Mosquitoes can taste your blood using unique sensory abilities. Can we use that to keep them off us?
- A recent study demonstrates that mosquito brains react to the taste of human blood in strange ways.
- Some neurons only activated when presented with all four flavor elements. This is thought to be a unique adaptation.
- The findings may lead to novel ways to prevent mosquito bites.
Like many things, it's all a matter of taste.<p> In a move dubbed a "tour de force" by other scientists involved in <a href="https://medicalxpress.com/news/2020-10-mosquitoes-blood-neurons.html" target="_blank" rel="noopener noreferrer">mosquito research</a>, the researchers genetically modified mosquitoes so that specific neurons associated with taste lit up florescent tags when activated. They then offered these Franken-mosquitos a variety of tempting drinks to see if they would consume them and, if so, what taste neurons activated. <br> <br> Sheep's blood was found to appeal to the insects, which consumed it with <a href="https://phys.org/news/2020-10-scientists-mosquitoes-unique-blood-taste-detectors.html" target="_blank" rel="noopener noreferrer">delight</a>. However, attempts to get them interested in saline or sugar water mixtures that had only single components of blood didn't work, even when the signatures of animals like carbon dioxide or heat (typically used by the parasites as guides towards sources of blood) were added. <br> <br> To draw them back, the researchers whipped up a blood-like concoction of glucose (sugar), sodium bicarbonate (present in both blood and baking soda), sodium chloride (salt), and adenosine triphosphate, or ATP, a compound that provides energy to cells which is found in all known forms of life. This was a success, and the little parasites flocked to it.<br> <br> Next, the scientists offered the mosquitoes small tastes of each of the flavor components in the blood mixture to see which neurons reacted. While giving them glucose did not activate any of the neurons associated with the blood-drinking system— perhaps because glucose is also found in nectar—small doses of salt, sodium bicarbonate, and ATP did. Each flavor activated its own set of neurons, similar to how our taste buds react to a specific flavor element. </p><p> However, one large cluster of neurons only activated when all four ingredients were present. <br> <br> According to lead author Veronica Jové, this detection of combinations rather than taste components is a unique adaptation. She explained, "These neurons break the rules of traditional taste coding, thought to be conserved from flies to humans."<strong><br> <br> </strong>And for the curious, the researchers did sample the ATP mixture they prepared in the lab. They didn't taste <a href="https://www.ibtimes.sg/how-do-mosquitoes-taste-human-blood-scientists-find-four-neurons-regulating-mosquitos-taste-blood-52466" target="_blank" rel="noopener noreferrer">anything</a>. Presumably, the taste of human blood to mosquitoes is akin to the sight of a flower in all its ultra-violet glory to a honey bee. It's just something we can't sense or hope to grasp. Though, given the sugar and salt element, perhaps to them it is like the sweet and salty flavor of salted caramels or saltwater taffy. </p>
So, can we use this to finally destroy mosquitoes once and for all?<iframe width="730" height="430" src="https://www.youtube.com/embed/9nCHK97kwR4" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> <strong></strong>Not quite, but by increasing our understanding of how mosquitoes work, we can figure out how to keep them off us. <br> <br> Co-author Dr. Leslie B. Vosshall suggests that, just as we give our pets medicine to keep fleas, ticks, and mosquitoes at bay, this discovery may lead to a drug that makes human blood unappealing to mosquitoes for use by those going into infested areas. If they can't taste blood, they may not bite in a way that can spread disease. </p><p> Mosquitoes are also known to prefer <a href="https://academic.oup.com/jme/article/41/4/796/885285" target="_blank" rel="noopener noreferrer">O</a><a href="https://academic.oup.com/jme/article/41/4/796/885285" target="_blank" rel="noopener noreferrer"> type </a><a href="https://academic.oup.com/jme/article/41/4/796/885285" target="_blank" rel="noopener noreferrer">blood</a> over all other types. This study may lead to further ones which help explain why. Additionally, because many neurons did not activate at all when the insects fed on blood or its components, further research will have to investigate if they are associated with still other flavors, or if they are related to the act of feeding on blood in different ways. <br> <br> </p>
Just what every arachnophobe needed to hear.
- A new study suggests some spiders might lace their webs with neurotoxins similar to the ones in their venom.
- The toxins were shown to be effective at paralyzing insects injected with them.
- Previous studies showed that other spiders lace their webs with chemicals that repel large insects.
Just what we needed to know before walking into another spider web<div class="rm-shortcode" data-media_id="vV8EYzwn" data-player_id="FvQKszTI" data-rm-shortcode-id="37004fd34a066f4eee06fa5feba6c111"> <div id="botr_vV8EYzwn_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/vV8EYzwn-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/vV8EYzwn-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/vV8EYzwn-FvQKszTI.js"></script> </div> <p>The study, published in the <a href="https://doi.org/10.1021/acs.jproteome.0c00086" target="_blank">Journal of Proteome Research</a>, was carried out by Biochemical Ecologist Mario Palma of the University of São Paulo State, their Ph.D. student, Franciele Esteves, and their colleagues. They focused on the webs of the striking <a href="https://en.wikipedia.org/wiki/Trichonephila_clavipes" target="_blank">T. clavipes</a><em>,</em> also known as the Banana Spider.</p><p>These spiders are orb weavers, known for their complex and often large webs. They can have up to seven glands that produce silk for various <a href="https://www.loc.gov/everyday-mysteries/item/how-do-spiders-avoid-getting-tangled-in-their-own-webs/" target="_blank">purposes</a>, including catching prey, shielding themselves, protecting their eggs, mating rituals, and making webbing to walk on.<em></em></p><p>The researchers examined the spiders' various web producing glands. This revealed a spectrum of neurotoxin-like proteins not dissimilar to those found in the spider's venom present on the silk. On the web, these proteins are suspended in oily, fatty acids. <br> <br> Following up on this discovery, they tested the proteins' effectiveness on insects. Most of those test subjects were paralyzed less than a minute after exposure, and a few died. These experiences relied on the injection of the proteins rather than on absorption but did demonstrate their capacity. Further tests showed that the fatty acids the proteins reside in could allow them to enter the body of prey <a href="https://www.sciencealert.com/spider-webs-me-be-more-than-just-a-trap-they-might-also-do-the-butchering" target="_blank">insects</a>. </p><p>Previous studies demonstrated that some spiders can add certain chemicals to their webs to repel larger insects which could cause the spider trouble. So, the idea that some spiders are adding another chemical to the mix, this time to cause paralysis, isn't too far-fetched. </p><p>However, some scientists aren't so sure about all <a href="https://www.sciencenews.org/article/spiders-poisonous-webs-neuro-toxins-genes" target="_blank">this</a>. They call for further study into the mechanism of action to demonstrate that these proteins cause paralysis and rule out potential other applications.</p><p>So, those of you who like animal facts can take pride in knowing that spider webs sometimes have poison in them to stun their prey. Those of you who are terrified of spiders can fear the same information. Either way, walking into a spider web just got even less pleasant. </p>
Certain water beetles can escape from frogs after being consumed.
- A Japanese scientist shows that some beetles can wiggle out of frog's butts after being eaten whole.
- The research suggests the beetle can get out in as little as 7 minutes.
- Most of the beetles swallowed in the experiment survived with no complications after being excreted.
Declining bee populations could lead to increased food insecurity and economic losses in the billions.
From bee to farm to table<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUyOTUzOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NzM3MDkwNH0.coXBXgDBoRvXaZYIgKaH9fH_jhlUKp3O22-h2rY8jMQ/img.jpg?width=980" id="a317b" class="rm-shortcode" data-rm-shortcode-id="bd61c660c9d52353ba975145fab59625" data-rm-shortcode-name="rebelmouse-image" data-width="1569" data-height="628" />
A bar graph showing the percentage of pollination limitation for the seven crops studied.
Ecological and edible incentives<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUyOTUzMS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNTM4NzQwMX0.vclSktT0d_Mvns_QTZ7ZkFT_pWgIIpyb6ZNP1Tla2Qs/img.jpg?width=1245&coordinates=0%2C215%2C0%2C215&height=700" id="f15a3" class="rm-shortcode" data-rm-shortcode-id="b1e5b70e616daf5fcc0a63a041675e7a" data-rm-shortcode-name="rebelmouse-image" alt="hand holding dead bees" data-width="1245" data-height="700" />
A protester shows a handful of bees that died by pesticides. The protest was held during the Bayer AG shareholder meeting in 2019.
(PhooMaja Hitiji/Getty Images)<p>The concern extends beyond these seven. Crops such as coffee, avocados, lemons, limes, and oranges are also highly dependent on pollinators and may prove pollination limited. If declining bee populations are tied to such yields, it could mean barer supermarket shelves and increased prices. While that may only be an annoyance to some, to poor and vulnerable communities who already struggle to secure <a href="https://www.ers.usda.gov/amber-waves/2011/december/data-feature-mapping-food-deserts-in-the-us/" target="_blank">salubrious, affordable food</a>, such a deficit would present another barrier to the vital micronutrients necessary for a healthy life and diet.</p><p>Unfortunately, <a href="http://sro.sussex.ac.uk/id/eprint/54228/1/Science_1255957_Goulson_RV_revised_CA_edited.pdf" target="_blank">the threats to bees are numerous</a>. Parasites, agrochemicals, monoculture farming, and habitat degradation all play a role, and neither stressor works in isolation. Sublethal exposure to neonicotinoids, an insecticide, can cause <a href="https://bigthink.com/surprising-science/baby-bees-and-pesticides" target="_self">impairments in bees</a>, while monoculture farming serves up a monotonous and unhealthy floral buffet. Both impede bees' immune systems, rendering them vulnerable to parasites such as <a href="http://entnemdept.ufl.edu/creatures/misc/bees/varroa_mite.htm" target="_blank"><em>Varroa destructor</em></a>, a mite that can transmit debilitating viruses as it feeds on bees' fat bodies. And all of these stressors will likely be inflamed by climate change in the years to come. </p><p>Some have proffered mechanical solutions, such as Japan's National Institute of Advanced Industrial Science and Technology where technicians are developing <a href="https://www.newscientist.com/article/2120832-robotic-bee-could-help-pollinate-crops-as-real-bees-decline/" target="_blank">robotic bees</a>. These micro-drones are covered in gelled horsehair and have successfully cross-pollinated Japanese lilies. Other experiments include <a href="https://www.capitalpress.com/ag_sectors/orchards_nuts_vines/pollen-spray-could-replace-honeybees/article_f9a1c102-d5b3-519d-9dab-b0c44cfb99c5.html" target="_blank">pollen sprays</a>. However, the large-scale viability of tech-centric solutions seems questionable. After all, wild bees currently perform their ecological services pro bono and are as effective as managed honeybees. Any technological solution implemented in their absence would add to the agricultural costs and likely increase prices anyway.</p><p>Ecological amelioration will be necessary. To combat habitat fragmentation and strengthen biodiversity, many cities are implementing green-way strategies. For example, the Dutch city of Utrecht has decked its bus stop roofs with plants and grasses to <a href="https://bigthink.com/technology-innovation/urban-bees?rebelltitem=1#rebelltitem1" target="_self">create bee and butterfly shelters</a>, while other cities are looking to foster <a href="https://www.csmonitor.com/Environment/2020/0731/Can-roadsides-offer-a-beeline-for-pollinators" target="_blank">bee-friend roadsides</a>. And <a href="https://www.fsa.usda.gov/Assets/USDA-FSA-Public/usdafiles/FactSheets/2015/CRPProgramsandInitiatives/Honey_Bee_Habitat_Initiative.pdf" target="_blank">government initiatives</a> incentivize farmers and landowners to adopt bee-friendly management practices. These solutions aren't only a matter of ecological conservation but also food security and public health.</p>
Scientists think an insect similar to the modern millipede crawled around Scotland 425 million years ago, making it the first-ever land-dweller.
- An ancient millipede-like creature living in Scotland may have been the first creature to live on land.
- A fossil representing Kampecaris obanensis was first discovered in 1899 on the Scottish isle of Kerrera. It's now been radiometrically dated to 425 million years ago.
- If the new research is correct about the age of the fossil, then scientists have been greatly underestimating how rapidly bugs and plants evolved to transition to life on land.
A pioneering insect<p>One idea about how life began on Earth theorizes that it began in bodies of water. The cocktail of gases in the atmosphere mixed with lightning strikes is thought to have allowed monomers such as amino acids to spontaneously form in the oceans. This is known as the "primordial soup" theory. Out of this life-creating stew, bugs known as <a href="https://www.britannica.com/animal/arthropod" target="_blank">arthropods</a> (which includes insects, spiders, crustaceans, and centipedes) are thought to have been some of the very first animals to venture onto land. </p><p>There's indirect soil-based evidence that other insects like soil worms crawled on land before the myriapods. However, the evidence may only indicate fleeting trips to the land above water. Myriapods, we know, made land their permanent home. The fossil of the ancient millipede-like creature, <a href="https://en.wikipedia.org/wiki/Kampecaris" target="_blank"><em>Kampecaris</em></a><em> obanensis</em>, <a href="http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=374000" target="_blank">was first discovered</a> in 1899 on the Scottish isle of Kerrera. Now, it's been radiometrically dated to 425 million years ago. That would make these multi-legged critters the oldest land animal ever to have lived out of water. (At least, that we know of.) Their pioneering journey out of the sea set forth an explosive multiplication of new terrestrial life forms. Just 20 million years after <em>Kampecaris</em> made the move to land, the fossil record shows a plethora of bug deposits. Fast-forward another 20 million years and there is evidence that spiders, insects, and tall trees were thriving in ancient forest communities. </p><p>"It's a big jump from these tiny guys to very complex forest communities, and in the scheme of things, it didn't take that long," <a href="https://news.utexas.edu/2020/05/27/worlds-oldest-bug-is-fossil-millipede-from-scotland/" target="_blank">said geoscientist Michael Brookfield</a> from the University of Texas and the University of Massachusetts in Boston, in a press release. "It seems to be a rapid radiation of evolution from these mountain valleys, down to the lowlands, and then worldwide after that."</p>
Remaining questions<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="12ce877e7e1d97ea8cb8294a8f73bad5"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/SjNQUOYtZC0?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>We can't be sure that <a href="https://en.wikipedia.org/wiki/Kampecaris" target="_blank"><em>Kampecaris</em></a> is actually the very first creature to have lived on land, as it's possible that there are older undiscovered fossils of both plants and bugs. However, no earlier findings have been made despite the fact that researchers have been investigating some of the most well-preserved fossils from this era. The team thinks this may indicate that they have reached the end of the land fossil record and that this ancient millipede represents the vital turning point at which life moved onto land.</p><p>According to this new study, <em>Kampecaris</em> is about 75 million years younger than the age other scientists have estimated the oldest millipede to be using a technique known as molecular clock dating, which is based on DNA's mutation rate. Similarly, fossils of stemmed plants in Scotland have also been evaluated as being roughly 75 million years younger than researchers once thought. So, if this ancient critter really was the first bug to blaze the trail onto Earth, then scientists have been greatly underestimating how rapidly bugs and plants evolved to transition to life on land. </p><p>"Who is right, us or them?" study co-author Elizabeth <a href="https://news.utexas.edu/2020/05/27/worlds-oldest-bug-is-fossil-millipede-from-scotland/" target="_blank">Catlos said</a>. "We're setting up testable hypotheses – and this is where we are at in the research right now."</p>
Mastering zircons<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzM4MzI2Ni9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzNjUxMzQzOH0.pnxG9fxIx8eMJxbj18j4sMkZerjoniCAvmMVQazkemc/img.png?width=980" id="7f6ec" class="rm-shortcode" data-rm-shortcode-id="37946233816f7957836612f030d92ace" data-rm-shortcode-name="rebelmouse-image" alt="modern millepede" data-width="1245" data-height="702" />
Javier Fernández Sánchez / Getty Images<p>Despite the potentially huge evolutionary significance of <em>Kampecaris</em>, this was the first study to address the fossil's age. One reason for that could be the challenge of extracting zircons (a microscopic mineral necessary to accurately date fossils) from the ashy rock sediment in which the fossil was preserved. Extraction requires impeccable vision and a flawlessly steady hand, as the zircons can easily be flushed away by accident. There's almost no room to err.</p><p>One of the co-authors of the study, geoscientist Stephanie Suarez, has been mastering the technique for separating the zircon grain from sediment since her time as an undergraduate student. </p><p>"That kind of work trained me for the work that I do here in Houston," Suarez said. "It's delicate work."</p><p>As an undergrad, Suarez used the technique to find that a different millipede specimen that was once thought to be the oldest bug specimen was <a href="https://www.jsg.utexas.edu/news/2017/07/ancient-animal-thought-to-be-first-air-breather-on-land-loses-claim-to-fame/" target="_blank">actually 14 million years younger</a> than estimated. Her technique now passes the Oldest Bug To Walk The Earth title onto a new species; <em>Kampecaris</em>.</p>The study was published in <a href="https://www.tandfonline.com/doi/full/10.1080/08912963.2020.1761351" target="_blank" style="">Historical Biology</a>.