tag:theconversation.com,2011:/us/topics/varroa-destructor-10513/articlesVarroa destructor – The Conversation2023-09-21T03:39:32Ztag:theconversation.com,2011:article/2140022023-09-21T03:39:32Z2023-09-21T03:39:32ZAustralia has officially given up on eradicating the Varroa mite. Now what?<figure><img src="https://images.theconversation.com/files/549465/original/file-20230921-29-20q28x.jpeg?ixlib=rb-1.1.0&rect=0%2C45%2C766%2C553&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Varroa mites on drone pupae.</span> <span class="attribution"><span class="source">Cooper Schouten/Southern Cross University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The <a href="https://www.directory.gov.au/portfolios/agriculture-water-and-environment/department-agriculture-water-and-environment/national-management-group">federal government body</a> in charge of pest control has announced Australia will abandon efforts on eradicating the Varroa mite.</p>
<p>This parasitic mite (<em>Varroa destructor</em>) lives in honey bee colonies, feeding on <a href="https://hbrc.ca/stages-of-bee-growth/">pupae</a> and adult bees. The mites spread viruses, impair the bees’ ability to fly and communicate, and makes them more susceptible to pesticides, eventually causing a colony collapse if left unmanaged.</p>
<p>Until recently, Australia remained free of Varroa thanks to stringent biosecurity measures. But <a href="https://www.outbreak.gov.au/current-outbreaks/varroa-mite">in June 2022</a>, the mite was detected in the New South Wales coastal area near Newcastle and has continued to spread.</p>
<p>A recent increase in detections over a greater area has now made eradication technically unfeasible. As a result, Australia is transitioning from <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response">eradication to management</a> of the Varroa mite.</p>
<h2>Can we fight the mite?</h2>
<p>It has been a tough time for beekeepers, the broader beekeeping community and the growers of crops relying on honey bees for pollination. </p>
<p>Varroa mite is already causing significant economic damage to livelihoods, due to restrictions on hive movements and the euthanasia of around 30,000 bee colonies.</p>
<p>To manage it, we will need to learn from overseas, where people have lived with Varroa for decades. However, Australia also has to develop its own solutions because of our unique climate, biodiversity and agricultural systems.</p>
<p>As seen <a href="https://link.springer.com/content/pdf/10.1051/apido/2010010.pdf">in other countries</a>, honey production and hive numbers may remain relatively stable. But beekeepers will need to invest significant time and resources to monitor, manage and replace hives due to Varroa losses. </p>
<p>There are effective <a href="https://pubmed.ncbi.nlm.nih.gov/34536080/">chemical control options</a>, but these cannot eliminate the mites completely. They also have impacts on bees and can leave residues in hive products. Over-reliance on synthetic chemicals will rapidly lead to resistance in Varroa populations, as seen in <a href="https://academic.oup.com/jinsectscience/article/21/5/6/6372257">almost every country Varroa exists</a>.</p>
<p>Effective <a href="https://academic.oup.com/jinsectscience/article/21/5/6/6372257">organic and non-chemical treatments exist</a>, but they are comparatively labour intensive – an additional burden on certified organic beekeepers. </p>
<p>To keep Varroa mite numbers below economically damaging thresholds, beekeepers will need to use integrated pest management solutions – a combination of approaches to reduce mite populaitons, while following up to ensure these appraoches have been effective.</p>
<iframe width="100%" height="994" src="https://www.youtube.com/embed/SjJS9jPmjlw" title="Varroa mites crawling around weak and deformed worker nurse bees after following uncapping of brood." frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen=""></iframe>
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Read more:
<a href="https://theconversation.com/australia-is-in-a-unique-position-to-eliminate-the-bee-killing-varroa-mite-heres-what-happens-if-we-dont-205926">Australia is in a unique position to eliminate the bee-killing Varroa mite. Here's what happens if we don't</a>
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<h2>Beekeeping will become more complex and expensive</h2>
<p>Costs for the average-sized Australian bee business could increase <a href="https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/animal-plant/pests-diseases/bees/honeybee-report.pdf">by as much as 30%</a>. Experience <a href="https://academic.oup.com/jee/article-abstract/102/3/868/2199132?redirectedFrom=fulltext">in other countries</a> suggests there will be <a href="https://agrifutures.com.au/product/a-study-of-new-zealand-beekeeping-lessons-for-australia/">significant declines</a> (up to 50%) of hobbyist and semi-commercial operators. Currently, recreational beekeeping is worth <a href="https://agrifutures.com.au/product/size-and-scope-of-the-australian-honey-bee-and-pollination-industry-a-snapshot/">A$173 million</a> in Australia annually.</p>
<p>We also know Varroa will <a href="https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/animal-plant/pests-diseases/bees/honeybee-report.pdf">progressively kill around 95%</a> of Australia’s feral honey bees within approximately three years. Therefore, we will likely need more bee colonies per hectare to pollinate some crops effectively. </p>
<p>Cumulatively, increased costs of production, a decrease in the numbers of beekeepers and fewer feral bees will likely result in higher demand for bee hives to service <a href="https://agrifutures.com.au/product/pollination-aware-the-real-value-of-pollination-in-australia-fact-sheet/">35 pollination dependent industries</a> across the country. As seen in Aotearoa New Zealand, where the Varroa mite established in 2000, prices for bee hives rented to growers increased by <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/06-1632.1">30–100% per hive within five years.</a>.</p>
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<a href="https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549466/original/file-20230921-27-e6wfq6.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>
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<span class="caption">A frame with worker bees, capped brood, brown open brood, white larva, a diversity of coloured pollen, fresh nectar and some ripe capped honey.</span>
<span class="attribution"><span class="source">Cooper Schouten/Southern Cross University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>What should Australia do to minimise the impact?</h2>
<p>We need a national program in Australia that <a href="https://beeinformed.org/2023/06/22/united-states-honey-bee-colony-losses-2022-23-preliminary-results-from-the-bee-informed-partnership/">monitors colony losses</a> so we can quantify the impacts across the sector. This also holds true for Australian native bees which play an important role in pollination of tropical crops – we do not have the monitoring and baseline data needed to evaluate the changes about to occur.</p>
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Read more:
<a href="https://theconversation.com/move-over-honeybees-aussie-native-bees-steal-the-show-with-unique-social-and-foraging-behaviours-200536">Move over, honeybees: Aussie native bees steal the show with unique social and foraging behaviours</a>
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<p>As an industry that contributes more than <a href="https://www.wheenbeefoundation.org.au/wp-content/uploads/2020/02/Karasinski-JM-2018_The-Economic-Valuation-of-Australian-Managed-and-Wild-Honey-Bee-Pollinators-in-2014-2015.pdf">$14.2 billion</a> to the economy, we now have a critical need for national capacity building for beekeeping, Varroa and pollination research, development and training.</p>
<p>Western Australia and Tasmania have significant opportunities to remain free from Varroa for as long as possible because the mite is currently only in NSW on the eastern boarder. Restricted movements of honey bees across the Bass Strait and the Nullarbor offer an additional biosecurity buffer. </p>
<p>Australia also remains free from virulent bee viruses, such as the <a href="https://www.westernsydney.edu.au/newscentre/news_centre/story_archive/2019/bees_broken_wings">deformed wing virus</a>. Hopefully, the Varroa incursion will lead to strengthened biosecurity for honey bee pests and diseases we do not have in the country yet, like <a href="https://pubmed.ncbi.nlm.nih.gov/32072354/"><em>Tropilaelaps</em> mites</a>.</p>
<p>We also need to strengthen compliance with the <a href="https://www.planthealthaustralia.com.au/wp-content/uploads/2022/05/Bee-Biosecurity-Program-Code-of-Practice-May-2022-for-web_final.pdf">honey bee biosecurity code of practice</a> and improve monitoring of bee losses, bee viruses and native bees. In the long term, we will need to establish breeding programs for bees with Varroa tolerance, as seen in other countries such as the United States, New Zealand and Hawaii.</p><img src="https://counter.theconversation.com/content/214002/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 Agriculture Research and is a Member of the NSW Apiarists Association and QLD Beekeepers Association. </span></em></p>The Varroa mite is here to stay. This will have wide-ranging impacts on beekeeping and the crops that rely on honey bee pollination in Australia.Cooper Schouten, Project Manager - Bees for Sustainable Livelihoods, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2071532023-07-25T20:05:41Z2023-07-25T20:05:41ZThe feral flying under the radar: why we need to rethink European honeybees<p>Australia’s national parks, botanic gardens, wild places and green spaces are swarming with an invasive pest that is largely flying under the radar. This is yet another form of livestock, escaped from captivity and left to roam free. </p>
<p>Contrary to popular opinion, in Australia, feral colonies of the invasive European honeybee (<em>Apis mellifera</em>) are not “<a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response/wild-european-honey-bee-management">wild</a>”, threatened with <a href="https://www.science.org/doi/full/10.1126/science.aar2269">extinction</a> or “good” for the Australian environment. The truth is feral honeybees compete with native animals for <a href="https://www.publish.csiro.au/pc/pc21064">food</a> and <a href="https://www.nature.com/articles/s41598-022-07635-0">habitat</a>, disrupt native <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/aec.13040">pollination systems</a> and pose a serious biosecurity threat to our honey and pollination industries.</p>
<p>As ecologists working across Australia, we are acutely aware of the damage being done by invasive species. There is rarely a simple, single solution. But we need to move feral bees out of the “too hard” basket. </p>
<p>The arrival and spread of the parasitic <a href="https://www.outbreak.gov.au/current-outbreaks/varroa-mite"><em>Varroa</em> mite in New South Wales</a> threatens to decimate honeybee colonies. So now is the time to rethink our relationship with the beloved European honeybee and target the ferals.</p>
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<img alt="Closeup photograph of a honeybee collecting pollen from a purple flower" src="https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531089/original/file-20230609-21-l1e8uh.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">Feral honeybee foraging on native <em>Boronia ledifolia</em> in the World Heritage-listed Blue Mountains National Park.</span>
<span class="attribution"><span class="source">Amy-Marie Gilpin</span></span>
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Read more:
<a href="https://theconversation.com/buzz-off-honey-industry-our-national-parks-shouldnt-be-milked-for-money-131891">Buzz off honey industry, our national parks shouldn’t be milked for money</a>
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<h2>What makes a hive feral?</h2>
<p>European honeybees turn feral when a managed hive produces a “swarm”. This is a mass of bees that leaves the hive seeking a new nest. The swarm ultimately settles, either in a natural hollow or artificial structure such as a <a href="https://www.lfwseq.org.au/bees-nest-boxes-sticky-problem/">nesting box</a>. </p>
<p>With up to 150 hives per square kilometre, Australia has among the <a href="https://www.nature.com/articles/s41598-022-07635-0">highest</a> feral honey bee densities in the world. In NSW, feral honeybees are listed as a “<a href="https://www.environment.nsw.gov.au/topics/animals-and-plants/threatened-species/nsw-threatened-species-scientific-committee/determinations/final-determinations/2000-2003/competition-from-feral-honeybees-key-threatening-process-listing">key threatening process</a>”, but they lack such recognition elsewhere. </p>
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<img alt="" src="https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1082&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1082&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1082&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1360&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1360&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531088/original/file-20230609-21-ohn2oi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1360&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">A nesting box installed for native animals filled with feral honeybees (Apis mellifera).</span>
<span class="attribution"><span class="source">Cormac Farrell</span></span>
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<p>Feral honeybees have successfully invaded most land-based ecosystems across Australia, <a href="https://bie.ala.org.au/species/https:/biodiversity.org.au/afd/taxa/1a490f00-368f-427c-8d4c-fa3f3271d75f">including</a> woodlands, rainforests, mangrove-salt marsh, alpine and arid ecosystems.</p>
<p>They can efficiently harvest large volumes of nectar and pollen from native plants that would otherwise provide food for native animals, including birds, mammals and flower-visiting insects such as native bees. Their foraging activities alter seed production and reduce the <a href="https://academic.oup.com/aob/article/103/9/1395/146886?login=false">genetic diversity</a> of native plants while also pollinating <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.34.011802.132355">weeds</a>.</p>
<p>Unfortunately, feral honeybees are now the most <a href="https://www.publish.csiro.au/pc/pc21064">common</a> visitors to many native flowering plants.</p>
<h2>Are feral bees useful in agriculture?</h2>
<p>Feral honeybees can pollinate crops. But they compete with managed hives for nectar and pollen. They can also be an reservoir of honeybee pests and diseases such as the <em>Varroa</em> mite, which ultimately threaten crop production. That’s because many farms rely on honeybees from commercial hives to pollinate their crops. </p>
<p>So reducing feral honeybee density would benefit both honey production and the crop pollination industry, which is worth <a href="https://www.agriculture.gov.au/agriculture-land/farm-food-drought/hort-policy/honeybees#pollination">A$14 billion annually</a>. </p>
<p>Improved management of feral honeybees would not only help to limit the biosecurity threat, but increase the availability of pollen and nectar for managed hives. It would also increase demand for managed honeybee pollination services for pollinator dependent crops. </p>
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Read more:
<a href="https://theconversation.com/hear-me-out-we-could-use-the-varroa-mite-to-wipe-out-feral-honey-bees-and-help-australias-environment-185959">Hear me out – we could use the varroa mite to wipe out feral honey bees, and help Australia's environment</a>
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<h2>What are our current options?</h2>
<p>Tackling this issue will not be straightforward, due to the sheer extent of feral colony infestation and limited tools at the disposal of land managers.</p>
<p>If the current parasitic <em>Varroa</em> mite <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response">infestation in NSW</a> spins out of control, it may reduce the number of feral hives, with <a href="https://theconversation.com/hear-me-out-we-could-use-the-varroa-mite-to-wipe-out-feral-honey-bees-and-help-australias-environment-185959">benefits</a> for the environment. Fewer feral hives would be good for the honey industry too. </p>
<p>Targeted strategies to remove feral colonies on a small scale do exist and are being applied in the <em>Varroa</em> mite emergency response. This includes the deployment of <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response/wild-european-honey-bee-management">poison (fipronil) bait stations</a> in areas exposed to the mite.</p>
<p>While this method seems to be <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response/wild-european-honey-bee-management">effective</a>, the extreme toxicity of fipronil to honeybees limits its use to areas that do not contain managed hives. In addition, the possible effects on non-target, native animals that feed on the bait, or poisoned hive remains, is still unstudied and requires careful investigation.</p>
<p>Where feral hives can be accessed, they can be physically removed. But in many ecosystems feral colonies are high up in trees, in difficult to access terrain. That, and their overwhelming numbers, makes removal impractical.</p>
<p>Another problem with hive removal is rapid recolonisation by uncontrolled swarming from managed hives and feral hives at the edges of the extermination area.</p>
<p>Taken together, there are currently no realistic options for the targeted large-scale removal of feral colonies across Australia’s vast natural ecosystems.</p>
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<img alt="" src="https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531090/original/file-20230609-21-eplmrs.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">Drone (male) honeybee.</span>
<span class="attribution"><span class="source">James Dorey</span></span>
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<h2>Where to now?</h2>
<p>For too long, feral honeybees have had free reign over Australia’s natural environment. Given the substantial and known threats they pose to natural systems and industry, the time has come to develop effective and practical control measures. </p>
<p>Not only do we need to improve current strategies, we desperately need to develop new ones.</p>
<p>One promising example is the use of traps to catch bee swarms, and such work is underway in Victoria’s <a href="https://www.abc.net.au/news/rural/2023-05-28/bee-swarm-monitoring-in-macedon-ranges/102385310">Macedon Ranges</a>. However, this might be prohibitively expensive at larger scales.</p>
<p>Existing strategies for other animals may be a good starting place. For example, the practice of <a href="https://theconversation.com/the-ultimate-invader-high-tech-tool-promises-scientists-an-edge-over-the-cane-toad-scourge-186542">using pheromones to capture cane toad tadpoles</a> might be applied to drones (male bees) and swarms. Once strategies are developed we can model a combination of approaches to uncover the best one for each case.</p>
<p>Developing sustainable control measures should be a priority right now and should result in a win-win for industry, biosecurity and native ecosystems. </p>
<p>If there is something to learn from the latest <em>Varroa</em> incursion, it is that we cannot ignore the risks feral honeybees pose any longer. We don’t know how to control them in Australia yet, but it is for lack of trying. </p>
<p><em>We would like to acknowledge the substantial contribution made by environmental scientist and beekeeper Cormac Farrell to the development of this article.</em></p>
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Read more:
<a href="https://theconversation.com/a-new-2-coin-features-the-introduced-honeybee-is-this-really-the-species-we-should-celebrate-181089">A new $2 coin features the introduced honeybee. Is this really the species we should celebrate?</a>
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<img src="https://counter.theconversation.com/content/207153/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amy-Marie Gilpin receives funding from Horticulture Innovation Australia and is a member of the IUCN Wild Bee Specialist Group Oceania. </span></em></p><p class="fine-print"><em><span>James B. Dorey is affiliated with Flinders University and the University of Adelaide. </span></em></p><p class="fine-print"><em><span>Katja Hogendoorn is a member of the board of the Australian Entomological Society and receives funding from the Department of Agriculture, Water and the Environment, HortInnovations, AgriFutures, and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Kit Prendergast is an adjunct at Curtin University and Murdoch University. She has previously received funding from the Federal Government for the Bushfire Recovery Project, from the Forrest Research Foundation for her PhD, and from the Australian Wildlife Society. </span></em></p>Feral honeybees have become a major problem in Australia. It’s time to develop effective and practical control measures.Amy-Marie Gilpin, Research Fellow, Ecology, Western Sydney UniversityJames B. Dorey, Adjunct Lecturer, Flinders UniversityKatja Hogendoorn, Research fellow, University of AdelaideKit Prendergast, Native bee ecologist, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2059262023-05-24T01:51:10Z2023-05-24T01:51:10ZAustralia is in a unique position to eliminate the bee-killing Varroa mite. Here’s what happens if we don’t<figure><img src="https://images.theconversation.com/files/527408/original/file-20230522-17-by2qo7.jpg?ixlib=rb-1.1.0&rect=57%2C23%2C3767%2C2562&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Théotime Colin</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Varroa mites – notorious honey bee parasites – have recently reached Australian shores, <a href="https://www.abc.net.au/news/rural/2022-06-24/varroa-mite-detected-at-newcastle-port/101180446">detected at the Port of Newcastle</a> in New South Wales last year. If they establish here, there would be significant implications for agricultural food security, as honey bees are heavily relied on for the pollination of many crops.</p>
<p>However, while Australia is the last continent to be invaded by the mite, it has an opportunity to be the first to eradicate it.</p>
<p><em>Varroa destructor</em> is a small mite that attaches to bees and <a href="https://www.sciencedaily.com/releases/2019/01/190114161137.htm">eats their “fat body</a>”. The fat bodies of honey bees are the insect equivalent of a liver. Varroa weakens bees, reduces their lifespan and increases the spread of deadly viruses.</p>
<p>Scientists need to be ready: this might be Australia’s best chance to collect important data on the spread and evolution of this parasite. Our new paper <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2022.0589">published today in Biology Letters</a> outlines what questions scientists need to ask and what data they need to collect if Varroa spreads in Australia.</p>
<p>Such data could help us understand how parasites evolve, why Varroa are so damaging for honey bees, and how Varroa mites impact other insects and the environment.</p>
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Read more:
<a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">Explainer: Varroa mite, the tiny killer threatening Australia's bees</a>
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<h2>Will Varroa establish in Australia?</h2>
<p>Australia is in close proximity to countries that have the mite, including New Zealand, Papua New Guinea, Timor-Leste and Indonesia.</p>
<p>This probably explains why invasive honey bee swarms are frequently intercepted at our ports, <a href="https://www.beeawarebrisbane.org/blog/a-brief-history-of-honey-bee-incursions-into-australia">many of these carrying Varroa</a>. Australia currently bans importation of honey bee colonies due to the biosecurity risk, so these interceptions are typically due to stowaway swarms taking up residence in shipping containers.</p>
<p>Previous invasions of Varroa have been successfully <a href="https://www.abc.net.au/news/rural/2018-06-29/varroa-mite-detected-in-melbourne/9923972">eradicated before establishing</a>, but this time Varroa circumvented the biosecurity surveillance near Newcastle and spread locally.</p>
<p>The New South Wales Department of Primary Industries has been <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response">contact-tracing and culling hives in contaminated areas</a>, and the spread has been slow so far. Australia has large populations of feral honey bees, which could potentially act as a reservoir for Varroa and are much harder to trace and control, so the department is tackling this with a <a href="https://www.dpi.nsw.gov.au/emergencies/biosecurity/current-situation/varroa-mite-emergency-response/wild-european-honey-bee-management">wild honey bee baiting program</a>.</p>
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<a href="https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small red mite facing the camera on a grey metallic background, the many legs of the mites are visible as well as a few pieces of wax" src="https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527017/original/file-20230518-29-xsgvbi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&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 Varroa mite fallen from a hive in France.</span>
<span class="attribution"><span class="source">Théotime Colin</span>, <span class="license">Author provided</span></span>
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<h2>What threats does Varroa pose?</h2>
<p>Varroa mites are a threat to food security. Although Australia has an abundance of food and <a href="https://www.agriculture.gov.au/abares/products/insights/australian-food-security-and-COVID-19">exports it to other nations</a>, the price of food is likely to increase if Varroa escapes confinement.</p>
<p>Currently, pollination of crops in eradication zones such as <a href="https://www.abc.net.au/news/rural/2022-07-27/varroa-mite-nsw-berry-production-price-detection-coffs-harbour/101272874">berries in Coffs Harbour</a> is at risk due to the removal of all honey bees in the region, which may lead to short-term increases in food costs.</p>
<p>However, establishment and spread of Varroa will lead to lower pollination and lower crop production across the country, which will raise the price of most fruit and vegetables that depend on bee pollination.</p>
<p>This could worsen the <a href="https://www.theguardian.com/australia-news/2022/oct/17/inflation-and-inadequate-welfare-fuelling-australias-food-insecurity-crisis-foodbank-finds">food affordability crises caused by the current inflation</a>, affecting the ability of low income households to buy nutritious and fresh produce. Almond pollination has already noted a deficit of <a href="https://www.abc.net.au/news/rural/2022-07-18/victoria-to-be-80-000-bee-hives-short-for-almond-pollination/101246392">80,000 hives in the last season</a>. </p>
<p>Many of the honey bee colonies that pollinate our crops are <a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">thought to be feral</a>, living in tree hollows or nest-boxes designed for native animals. These feral bees are not managed by beekeepers and so won’t be saved by the use of Varroa treatments, meaning they will most likely disappear. </p>
<p>Varroa may be a threat to wild pollinators including native bees. Varroa often spreads viruses, which can jump between species and may threaten our wild native pollinators. Of particular concern are viruses that deform insect wings and cause paralysis. Fortunately, these viruses have not been detected in the current Varroa incursion.</p>
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<a href="https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of different bee species pollinating flowers from crops and native plants" src="https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527330/original/file-20230520-29-w4rnrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&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">Australia currently relies on pollination by commercial honey bees (yellow), supplemented by feral honey bees (brown), though we have many native bee species like stingless bees and blue banded bees that are also being used in crop pollination.</span>
<span class="attribution"><span class="source">Boris Yagound, adapted from Chapman et al. 2023</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>How can we secure Australia’s agricultural industry?</h2>
<p>Australia’s agricultural industry relies mostly on pollination by European honey bees. This choice has been risky.</p>
<p>In Europe, pollination services are also provided by diverse species like bumble bees, mining bees and mason bees (e.g. <em>Osmia rufa</em>), many of which are un-managed wild species that nest alone.</p>
<p>If Varroa escapes confinement, beekeepers will still be able to maintain colonies of honey bees but at greater costs, due to colony losses and the need for chemicals to treat Varroa mites in the hives. These costs have the potential to sink businesses, and affect the livelihoods of beekeepers. </p>
<p>Australia needs to decrease its reliance on the European honey bee in agriculture and improve pollinator diversity via the use of <a href="https://beeaware.org.au/pollination/native-bees/native-bees-as-alternative-pollinators/">other native pollinator species</a> such as native stingless bees, blue banded bees, <a href="https://www.horticulture.com.au/hort-innovation/news-events/media-releases/2022/Scientists-bring-flies-to-Varroa-Mite-Red-Zone">or even flies</a>. For example, native Australian stingless bees aid in the pollination of macadamia and capsicum crops and could be used for the pollination of other crops.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/7MILt82Y5ig?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Native blue banded bees pollinating tomatoes in Australia.</span></figcaption>
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<h2>Australia’s unique situation</h2>
<p>Australia is different from other Varroa infected regions of the world. Our incursion was smaller, it was identified early and the management zone is small enough to be feasibly eradicated.</p>
<p>Even if Varroa spreads in Australian landscapes, hopes are that the pace of the spread may be slower in Australia than it was in other regions due to the smaller incursion, the colossal eradication effort and large tracts of land that are inhospitable to honey bees. Managed honey bee populations are <a href="https://extensionaus.com.au/professionalbeekeepers/670000-registered-honey-bee-hives-in-australia/">concentrated around coastal regions</a>, or in Australia’s major rural food bowl regions where pollinator-dependant crops (such as almonds, blueberries and apples) are located. </p>
<p>This gives us a chance to prevent the spread of Varroa across inland Australia, where there are no honey bees.</p>
<p>Luckily for us, most of the world has already spent the last few decades trying to minimise Varroa mite management costs. As a nation, we now have the chance to initiate a fresh and coordinated management response. Australia could organise state-wide <a href="https://www.epa.nsw.gov.au/your-environment/pesticides/integrated-pest-management">integrated pest management</a> approaches and treatment regimes to prevent Varroa’s resistance to chemical treatments from developing rapidly.</p>
<p>In short, there are good reasons to remain positive about the future of Australian beekeeping and horticultural industries, but there is still much work for our research community to do.</p>
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Read more:
<a href="https://theconversation.com/bees-can-do-so-much-more-than-you-think-from-dancing-to-being-little-art-critics-204039">Bees can do so much more than you think – from dancing to being little art critics</a>
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<img src="https://counter.theconversation.com/content/205926/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scarlett Howard has received funding from Australian Government, RMIT University, Fyssen Foundation, L’Oreal-UNESCO, Australian Academy of Sciences, Hermon Slade, Deakin University, and Monash University. She has been affiliated with Pint of Science Australia.</span></em></p><p class="fine-print"><em><span>Alexander Mikheyev receives funding from the Australian Research Council and Agrifutures Australia. </span></em></p><p class="fine-print"><em><span>Emily Remnant has received funding from The University of Sydney, Horticulture Innovation Australia, Agrifutures Australia, the Australia and Pacific Science Foundation, the Australian Government and the NSW Government. She has volunteered for the NSW Apiarists Association.</span></em></p><p class="fine-print"><em><span>Simon Tierney has received funding from Australian Entomological Society, Centre for Biodiversity Analysis, Flinders University, Hort Innovation, National Geographic Society, Royal Entomological Society, Smithsonian Institution, Smithsonian Tropical Research Institute, The University of Adelaide, Tokyo Metropolitan University and Western Sydney University. </span></em></p><p class="fine-print"><em><span>Théotime Colin receives funding from Macquarie University, the Lord Mayor's Charitable Foundation, the Eldon & Anne Foote Trust, Hort Innovation Australia, the Innovation Connections program, the The Department of Agriculture, Water and the Environment and Agrifutures Australia. He is a member of the New South Wales Apiarists' Association.</span></em></p>Australia is the last continent to be invaded by the dangerous honey bee parasite, and has an opportunity to be the first to eradicate it.Scarlett Howard, Lecturer, School of Biological Sciences, Monash UniversityAlexander Mikheyev, Group Leader, Mikheyev Group - Evolutionary genomics, Australian National UniversityEmily Remnant, Lecturer, School of Life and Environmental Sciences, University of SydneySimon Tierney, Lecturer & Research Fellow, Western Sydney UniversityThéotime Colin, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1859592022-06-29T19:55:51Z2022-06-29T19:55:51ZHear me out – we could use the varroa mite to wipe out feral honey bees, and help Australia’s environment<p>A tiny parasitic mite that lives on the European honeybee (<em>Apis mellifera</em>) has breached Australia’s border <a href="https://www.abc.net.au/news/2022-06-26/nsw-stops-movement-of-bees-due-to-varroa-mite-parasite/101184770">quarantine</a> and been detected in managed bee hives in New South Wales. </p>
<p>This is bad news for Australia’s <a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">honey industry</a>, with over 300 hives in Newcastle set to be destroyed and biosecurity zones in place. The potential economic impact to the honey industry is estimated at around <a href="https://www.abc.net.au/news/rural/2022-06-27/what-is-varroa-mite-and-how-will-it-impact-australias-honey/101185714">A$70 million per year</a>, but the broader impacts to agriculture are not yet known. </p>
<p>This is where much of the dialogue on the impact of varroa mite settling in Australia usually stops. But there’s another way to look at this pest: as an effective biocontrol for feral honeybees in Australia’s natural environment. </p>
<p>Honeybees were introduced to Australia almost 200 years ago and out-compete native pollinators, which may have dire flow-on effects for ecosystems. The varroa mite’s arrival in Australia was <a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">only a matter of time</a> – and with better planning, we could benefit from one pest fighting another.</p>
<h2>Making trade-offs</h2>
<p>The varroa mite infests hives, parasitises the bees, and can spread viruses and other pathogens. They mainly feed and breed on honeybee larvae and pupae, causing malformation. If left unmanaged, heavy mite infestation can cause colony collapse in some circumstances. </p>
<p>The mite has <a href="https://entnemdept.ufl.edu/creatures/misc/bees/varroa_mite.htm">spread across the world</a> to colonise almost every known location of European honeybees. It has been kept out of Australia thanks to stringent border quarantine measures, but this tiny mite can easily hitchhike on imports, then establish and spread when it reaches a honeybee colony.</p>
<p>So would Australia benefit more from treating the varroa mite as a pest, or an environmental biocontrol? More research is needed to resolutely answer this question, but let’s look at a the potential trade-offs of either option. </p>
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Read more:
<a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">Explainer: Varroa mite, the tiny killer threatening Australia's bees</a>
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<p><u><strong>Treating the mite as a pest</strong></u></p>
<p>Treating the mite as a pest would mean chasing down known outbreaks and destroying hives, beefing up border quarantine measures and supporting the beekeeping industry to tide them over the impact and adjustment period. </p>
<p>Beekeepers can stop the mite in its tracks in managed hives with chemical controls, but this comes at a cost, including some loss of productivity. And a loss of productivity in managed hives can have a knock-on effect on the pollination industry, as beekeepers are paid to take their bees to pollinate crops. </p>
<p><a href="https://www.abc.net.au/news/rural/2022-06-28/bee-eradication-nsw-government-control-varroa-mite/101188568">Thirty-five agricultural industries</a> in Australia rely entirely or in part on bee pollination, including almonds, apples and cherries. Indeed, the total contribution of honeybees to Australia’s economy is estimated at <a href="https://www.agrifutures.com.au/rural-industries/honey-bee-pollination/">$14.2 billion</a>. </p>
<p>The potential consequences for industrial beekeeping and agriculture, and increased costs of production, can have unwelcome effects on food prices.</p>
<p><u><strong>Treating the mite as a biocontrol</strong></u></p>
<p>Treating the mite as an environmental biocontrol would mean diverting money for eradication and control measures to help industries live with varroa. This could be by, for instance, increasing the use of <a href="https://www.abc.net.au/news/rural/2022-06-29/native-bees-could-help-mitigate-varroa-mite-impacts-on-orchards/101189080?utm_campaign=abc_news_web&utm_content=link&utm_medium=content_shared&utm_source=abc_news_web">native pollinators</a> for Australian agriculture. </p>
<p>It could also involve releasing the mite into feral honeybee hives, where we believe a rapid recovery of native pollinators is needed, such as in areas recovering from bushfires. The varroa mite has little impact on native bees because it’s specific to the <em>Apis</em> genus of the introduced bee, though the usual rules for biocontrol release would need to be followed.</p>
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Read more:
<a href="https://theconversation.com/buzz-off-honey-industry-our-national-parks-shouldnt-be-milked-for-money-131891">Buzz off honey industry, our national parks shouldn’t be milked for money</a>
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<p><a href="https://www.awe.gov.au/biosecurity-trade/invasive-species/insects-and-other-invertebrates/invasive-bees#:%7E:text=There%20are%20several%20species%20of,(Apis%20cerana)%20in%20Queensland">Feral European honeybee</a> populations are recognised as a <a href="https://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=20004">key threatening process</a> to Australia’s native biodiversity, with <a href="https://theconversation.com/buzz-off-honey-industry-our-national-parks-shouldnt-be-milked-for-money-131891">impacts</a> felt across the country. Feral bees are abundant and efficient pollinators, and compete with native birds, insects and mammals (such as pygmy possums) for nectar from flowers.</p>
<p>Honeybees avoid, or only partially pollinate, some native plants. This means a high concentration of honeybees could shift the make-up of native vegetation in a region. They also pollinate invasive weeds such as <a href="https://www.jstor.org/stable/30033767?seq=1">gorse</a>, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3180.2004.00391.x">lantana</a> and <a href="https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-2005-865855">scotch broom</a>, which are particularly expensive to control in the wake of bushfires. </p>
<p>When the varroa mite breached New Zealand, feral honeybees <a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710">declined</a> by about 90% within a few years. However, there’s <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591231/">limited information</a> about the ecological benefits of this, because the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591231/">data was not collected</a> while the focus was on agricultural industry impact.</p>
<p>It’s also worth noting that knocking down feral honeybees could also be good for the honeybee industry, as feral honeybees are a recognised <a href="https://www.frontiersin.org/articles/10.3389/fevo.2019.00060/full">competitor</a> with commercial ones.</p>
<h2>Making the best decision</h2>
<p>Questions about trading-off potential agricultural costs for environmental benefits are difficult to answer. This is, in part, because any environmental benefits gained from reducing a widespread threat are usually indirect, such as flow-on effects of increased ecosystem health. </p>
<p>Another reason is because markets are well established for agricultural products and services, but they’re usually missing or only just forming for ecosystem services (such as flood control, water supply and quality, and cultural values).</p>
<p>To calculate the economic benefit of reducing feral honeybees, we first must put a value on the services natural ecosystems provide. </p>
<p>While <a href="https://eea.environment.gov.au/">some steps</a> have been made, progress on implementation has been slow for the last decade. So far, we’ve predominately put values on ecosystem services from discrete natural assets, such as the Great Barrier Reef, which <a href="https://www2.deloitte.com/au/en/pages/economics/articles/great-barrier-reef.html">contributed an estimated</a> $6.4 billion in 2015-2016 to Australia’s economy. </p>
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Read more:
<a href="https://theconversation.com/pest-plants-and-animals-cost-australia-around-25-billion-a-year-and-it-will-get-worse-164969">Pest plants and animals cost Australia around $25 billion a year – and it will get worse</a>
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<p>In the case of the varroa mite, we have known the potential for opportunities and costs from a likely invasion for more than a decade. But the focus has been on preventing the invasion to protect agriculture, because we’re mostly concerned about the industry’s direct benefits and impacts. </p>
<p>There have been no estimations of the economic benefits of using the mite as an environmental biocontrol to lower feral honeybee populations, even though our New Zealand friends did <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591231/">suggest</a>, in a paper, we prepare ourselves. </p>
<p>We may successfully eradicate the varroa mite’s recent incursion to the relief of agriculture and beekeepers. But given the near inevitability of the mite establishing in Australia, we must invest in better understanding the holistic economics of keeping a potentially very important biocontrol out of the country.</p><img src="https://counter.theconversation.com/content/185959/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick O'Connor receives funding from the Australian Research Council, Agrifutures Australia and State Governments. </span></em></p>The varroa mite’s arrival in Australia was only a matter of time. We could benefit from one pest fighting another.Patrick O'Connor, Associate Professor, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1629452021-07-22T14:56:21Z2021-07-22T14:56:21ZBees, mites and viruses: assessing the risk to South African crop pollinators<figure><img src="https://images.theconversation.com/files/411685/original/file-20210716-22-r99ejf.jpg?ixlib=rb-1.1.0&rect=19%2C127%2C2567%2C1997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mite on a bee.</span> <span class="attribution"><span class="source">E. Villalobos</span></span></figcaption></figure><p>The world’s bees face a major threat from <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022201109001839">deformed wing virus</a>, a pathogen transmitted by the parasitic varroa mite. It is responsible for causing the death of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004071">millions of colonies</a> in the US, Europe and Asia. The major losses started in the early 1990s with at least 30% of colonies <a href="https://www.tandfonline.com/doi/abs/10.3896/IBRA.1.49.1.02">dying each year</a>. </p>
<p>The virus has been seen in 18 species of bees so far, as well as 64 other insect species, where it is typically benign.</p>
<p>Honeybees are very important for the pollination of crops, contributing between US$235 billion and $577 billion to <a href="http://www.fao.org/3/I9527EN/i9527en.pdf">global agricultural production</a> every year. Any disease that causes colony deaths is therefore a major problem, though the cost of the damage caused by deformed wing virus is still unknown.</p>
<p>The continents of South America and Africa have not recorded major honeybee colony losses associated with the varroa mite, the number one pest of honeybees in the northern hemisphere. We <a href="https://link.springer.com/article/10.1007/s00705-020-04863-5">investigated</a> why varroa was not a problem in South Africa. One factor may be the presence or absence of the deformed wing virus, since it is this pathogen – when transmitted by varroa – that kills the infested colony. </p>
<h2>Mutating virus</h2>
<p>Two subspecies of indigenous bees in South Africa (<em>Apis mellifera capensis</em> and <em>Apis mellifera scutellata</em>) make up a well-developed bee industry. They produce honey, wax and other related products, and also provide pollination services in crops such as oil seeds, deciduous fruits, subtropicals and nuts. In South Africa a <a href="https://scholar.sun.ac.za/handle/10019.1/100915">total</a> of 1,069 beekeepers are registered, managing 60,351 colonies. </p>
<p>Bees are the main pollinators of both natural flora and commercial crops and, therefore, of great economic importance. It’s important to track the deformed wing virus, following its evolution and the impacts that each variant has on the various host insects.</p>
<p>The varroa mite is an external parasite of the honeybee which feeds on the bee’s fat cells. The fat cells are nutrient rich and located near the surface of both adult and immature honey bees. The parasite’s mouth-parts inadvertently transfer deformed wing virus into the bee’s body where it multiplies rapidly. This reduces the bee’s life expectancy, leading to the death of the colony. </p>
<p>The virus consists of three closely related variants (genotypes A, B and C). It is constantly mutating, like all other RNA (ibonucleic acid) viruses whose genetic material is encoded in RNA. The most commonly detected type is the A variant, which has been associated with widespread <a href="https://www.mdpi.com/1999-4915/9/11/314">colony decline</a>. The more recent B variant is starting to dominate colonies across the world but the danger it poses is <a href="https://www.mdpi.com/1999-4915/13/6/969">not clear yet</a>. The effects of type C are still unknown, as it is the most recently described variant and <a href="https://www.nature.com/articles/s41598-017-17802-3">is very rare</a>.</p>
<h2>Dominant variant</h2>
<p>We used honeybee samples of both South African subspecies collected between 2004 and 2018 across the south of the country to compare the virus variant distribution and viral load. Pools of 10 adult bees or one infested pupa from each colony were analysed to access the RNA viral load within the bee’s body and thus allowing us to identify which variant of deformed wing virus existed in South Africa.</p>
<p>Our <a href="https://link.springer.com/article/10.1007/s00705-020-04863-5">study</a> found that the B type variant was dominant in South Africa. Since the country has not had serious colony losses, this might suggest that type B is not so lethal. But in Brazil – another country which has not recorded major losses – type A dominates, so the relationship must be more complex than first thought.</p>
<p>The most important finding was that the viral loads in both South Africa and Brazil were much lower than what has been found in the <a href="https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.001206">northern hemisphere</a>. This may be why the colonies did not die, since high viral loads are required to kill a colony. </p>
<p>A lower mite population would help explain the lower viral loads in South Africa and Brazil. The lower population may be achieved by the bees themselves: <a href="https://www.nature.com/articles/s41598-018-26001-7">a recent study</a> indicated that honeybees in South Africa and Brazil have learnt to detect and remove mite infested cells. This prevents mite reproduction. And this “hygienic” behaviour appears to be <a href="https://academic.oup.com/gbe/article/11/3/937/5318327">gentically heritable</a>. </p>
<p>Our studies confirmed the low levels of the virus and the low infestation by the mite. More research is needed, however, to prove if there is a link between the hygienic bee behaviour and lower viral loads in colonies. </p>
<p>The only way to prevent colonies dying is to control the varroa mite. In the northern hemisphere this is typically done by using pesticides. Understanding how low viral loads are achieved would help beekeepers to use other control methods. They could selectively breed colonies that have hereditary traits of resisting the mite, or collect swarms from naturally surviving colonies that have already developed varroa resistance.</p><img src="https://counter.theconversation.com/content/162945/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen John Martin receives funding from BBKA and BDI. </span></em></p><p class="fine-print"><em><span>Flaviane Santos Souza 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>Bees are the main pollinators of many crops. It’s important to track the deformed wing virus and its impacts.Flaviane Santos Souza, PhD abroad School of Environment and Life Sciences, University of SalfordStephen John Martin, Chair in Social Entomology, University of SalfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1217922019-09-09T12:22:28Z2019-09-09T12:22:28ZTo save honey bees we need to design them new hives<figure><img src="https://images.theconversation.com/files/291507/original/file-20190909-109952-ngkno6.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/close-flying-bees-wooden-beehive-plenty-1399101203?src=AsbFqAb3cDNMZwdD4SoXdA-3-27">Aleksandr Gavrilychev/Shutterstock</a></span></figcaption></figure><p>Honey bees are under extreme pressure. Beekeepers in the US have been losing and then replacing an <a href="https://beeinformed.org/results/2018-2019/">average of 40%</a> of their honey bee colonies every year since 2010, a rate that is probably unsustainable and would be unacceptable in other kinds of husbandry. The biggest contributor to this decline is viruses spread by a parasite, <em>Varroa Destructor</em>. But this isn’t a natural situation. The parasite is spread by beekeeping practices, including keeping the bees in conditions that are very different from their natural abode of tree hollows.</p>
<p>A few years ago, <a href="http://dx.doi.org/10.1007/s00484-015-1057-z">I demonstrated</a> that the heat losses in man-made honey bee hives are many times greater than those in natural nests. Now, using engineering techniques more commonly found probing industrial problems, <a href="http://dx.doi.org/10.1098/rsif.2019.0048">I’ve shown</a> that the current design of man-made hives also creates lower humidity levels that favour the <em>Varroa</em> parasite.</p>
<p>Natural nests inside tree cavities create high humidity levels in which honey bees thrive and which prevent <em>Varroa</em> from breeding. So if we can redesign beekeeper hives to recreate these conditions, we could help stop the parasite and give honey bees a chance to recover. </p>
<p>The life of the honey bee colony is intimately entwined with its home. We can see this from the <a href="https://press.princeton.edu/titles/9267.html">sophisticated way</a> honey bees choose nests of the correct sizes and properties, and how hard they work to modify them. In fact, the nest can be seen as part of the honey bee itself, a concept that in biology is known as an “<a href="http://wallace.genetics.uga.edu/groups/evol3000/wiki/94a1a/Extended_Phenotype.html">extended phenotype</a>”, which refers to all the ways a creature’s genes affect the world.</p>
<p>Perhaps the most common example of an extended phenotype is that of the beaver, which shapes its environment by controlling the flow of water with dams. Nests enable honey bees to similarly adjust their environment by controlling the flow of two fluids – air and water vapour – plus something that acts like a fluid – heat.</p>
<p>The honey bees select a tree hollow with an entrance at the bottom that makes rising hot air inside the nest less likely to escape. They then modify it by applying an antibacterial vapour-retarding sealant of tree resin over the inside walls and any small holes or cracks. This further prevents any warm air leaks and helps maintain the right level of water vapour. Inside the nest, the bees build a honeycomb containing thousands of cells, each of which provides an insulated microclimate for growing larvae (baby bees) or making honey.</p>
<h2>Unnatural designs</h2>
<p>Despite the importance of nests to honey bees, the hives we build them bear little resemblance and have few of the properties of the natural tree nests European honey bees evolved with. In the 21st century, we’re still using hives designed in the 1930s and 1940s, based on ideas from the 1850s. Natural nests were only scientifically <a href="http://dx.doi.org/10.1007/BF02223477">surveyed as recently as 1974</a> and research into their <a href="http://dx.doi.org/10.1007/s00484-015-1057-z">physical properties only began in 2012</a>.</p>
<p>Man-made hives are squat and squarish (for example 45cm high), constructed from thin wood (under 2cm thick) with large entrances (around 60cm²) and often large openings of wire mesh underneath. They were designed to be cheap and for beekeepers to easily access the bees and remove the honey. In contrast, European honey bees evolved with natural tree nests that are on average tall (around 150cm), narrow (20cm) with thick walls (15cm) and small entrances (7cm²).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288425/original/file-20190818-192258-1qv9g1b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Man-made hives versus natural nests.</span>
<span class="attribution"><span class="source">Derek Mitchell</span></span>
</figcaption>
</figure>
<p>In order to assess how well man-made hives recreate the conditions of natural nests, I needed to measure the flow of fluids (air, water vapour and heat) around them. To do that, I turned to an aspect of physical science and engineering called <a href="https://www.sciencedirect.com/topics/engineering/thermofluids">thermofluids</a>, the study of liquids, gases and solids of combustion, and changes of state, mass and energy movement.</p>
<p>In the honey bee nest, this means the “combustion” of sugars in honey and nectar, the evaporation and condensation of water, and air flow through the nest. It also includes everything being transported by the honey bees through the entrance or leaking through the walls.</p>
<p>The various barriers that honey bee nests create can be used as convenient boundaries in mathematical models of the energy needed and humidity produced inside the nest. My new study combines these models with data from <a href="http://dx.doi.org/10.1007/s00484-015-1057-z">experimental research</a> on the thermal properties of honey bee nests and hives and <a href="http://dx.doi.org/10.1016/j.jinsphys.2008.08.011">behavioural studies</a> on how honey bees ventilate their nest.</p>
<p>This enabled me to compare the average humidity in man-made hives and tree nests with that needed by honey bees and their parasites. I found that most man-made hives have seven times higher heat loss and eight times bigger entrance size than tree nests. This creates the lower humidity levels that favour the parasite.</p>
<p>My research shows the role of the honey bee nest is clearly far more sophisticated than just simple shelter. Simple changes to hive design in order to lower heat loss and increase humidity, for example using smaller entrances and thicker walls, could reduce the stress on the honey bee colonies caused by <em>Varroa Destructor</em>. <a href="http://dx.doi.org/10.1098/rsif.2018.0879">We already know</a> that simply building hives from polystyrene instead of wood can significantly increase the survival rate and honey yield of the bees. More research into the thermofluidic complexity of nests would allow us to design the optimal hives that balance the needs of honey bees with their human keepers.</p>
<p><em>This article has been amended to make clear that the average 40% of US honey bee colonies lost each year are replaced.</em></p><img src="https://counter.theconversation.com/content/121792/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Derek Mitchell is affiliated with Institute of Thermofluids, School of Mechanical Engineering, University of Leeds</span></em></p>Beehive designs haven’t changed since the 1940s.Derek Mitchell, PhD Candidate in Mechanical Engineering, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/771642017-05-07T19:38:51Z2017-05-07T19:38:51ZTen years after the crisis, what is happening to the world’s bees?<figure><img src="https://images.theconversation.com/files/168231/original/file-20170507-7673-kg7lmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bees have been living with the mysterious Colony Collapse Disorder for a decade.</span> <span class="attribution"><span class="source">Simon Klein</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Ten years ago, beekeepers in the United States raised the alarm that thousands of their hives were mysteriously empty of bees. What followed was global concern over a new phenomenon: <a href="https://www.epa.gov/pollinator-protection/colony-collapse-disorder">Colony Collapse Disorder</a>. </p>
<p>Since then we have realised that it was not just the US that was losing its honey bees; <a href="https://theconversation.com/honeybee-decline-warrants-concern-but-not-panic-5707">similar problems</a> have manifested all over the world. To make things worse, we are also losing many of our populations of wild bees too. </p>
<p>Losing bees can have tragic consequences, for us as well as them. Bees are pollinators for about one-third of the plants we eat, a service that has been valued at <a href="http://www.sciencedirect.com/science/article/pii/S0921800908002942">€153 billion (US$168 billion) per year</a> worldwide. </p>
<p>Ten years after the initial alarm, what is the current status of the world’s bee populations, and how far have we come towards understanding what has happened?</p>
<h2>The current status of bees worldwide</h2>
<p>Since the alarm was first raised, many countries have created new monitoring methods to judge the status of their bee stocks. As a result we have much more data on bee populations, although coverage is still patchy and differences in survey methods make it hard to compare between continents. </p>
<p>It is clear that bees in the United States are still struggling. Beekeepers can tolerate up to 15% losses of colonies over winter, but the US is massively above this threshold, having <a href="https://beeinformed.org/results/colony-loss-2015-2016-preliminary-results/">lost 28.1% of colonies</a> over the 2015-16 winter. </p>
<p>Canada, by contrast, reported <a href="http://www.capabees.com/shared/2015/07/2016-CAPA-Statement-on-Colony-Losses-July-19.pdf">16.8% losses</a>. This is better, but still above the level of losses at which beekeepers can easily restock. </p>
<p>Only recently have we had data from central Europe. There, honey bees seem to be doing better: <a href="http://www.coloss.org/announcements/losses-of-honey-bee-colonies-over-the-2015-16-winter">11.9% losses</a> in 2015-16. Meanwhile, in New Zealand surveys only began in the last year and have reported <a href="http://www.landcareresearch.co.nz/science/portfolios/enhancing-policy-effectiveness/bee-health">winter loss of 10.7%</a>. Australia does not yet have a countrywide survey of the state of bee colonies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168232/original/file-20170507-7692-1racbi4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fortunes are mixed for bees around the world.</span>
<span class="attribution"><span class="source">Simon Klein</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Honey bees are not the only bees that we should care about: <a href="https://theconversation.com/theres-much-more-to-bees-than-queens-honey-and-hives-41380">wild bees</a> are <a href="https://theconversation.com/not-just-bees-the-buzz-on-our-other-vital-insect-helpers-52373">vital pollinators too</a>. Some plants are pollinated by only one wild bee species, such as the <a href="http://www.iucnredlist.org/details/13323697/0">macropis bees</a> that forage on the loosetrife plant. </p>
<p>Unsurprisingly, we have much less data on wild bees than honey bees, and those data we do have point to bigger concerns. For our wild bees we only really have good data for populations that are endangered or that have completely disappeared. Between 2008 and 2013, wild bee diversity in the US <a href="http://www.pnas.org/content/113/1/140.full.pdf">dropped by 23%</a>, and a previously common bumblebee species was recently <a href="http://xerces.org/">listed as endangered</a>.</p>
<h2>Do we understand why?</h2>
<p>The good news is that the past decade has seen plenty of progress in understanding the mystery of Colony Collapse Disorder. The bad news is that we now recognise it as a <a href="http://www.sciencedirect.com/science/article/pii/S2214574515000541">complex problem with many causes</a>, although that doesn’t mean it is unsolvable.</p>
<p>For all bees, foraging on flowers is a hard life. It is energetically and cognitively demanding; bees have to travel large distances to collect pollen and nectar from sometimes hard-to-find flowers, and return it all to the nest. To do this they need finely tuned senses, spatial awareness, learning and memory. </p>
<p>Anything that damages such skills can make bees struggle to find food, or even get lost while trying to forage. A bee that cannot find food and make it home again is as good as dead. </p>
<p>Because of this, bee populations are very vulnerable to what we call “sublethal stressors” – factors that don’t kill the bees directly but can hamper their behaviour.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168233/original/file-20170507-7695-10hcl8u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For solitary species such as the blue-banded bee, difficulty foraging can be a very serious problem.</span>
<span class="attribution"><span class="source">Simon Klein</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In a <a href="http://www.sciencedirect.com/science/article/pii/S0169534716302439">recently published review</a>, we argue that modern agriculture and industry have created a host of sublethal stressors that damage bees’ cognition. For example, <a href="https://phys.org/news/2013-10-diesel-exhaust-honeybees-forage.html">diesel fumes</a> and <a href="https://theconversation.com/neonicotinoids-linked-to-wild-bee-and-butterfly-declines-in-europe-and-us-63999">neonicotinoid pesticides</a> both reduce bees’ foraging efficiency by disturbing chemical communications in their brains. Modern intensive agriculture <a href="https://theconversation.com/poor-nutrition-may-be-another-reason-for-the-declining-honey-bee-population-48684">disturbs bee nutrition</a>, which impairs their brain. <a href="http://www.telegraph.co.uk/news/earth/earthnews/10730667/Bees-and-the-crops-they-pollinate-are-at-risk-from-climate-change-IPCC-report-to-warn.html">Climate change</a> interferes with the relationship between bees and the plants on which they feed. </p>
<p>In addition, managed honey bees are afflicted by a range of pests, viruses and predators that have been spread around the world as a side-effect of international trade. The worst is the ominously named <a href="https://theconversation.com/explainer-varroa-mite-the-tiny-killer-threatening-australias-bees-25710"><em>Varroa destructor</em> mite</a>, which causes brain development disorders.</p>
<h2>What can we do?</h2>
<p>At the global level, to preserve our bees we have to improve the environments in which they collect food. Every small action can make a difference. Planting flower borders with <a href="https://rirdc.infoservices.com.au/items/12-014">bee-friendly flowers</a> in your garden can provide food for both wild and domestic bees. You can reduce or eliminate the use of herbicides or pesticides when gardening. Even <a href="https://www.researchgate.net/publication/301688107_Influence_of_the_reduction_of_urban_lawn_mowing_on_wild_bee_diversity_Hymenoptera_Apoidea">mowing the lawn less often</a> can help bees out. </p>
<p>You could install a <a href="http://www.sugarbag.net/">native bee hive</a> or <a href="http://www.sgaonline.org.au/insect-hotels/">insect hotel</a>. Another tempting option is to buy local honey, which often has a more distinctive flavour than mass-produced versions.</p>
<p>In Australia, we are fortunate in that our bees seem to be doing better than many other parts of the world. The Varroa mite has not yet invaded our shores, and in many areas bees can access pesticide-free bushland (although unlike Europe, Australia has <a href="https://independentaustralia.net/environment/environment-display/australias-complacency-in-the-face-of-worldwide-bee-decline,8002">not yet banned use of neonicotinoids in agriculture</a>).</p>
<p>Australia also has an incredibly rich diversity of wild native bees: <a href="http://www.aussiebee.com.au/">up to 1,600 different species</a>, including our emblematic stingless bees. Even so, to protect this diversity we need better surveys of how these species are doing.</p>
<p>Ten years on from the alarm over disappearing bees, it is fair to say we now know the nature of the problem and what can be done to fix it. It’s up to us to take the steps needed to sustain these precious pollinators of our food for the future.</p><img src="https://counter.theconversation.com/content/77164/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Barron receives funding from a Special Cooperative Agreement with the US Department of Agriculture.</span></em></p><p class="fine-print"><em><span>Simon Klein does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s a decade since US beekeepers first noticed that their bees were mysteriously dying. Now we know much more about Colony Collapse Disorder, raising hopes that we can turn bees’ fortunes around.Simon Klein, Doctorant, Université de Toulouse III – Paul SabatierAndrew Barron, Associate Professor, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/486842015-10-20T03:35:40Z2015-10-20T03:35:40ZPoor nutrition may be another reason for the declining honey bee population<figure><img src="https://images.theconversation.com/files/98260/original/image-20151013-31126-3mupea.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sunflowers contain less protein than aloe plants and bees need more of this. </span> <span class="attribution"><span class="source">Chamanti Laing</span></span></figcaption></figure><p>Honey bees are essential for pollination of wild and cultivated plants, and honey production. As a result honeybee colonies are managed all over the world. Bees and other pollinators are in the <a href="http://news.nationalgeographic.com/news/2013/13/130510-honeybee-bee-science-european-union-pesticides-colony-collapse-epa-science/">news</a> a lot more recently because they are declining in numbers, while the demand for crop production increases.</p>
<p><a href="http://www.economist.com/node/21551451">Pesticides</a> and bee <a href="http://www.dpi.nsw.gov.au/agriculture/livestock/honey-bees/pests-diseases">diseases</a> seem to draw the most attention as the cause of declining bee numbers. But nutritional stress could be another. Habitat loss and intensified agriculture lead to diminishing food resources for bees. This additional stress lowers their resistance to pesticides and diseases.</p>
<h2>Nutritional requirements of bees</h2>
<p>Adult bees need mainly carbohydrates, and sugars in nectar provide energy for foraging and thermoregulation. Their larvae need protein, fats, vitamins and minerals for growth. These nutrients come from <a href="http://health.howstuffworks.com/diseases-conditions/allergies/outdoor-allergies/what-is-pollen.htm">pollen</a>. Among solitary bees, larvae are the main pollen consumers. Honey bees differ in that the main consumers are nurse bees, young workers who digest pollen and produce jelly that they feed to the larvae, also known as brood.</p>
<p>We need to distinguish between the quality and quantity of bee food. Mass-flowering crops such as sunflower or canola provide superabundant food. But this has disadvantages: it’s for a limited period only, it increases exposure to pesticides and it is unlikely to be nutritionally balanced. Sunflower pollen for example, contains much less protein than <a href="http://www.honeybadger.co.za/sabj_7401.html">aloe pollen</a>.</p>
<p>In addition to the total amount of protein, amino acids are important. Some pollen lacks essential amino acids, or the proportions may be wrong for developing larvae. A mixed pollen diet is much better than a single pollen source.</p>
<p>In a recent <a href="https://honeymedic.files.wordpress.com/2015/03/science-2015-goulson.pdf">review</a> of bee problems, bees feeding on monoculture crops were likened to humans eating only sardines, chocolate or parsnips for a month!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/98664/original/image-20151016-25152-1wgvn7d.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">Bee on an aloe plant.</span>
<span class="attribution"><span class="source">Massimo Nepi</span></span>
</figcaption>
</figure>
<h2>Nectar and pollen</h2>
<p>Nectar is mainly a solution of simple sugars; sucrose, glucose and fructose in varying proportions. It also contains amino acids but in much smaller amounts. Water has to be removed from the nectar before storage as honey. This is achieved by repeated regurgitation and evaporation in the hive.</p>
<p>Pollen is much more complex. Much of its nutritional value is in the protein - this can be more than half the dry mass. When bees collect pollen they add nectar to stick the grains together for transport on their legs, so pollen brought into the hive contains extra sugar.</p>
<p>This stored pollen is known as bee bread. It’s been assumed that microbes in stored pollen improve its nutritional value through fermentation, but recent <a href="http://www.nzbees.net/threads/pollen-nutrition-research.6009/">research</a> has shown that microbes are essentially absent. In fact the added nectar has a preservative function. This confirms our analyses of sunflower and aloe pollens, which do not change in composition during storage.</p>
<p>Social existence makes nutrient regulation more complex. Does a bee forage for herself or the colony? Foraging bees tend to specialise in either nectar or pollen collection, but they forage for the whole colony. Its protein requirements depend on the worker/brood ratio. More brood means a greater need for pollen protein. Storage of food resources as honey or bee bread can buffer nutritional imbalances to some extent.</p>
<h2>Interacting effects of disease, pesticides and nutrition</h2>
<p>Honey bees are plagued by many parasites and pathogens that can affect their health. Multiple pathogen infections are common, often associated with the parasitic mite <a href="http://entnemdept.ufl.edu/creatures/misc/bees/varroa_mite.htm">Varroa destructor</a>. This infects most managed colonies world-wide and also transmits viral diseases. </p>
<p>Some pathogens have a direct influence on nutrition. The gut parasite Nosema competes with host bees for carbohydrates, placing them under energetic stress, and interferes with digestion. Poor nutrition in honey bees, as when consuming a single pollen type compared to a mixture, reduces their immunity to infection.</p>
<p>Malnourished honey bees may also be less efficient at detoxifying pesticides. The widely used neonicotinoids are systemic pesticides that spread throughout plant tissues and into <a href="http://www.npr.org/sections/thesalt/2013/03/27/175278607/are-agricultures-most-popular-insecticides-killing-our-bees">nectar and pollen</a>. Apart from direct toxicity, they have been shown to have subtle, sublethal effects on flight, navigation and learning in bees. This behaviour is important for food collection. A recent study showing that bees can’t taste neonicotinoid pesticides is especially <a href="http://www.bbc.com/news/science-environment-32399907">worrying</a>.</p>
<p>Even without going out to forage, honey bees are exposed to multiple pesticides at home. Many toxic chemicals end up in stored pollen in the <a href="http://www.honeycolony.com/article/honeybee-pollen-contaminated-cocktail-pesticides/">hive</a>, including the miticides that are used by beekeepers to combat Varroa.</p>
<p>These complex interactions between poor nutrition and other stress factors contribute to poor health of both wild and managed honey bees. But there are ways to improve bee nutrition. An obvious one is preserving semi-natural habitat in farmland, so that wild flowers sustain the bees and add variety to their diet.</p><img src="https://counter.theconversation.com/content/48684/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sue Nicolson receives funding from the National Research Foundation of South Africa.</span></em></p>Nutrition is another factor - in addition to pesticides and bee disease - that has led to the dwindling of the global bee population.Sue Nicolson, Professor of Zoology, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/479542015-10-08T03:39:27Z2015-10-08T03:39:27ZHow African honey bees can help mitigate global colony losses<figure><img src="https://images.theconversation.com/files/97397/original/image-20151006-7349-1d1ub7l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The African honeybee is more resistant to pests and pathogens than its European counterparts.</span> <span class="attribution"><span class="source">Jon Hrusa/EPA</span></span></figcaption></figure><p>Managed honeybee population stocks are declining in many <a href="http://www.ibra.org.uk/articles/Guest-Editorial-Honey-bee-colony-losses">countries</a>, worrying scientists, the public and politicians. This decline affects us all, as it poses a risk to food security. </p>
<p>Honeybees can be moved where needed and are not picky about the flower they visit to collect pollen and nectar which they feed on. Thanks to these qualities, they are the major crop pollinators relied on by humans. The honeybee equals and sometimes surpasses all other wild pollinators for this task. </p>
<p>In the last decade, many studies focused on honeybee health to identify the causes of unusually high colony losses. Most of this work has been performed in <a href="http://www.ibrabee.org.uk/index.php/component/k2/item/3131">Europe</a> and <a href="http://www.ibra.org.uk/articles/US-honey-bee-colony-mortality-2012-13">North America</a> where bees are exploited in large scale commercial operations. Scientists observe interactions of many factors affecting honeybee <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0043562">health</a>. </p>
<p>But these results are so far not sufficiently clear to understand the causes of the declines and implement adapted mitigation measures. Scientists and beekeepers will first need to understand the reasons for deaths amongst bees before they can adjust their practices to ensure the stocks’ survival.</p>
<p>Honeybee health status or even basic data of population sizes in the wild before the modern beekeeping area is unknown. We lack important information to evaluate the severity of the current problem. Understanding how bees deal with pests, pathogens and other environmental factors in Africa, where beekeeping has not been as intrusive, could help scientists understand more about why the bees of Europe and North America struggle. </p>
<h2>How can African honeybees help?</h2>
<p>The honeybee, <em>Apis mellifera</em>, is also present in <a href="http://entnemdept.ufl.edu/creatures/misc/bees/ahb.htm">Africa</a>. In contrast to the docile European honeybees, African honeybees are more <a href="http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Apis_mellifera_scutellata.htm">aggressive</a> to beekeepers and are rarely confined to man-made hives. The majority of their estimated 310 million colonies strong <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2009.01331.x/suppinfo">population</a> is <a href="http://edis.ifas.ufl.edu/mg113">wild</a> and lives in natural cavities in trees or ground. </p>
<p>A lack of data on the health status of African honeybees has prompted several international teams to investigate this issue in recent years. In attempting to deal with the problem of colony losses, beekeepers and scientists throughout the world posed the following questions:</p>
<ol>
<li><p>Is it possible that by developing beekeeping to the current industrial level, we pushed the honeybees to their biological limits? When managing these pollinators, do we place them in such unnatural situations that they are weakened?</p></li>
<li><p>Was the selective breeding used to improve desirable traits such as honey production or docility done at the expense of their defence mechanisms? </p></li>
<li><p>Does the wide scale honeybee trade result in the spread of damaging pathogens to which the honeybees are not adapted? </p></li>
</ol>
<p>By studying African honeybees in their unique <a href="http://www.apidologie.org/articles/apido/abs/2009/03/m08180/m08180.html">context</a>, we could obtain the answers.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/97425/original/image-20151006-7375-1akj0fi.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">Bee with deformed wings caused by a virus transmitted by the varroa mite.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Increased knowledge on African honey bee health</h2>
<p>Recent health surveys indicated that honeybee populations in <a href="http://www.sciencedirect.com/science/article/pii/S0022201113000748">South Africa</a>, <a href="http://www.sciencedirect.com/science/article/pii/S0022201110000571">Uganda</a>, <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0094459">Kenya</a> and <a href="http://link.springer.com/article/10.1007%2Fs13592-015-0372-z">Benin</a> are indeed healthy. Pathogens, either endemic or imported, are present but do not at this time seem to generate unusual and widespread mortality. A notable exception is the damage done by a certain <a href="http://www.ibra.org.uk/articles/Colony-losses-in-South-Africa-2009-11">honeybee</a>. A particular honeybee lineage originating in the Cape region in South Africa functions as a social <a href="http://www.americanscientist.org/issues/pub/2002/9/attack-of-the-pseudo-clones">parasite</a>.</p>
<p>To promote its own reproduction, this parasitic honeybee invades colonies of other subspecies and exhausts their resources until they dwindle to death. Tens of thousands of managed colonies in the hands of the beekeepers have been lost to this parasite, while the wild populations still living in natural nests fortunately seem spared. This means that beekeepers are seen as the vectors of the parasitic bee as it largely affects managed <a href="http://www.apidologie.org/articles/apido/abs/2006/04/M6021/M6021.html">honeybees</a>. </p>
<p>This phenomenon is one example of an unexpected and negative consequence of trade involving the displacement of a subspecies of bees from their natural distribution range. The huge numbers of bees being traded all over the word exposes them to numerous <a href="http://web.oie.int/boutique/index.php?page=ficprod&id_prec=945&id_produit=1062&lang=en&fichrech=1">diseases</a>.</p>
<p>In contrast, the invasion by the most damaging honeybee parasite, the well named mite <em>Varroa destructor</em>, does not show the same long term devastating effect on some African honeybee <a href="http://link.springer.com/article/10.1007%2Fs10493-014-9842-7">populations</a>. </p>
<p>Researchers are very interested in identifying the tolerance mechanisms of the honeybee populations able to survive infestation without treatments. Selective breeding of the responsible behavioural or physiological traits could help the currently susceptible populations survive in presence of the parasite. Control efforts of the past decades have not resulted in parasite eradication and new methods are required. Honeybees that can live in the presence of this mite without human intervention are the Holy Grail for many scientists and beekeepers.</p>
<h2>Learning from past mistakes</h2>
<p>The African honeybee populations have so far largely coped with the arrival of new parasites and <a href="http://www.apidologie.org/articles/apido/abs/2009/03/m08180/m08180.html">pathogens</a>. But measures should be put in place to maintain their apparently healthy status. Beekeepers should work with local honeybee populations and refrain from importing colonies from distant places. </p>
<p>Despite the general positive situation, worrying signs of declining populations have recently been <a href="http://www.bioone.org/doi/abs/10.4001/003.022.0313?journalCode=afen">reported</a> in Madagascar, Kenya and South Africa. This is where colonies succumb to the newly arrived varroa mite or where beekeepers have increasing difficulty trapping wild swarms to build their stocks.</p>
<p>Africa would benefit from the mistakes made elsewhere by preventing such problems through the protection of honeybee populations. Before the states establish rules and restrictions, better information for the primary stakeholders are needed. Beekeepers play a vital role. They can help keep African honeybees healthy. The African honeybee could be a major tool for researchers and beekeepers if they want to learn about conserving the western honeybee.</p><img src="https://counter.theconversation.com/content/47954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Dietemann receives funding from the government and other foundations for his research. He is also part of part of the COLOSS (Preventing Honeybee Colony Losses) network.</span></em></p>The way the Africa honeybee’s deal with parasites and pathogens can teach western beekeepers and researchers how to adapt their bees to fight diseases.Vincent Dietemann, Extraordinary lecturer in Zoology and Entomology, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/345202014-11-24T19:38:26Z2014-11-24T19:38:26ZAustralian farmers face increasing threat of new diseases: report<figure><img src="https://images.theconversation.com/files/65260/original/image-20141124-1061-1ku4ptd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Honeybees pollinate a third of Australia's food crops. Losing them due varroa might would cost the economy billions of dollars. </span> <span class="attribution"><span class="source">David McClenaghan</span>, <span class="license">Author provided</span></span></figcaption></figure><p>A nationwide outbreak of foot and mouth disease; an invasion of a devastating wheat disease; our honeybees completely wiped out. These are just three possible disastrous scenarios facing Australia; they’re considered in the <a href="http://www.csiro.au/Organisation-Structure/Flagships/Biosecurity-Flagship/Biosecurity-Futures-Report.aspx">Australia’s Biosecurity Future</a> report published today by CSIRO and its partners. </p>
<p>Intensifying and expanding agriculture, biodiversity loss, and more people and goods moving around the world are the “megatrends” driving what we have called “megashocks” — new outbreaks of diseases and pests. </p>
<p>These three events alone could not only cost Australia’s economy billions of dollars, but would also devastate our agricultural industries and environment and severely alter our way of life. </p>
<p>How well prepared is Australia, and how would our biosecurity system cope with such a situation? </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65324/original/image-20141124-19627-1rdrnzq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cucumber Mottle Mosaic Virus, currently affecting cucumbers in the NT.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Cucumber_mosaic_virus#mediaviewer/File:Cucumber_mosaic_virus_symptoms.jpg">USDA Forest Service/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>For example, governments and farmers near Katherine in the Northern Territory are mounting an emergency response to deal with an outbreak of a new disease — Cucumber Green Mottle Mosaic Virus — and while this virus is not likely to create headlines, it is devastating crops, <a href="http://www.abc.net.au/news/2014-10-13/northern-territory-watermelon-crops-destroyed/5809196">severely affecting</a> the NT farming community financially and threatening industries elsewhere in Australia. </p>
<h2>An ever-hungrier world</h2>
<p>As part of the drive to help feed the world, Australia will have to increase agricultural production — both through intensification and expansion. Both of these processes could expose new biosecurity challenges. </p>
<p>The United Nations <a href="http://www.fao.org/home/en/">Food and Agriculture Organization</a> (FAO) has forecast that food production will need to increase by 60% (compared to 2005/2007 levels) to meet demand in 2050. </p>
<p>This 2050 scenario could see the value of Australian food exports increasing by 140% compared to 2007 levels.</p>
<p>However, Australia’s agriculture sector is already constrained by limited soil and water resources and future intensification will bring its own challenges through herbicide resistance and more intensive animal production systems. These factors could all increase the impacts of a biosecurity incident, and reduce the industry’s ability to sustainably meet demand. </p>
<p>In 1973 Australia’s wheat production industry was devastated by an outbreak of wheat stem rust, causing an estimated A$200-300 million in damages. While wheat stem rust has been under control since that time, there are new threats on the horizon. </p>
<p>Currently sweeping the world is the even more virulent Ug99, and without stepping up our biosecurity, it is likely to reach Australia. Luckily in this case we have time to prepare by developing varieties resistant to Ug99, but we may not always have such forewarning. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65323/original/image-20141124-19636-9sz82m.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 researcher investigates the wheat rust Ug99 in Kenya.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cimmyt/5809673838">International Maize and Wheat Improvement Center/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Expanding into new areas</h2>
<p>Intensifying food production alone may not be sufficient to meet global demand. We may also have to expand into new or previously marginal areas. This could expose agriculture to new biosecurity threats, some that we may not fully understand, through new pathways or new hosts for pests and diseases. </p>
<p>For example, there is considerable government and industry interest in increased agricultural development in Northern Australia. Various reports, including the recent <a href="http://northernaustralia.dpmc.gov.au/sites/default/files/papers/green_paper.pdf">Green Paper on Developing Northern Australia</a> suggest that northern agricultural production could increase substantially through targeted use of soil and water resources. </p>
<p>But this could expose Australia to new biosecurity threats. There are already a number of established pests and diseases in NT. And, importantly, these small areas of northern irrigated agriculture could act as a target for exotic pests and as a bridge for exotic pests to enter, establish and spread southwards.</p>
<p>This could have more severe consequences for established agricultural systems in southern Australia. In 1998 sugarcane smut appeared in the Ord, Western Australia. It then spread to Queensland in 2006, ultimately costing a 10-30% reduction in gross margins thanks to loss of yield, and the cost of planting resistant sugarcane varieties. </p>
<p>So biosecurity needs to be explicitly considered in any plan to expand agriculture in northern Australia – we need to anticipate future threats and mitigate them where possible. </p>
<h2>Diversity dilemma</h2>
<p>Invasive species are one of the most significant known threats to biodiversity and ecosystem services around the world. In Australia invasive vertebrates such as rabbits, <a href="https://theconversation.com/to-save-australias-mammals-we-need-a-change-of-heart-27423">feral cats</a>, pigs and camels impose severe impacts on Australian habitats and wildlife. </p>
<p>But biodiversity is also important in underpinning the ecosystem services for agriculture and the economy. Healthy soil function, pollination, and natural pest control are all driven by biodiversity within agricultural landscapes. Over the past century, crops have lost 75% of their genetic diversity, making them potentially more susceptible to new pathogens or pests.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65327/original/image-20141124-19633-hb62h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A varroa mite on the head of a bee nymph.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/sanmartin/5048103407/in/photolist-8G5RgD-8G5Fdx-bzdBr-n45NQ-qJBy3-fuTnMP-fuTnRF-fv8Fh7-fuTnVT-fuTnPe-8G5NGF-8G5C5X-6RxAir-8G8SLb-8G5Q3X-8G8XEh-8G5KDx-8G8TGL-fv9VaG-6a9HTP-fva1GA-fv9Ngs-fva4S9-fv9NDf-fv9LDU-7G8bmM-8G5Drk-8G5J6D-8G8QZA-7Cqe1a-7Cqe8R-7Cqean-7Cu3Zu-7Cu3Vo-7Cqe3p-7Gc7VS-7CuyH1-dTj5DU-7G8ap8-dT7QXF-dTdsfm-7CutKA-7CqEb8-7CqLpz-7CuyNf-7CuyYh-7CuyTj-7CqJW6-7CuyBS-4EKHC">Gilles San Martin/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We rely on some species for the services they provide, such as the European honeybees which pollinate our largely non-indigenous crops. Australia is fortunate to be the only continent not yet affected by the devastating bee pest, <a href="https://www.daff.qld.gov.au/plants/weeds-pest-animals-ants/pest-animals/a-z-listing-of-pest-animals/photo-guide-to-pest-animals/varroa-mites">varroa mite</a>. There is very real potential for it to arrive and spread in Australia. </p>
<p>Elsewhere in the world, varroa mite is driving a complex of factors leading to a global decline of honeybees, and native pollinators are also threatened through pesticide use and habitat loss.</p>
<p>Losing these pollination services, would severely impact the 30% of food crops which are dependent on honeybees, particularly many fruits and vegetables. The impact on our economy would be in the order of A$4-6 billion each year. </p>
<h2>On the move</h2>
<p>The increased movement of people, goods and vessels around the globe increases the chance of biosecurity threats hitting our shores. That’s why our biosecurity border protection is so important.</p>
<p>Inadvertent spread of exotic organisms in shipping containers such as European house borer in Western Australia, on contaminated equipment or carried by people such as the introduction of fire ants, as well as the spectra of deliberate introductions which haven’t yet happened in Australia show the scale and breadth of the issues we have to deal with. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65328/original/image-20141124-19608-1tuzcny.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">An outbreak of foot and mouth disease in Australia livestock could cost tens of millions of dollars.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/mdalmuld/7180902804">Marc Dalmulder/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>An outbreak of an exotic pest or disease, such as foot and mouth disease (FMD) in Australia, which affects cloven hoofed animals such as cattle, pigs and sheep, could close down export markets overnight or make other countries more competitive.</p>
<p>An FMD outbreak in Australia could lead to industry-wide <a href="http://www.agriculture.gov.au/abares/publications/display?url=http://143.188.17.20/anrdl/DAFFService/display.php?fid=pb_pseiFMDd9abbl20131011_11a.xml">revenue losses for livestock producers</a> of around A$6 billion for a small outbreak and A$50 billion for a large multi-state outbreak over a 10-year period. Additional costs related to disease control, such as labour, decontamination, slaughter, disposal and facilities, would be expected to range from A$60 million to A$373 million.</p>
<h2>Pre-empting the threat</h2>
<p>As an island nation, Australia has been able to maintain an enviable biosecurity status, keeping out many of the world’s worst pests and diseases. This means we have market access for a vast array of export produce, a status which will be increasingly valuable in a growing and highly competitive global market for food. </p>
<p>To ensure we maintain this status, the management of Australia’s biosecurity will require a step change towards smarter and more efficient strategies that are ideally ahead of the pace of change around the world. Smarter technologies, strengthened integration across governments and industry and great commitment will be needed. If we do this, we are surely better able to protect our farmers, communities and environment from the impacts of exotic pests and diseases. </p>
<p>Clearly, we can’t afford to become complacent with our nation’s biosecurity measures. As is true of any threat, it is much better to pre-empt and avoid than have to deal with the costly consequences.</p><img src="https://counter.theconversation.com/content/34520/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The CSIRO Biosecurity Flagship receives funding from government and industry R&D bodies and works in collaboration with many research and industry partners..</span></em></p>A nationwide outbreak of foot and mouth disease; an invasion of a devastating wheat disease; our honeybees completely wiped out. These are just three possible disastrous scenarios facing Australia; they’re…Gary Fitt, Science Director, Biosecurity Flagship, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/257102014-05-19T04:34:57Z2014-05-19T04:34:57ZExplainer: Varroa mite, the tiny killer threatening Australia’s bees<figure><img src="https://images.theconversation.com/files/48551/original/6nwp4rcb-1400116742.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A busy bee, giving free horticultural help by collecting pollen. But a tiny mite has devastated bee populations around the world – and it's now on Australia's doorstep.</span> <span class="attribution"><span class="source">David McClenaghan/CSIRO</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>A tiny mite has been killing honey bees all around the world, and will inevitably reach Australian shores. So what is this destructive mite, and what we can do to protect Australian honey bees?</p>
<p>The Varroa mite, also known as <em>Varroa destructor</em>, is only the size of a pin head but it is the most serious threat to the viability of the Australian honey bee industry. </p>
<p>The mite is parasitic and feeds on the blood of adult and larval honey bees. It also transmits viral and other pathogens, which kill entire bee colonies. Varroa mite is part of the syndrome leading to honey bee declines in many places around the world.</p>
<h2>The global invasion heading our way</h2>
<p>Varroa mite has been highly invasive. It originated in north Asia in the 1950s and spread to Europe in the 1970s. It then spread to the USA, southeast Asia, South America and Africa. In 2000 it turned up in New Zealand.</p>
<p>Varroa kills honey bees that are managed by beekeepers as well as honey bees living in the wild (known as “feral” bees). Beekeepers need to use chemicals to protect their bees, which increases their costs and yet offers only a partial solution.</p>
<p>Honey bees living in the wild are even more vulnerable, and widespread declines occur. Within four years of the invasion of New Zealand’s North Island, feral bee populations plummeted to about 10% of what they had been. </p>
<p>Australia is <a href="https://theconversation.com/honeybee-decline-warrants-concern-but-not-panic-5707">one of the last remaining regions</a> in the world still free of Varroa. But it is closer to coming here than ever, having now spread to our neighbours in New Zealand and Indonesia.</p>
<p>Just to complicate matters further, a new Varroa mite has emerged in Papua New Guinea, where a near relative of <em>Varroa destructor</em> has made a similar behavioural jump from the Asian Honey Bee, and now also attacks the European Honey Bee. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Nfn4jwqUqvI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A camera inside a hive shows a varroa mite on a bee, which is unable to shake it off.</span></figcaption>
</figure>
<h2>Why bees are so crucial to farming</h2>
<p>Varroa mite threatens one of our key crop pollinators, just as we have begun to realise that improved pollination is part of the secret to raising agricultural productivity.</p>
<p>Australian agriculture is vulnerable to honey bee declines because a number of our most significant horticultural crops rely on honey bee pollination, and many growers have been accustomed to a high level of free service from feral honey bees.</p>
<p>When free pollination from feral bees declines, horticultural industries will look to managed bees to fill the gap. Unfortunately, beekeepers and their managed bees will be dealing with the same crisis.</p>
<p>Nowhere is this shown better than in the USA, where the mite entered in 1987. After its arrival, the feral honey bee population crashed, managed hives were reduced by about 30% and many beekeepers left the industry.</p>
<p>The decline in managed hives, along with increasing demand from crop growers, has seen a four-fold increase in the cost of hives. Each year, there has been a growing gap between demand for hives and the capacity to supply them.</p>
<h2>Better border protection and beyond</h2>
<p>Here in Australia, that gap between the supply and demand – the number of bees that beekeepers could supply and how many bees are needed – is where we are most vulnerable.</p>
<p>Our heavy reliance on feral honey bees means there has been a relatively low demand for managed hives. As a consequence, our managed pollination industry is only in the early stages of development.</p>
<p>Given that beekeepers in the USA and NZ have failed to keep pace with demand for crop pollination, Australia may experience an even greater shock to our horticultural industries in future.</p>
<p>The threat of Varroa mite incursion into Australia is real. Any European honey bee swarm arriving on a vessel at an Australian port could be carrying Varroa.</p>
<p>The arrival of Asian honey bees by ship at Australian ports, as occurred at Cairns in North Queensland, provides another pathway for the mite’s incursion.</p>
<p>And it should be noted that the mite managed to slip through New Zealand’s quarantine defences, which are similar to Australia. </p>
<p>In 2007, bio-economic modelling by CSIRO examined the risk to Australian plant industries. It was estimated that the economic risk from Varroa incursion was great enough to justify spending between A$21 million and A$50 million annually over the next thirty years to delay incursion. </p>
<p>Reducing the risk of incursion is sensible, but there must also be a strategy to combat the pest in the likely event that it eventually establishes. This conclusion was reported in the 2008 House of Representatives <a href="http://www.aph.gov.au/parliamentary_business/committees/house_of_representatives_committees?url=/pir/honeybee/report.htm">“More than Honey” inquiry</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/48550/original/y9xhh7f4-1400116685.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Varroa mite on a bee pupae.</span>
<span class="attribution"><span class="source">CSIRO</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Finding local solutions to help the world</h2>
<p>Threats to the European honey bee should remind us that reliance on a single species for crop pollination is a risky strategy. There are thousands of other insect species that contribute to crop pollination, and there are strategies available to better support them, and keep them in our production landscapes.</p>
<p>Nevertheless, we still need managed pollinators that can be supplied on demand to supplement wild pollinators. And the European honey bee will continue to be the most important managed pollinator. </p>
<p>Australia is uniquely placed to contribute to the global effort to deal with Varroa mite impacts on honey bees. As long as we keep Varroa out, we can provide the “Varroa free” comparison needed to understand management options for honey bee health.</p>
<p>Further, because the Varroa mite-honey bee relationship evolved in our region (Asia), we are well placed to contribute to the genetic and evolutionary studies that will underpin options for Varroa control.</p>
<p>The Varroa mite has caused problems worldwide, and there is worldwide interest in finding solutions. We need to mobilise the Australian scientists to collaborate globally, in the interests of healthy bees and productive crops.</p>
<p><em>* This article is based on the <a href="https://drive.google.com/file/d/0B0vOSyC-9daBY1BGX19SaHppU00/edit?usp=sharing">CSIRO submission</a> to a Senate inquiry into the <a href="http://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Rural_and_Regional_Affairs_and_Transport/Beekeeping">Future of the beekeeping and pollination service industries in Australia</a>. The Senate committee is holding a <a href="http://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Rural_and_Regional_Affairs_and_Transport/Beekeeping/Public_Hearings">public hearing in Brisbane</a> tomorrow (May 20), and is due to complete its report by June 19.</em></p><img src="https://counter.theconversation.com/content/25710/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Saul Cunningham receives funding from Horticulture Australia Limited, the Grains Research and Development Corporation and the Commonwealth Government's Caring for Our Country program. He provides advice to the Commonwealth Government on strategies for dealing with Varroa mite impacts on agriculture.</span></em></p><p class="fine-print"><em><span>Paul De Barro leads the Reducing Likelihood theme in the CSIRO Biosecurity Flagship. Researchers in this theme receive funding from a number of agricultural industries that benefit from pollination and would be directly impacted by an incursion of Varroa mite and honey bee pathogens.</span></em></p>A tiny mite has been killing honey bees all around the world, and will inevitably reach Australian shores. So what is this destructive mite, and what we can do to protect Australian honey bees? The Varroa…Saul Cunningham, Researcher, CSIROPaul De Barro, Senior Principal Research Scientist, Ecosystem Sciences, CSIROLicensed as Creative Commons – attribution, no derivatives.