First picture of worldwide bee distribution fills knowledge gaps and may help protect species.
Bee diversity<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg2NzM0My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTY3NzgyMH0.sdzn0MenrQ85gIvjYM4rm-7oOVd3dO9gx7nqcm9QMwM/img.jpg?width=980" id="fe916" class="rm-shortcode" data-rm-shortcode-id="2961b6dac8da97fa083cb568b19bab10" data-rm-shortcode-name="rebelmouse-image" alt="\u200bTwelve different species of bees swarming a flowery meadow. Etching by J. Bishop, after J. Stewart." data-width="2996" data-height="1766" />
Twelve different species of bees swarming a flowery meadow. Etching by J. Bishop, after J. Stewart.
Credit: Wellcome Collection, CC BY 4.0<p>How many bee species are there? Wait a minute: honeybee, bumble bee, erhm… five? Five hundred? Five thousand? Not even close: the total is well over 20,000 – which means there are more species of bees than of birds and mammals combined. </p><p><span></span>There's no shame (nor surprise) for bee civilians like you or me in not knowing that. What is surprising, is that even scientists who specialise in bees didn't quite know how those species are distributed all over the world. Until now. </p><p><span></span>By combining and filtering more than 5.8 million public records of bee occurrences, a team of researchers from China, the U.S., and Singapore have built up the very first comprehensive picture of bee diversity worldwide. And that picture presents a few surprises, both for laypersons and specialists.</p><p>Bee ignoramuses will be surprised to learn that the United States is the throbbing heart of bee diversity. The U.S. has far more bee species than any other region on Earth. And by the fact that large tracts of Africa and the Middle East remain <em>terra incognita</em>, in terms of apiary diversity. <br></p>
Counter-intuitive distribution<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg2NzM0NS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzNzQ3NTMwMX0.poqkJqPj6CPWWN9u_FOt7nBu1lrOc2aSnv1vRO4yOHY/img.png?width=980" id="2acb0" class="rm-shortcode" data-rm-shortcode-id="407b1e60d42246f6cdfd91cfc6ef7839" data-rm-shortcode-name="rebelmouse-image" alt="\u200bRelative bee species richness in the New World. Note the low density in the Amazon Basin." data-width="1586" data-height="1372" />
Relative bee species richness in the New World. Note the low density in the Amazon Basin.
Credit: Current Biology, open access<p>In general, there are more bee species in the Northern Hemisphere than the Southern and—confirming previous hypotheses–more in arid and temperate climates than in the tropics.</p><p>That goes against the common pattern in biology known as the 'latitudinal gradient', which predicts that species diversity (of most plants and animals) increases towards the tropics and decreases towards the poles. Bees are an exception, with a higher species concentration away from the poles (in what scientists call a 'bimodal latitudinal gradient').</p><p>To give that difference some visual immediacy, imagine a graph with one hump in the middle (i.e. the latitudinal gradient) versus one with two humps, one on either side of the middle (i.e. the bimodal latitudinal gradient). In other words: dromedary (one-hump) versus camel (two-hump). </p><p>It seems counter-intuitive that bees would thrive better in arid deserts than in lush tropical jungles; but that's because trees–the dominant vegetation type in the tropics–provide less bee food than the plants and flowers that grow elsewhere. <span></span></p>
Much-needed baseline<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg2NzM0Ni9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MzY5ODU4MX0.0B0Ixka9uJpMFDozhQ9YcJAX0a6LFuy1HZ0rWWvEA3A/img.png?width=980" id="c7b8b" class="rm-shortcode" data-rm-shortcode-id="5d8f1e55aeeda42ef836931ad0095101" data-rm-shortcode-name="rebelmouse-image" alt="Three ways of measuring species richness in the Americas: (A) richness of polygons, (B) sPCA and (c ) turnover. All suggest a large, distinct bee fauna in the southwestern U.S." data-width="1748" data-height="671" />
Three ways of measuring species richness in the Americas: (A) richness of polygons, (B) sPCA and (c ) turnover. All suggest a large, distinct bee fauna in the southwestern U.S.
Credit: Current Biology, open access<p>Also, bees don't like it too wet, unlike their cousins the ants, whose populations peak in the humid tropics. The researchers think humidity may play a role in limiting bee distribution by spoiling pollen resources.</p><p><span></span>The relative absence of bees from the tropics has consequences for pollination, which in those regions is performed by a wide variety of alternative species: wasps, moths, and even cockroaches.</p><p><span></span>Previous datasets of global bee distribution were either inaccurate, incomplete, or difficult to interpret. This world map clearly establishes that bees prefer dry and temperate zones to wet and tropical ones. For bee scientists, it provides a much-needed baseline to predict the geographic distribution of bees and interpret the relative richness of species. </p><p><span></span>While much work needs to be done to fill additional knowledge gaps, this baseline is an excellent starting point, not just for greater understanding, but also for better conservation. Because bees are not just for making honey. In many countries, they're the top pollinator species. And they typically visit 90 percent of the leading crop types. </p>
Carpenter bee (Xylocopa latipes) pollinating a flower in the Indian state of Kerala.
One of the world's most isolated island groups has just been made one of the world's largest ocean reserves.
- The small island group of Tristan da Cunha has created one of the world's largest ocean sanctuaries.
- Neither fishing nor extractive activities will be allowed in the area, which is three times the size of the United Kingdom.
- Animals protected by this zone include penguins, sharks, and many seabirds.
Tristan da where now?<p> <a href="https://en.wikipedia.org/wiki/Tristan_da_Cunha" target="_blank">Tristan da Cunha</a> is a British Overseas Territory consisting of an archipelago in the south Atlantic. The titular island is the largest in the group at about 100 square kilometers. Those hoping to visit will have to get there by a week-long boat ride from Cape Town. The island's government gleefully notes that it takes longer to get there than it takes astronauts to get to the Moon. <br> <br> The marine protection zone will cover 627,247 square kilometers (over 242,000 miles) of the ocean around the islands. It will be the "gold standard" in ocean conservation, with neither fishing nor other extractive activities allowed, often referred to as "no-take." It will be the largest no-take zone in the Atlantic, and the fourth largest anywhere in the world. <br> <br> The zone includes small areas just off the inhabited islands in which sustainable fishing will be allowed, but these areas are a small fraction of the no-take area's size. Given the historical reliance of the island's economy on the sea, this consideration is quite understandable. <br> <br> These protected areas join many others covered by the United Kingdoms' <a href="https://www.gov.uk/government/publications/the-blue-belt-programme" target="_blank">Blue Belt Programme</a> of marine protection, which aims to preserve 30 percent of the world's oceans by 2030. </p>
Most important of all, what animals are protected by this?<p> The now protected fish that inhabit the waters are a vital food source for many kinds of animals, all of which will benefit from not having to share their food supply with humans. </p><p>The vast area is home to many species of whales, sharks, and seals. Endangered species of albatross also drop by. Many birds that live on the islands and cannot be found elsewhere, such as the Wilkins bunting and the Inaccessible rail, also stand to benefit from the new protections. </p><p>Most adorable of all, the endangered northern <a href="https://en.wikipedia.org/wiki/Rockhopper_penguin" target="_blank">rockhopper penguins</a> make a home on one of the archipelago islands. With luck, they may not be endangered much longer. </p>
Across the world, wildlife is under severe threat.
Earth's fate and the devastation of the natural world were recently put under the microscope with the release of Sir David Attenborough's Netflix documentary A Life On Our Planet.
We're in an era of 'megafires'.
A headline that reads 'The Worst Year in History for Wildfires' should be a shocking and dramatic statement. Instead, it's in danger of becoming a cliché, a well-worn phrase, an annual event.
On the list of animals at risk are several endangered species.
- SARS-CoV-2 enters our cells by binding with ACE2 receptors.
- A study finds many animals may provide a similar point of entry for the infection.
- COVID-19 has already been seen in a range of non-humans.
ACE2<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU4MTgwMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMTI3NDU4NH0.BceDb6l6wcwImHgniUPCNX_F5NeJ8vSsrAWNH7DG-x0/img.jpg?width=980" id="2fb6e" class="rm-shortcode" data-rm-shortcode-id="77a7d2b0d83cfc72479f2b9089e512ac" data-rm-shortcode-name="rebelmouse-image" alt="3D illustration of SARS-CoV-2 binding with ACE2 receptors" data-width="1440" data-height="960" />
3D illustration of SARS-CoV-2 binding with ACE2 receptors
Image source: Kateryna Kon/Shutterstock<p>SARS-CoV-2's main point of entry into our systems, its main cellular receptor, is an angiotensin converting enzyme-2 known as ACE2. There are many types of cells and tissues in humans that contain ACE2, including the epithelial cells found in the mouth, nose, and lungs. SARS-CoV-2 binds to 25 ACE2 amino acids to get into our cells.</p><p>The researchers investigated the presence of these amino acids in other organisms on the assumption that their presence would provide SARS-CoV-2 entry to their cells as they do in ours. Says first author of the study <a href="https://www.ucdavis.edu/person/articles/27275" target="_blank">Joana Dama</a> of UC Davis, "Animals with all 25 amino acid residues matching the human protein are predicted to be at the highest risk for contracting SARS-CoV-2 via ACE2."</p><p>The precise mechanism by which SARS-CoV-2 infections occur and lead to COVID-19 is still under exploration. Nonetheless, the study operates on the principle that more of the 25 amino acids an animal has, the higher its risk of infection. "The risk is predicted to decrease the more the species' ACE2 binding residues differ from humans," says Dama.</p>
Which species are at risk?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU4MTgwMi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY2NjE3MDY4Nn0.w7PBKqk63nB5qybhVdM5rfjALO2ay5kfUBo48kSyZ2E/img.png?width=980" id="e5a23" class="rm-shortcode" data-rm-shortcode-id="8edb6a4f609576554b9067ee019ab08b" data-rm-shortcode-name="rebelmouse-image" alt="species risk chart" data-width="900" data-height="690" />
Image source: Matt Verdolivo/UC Davis<p>Their analysis leads Dama and her co-authors to the conclusion that about 40 percent of the species at risk of SARS-CoV-2 infection are on the International Union for Conservation of Nature's <a href="https://www.iucn.org/resources/conservation-tools/iucn-red-list-threatened-species" target="_blank">"threatened" list</a>.</p><p>Sumatran orangutans, Northern white-cheeked gibbons, and the Western lowland gorillas are all critically endangered and are vulnerable to infection. Some marine animals are also at high risk, including bottlenose dolphins and gray whales.</p><p><span></span>The study asserts that many animals most likely to live among humans are apparently at low risk, including cats, dogs, cattle, sheep, horses, and pigs. Chinese hamsters carry a high risk.</p><p>It's worth noting, however, that there <em>are</em> cases on record of SARS-CoV-2 infections in <a href="https://www.statnews.com/2020/05/13/cats-can-catch-covid-19-from-one-another-study-finds-the-question-is-can-we/" target="_blank">cats</a> and <a href="https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/sa_by_date/sa-2020/sa-06/sars-cov-2-dog" target="_blank">dogs</a>. <a href="https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa325/5811871" target="_blank">Hamsters</a>, too. Less likely house pets like <a href="https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2020/ny-zoo-covid-19" target="_blank" rel="noopener noreferrer dofollow">lions, tigers</a>, and <a href="https://www.npr.org/sections/goatsandsoda/2020/06/25/882095588/dutch-minks-contract-covid-19-and-appear-to-infect-humans" target="_blank">mink</a> have also been infected.</p><p>Bats, the presumed <a href="https://www.nature.com/articles/s41586-020-2012-7" target="_blank" rel="noopener noreferrer dofollow">source of SARS-CoV-2</a>, are found by the study to be at very low risk of infection due to a lack of ACE2 receptors. Other experimental data lines up with the study's finding, which suggests that spread of SARS-CoV-2 from bats is likely to have involved intermediate hosts en route to infecting humans.</p><p>The authors have made available for <a href="https://www.pnas.org/highwire/filestream/945399/field_highwire_adjunct_files/1/pnas.2010146117.sd01.xlsx" target="_blank">download</a> the full list of animals its authors find may be susceptible to SARS-CoV-2 infection.</p>