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.
Exceptionally high-quality videos allow scientists to formally introduce a remarkable new comb jelly.
- Gorgeous simplicity characterizes the comb jelly recently discovered by National Oceanic and Atmospheric Administration Fisheries.
- The small denizen of the deep was spotted three times beneath the waters off Puerto Rico.
- Though it's unusual to formally identify an animal strictly based on video observations, the quality of NOAA's video made it possible in a case where there's no better alternative.
Meet cute beneath the waves<p>The first encounter humanity had with the jelly<em> </em>occurred on April 10, 2015, when Deep Discoverer (a remotely operated vehicle or ROV) came across the gelatinous wonder. Fortunately, the ROV sports cameras that were sufficiently high-definition to clearly capture <em>Duobrachium sparksae's</em> fine details.</p><p>The animal was first noticed in a video feed by Mike Ford of the shoreside science team working in NOAA's Exploration Command Center far away, outside of Washington, D.C. The ROV was working the Arecibo amphitheater canyon. What Ford saw was, in his words, "a beautiful and unique organism."</p><p>Deep Discoverer's cameras produce externally high-resolution images, and are capable of measuring objects as small as a millimeter.The comb jelly's body is about 6 centimeters in size, and its tentacles are about 30 cm long.</p><p>While video-based animal identification can be controversial, there was little choice in this case. "We didn't have sample collection capabilities on the ROV at the time," says Collins. "Even if we had the equipment, there would have been very little time to process the animal because gelatinous animals don't preserve very well; ctenophores are even worse than jellyfish in this regard."</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODEwNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2NjA0MjMxMH0.X3YXqsUtddtArtXOz7z5w-Zli0Z2vCE1UoSRLU63898/img.jpg?width=980" id="fffe5" class="rm-shortcode" data-rm-shortcode-id="5b42f13f528c33eeaeb512320cac7f23" data-rm-shortcode-name="rebelmouse-image" data-width="1232" data-height="1440" />
Credit: Nicholas Bezio/NOAA Office of Ocean Exploration and Research
Describing Duobrachium sparksae<p>All told, three individuals were observed by the scientists in three separate encounters with the ROV. The image at the top of this article is from the second encounter. The fact that three separate examples were easily spotted leaves scientists hopeful that the creature is not a rarity in the seas.</p><p>Ford describes what they saw:</p><p style="margin-left: 20px;">"The ctenophore has long tentacles, and we observed some interesting movement. It moved like a hot air balloon attached to the seafloor on two lines, maintaining a specific altitude above the seafloor. Whether it's attached to the seabed, we're not sure. We did not observe direct attachment during the dive, but it seems like the organism touches the seafloor."</p><p>The role that <em>Duobrachium sparksae</em> plays in its ecosystem is not yet understood.</p><span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="83f6005db2fc4b5e7ec6fc207ff70639"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/o0nkwCKpaRA?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Finding a place in the family<p>The manner in which light refracted prismatically off the jelly's cilia combs immediately placed it in the ctenophore family as a start.</p><p>Collins explains, "We don't have the same microscopes as we would in a lab, but the video can give us enough information to understand the morphology in detail, such as the location of their reproductive parts and other aspects."</p><p>"We went," says Ford, "through the historical knowledge of ctenophores and it seemed clear this was a new species and genus as well. We then worked to place it in the tree of life properly."</p><p>The videos—the only "specimens" there are of <em>Duobrachium sparksae</em>—are now publicly accessible as part of the Smithsonian National Museum of Natural History Collection.</p>
Researchers document the first example of evolutionary changes in a plant in response to humans.
- A plant coveted in China for its medicinal properties has developed camouflage that makes it less likely to be spotted and pulled up from the ground.
- In areas where the plant isn't often picked, it's bright green. In harvested areas, it's now a gray that blends into its rocky surroundings.
- Herbalists in China have been picking the Fritillaria dealvayi plant for 2,000 years.
Fritillaria dealvayi<p>The plant is <em> </em><a href="http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200027633" target="_blank"><em>Fritillaria dealvayi</em></a><em>,</em> and its bulbs are harvested by Chinese herbalists, who grind it into a powder that treats coughs. The cough powder sells for the equivalent of $480 per kilogram, with a kilogram requiring the grinding up of about 3,500 bulbs. The plant is found in the loose rock fields lining the slopes of the Himalayan and Hengduan mountains in southwestern China.</p><p>As a perennial that produces just a single flower each year after its fifth season, it seems <em>Fritillaria</em> used to be easier to find. In some places its presence is betrayed by bright green leaves that stand out against the rocks among which which it grows. In other places, however, its leaves and stems are gray and blend in with the rocks. What's fascinating is that the bright green leaves are visible in areas in which Fritillaria is relatively undisturbed by humans while the gray leaves are (just barely) visible in heavily harvested areas. Same plant, two different appearances.</p><div id="19cbf" class="rm-shortcode" data-rm-shortcode-id="c68d3086f5411ffd951edaad1cb811b9"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1329832938985435138" data-partner="rebelmouse"><div style="margin:1em 0">2/2: The picture on the left shows a Fritillaria delavayi in populations with high harvest pressure, and the one on… https://t.co/oriBNZGcsV</div> — University of Exeter News (@University of Exeter News)<a href="https://twitter.com/UniofExeterNews/statuses/1329832938985435138">1605891854.0</a></blockquote></div>
How we know we're the cause<p>There are other camouflaging plants, but the manner in which <em>Fritillaria</em> has developed this trait strongly suggests that it's a defensive response to being picked. "Many plants seem to use camouflage to hide from herbivores that may eat them — but here we see camouflage evolving in response to human collectors."</p><p>"Like other camouflaged plants we have studied," Niu says, " we thought the evolution of camouflage of this fritillary had been driven by herbivores, but we didn't find such animals." His close examination of Fritillaria leaves revealed no bite marks or other signs of non-human predation. "Then we realized humans could be the reason."</p><p>In any event, says Professor Hang Sun the Kunming Institute, "Commercial harvesting is a much stronger selection pressure than many pressures in nature."</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDgyNzM0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzMDc3NDQwMn0.lXwsG0ShcnMcVLl06APdEeEOY5_WOs4UfN8oVCKsgtc/img.png?width=980" id="ccc8e" class="rm-shortcode" data-rm-shortcode-id="907e152dd5ad0429aa6350c53f5a85aa" data-rm-shortcode-name="rebelmouse-image" alt="herb shop" data-width="2448" data-height="1377" />
Credit: maron/Adobe Stock
The study<p>Since herbalists have been plucking <em>Fritillaria</em> from the rocks for 2,000 years, one might hope a record would exist that could allow researchers to identify areas in which the plant has been most thoroughly picked. There is no such documentation, but Liu and Stevens were able to acquire this type of information for five years (2014–2019), tracking the harvests at seven <em>Fritillaria</em> study sites. This allowed them to identify those areas in which the plant was most heavily harvested. These also turned out to be the locations with the gray-leaf variant of <em>Fritillaria</em>.</p><p>Further supporting the scientists' conclusion that gray <em>Fritillaria</em> was more likely to evade human hands and live long enough to reproduce was that participants in virtual plant-identification tests confirmed the species was hard to spot in the wild.</p><p>"It's possible that humans have driven evolution of defensive strategies in other plant species, but surprisingly little research has examined this," Stevens notes.</p><p>Hang Sun says such studies make clear that humans have become drivers of evolution on our planet: "The current biodiversity status on the earth is shaped by both nature and by ourselves."</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.
A study finds 1.8 billion trees and shrubs in the Sahara desert.
- AI analysis of satellite images sees trees and shrubs where human eyes can't.
- At the western edge of the Sahara is more significant vegetation than previously suspected.
- Machine learning trained to recognize trees completed the detailed study in hours.
Why this matters<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzOTkyODg5NX0.O3S2DRTyAxh-JZqxGKj9KkC6ndZAloEh4hKhpcyeFDQ/img.jpg?width=980" id="3770d" class="rm-shortcode" data-rm-shortcode-id="3c27b79d4c0600fb6ebb82e650cabec0" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="786" />
Area in which trees were located
Credit: University of Copenhagen<p>As important as trees are in fighting climate change, scientists need to know what trees there are, and where, and the study's finding represents a significant addition to the global tree inventory.</p><p>The vegetation Brandt and his colleagues have identified is in the Western Sahara, a region of about 1.3 million square kilometers that includes the desert, <a href="https://en.wikipedia.org/wiki/Sahel" target="_blank">the Sahel</a>, and the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/subhumid-zones" target="_blank" rel="noopener noreferrer">sub-humid zones</a> of West Africa.</p><p>These trees and shrubs have been left out of previous tabulations of carbon-processing worldwide forests. Says Brandt, "Trees outside of forested areas are usually not included in climate models, and we know very little about their carbon stocks. They are basically a white spot on maps and an unknown component in the global carbon cycle."</p><p>In addition to being valuable climate-change information, the research can help facilitate strategic development of the region in which the vegetation grows due to a greater understanding of local ecosystems.</p>
Trained for trees<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ3MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTk5NTI3NH0.fR-n1I2DHBIRPLvXv4g0PVM8ciZwSLWorBUUw2wc-Vk/img.jpg?width=980" id="e02c0" class="rm-shortcode" data-rm-shortcode-id="79955b13661dca8b6e19007935129af1" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: Martin Brandt/University of Copenhagen<p>There's been an assumption that there's hardly enough vegetation outside of forested areas to be worth counting in areas such as this one. As a result the study represents the first time a significant number of trees — likely in the hundreds of millions when shrubs are subtracted from the overall figure — have been catalogued in the drylands region.</p><p>Members of the university's Department of Computer Science trained a machine-learning module to recognize trees by feeding it thousands of pictures of them. This training left the AI be capable of spotting trees in the tiny details of satellite images supplied by NASA. The task took the AI just hours — it would take a human years to perform an equivalent analysis.</p><p>"This technology has enormous potential when it comes to documenting changes on a global scale and ultimately, in contributing towards global climate goals," says co-author Christian Igel. "It is a motivation for us to develop this type of beneficial artificial intelligence."</p><p>"Indeed," says Brandt says, "I think it marks the beginning of a new scientific era."</p>