory viruses, such as the flu virus and other SARS viruses.</p>
<p>In this study, we looked specifically at COVID-19. We wanted to see how the number of new infections changed with the rise and fall of pollen levels in 31 countries around the world. We found that, on average, about 44% of the variability in COVID-19 case rates was related to pollen exposure, often in synergy with humidity and temperature.</p>
<p>The infection rates tended to rise four days after a high pollen count. If there was no local lockdown, the infection rate increased by an average of about 4% per 100 pollen grains in a cubic meter of air. A strict lockdown cut the increase by half.</p>
<p>This pollen exposure isn’t just a problem for people with hay fever. It’s a reaction to pollen in general. Even types of pollen that typically don’t cause allergic reactions were correlated with an increase in COVID-19 infections.</p>
<h2>What precautions can people take?</h2>
<p>On days with high pollen counts, try to stay indoors to limit your exposure as much as possible.</p>
<p>When you’re outdoors, wear a mask during pollen season. Pollen grains are large enough that almost any mask designed for allergies will work to keep them out. However, if you’re sneezing and coughing, wear a mask that’s effective against the coronavirus. If you’re asymptomatic with COVID-19, all that sneezing increases your chances of spreading the virus. Mild cases of COVID-19 could also be <a href="https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/covid-19-cold-flu-and-allergies-differences/art-20503981">mistaken for allergies</a>. </p>
<h2>Why is pollen season lasting longer?</h2>
<p>As the climate changes, we’re seeing <a href="https://doi.org/10.1073/pnas.2013284118">three things</a> that relate specifically to pollen.</p>
<p>One is an earlier start to pollen season. Spring changes are starting earlier, and there are signals globally of exposure to pollen earlier in the season.</p>
<p>Second, the overall pollen season is getting longer. The time you’re exposed to pollen, from spring, which is primarily driven by tree pollen, to the summer, which is weeds and grasses, and then the fall, which is primarily ragweed, is about <a href="https://doi.org/10.1073/pnas.2013284118">20 days longer</a> in North America now than it was in 1990. As you move toward the poles, where <a href="https://arctic.noaa.gov/Report-Card/Report-Card-2019/ArtMID/7916/ArticleID/831/Executive-Summary">temperatures are rising faster</a>, we found that the season is becoming even more pronounced.</p>
<p>Third, more pollen is being produced. Colleagues and I <a href="https://doi.org/10.1073/pnas.2013284118">described all three changes</a> in a paper published in February.</p>
<p>As climate change drives pollen counts upward, that could potentially result in greater human susceptibility to viruses.</p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>.]</p>
<p>These changes in the pollen season have been underway for several decades. When my colleagues and I looked back at as many different <a href="https://doi.org/10.1016/S2542-5196(19)30015-4">records of pollen keeping</a> as we could locate since the 1970s, we found solid evidence suggesting that these shifts have been happening for at least the past 30 to 40 years.</p>
<p>Greenhouse gas concentrations are rising and the surface of the Earth is warming, and that’s going to <a href="https://nca2018.globalchange.gov/">affect life as we know it</a>. I’ve been studying climate change for 30 years. It’s so endemic of the current environment that it’s going to be hard to look at any medical issue without at least trying to understand whether climate change has already affected it or is going to do so.</p><img src="https://counter.theconversation.com/content/156754/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lewis Ziska 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>As climate change drives pollen counts upward, that could potentially result in greater human susceptibility to other viruses, as well.Lewis Ziska, Associate Professor of Environmental Health Sciences, Columbia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1516722021-03-01T13:16:26Z2021-03-01T13:16:26ZWhy do flowers smell?<figure><img src="https://images.theconversation.com/files/376865/original/file-20201231-17-b5tlb0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A floral scent can be enjoyable for a person, but it has an important job for the flower.</span> <span class="attribution"><span class="source">Richard L. Harkess</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</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">
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<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 flowers smell? – Henry E., Age 9, Somerville, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Imagine walking through a tropical forest as a sweet scent wafts through the air. A little farther down the path, the putrid stench of rotting flesh makes you catch your breath. Upon investigation, you find that both odors originate from flowers – but why do flowers smell like anything at all?</p>
<p>It’s actually part of a strategy that helps flowering plants reproduce themselves and spread their species. Certain scents help these flowers solve a big problem.</p>
<p>Plants flower to produce seeds that can go on to become new plants. To make a viable seed, pollen from one part of the flower must <a href="https://www.fs.fed.us/wildflowers/pollinators/What_is_Pollination/">fertilize the ovules</a> in another part of the flower. <a href="https://www.fs.fed.us/wildflowers/pollinators/What_is_Pollination/birdsandbees.shtml">Some plants can self-pollinate</a>, using their own pollen to fertilize the ovule. Others require pollen from another plant of the same species – that’s called <a href="https://www.fs.fed.us/wildflowers/pollinators/What_is_Pollination/birdsandbees.shtml">cross-pollination</a>.</p>
<p>So how does one plant get some other individual plant’s pollen where it needs to be?</p>
<p>Sometimes gravity helps pollen fall into place. Sometimes wind carries it. Wind-pollinated flowers, like those of many trees and grasses, don’t produce a scent.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bee transfers pollen from one blossom to another" src="https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382302/original/file-20210203-21-1afen3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Animal pollinators can carry pollen from one flower’s stigma to another flower’s ovule as they forage for food.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/the-process-of-cross-pollination-with-bee-royalty-free-illustration/1060121100">ttsz/iStock via Getty Images Plus</a></span>
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<p>Other flowers are pollinated by birds, bats, insects or even small rodents carrying the pollen from one flower to another. In these cases, the flowers might provide a little incentive. <a href="https://www.esa.org/blog/2018/04/04/vertebrate-polinator-metaanalysis/">Animal pollinators are rewarded</a> by sweet energy- and nutrient-rich nectar or protein-packed pollen they can eat.</p>
<p>Flowers that need the help of insects and bats go one step further, producing a floral scent that acts as a smelly kind of welcome sign for just the right pollinator.</p>
<p>An orchid blooming in the tropical forest or a rose in your garden needs to attract a pollinator to bring pollen from flowers of the same species. However, there are flowers which look similar but are from other species. To differentiate itself from other flowers, each species’ flowers puts out a unique scent to attract specific pollinators.</p>
<p>Similar to the perfumes at a department store counter, flower scents are made up from a large and diverse number of chemicals which evaporate easily and float through the air. The type of chemical, its amount and its interaction with other chemicals give the flower its unique scent. The <a href="https://www.smithsonianmag.com/smart-news/why-do-flowers-smell-good-349826/">scent of a rose</a> may consist of as many as 400 different chemicals.</p>
<p>People can smell these floral scents because they easily evaporate from the flower, drifting on the air currents to attract pollinators. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="corpse flower blossom in a greenhouse" src="https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382303/original/file-20210203-21-8gnlyv.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">The giant corpse flower has a very stinky scent that its pollinators love.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/titan-arum-royalty-free-image/911610946">Photography by Mangiwau/Moment via Getty Images</a></span>
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<p>Flower fragrances may be sweet and fruity, or they can be musky, even stinky or putrid depending on the pollinator they are trying to attract. A blooming apple or cherry tree emits a sweet scent to attract bumblebees, honeybees and other bees. But stick your nose into the beautiful flowers of a pear tree – a close relative of apples and cherries – and you may recoil in disgust, as these flowers smell musky or putrid to attract flies as pollinators. Similarly, the <a href="https://www.usbg.gov/corpse-flowers-us-botanic-garden">corpse flower</a>, native to Indonesian rainforests, emits a foul odor reminiscent of rotting flesh to attract flies and beetles to pollinate its flowers.</p>
<p>Moths and bats flying at night locate flowers by the scent some release after the Sun goes down. The night-blooming cereus, the saguaro cactus and the dragon fruit all have large white flowers which open at night – they seem to glow in the moonlight, making them visible to nocturnal visitors. Their strong perfume helps guide pollinators inside. While drinking the sweet nectar, the pollinator picks up pollen which it then deposits in the next flower visited.</p>
<p>Once pollinated, the flower stops producing a floral scent and nectar and redirects its energy to the fertilized embryo that will become the seed.</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/151672/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Harkess has received funding from USDA/NIFA. </span></em></p>Not all flowers smell good, to people at least, but their scents are a way to attract pollinators.Richard L. Harkess, Professor of Floriculture and Ornamental Horticulture, Mississippi State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1461092020-09-29T20:01:34Z2020-09-29T20:01:34ZOnce again, wattles are out in bloom: here’s what makes our iconic flowers so special<figure><img src="https://images.theconversation.com/files/359953/original/file-20200925-14-11k2voc.jpg?ixlib=rb-1.1.0&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>Spring has arrived, and all over the country the hills and riversides are burnished with the green and gold of Australian wattles, all belonging to the genus <em>Acacia</em>. </p>
<p>It’s a spectacular sight, but not a surprising one as there are about 1,000 Australian species in the <a href="http://www.anbg.gov.au/acacia/"><em>Acacia</em></a> genus ranging from very small shrubs to tall, longed-lived trees. They occur in ecosystems from the arid inland to the wet forests of the east coast. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/tree-ferns-are-older-than-dinosaurs-and-thats-not-even-the-most-interesting-thing-about-them-138435">Tree ferns are older than dinosaurs. And that's not even the most interesting thing about them</a>
</strong>
</em>
</p>
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<p>Wattles have been widely used by Indigenous people for millenia, and celebrated by “<a href="http://www.wattleday.asn.au/about-wattles/what-do-you-know-a-few-wattle-facts">Wattle Day</a>” on September 1 for more than a century. </p>
<p>But their lineage may be much older. Australian wattles have relatives in Africa, South America, India and parts of Southeast Asia. This distribution suggests the wattles may have originated in Gondwana before the super-continent fragmented about 180 million years ago. </p>
<p>So let’s take a closer look at what makes these iconic flowers so special. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wattle on a cloudy day" src="https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.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">Wattle can always brighten a dreary day.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Don’t blame wattles for your hay fever</h2>
<p>Not everyone welcomes the wattles’ golden blooms — many blame wattle pollen for their hay fever or asthma. </p>
<p>However, many species of wattle have <a href="https://www.abc.net.au/news/health/2015-09-23/dont-blame-the-wattle/6791396">aggregated pollen</a>, which means it’s very heavy and tends to fall straight to ground. You have to be virtually under the plant for it to affect you. </p>
<p>They can cause trouble, but it’s more likely your allergy is due to some other inconspicuous plant, such as grass, that you haven’t noticed compared to the bright yellow of the wattles. It’s worth having an allergy test.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-manage-grass-pollen-exposure-this-hay-fever-season-an-expert-guide-123271">How to manage grass pollen exposure this hay fever season: an expert guide</a>
</strong>
</em>
</p>
<hr>
<p>While a majority of wattles flower in spring and summer, a significant group — such as the sunshine wattle (<em>A. botrycephala</em>), Gawler Range wattle (<em>A. iteaphylla</em>) and flax wattle (<em>A linifolia</em>) — flowers in <a href="https://www.abc.net.au/science/articles/2003/07/03/2578547.htm">autumn and winter</a>. This can give the impression in some places that they’re flowering year-round. </p>
<p>What’s more, many species are hardy, and they can help in the process of taking nitrogen from the air and adding to the soil. That means they can be very handy in ancient, nutrient-poor Australian soils. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A mulga in the Australian desert" src="https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mulga grows over about 20% of our continent.</span>
<span class="attribution"><span class="source">Mark Marathon/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many of the smaller shrub wattles may live for only a decade or so, but some, <a href="http://theconversation.com/the-mighty-mulga-grows-deep-and-lives-long-118838">such as mulga</a> (<em>Acacia aneura</em>) can live for centuries and are crucial to the viability and stability of arid inland ecosystems. They can have surprisingly large and deep root systems for such small shrubs or trees. This is to obtain water, but also binds the soil.</p>
<p>However, mulga-munching horses, cattle and other feral grazers threaten the persistence of mulga-dominated communities. If mulga and other inland <em>Acacia</em> species are lost, the soils can become loose and mobile, which results in stable productive land becoming desert.</p>
<h2>By any other name</h2>
<p>In the early 2000s, there was <a href="https://www.australiangeographic.com.au/topics/wildlife/2016/03/the-wattle-war/">fierce debate</a> among plant taxonomists about how closely the African and Australian species were related. </p>
<p>The name “Acacia” rightly belonged to the African group, but because there were so many Australian species that would need to be renamed, Australia was allowed to keep the name “Acacia” in 2011 — much to the chagrin of foreign taxonomists. </p>
<p>This resulted in the genus being divided. Australian wattles stayed as <em>Acacia</em>, but African wattles are now in the genera <em>Vachellia</em> or <em>Senegalia</em>, and those from the middle Americas (around Mexico) are <em>Acaciella</em> and <em>Mariosousa</em>. </p>
<p>The different names reflect long, separate histories and different ecological characteristics. (The name changes rankle still with taxonomists!) </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of black wattle flowers" src="https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Black wattle is a pest overseas.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>There are also weedy wattles in Australia and elsewhere. Many of us know from hard experience that the splendid ornamental tree, Cootamundra wattle (<em>Acacia baileyiana</em>), can become a weed if it grows outside its very restricted natural range in New South Wales. And Australia’s <a href="http://theconversation.com/the-black-wattle-is-a-boon-for-Australians-and-a-pest-everywhere-else-100529">black wattle</a> (<em>A. mearnsii</em>) is a significant weed in other parts of the world. </p>
<p>It can come as a bit of a blow to know Australia’s floral emblem, golden wattle (<em>A. pycnantha</em>), can be weedy both at home and when it travels abroad (perhaps like some Australians). </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-black-wattle-is-a-boon-for-australians-and-a-pest-everywhere-else-100529">The black wattle is a boon for Australians (and a pest everywhere else)</a>
</strong>
</em>
</p>
<hr>
<p>Interestingly, most of the Australian wattles lack thorns, unlike <a href="http://worldwidewattle.com/schools/animals.php">their relatives in Africa</a>. In Africa, thorns protect the plants from large mammalian grazers such as giraffes. </p>
<h2>Ants love wattles, too</h2>
<p>If you don’t like ants, it might be worth checking which species of wattle you have in your backyard, or intend to buy.</p>
<p>Many wattles have a very special relationship with some insects. In Central America, ants penetrate the thorns of Bulls Horn wattle trees and establish their colonies. They then defend the tree against other insects, and if branches of another tree touch the host tree, the ants will cause such damage that the other tree will die back. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.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">There are more than 1,000 species of wattle in the <em>Acacia</em> genus.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>In Australia, the relationship between ants and wattles is based on food. The hard wattle seeds have a tasty and oil-rich outgrowth called an “aril”, which is irresistible to some ant species. </p>
<p>The ants harvest the seeds and take them back to their nest, where they’re safe from other hungry grazers until it is damaged by fire or flood and the seeds germinate. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-tiny-ants-have-invaded-your-house-and-what-to-do-about-it-132092">Why tiny ants have invaded your house, and what to do about it</a>
</strong>
</em>
</p>
<hr>
<p>Some wattles, the mulga among them, have little <a href="http://worldwidewattle.com/schools/animals.php">glands</a> at the base of their phyllodes (the modified leaf stalks). These glands secrete a form of sugary syrup that attracts feeding ants. These ants may also protect host trees or perhaps leave the flowers alone to allow a greater seed set to grow. </p>
<p>It’s clear wattles have a lot going for them. They are diverse in number, habit, size, longevity and flowering season — there’s a wattle for every occasion. For all of these great traits, it’s still that green and gold that endears them to Australians.</p><img src="https://counter.theconversation.com/content/146109/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>With their vibrant blooms and a lineage tracing back to the ancient supercontinent of Gondwana, wattles have a lot going for them.Gregory Moore, Doctor of Botany, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1434502020-08-21T03:33:07Z2020-08-21T03:33:07ZCurious Kids: how do bees make honey?<figure><img src="https://images.theconversation.com/files/353320/original/file-20200818-22-1mc897p.jpg?ixlib=rb-1.1.0&rect=247%2C53%2C11547%2C8789&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Worker bees with capped brood (brown), open brood (white larva), all sorts of coloured pollen and shiny fresh nectar.</span> <span class="attribution"><span class="source">Cooper Schouten</span>, <span class="license">Author provided</span></span></figcaption></figure><blockquote>
<p><strong>How do bees make honey? Finn, age 7, Sunshine Coast, Queensland</strong></p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Hi Finn, that’s a sweet question! </p>
<p>Well, when we talk about “bees”, we’re usually referring to the European honey bee (its scientific name is <em>Apis Mellifera</em>). Humans have been drooling over its honey and taking advantage of its pollination powers for <a href="https://www.tandfonline.com/doi/abs/10.2752/089279394787001835?journalCode=rfan20">thousands of years</a>.</p>
<p>So how do these insects make honey, you ask? You’ll find the task is one requiring <a href="https://www.cornell.edu/video/honeybee-decision-making">teamwork and organisation</a>.</p>
<h2>Busy buzzing bees</h2>
<p>You probably already know about the most important ingredient needed to make honey: flowers.</p>
<p>A colony of bees can visit up to 50 million flowers each day, with as many as 60,000 bees in each colony. They’re not called busy bees for nothing! </p>
<p>Honey bees work together as a team to make decisions about where the best flowers are. They communicate with each other using bumps, noises and even dance moves known as the waggle dance. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/LOZrNs22FAU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Some bees do the “waggle dance”.</span></figcaption>
</figure>
<p>All bees during their life have <a href="https://www.nationalgeographic.com/animals/2019/03/honey-bee-job-queen-hive-animals/">different roles</a>, depending on how old they are. To make honey, worker honey bees fly up to 5km searching for flowers and their sweet nectar. Usually, they’ll visit between 50 and 100 flowers per trip.</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>
<p>Nectar is the main ingredient for honey and also the main source of energy for bees. Using a long straw-like tongue called a proboscis, honey bees suck up nectar droplets from the flower’s special nectar-making organ, called the <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/nectary">nectary</a>.</p>
<p>When the nectar reaches the bee’s honey stomach, the stomach begins to break down the complex sugars of the nectar into more simple sugars that are less prone to <a href="http://honeypedia.info/why-does-honey-crystallize-fast">crystallization</a>, or becoming solid. This process is called “inversion”.</p>
<p>Once a worker honey bee returns to the colony, it passes the nectar onto another younger bee called a house bee (between 12-17 days old). </p>
<p>House bees take the nectar inside the colony and pack it away in hexagon-shaped beeswax honey cells. They then turn the nectar into honey by drying it out using a warm breeze made with their wings.</p>
<figure class="align-center ">
<img alt="Bees crawling on honeycomb" src="https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350589/original/file-20200731-19-yg6ygv.jpeg?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">Honey bees filling honey beeswax cells before ‘capping’ the cells.</span>
<span class="attribution"><span class="source">Cooper Schouten/Author provided</span></span>
</figcaption>
</figure>
<p>Once the honey has dried out, they put a lid over the honey cell using fresh beeswax – kind of like a little honey jar. In the winter, when the flowers have finished blooming and there’s not as much nectar available, the bees can open this lid and share the honey they saved. </p>
<h2>Honey: a food fit for all workers, human and bee</h2>
<p>Because nectar comes from flowers, there are hundreds of different types of honey with different colours, smells and flavours. Some honey can even be used as <a href="https://www.sciencedirect.com/science/article/pii/S1319562X16301863">medicine</a>.</p>
<p>Also, bees don’t just collect nectar to make honey. When they visit flowers, they also collect pollen – which is a great source of protein to keep them healthy and strong. </p>
<p>Pollen is a kind of powder which flowering plants, trees and grasses make (and must spread) to help more of the same plants grow around them. Pollen can spread in ways such as being blown around by the air, or being carried between two of the same plant by an insect.</p>
<p>So by transferring pollen between flowers, bees also help pollinate flowers. These often turn into the seeds of the fruit and nuts we eat. In fact, about <a href="https://www.sciencedaily.com/releases/2006/10/061025165904.htm">one-third</a> of the food we eat is pollinated by bees. </p>
<figure class="align-center ">
<img alt="Man holds up section from beehive" src="https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350584/original/file-20200731-25-udfvt7.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">Beekeeping entrepreneur and manager at Highlands Honey, Henao Longgar, holds up a bee-utiful pollen frame covered in bees in the Eastern Highlands of Papua New Guinea.</span>
<span class="attribution"><span class="source">Cooper Schouten/Author provided</span></span>
</figcaption>
</figure>
<h2>Pollinators around the globe</h2>
<p>Did you know the yellow fuzzy honey bee is just one of over 20,000 bee species in the world? There are more than 1,700 in Australia alone, some of which can make honey. </p>
<p>Some native stingless bees <a href="https://www.aussiebee.com.au/beesinyourarea.html">only found in Australia</a>, such as <em>Tetragonula carbonaria</em> and <em>Austroplebeia australis</em>, produce honey too. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Beekeeper cuts honeycomb from tree branch" src="https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350585/original/file-20200731-21-1d1twuu.jpg?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">Collecting honey made by giant honey bees in Sumbawa, Indonesia.</span>
<span class="attribution"><span class="source">Cooper Schouten/Author provided</span></span>
</figcaption>
</figure>
<p>There are also ten other honey bee species overseas, such as the <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/1745-5871.12380">giant honey bee</a> (<em>Apis dorsata</em>) in Nepal and Indonesia, which live at the top of high cliffs and large trees. </p>
<p>There’s also the <a href="https://www.tandfonline.com/doi/full/10.1080/0005772X.2018.1564497">Eastern honey bee</a> (<em>Apis cerana</em>) which is managed by beekeepers in rural and remote areas throughout Southeast Asia. </p>
<p>There’s never been a better time to put in native flowering plants and stop to smell the flowers. It’s important to remember, just like your puppy or kitten, bees need to be looked after too.</p>
<iframe src="https://giphy.com/embed/8shyTgbZKKLzW" width="100%" height="374" frameborder="0" class="giphy-embed" allowfullscreen=""></iframe>
<p><a href="https://giphy.com/gifs/food-bees-8shyTgbZKKLzW"></a></p><img src="https://counter.theconversation.com/content/143450/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cooper Schouten receives funding from The Australian Centre for International Agricultural Research.</span></em></p>A single colony of bees can have 60,000 bees in it. Together, they can visit up to 50 million flowers each day to collect pollen and nectar. They’re not called ‘busy bees’ for nothing!Cooper Schouten, Project Manager - Bees for Sustainable Livelihoods, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1232712019-09-27T02:25:29Z2019-09-27T02:25:29ZHow to manage grass pollen exposure this hay fever season: an expert guide<figure><img src="https://images.theconversation.com/files/294008/original/file-20190925-51410-f2ecs2.jpg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spring has sprung, which means it's hay fever season.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>Nearly <a href="https://www.aihw.gov.au/reports/chronic-respiratory-conditions/allergic-rhinitis-hay-fever/contents/allergic-rhinitis">one in five</a> Australians are affected by <a href="https://www.allergy.org.au/patients/allergic-rhinitis-hay-fever-and-sinusitis">hay fever</a>. If you’re one of the unlucky ones, you’ll know how troublesome the symptoms can be.</p>
<p>Grass pollen is the major outdoor trigger of hay fever and allergic asthma. Pollen grains contain a variety of allergens that can trigger allergic reactions in people who are sensitised to pollen. </p>
<p>The good news is, if pollen is a problem for you, there are things you can do to manage your exposure to it. By adopting some simple tips alongside preventative medications, you may find this hay fever season a little more manageable.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-you-know-if-your-child-has-hay-fever-and-how-should-you-treat-it-122853">How do you know if your child has hay fever and how should you treat it?</a>
</strong>
</em>
</p>
<hr>
<h2>What causes hay fever?</h2>
<p>People who are <a href="https://www.nature.com/articles/ng.3985">genetically prone to develop allergies</a> may become sensitised to pollen.</p>
<p>Sensitisation involves development of specific antibodies (called Immunoglobulin E, or IgE) that can bind to the triggering allergen. Repeated exposure to the triggering allergen leads to the activation of inflammatory cells, causing the release of histamine and other mediators. That’s when the symptoms kick in.</p>
<p>An allergic reaction to pollen can lead to hay fever symptoms affecting the upper airways, including itchy, watery eyes, an itchy, inflamed throat, a runny or blocked nose, and sneezing.</p>
<p>Pollen allergy can also lead to what we call allergic asthma – if the allergen components enter deeper into the lungs, this can cause inflammation and symptoms of asthma, like shortness of breath.</p>
<p>While hay fever has long been regarded a trivial condition, it can be <a href="https://medicinetoday.com.au/2015/october/feature-article/hay-fever-%E2%80%93-underappreciated-and-chronic-disease">a serious chronic disease</a> associated with other problems such as sinusitis, sleep disturbance because of nasal blockage, and asthma, leading to fatigue and poor performance at work or school. </p>
<h2>What can you do to reduce exposure to pollen allergens?</h2>
<p>The tragic thunderstorm asthma epidemic of <a href="https://www.thelancet.com/pdfs/journals/lanplh/PIIS2542-5196(18)30120-7.pdf">November 2016 in Melbourne</a> shocked many and elucidated the potential harm of grass pollen exposure. </p>
<p>Lessons from this event illustrate staying indoors with the windows closed reduces risk of experiencing severe symptoms.</p>
<p>Many people affected by thunderstorm asthma recall being outside prior to the passage of the thunderstorm <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/all.13609">across the greater Melbourne region</a> during the late evening of November 21, 2016. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-the-link-between-hay-fever-and-asthma-and-how-are-they-treated-64740">What's the link between hay fever and asthma, and how are they treated?</a>
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<p>Of course, this was an uncommon event, and the majority of people who get hay fever will not experience this level of illness.</p>
<p>On high pollen days, or after thunderstorms in spring, people who are allergic to pollen <a href="https://www.allergy.org.au/patients/allergy-treatment/allergen-minimisation">should stay inside</a> with windows closed when possible. They should also drive with the car windows closed and the air on a setting where it’s circulating, rather than coming in from outside. </p>
<p>Other actions people can take to reduce allergen exposure are to hang washing inside or use a tumble dryer on high pollen days, avoid activities such as mowing the lawn, wear sunglasses outdoors, and shower after activities likely to involve pollen exposure.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294018/original/file-20190925-51457-1t005rw.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">Close to one in five Australians suffer from hay fever.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<h2>A national standardised pollen monitoring network</h2>
<p>For people with hay fever, knowing when the pollen count is likely to be high can be helpful in managing exposure. There are an increasing number of <a href="https://www.melbournepollen.com.au/mobile-app/">mobile apps</a> you can use to monitor the pollen count in your area in real time.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A screenshot from pollen monitoring app ‘Melbourne Pollen Count’.</span>
<span class="attribution"><span class="source">Screenshot</span></span>
</figcaption>
</figure>
<p>In 2016, the National Health and Medical Research Council funded the <a href="https://auspollen.com.au/">AusPollen Partnership</a>. Since its inception, and with the efforts of many researchers, a national standardised pollen monitoring network is being established to help address unmet needs of patients with hay fever and allergic asthma in our community.</p>
<p>The AusPollen Partnership seeded the growth of a number of projects in which pollen monitoring is a key activity; for instance <a href="https://airrater.org/">AirRater</a> in Tasmania and VicTAPS in Victoria. Australian pollen monitoring sites now adopt <a href="https://www.allergy.org.au/hp/papers/australian-airborne-pollen-and-spore-monitoring-network-interim-standard-and-protocols">standard protocols</a> to harmonise pollen monitoring processes so data is comparable between locations. </p>
<p>While expanding the pollen monitoring network, we’ve had the opportunity to evaluate how providing people with local, current daily pollen information helps. </p>
<p>In a pilot study, we found people who didn’t have access to local pollen information indicated a desire to have local pollen information, while people who did have access to pollen information reported it was <a href="https://link.springer.com/article/10.1007%2Fs10453-019-09602-1">very useful</a>. Respondents used pollen information to plan their daily activities, to minimise pollen exposure and to optimise medication use.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-are-the-options-for-treating-hay-fever-48342">Health Check: what are the options for treating hay fever?</a>
</strong>
</em>
</p>
<hr>
<h2>Preventative medication has an important role</h2>
<p>While minimising exposure to pollen may help reduce symptoms when pollen levels are high, the cornerstone to symptom management and safety during the pollen season is preventative medication like steroid nasal sprays and antihistamines. These can reduce the underlying allergic inflammation and alleviate symptoms of hay fever.</p>
<p>Before the onset of the pollen season, people who are allergic to pollen and suffer from troublesome symptoms should start using medications daily. Control of underlying allergic inflammation in the upper airways is best achieved with nasal sprays containing a topically active steroid. Non-sedating antihistamine tablets and eye drops provide symptom relief (but don’t alter the underlying inflammation). </p>
<p><a href="https://www.allergy.org.au/patients/asthma-and-allergy/thunderstorm-asthma">Seasonal asthma and/or thunderstorm asthma</a> can occur during the grass pollen season in some people with pollen allergy. Those who experience lower airway symptoms during the grass pollen season such as a cough, tight chest, breathlessness or wheeze, should seek medical attention to consider whether they have undiagnosed <a href="https://asthma.org.au/about-asthma/how-we-can-help/first-aid/">asthma</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/thunderstorm-asthma-whos-at-risk-and-how-to-manage-it-86397">Thunderstorm asthma: who's at risk and how to manage it</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/123271/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janet Davies receives funding from The National Health and Medical Research Council, Australian Research Council, National Foundation for Medical Research Innovation, Emergency Medicine Foundation, Bureau of Meteorology, Victorian Department of Health and Human Services as well as co-sponsorship from Abionic Switzerland, Stallergenes Australia, Asthma Australia iwth in kind co-contributions from Australasian Society for Clinical Immunology and Allergy, CSIRO, Bureau of Meteorology,and Federal Office of Meteorology and Climatology MeteoSwiss, Switzerland. She is an inventor of patents assigned to QUT granted in Australia, allowed in USA and two applications pending examination. Prof. Davies’s institute has received Honorarium payments and travel expenses for education sessions and conference presentations from Stallergenes Australia, GlaxoSmithKliene, Wymedical, and Meda Pharmaceuticals. </span></em></p><p class="fine-print"><em><span>Connie Katelaris is a principal investigator on an NHMRC partnership grant for AusPollen Partnership. Dr Katelaris is also principal investigator on clinical trials in severe allergic asthma sponsored by Sanofi and Novartis. She receives honorarium for advisory board participation in Seqirus.</span></em></p><p class="fine-print"><em><span>Danielle Medek 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.</span></em></p>If you get hay fever, minimising your exposure to grass pollen is likely to be useful. Fortunately, it’s becoming easier to keep track of the pollen count. But what do you do when it’s high?Janet Davies, Professor, Queensland University of TechnologyConnie Katelaris, Professor of Immunology and Allergy, UWAS & Head of Unit, South Western Sydney Local Health DistrictDanielle Medek, Physician trainee, researcher, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1216812019-08-19T19:03:47Z2019-08-19T19:03:47ZStill sneezing? Climate change may prolong allergy season<figure><img src="https://images.theconversation.com/files/287429/original/file-20190808-144873-1mtiqbt.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5590%2C3741&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change has caused pollen seasons to start sooner and last longer. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Every year, without fail, summer brings changes to our surroundings: more sunlight, heat, greenness and flowers, among many others. For some people, these changes also mean increasing physical discomfort <a href="https://doi.org/10.1080/09603123.2011.574269">because along with the flowers, trees and grass comes pollen</a>.</p>
<p>The discomfort caused by pollen can be felt by many people, like watery eyes or a stuffy nose. More often than not, people first turn to the internet to find out what their symptoms mean and to identify some possible options for relief. </p>
<p>At its core, an allergic reaction means that our immune system is overreacting to a foreign particle that may be harmless otherwise. In some cases, the immune system deploys a defence, producing symptoms of airway irritation that <a href="https://asthma.ca/get-help/asthma-3/aboutasthma/ask-asc-expert/">resemble a cold, including a runny nose, watering eyes, fatigue and trouble breathing</a>. </p>
<p>Even though the symptoms of an allergic reaction or an asthma attack are mostly felt in the respiratory system, they have been linked to other health conditions like <a href="https://doi.org/10.1093/aje/kwv252">myocardial infarctions</a> and <a href="https://doi.org/10.1097/EDE.0000000000000573">earlier deliveries in pregnant women</a>.</p>
<p><a href="https://trends.google.com/trends/explore?q=seasonal%20allergies">As shown in this Google Trends result</a>, searches for the term “seasonal allergies” in Canada tend to spike around the same dates as the pollen concentrations in the air do: around the third week of April.</p>
<h2>Multiple pollen seasons</h2>
<p>In our 2018 review of aeroallergens in Canada, we described <a href="https://doi.org/10.3390/ijerph15081577">how pollen seasons for weeds, trees and grasses have different start and end dates</a>. Roughly, the seasons for most of the pollen that cause aches and irritation start around spring, with the exception of weeds — like ragweed — that tend to blossom in late summer. </p>
<p>Plant flowering depends on many environmental factors, <a href="https://doi.org/10.1016/S2542-5196(19)30015-4">such as humidity or minimum temperature</a>, so it’s hard to pinpoint a national start date for the pollen seasons. It’s more likely that different places will experience pollen seasons that match their particular range of temperatures, flora and other aspects of their geography.</p>
<p>Because pollen concentrations depend so much on the environmental conditions that surround the plant that produces it, <a href="https://doi.org/10.1111/imj.13699">many changes in the environment can affect pollen concentrations and pollen seasons</a>. </p>
<p>Climate change is already altering flowering seasons worldwide and in turn, <a href="https://doi.org/10.1111/2041-210X.13024">creating longer pollen seasons</a>. The dates that were traditionally considered the start and end of pollen seasons have become obsolete because the seasons are generally starting earlier and ending later. </p>
<p>Currently, in Canada, we breathe pollen for more days than before and, for those of us whose immune systems tend to overreact, <a href="https://doi.org/10.1016/S2542-5196(19)30015-4">we suffer from physical symptoms for longer stretches of time</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287461/original/file-20190809-144868-9d30ri.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">Ragweed is highly allergenic, and produces pollen beginning in August and into the autumn.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Individual differences</h2>
<p>In addition to the environmental differences, we must consider individual differences too. Not everyone is affected by pollen in the same degree; for some people, the pollen season might go unnoticed if not for the change in scenery. However, for people whose immune systems have been sensitized to the allergenic proteins in pollen, <a href="https://doi.org/10.1007/s11882-016-0603-z">the increased amounts of pollen in the air triggers very specific symptoms</a>.</p>
<p>The immune system is responsible for our bodies’ response to pollen and reacts to perceived threats in a continuum that goes from diminished responses, like <a href="https://aidsinfo.nih.gov/understanding-hiv-aids/fact-sheets">in immunocompromised individuals</a>, to no physical reaction and <a href="https://doi.org/10.1007/978-3-7091-1890-0_1">then to heightened responses (allergies)</a>.</p>
<p>Because there is no known single cause for the development of allergies, it’s impossible to suggest a solution to protect oneself. However, for people who already suffer from allergies, some actions are known to be effective in decreasing the discomfort caused by their symptoms:</p>
<ol>
<li><p>Be aware of the pollen concentrations in your area and <a href="https://asthma.ca/allergies/taking-control/">stay indoors when they are high</a>.</p></li>
<li><p>Take a shower or a bath before bedtime in order to avoid inhaling the pollen that <a href="https://www.aap.org/en-us/about-the-aap/aap-press-room/news-features-and-safety-tips/Pages/7-Tips-for-Kids-Allergies.aspx">might remain in your hair and body after going outdoors</a>.</p></li>
<li><p>If you have been diagnosed with allergies (or asthma), or even if you have not been diagnosed but have felt symptoms in the past, schedule a consultation with your primary care provider before pollen season starts. In this appointment you can discuss potential actions to prevent your symptoms and, maybe even plan to use over-the-counter or prescription medications.</p></li>
<li><p>Consider allergy testing. This can pinpoint <a href="https://www.theweathernetwork.com/news/articles/pollen-season-is-upon-us-whos-getting-it-bad-this-year/66940">the allergen causing your symptoms and help in the treatment plan your physician will design with you</a>.</p></li>
<li><p>Use air conditioners or a high-efficiency particulate air (HEPA) filter in your house, or in the rooms where you spend most of your <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165134/">oftime</a>. These filters have proven to be useful for pollen as well as for the smoke caused during the wildfire season, which in some Canadian cities runs parallel to the last leg of the pollen season.</p></li>
</ol>
<p>Even with the changes that climate change is already causing — <a href="https://doi.org/10.1029/2018GH000153">and will continue to cause in the near future</a> — pollen season still happens every year. </p>
<p>Taking a proactive stance and learning about your allergies and how pollen might affect you is a first step in controlling your symptoms, allowing you a more enjoyable spring, summer and fall outdoors.</p>
<p>[ <em><a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=expertise">Expertise in your inbox. Sign up for The Conversation’s newsletter and get a digest of academic takes on today’s news, every day.</a></em> ]</p><img src="https://counter.theconversation.com/content/121681/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cecilia Sierra-Heredia receives funding from Simon Fraser University (Faculty of Health Sciences, Graduate Student Society and KEY Big Data Initiative) and AllerGen.</span></em></p><p class="fine-print"><em><span>Jordan Brubacher receives funding from Simon Fraser University and has received funding from Toronto Public Health in the past. </span></em></p><p class="fine-print"><em><span><a href="mailto:ttakaro@sfu.ca">ttakaro@sfu.ca</a> receives funding from Health Canada.</span></em></p>Allergic reactions to pollen may occur at different times of the year and for prolonged periods, and this will worsen with climate change.Cecilia Sierra-Heredia, Lecturer, Simon Fraser UniversityJordan Brubacher, Research assistant, Simon Fraser UniversityTim Takaro, Professor, Associate Dean, Research Health Sciences, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1150172019-04-15T11:21:15Z2019-04-15T11:21:15ZDNA analysis finds that type of grass pollen, not total count, could be important for allergy sufferers<figure><img src="https://images.theconversation.com/files/268955/original/file-20190412-76840-ewwo7w.jpg?ixlib=rb-1.1.0&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/young-man-sneezes-because-allergy-ragweed-1039352290?src=edrdJA1AXwsin1njFbOuRQ-1-58">Elizaveta Galitckaia/Shutterstock</a></span></figcaption></figure><p>As the winter cold is replaced by warmer temperatures, longer days and an explosion of botanical life, up to 400m people worldwide will develop allergic reactions to airborne pollen from trees, grasses and weeds. Symptoms will range from itchy eyes, congestion and sneezing, to the aggravation of asthma and an associated cost to society that <a href="http://www.globalasthmanetwork.org/publications/Global_Asthma_Report_2014.pdf">runs into the billions</a>. </p>
<p>Ever since the 1950s, countries around the world have been recording pollen counts to create forecasts for allergy sufferers. In the UK this forecast is provided by <a href="https://www.metoffice.gov.uk/public/weather/pollen-forecast/#?tab=map&map=Pollen&fcTime=1554375600&zoom=5&lon=-4.00&lat=55.71">the Met Office</a> in collaboration with the University of Worcester. To date, pollen forecasts have been based on counting the total number of grains of pollen in the air from trees, weeds and grass. The pollen is collected using air sampling machines that capture the particles on a slowly rotating sticky drum. </p>
<p>However, while these forecasts focus on the level of all pollens in the air, people suffer from allergic reactions to different types of pollen. Grass pollen, for example, is the most harmful aeroallergen – more people are allergic to grass pollen <a href="https://erj.ersjournals.com/content/24/5/758">than any other airborne allergen</a>. And now our own <a href="http://dx.doi.org/%2010.1038/s41559-019-0849-7">preliminary health data</a> suggests that allergies to this pollen vary across the grass flowering season. </p>
<h2>Pinpointing pollen</h2>
<p>In an effort to improve the accuracy of pollen counts and forecasts, we have been working <a href="https://theconversation.com/were-working-on-a-more-accurate-pollen-forecasting-system-using-plant-dna-97474">on a new project</a> to distinguish between different types of grass pollen in the UK. The aim is to find out what species of pollen are present across Britain throughout the grass flowering season. </p>
<p>Microscopes are used to identify the pollen of many allergenic tree and weeds, but unfortunately this can’t be done for grass pollen, since all grass pollen grains look highly similar underneath a microscope. This means it is almost impossible to routinely distinguish the species of grass they come from using visual observation.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/BAG-4TrAddU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>So, over the past few years, our research team, <a href="http://pollergen.bangor.ac.uk/">PollerGEN</a>, has been investigating whether a new wave of approaches, including molecular genetics, can be used to identify different airborne grass pollens instead. One method that our team has employed to identify the pollen relies on using DNA sequencing to examine millions of short sections of DNA (also called barcode markers). These markers are unique to each species or genus of grass pollen. </p>
<p>This approach is called “metabarcoding” and it can be used to analyse DNA derived from mixed communities of organisms, as well as DNA from many different types of environmental sources (for example, soil, aquatic sources, honey and the air). It means that we can assess the biodiversity of hundreds to thousands of samples. In particular, it has allowed us to analyse pollen DNA collected by aerial samplers at 14 rooftop locations across Britain.</p>
<h2>Flowering season</h2>
<p>By comparing the pollen we captured to samples in the <a href="https://botanicgarden.wales/science/collections/barcode-uk/">UK plant DNA barcode library</a> (an established reference DNA database of correctly identified grass species) we have been able to identify different types of grass pollen from complex mixtures of airborne pollen. This has allowed us to visualise how different types of grass pollen are distributed throughout Britain across the grass flowering season. </p>
<p>While there was a real chance that aerial pollen mixtures could be very varied and haphazard – due to the mobility of pollen in the environment and the fact that different grasses flower at different times of the season – our newly published study has found that <a href="http://dx.doi.org/%2010.1038/s41559-019-0849-7">this is not the case</a>. We have found that the composition of airborne pollen resembles a seasonal progression of diversity, featuring early, then mid and late-season flowering grasses. </p>
<p>By combining other historical and contemporary data, we also found that as the grass flowering season progresses, airborne pollen follows a sensible, but delayed appearance from the first flowering times noted from the ground. This means that different types of grass pollen are not present throughout each period of the flowering season. They disappear from the environmental mixture.</p>
<p>This research is important to more than just our understanding of plants. Our own emerging evidence suggests that over-the-counter medications are not uniform throughout the grass flowering season. So certain types of grass pollen may be contributing more to allergenic disease than others. It could be that when symptoms are particularly bad, allergies are caused by the type of grass pollen in the air, not just the amount. </p>
<p>In the next few months, we will be looking into different forms of pollen and health data, to investigate links between the biodiversity of aerial pollen and allergenic symptoms. The overarching aim of our work is to eventually provide better forecasting, planning and prevention measures to enable less people to suffer from grass allergenic disease.</p><img src="https://counter.theconversation.com/content/115017/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Creer receives funding from The Natural Environment Research Council.</span></em></p><p class="fine-print"><em><span>Georgina Brennan receives funding from The Natural Environment Research Council.</span></em></p>Pollen counts focus on the amount of grains in the air, but it could be the species that are more important.Simon Creer, Professor in Molecular Ecology, Bangor UniversityGeorgina Brennan, Postdoctoral Research Officer, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1147222019-04-03T10:47:10Z2019-04-03T10:47:10ZPollen is getting worse, but you can make things better with these tips from an allergist<figure><img src="https://images.theconversation.com/files/267206/original/file-20190402-177199-8izsl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A girl in a field of flowers.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pollen-allergy-girl-sneezing-field-flowers-93088627">Alex Cofaru/Shutterstock.com</a></span></figcaption></figure><p>Blooming spring flowers signal the beginning of spring, but for millions of people, they also signal the onset of the misery: <a href="https://acaai.org/allergies/seasonal-allergies">allergy and asthma season</a>. Itchy, watery eyes; sneezing, runny nose; cough and wheezing are triggered by an overreaction of the body to <a href="https://www.aaaai.org/conditions-and-treatments/conditions-dictionary/pollen">pollen.</a></p>
<p>Every spring, trees and grasses release billions of buoyant pollen granules into the air, using the wind to disburse across the countryside in an effort to reproduce. It’s all about survival; plants that release more pollen have the survival advantage. </p>
<p>As an adult and pediatric allergist-immunologist in the Midwest, the onset of spring signals my busy season treating hundreds of patients for their seasonal allergy and asthma symptoms. If you suffer through the season, know that you are not alone. Throughout history, pollen has taken the fun out of spring for many. In modern times, however, medical science has identified practices and treatments that help. </p>
<h2>Older than the dinosaurs, as wide as the world</h2>
<p>Fossilized specimens of pollen granules have been found predating dinosaurs and alongside <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5098096/">Neanderthals</a>. </p>
<p>And, sinus and asthma symptoms and treatments are documented throughout history and across the globe. People just didn’t know exactly how to treat the symptoms, or exactly what was causing them. </p>
<p>For example, over 5,000 years ago, the Chinese used the berries of the horse tail plant, ma huang (<em>Ephedra distachya</em>), to relieve congestion and decrease mucous production associated with “<a href="http://pennstatehershey.adam.com/content.aspx?productId=107&pid=33&gid=000240">plant fever</a>” - a condition affecting people during the fall. </p>
<p>In Egypt, the “<a href="https://babel.hathitrust.org/cgi/pt?id=coo.31924073200077;view=1up;seq=11">Papyrus Ebers</a>,” written around 1650 B.C., recommended over 20 treatments for cough or difficulty breathing, including honey, dates, juniper and beer. </p>
<p>Although <a href="https://www.ncbi.nlm.nih.gov/pubmed/6757243">Homer’s “Iliad”</a> describes the loud noise of breathing in battle as “asthma,” <a href="https://www.atsjournals.org/doi/full/10.1164/ajrccm.184.12.1420b">Aretaeus of Cappadocia</a> of the second century A.D. is credited with the first clinical description more consistent with modern understanding of this condition. He wrote of those who suffered that: </p>
<p>“They open the mouth since no house is sufficient for their respiration, they breathily standing, as if desiring to draw in all the air which they possibly can inhale… the neck swells with the inflation of the breath, the precordia (chest wall) retracted, the pulse becomes small and dense,” and if the symptoms persist, the patient “may produce suffocation after the form of epilepsy.” </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267207/original/file-20190402-177171-1xf3s40.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">
<figcaption>
<span class="caption">Tobacco leaves were exported to Europe for experimentation in treating the symptoms of spring time coughing and sneezing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tobacco-leaves-drying-shed-194524280">Jeep 2499/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>By the time Columbus landed, indigenous populations in Central and South American were utilizing <a href="https://benthamopen.com/contents/pdf/TONPJ/TONPJ-4-8.pdf">ipecacuanha</a>, a root found in Brazil with expectorant and emetic properties and <a href="https://www.merriam-webster.com/dictionary/balsam">balsam</a>, which is still used in some cold remedies today. <a href="https://www.hindawi.com/journals/emi/2016/4048764/">Coca</a> and tobacco leaves, used medicinally by the Incas, were later exported to Europe for additional experimentation for the treatment of rhinitis and asthma. </p>
<p>Aside from the “plant fever” described in China, the first written description of seasonal respiratory symptoms is credited to <a href="https://www.ncbi.nlm.nih.gov/pubmed/27840475">Rhazes</a>, a Persian scholar, around 900 A.D. He described the nasal congestion that coincided with the blooming of roses, termed “rose fever.” </p>
<h2>Symptoms noticed, but no cause identified</h2>
<p>As scientific advancement was stifled during the Middle Ages, in large part due to the plague, it wasn’t until 900 years later, in 1819, that <a href="https://www.bbc.com/news/magazine-28038630">Dr. John Bostock</a> published a description of his own seasonal allergies. But he didn’t know what was causing them.</p>
<p>Having suffered from “<a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(01)99507-8/fulltext">summer catarrh</a>” since childhood, Bostock persisted in his study of the condition, despite an initial lackluster response from the medical community. </p>
<p>In the nine years between his first and second publications, he found only <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110966/">28 additional cases</a> consistent with his own seasonal allergy symptoms, which perhaps demonstrates the lower prevalence of the condition at the time. He noted that nobility and the privileged classes were more often afflicted by seasonal allergies. This was thought to be the consequence of wealth, culture and an indoor life. </p>
<p>Societal changes with their roots in the Industrial Revolution, including increased exposure to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829390/">air pollution, less time spent outdoors, increased pollen counts and improved hygiene</a>, all likely contributed to the increased prevalence of allergies that we continue to see today. They also helped form the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841828/">hygiene hypothesis</a>, which states that in part decreased exposure to particular bacteria and infections could be leading to the increase in allergic and autoimmune diseases.</p>
<p>The source of seasonal symptoms at the time was also thought to be caused by the smell of new hay. This led to the coining of the term “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110966/">hay fever</a>.” </p>
<p>Bostock instead suspected the recurring symptoms were triggered by the summer heat, since his symptoms improved when he spent the summer on the coast. It would later became common for nobility and aristocrats to spend allergy season in coastal or mountain resorts to avoid bothersome symptoms. </p>
<h2>Identifying the true culprit</h2>
<p>Through methodical study and self-experimentation, <a href="https://hekint.org/2017/01/28/charles-harrison-blackley-the-man-who-put-the-hay-in-hay-fever/">Dr. Charles Blackley</a> identified that pollen was to blame for allergy symptoms. He collected, identified, and described various pollens and then determined their allergic properties by rubbing them into his eyes or scratching them on his skin. He then noted which ones resulted in redness and itching. This same technique is used in skin prick testing by allergists today. </p>
<p>Inspired by discoveries related to vaccination, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3651049/">Dr. Leonard Noon</a> and John Freeman prepared doses of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3651049/">pollen extracts for injection</a> in an effort to desensitize patients with allergic rhinitis in the early 1900s. This effective treatment, called <a href="https://acaai.org/allergies/allergy-treatment/allergy-immunotherapy">allergy immunotherapy</a>, also known as allergy shots, is still used today.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3667286/">Antihistamines</a> first became available in the 1940s, but they caused significant sedation. The formulations with fewer side effects that are used today have only been available since the 1980s. </p>
<h2>Pollen counts likely to grow</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=569&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=569&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267228/original/file-20190402-177184-15tteuy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=569&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pollen on a street in Atlanta, March 31, 2019.</span>
<span class="attribution"><span class="source">Lynne Anderson</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Though recognized by ancient civilizations, seasonal allergic rhinitis and allergic asthma have only increased in prevalence in recent history and are on the rise, now affecting <a href="https://www.aaaai.org/about-aaaai/newsroom/allergy-statistics">10 to 30 percent of the world’s population</a>.</p>
<p>Fueled by warmer temperatures and increased carbon dioxide levels, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829390/">pollen seasons are longer, and pollen counts are higher</a>. Many experts believe this will <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829390/">worsen</a> in the coming years due in large part to climate change.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267209/original/file-20190402-177167-h0ncsh.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">
<figcaption>
<span class="caption">To keep you and your loved ones safe from pollen, close windows and change out of clothes exposed to pollen as soon as you come indoors.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-boy-girl-school-lunch-table-1177724560">Monkey Business Images/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>What can you do? Often, those who are allergic need a multifaceted approach. </p>
<ul>
<li><p>Find out what allergens are causing your symptoms.
Take note of when your symptoms start by making a note in a calendar or planner.</p></li>
<li><p>Minimize exposure to allergens.
<a href="https://www.aaaai.org/global/nab-pollen-counts?ipb=1">Track pollen counts</a>. When pollen counts are high, keep the windows closed at home and in the car. After spending time outdoors, shower and change clothing to prevent ongoing exposure to pollen. </p></li>
<li><p>Take a pro-active approach to treating symptoms.
Starting medications before symptoms develop can prevent symptoms from getting out of control. This can also decrease the amount of medication needed overall. Long acting non-sedating antihistamines are helpful for itching and sneezing. Nasal corticosteroid sprays are more helpful for stuffy noses. </p></li>
<li><p>Consider a visit to see a <a href="https://acaai.org/locate-an-allergist">board certified allergist/immunologist</a>. She or he can help you determine which particular pollens maybe the source of your symptoms.</p></li>
<li><p>Explore the role of immunotherapy with your doctor. Immunotherapy changes the immune response through administration of small regimented doses of allergens over time. This induces a state of tolerance, eventually helping people become less allergic over time. </p></li>
</ul>
<p>While pollen season is coming, taking a multifaceted approach can provide much needed relief from the symptoms that have plagued humankind throughout the millennia.</p><img src="https://counter.theconversation.com/content/114722/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kara Wada 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>Pollen is ancient, but in recent times, it’s getting worse. An allergist offers ways to manage the suffering and enjoy the spring.Kara Wada, Clinical Assistant Professor, Allergy/Immunology, The Ohio State UniversityLicensed as Creative Commons – attribution, no derivatives.