Giant prehistoric flying reptile took off using similar method to bats, study finds

The pterosaur likely used all four limbs to propel itself in the air, as seen in bats today, researchers have found.

The findings, published today in PeerJ, provide new insights into how pterosaurs managed to take flight despite reaching sizes far larger than modern animals.

The research sheds new light on the flight initiating jumping ability of these animals, some of which had wingspans of over ten meters.

The study, carried out by scientists at the University of Bristol, Liverpool John Moores University, Universidade Federal do ABC and the University of Keele, follows years of analysis and modelling of how muscles interact with bones to create movement in other animals and is now being used to start answering the question of how the largest flying animals known managed to get off the ground.

The team created the first computer model for this kind of analysis of a pterosaur to test three different ways pterosaurs may have taken off: a vertical burst jump using just the legs like those used by primarily ground-dwelling birds, a less vertical jump using just the legs more similar to the jump used by birds that fly frequently, and a four-limbed jump using its wings as well in a motion more like the take-off jump of a bat.

By mimicking these motions, the researchers aimed to understand the leverage available to push the animal into the air.

"Larger animals have greater challenges to overcome in order to fly making the ability of animals as large as pterosaurs to do so especially fascinating." Dr Ben Griffin, the lead author of the study, said.

"Unlike birds which mainly rely on their hindlimbs, our models indicate that pterosaurs were more likely to rely on all four of their limbs to propel themselves into the air."

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Evolutionary chance made this bat a specialist hunter

Ask a biologist why predators don't exterminate all their prey, part of the answer often is that there is an ongoing arms race between predators and prey, with both parties continuously evolving new ways to cheat each other.

The hypothesis is particularly prevalent for bats and their prey; insects. 50 million years ago, the first bats evolved the ability to echolocate and thus hunt in the dark, and in response to this, some insects evolved ultrasound-sensitive ears so they could hear and evade the bats.

But if there is an ongoing arms race, bats should have responded to this, says University of Southern Denmark biologist, associate professor and bat expert Lasse Jakobsen, co-author of a new study published in Current Biology, In the study, he and colleagues question the evolutionary arms race between bats and insects.

The other authors are Daniel Lewanzik and Holger R. Goerlitz from the Max Planck Institute for Biological Intelligence and John M. Ratcliffe and Erik Etzler from the University of Toronto.

The main argument supporting the arms race hypothesis is that some bats do not call as loudly as others when hunting, and thus cannot be heard as easily by the insects. These are the barbastelles (Barbastella barbastellus), and they are approx. 20 dB quieter than other bats that hunt flying insects, which means that the sound pressure they emit is 10 times lower.

- The barbastelle is traditionally highlighted as the bat that has "struck back" at the insects, says Lasse Jakobsen.

But something puzzled him and his colleagues: If you look at the barbastelle's close relatives, there are virtually no other members catching insects in the air. Instead, they eat insects that sit on surfaces such as leaves and branches, and those species are all quieter than the species that hunt flying insects.

In bat research circles, the bats that catch insects in the air are called hawking bats, while the bats that pick insects from a surface, so to speak, are called gleaning bats. The barbastelle is a hawking bat.

- If most of the barbastelle's family are gleaners, then their ancestor was very likely also a gleaner, says Lasse Jakobsen.

Accordingly, it is therefore unlikely that the ancestor of the barbastelle was a loud hawker that evolved into the whispering barbastelle as a response to insect hearing.

- A species does not have free choice when it evolves in a new direction. For example, it is a condition for mammals that their ancestor did not have feathers, so their descendants will never evolve a wing with feathers. Instead, they have found another solution for flying: modified skin between the fingers, explains Lasse Jakobsen.

But if the barbastelle didn't evolve its ability to be quieter when hunting in the air, as part of the arms race between insects and bats; where does it come from?

- It is not an evolved ability. It just cannot produce louder calls than it does, because as a descendant of a gleaner it is probably morphologically limited. But it has found a niche, where it can use its low amplitude calls. It is an evolutionary coincidence; it sort of fell into this niche, where there was something to eat.

This niche is populated by flying, nocturnal insects that can hear and are thus good at avoiding nocturnal bats. But they cannot hear well enough to register the barbastelle, so they end up as their prey.

The reason for the morphological limitation must be found in how bats emit their sound. Most bats call out of their mouths, and this allows them to emit loud sounds. Many gleaners, on the other hand, emit sound with their noses, and this makes their calls 20 dB lower.

- So, the reason why the barbastelles are so quiet today is not an expression of an arms race between bats and insects, but rather simply an expression of the fact that it is descended from bats that cannot call as loudly as others, says Lasse Jakobsen.

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Vision via sound for the blind

Australian researchers have developed cutting-edge technology known as "acoustic touch" that helps people 'see' using sound. The technology has the potential to transform the lives of those who are blind or have low vision.

Around 39 million people worldwide are blind, according to the World Health Organisation, and an additional 246 million people live with low vision, impacting their ability to participate in everyday life activities.

The next generation smart glasses, which translate visual information into distinct sound icons, were developed by researchers from the University of Technology Sydney and the University of Sydney, together with Sydney start-up ARIA Research.

"Smart glasses typically use computer vision and other sensory information to translate the wearer's surrounding into computer-synthesized speech," said Distinguished Professor Chin-Teng Lin, a global leader in brain-computer interface research from the University of Technology Sydney.

"However, acoustic touch technology sonifies objects, creating unique sound representations as they enter the device's field of view. For example, the sound of rustling leaves might signify a plant, or a buzzing sound might represent a mobile phone," he said.

A study into the efficacy and usability of acoustic touch technology to assist people who are blind, led by Dr Howe Zhu from the University of Technology Sydney, has just been published in the journal PLOS ONE.

The researchers tested the device with 14 participants; seven individuals with blindness or low vision and seven blindfolded sighted individuals who served as a control group.

They found that the wearable device, equipped with acoustic touch technology, significantly enhanced the ability of blind or low-vision individuals to recognise and reach for objects, without causing too much mental effort.

"The auditory feedback empowers users to identify and reach for objects with remarkable accuracy," said Dr Zhu. "Our findings indicate that acoustic touch has the potential to offer a wearable and effective method of sensory augmentation for the visually impaired community."

The research underscores the importance of developing assistive technology in overcoming the challenges such as locating specific household items and personal belongings.

By addressing these day-to-day challenges, the acoustic touch technology opens new doors for individuals who are blind or have low vision, enhancing their independence and quality of life.

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Fruit, nectar, bugs and blood: How bat teeth and jaws evolved for a diverse dinnertime

They don't know it, but Darwin's finches changed the world. These closely related species -- native to the Galapagos Islands -- each sport a uniquely shaped beak that matches their preferred diet. Studying these birds helped Charles Darwin develop the theory of evolution by natural selection.

A group of bats has a similar -- and more expansive -- evolutionary story to tell. There are more than 200 species of noctilionoid bats, mostly in the American tropics. And despite being close relatives, their jaws evolved in wildly divergent shapes and sizes to exploit different food sources. A paper published Aug. 22 in Nature Communications shows those adaptations include dramatic, but also consistent, modifications to tooth number, size, shape and position. For example, bats with short snouts lack certain teeth, presumably due to a lack of space. Species with longer jaws have room for more teeth -- and, like humans, their total tooth complement is closer to what the ancestor of placental mammals had.

According to the research team behind this study, comparing noctilionoid species can reveal a lot about how mammalian faces evolved and developed, particularly jaws and teeth. And as a bonus, they can also answer some outstanding questions about how our own pearly whites form and grow.

"Bats have all four types of teeth -- incisors, canines, premolars and molars -- just like we do," said co-author Sharlene Santana, a University of Washington professor of biology and curator of mammals at the Burke Museum of Natural History & Culture. "And noctilionoid bats evolved a huge diversity of diets in as little as 25 million years, which is a very short amount of time for these adaptations to occur."

"There are noctilionoid species that have short faces like bulldogs with powerful jaws that can bite the tough exterior of the fruits that they eat. Other species have long snouts to help them drink nectar from flowers. How did this diversity evolve so quickly? What had to change in their jaws and teeth to make this possible?" said lead author Alexa Sadier, an incoming faculty member at the Institute of Evolutionary Science of Montpellier in France, who began this project as a postdoctoral researcher at the University California, Los Angeles.

Scientists don't know what triggered this frenzy of dietary adaptation in noctilionoid bats. But today different noctilionoid species feast on insects, fruit, nectar, fish and even blood -- since this group also includes the infamous vampire bats.

The team used CT scans and other methods to analyze the shapes and sizes of jaws, premolars and molars in more than 100 noctilionoid species. The bats included both museum specimens and a limited number of wild bats captured for study purposes. The researchers compared the relative sizes of teeth and other cranial features among species with different types of diets, and used mathematical modeling to determine how those differences are generated during development.

The team found that, in noctilionoid bats, certain "developmental rules" caused them to generate the right assortment of teeth to fit in their diet-formed grins. For example, bats with long jaws -- like nectar-feeders -- or intermediate jaws, like many insect-eaters, tended to have the usual complement of three premolars and three molars on each side of the jaw. But bats with short jaws, including most fruit-eating bats, tended to ditch the middle premolar or the back molar, if not both.

"When you have more space, you can have more teeth," said Sadier. "But for bats with a shorter space, even though they have a more powerful bite, you simply run out of room for all these teeth."

Having a shorter jaw may also explain why many short-faced bats also tended to have wider front molars.

"The first teeth to appear tend to grow bigger since there is not enough space for the next ones to emerge," said Sadier.

"This project is giving us the opportunity to actually test some of the assumptions that have been made about how tooth growth, shape and size are regulated in mammals," said Santana. "We know surprisingly little about how these very important structures develop!"

Many studies about mammalian tooth development were done in mice, which have only molars and heavily modified incisors. Scientists are not entirely sure if the genes and developmental patterns that control tooth development in mice also operate in mammals with more "ancestral" sets of chompers -- like bats and humans.

Sadier, Santana and their colleagues believe their project, which is ongoing, can start to answer these questions in bats -- along with many other outstanding questions about how evolution shapes mammalian features. They're expanding this study to include noctilionoid incisors and canines, and hope to uncover more of the genetic and developmental mechanisms that control tooth development in this diverse group of bats.

"We see such strong selective pressures in these bats: Shapes have to closely match their function," said Santana. "I think there are many more evolutionary secrets hidden in these species."

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Bat study reveals how the brain is wired for collective behavior

The same neurons that help bats navigate through space may also help them navigate collective social environments, finds a new study published today in the journal Nature.

Many mammals -- including bats and humans -- are believed to navigate with the help of a brain structure called the hippocampus, which encodes a mental "map" of familiar surroundings. For example, as you walk around your neighborhood or commute to work, individual "place" neurons in the hippocampus fire to indicate where you are.

In the new study, researchers at the University of California, Berkeley, used wireless neural recording and imaging devices to "listen in" on the hippocampal brain activity of groups of Egyptian fruit bats as they flew freely within a large flight room -- often moving among tightly clustered social groups -- while tracking technology recorded the bats' movements.

The researchers were surprised to find that, in this social setting, the bat's place neurons encoded far more information than simply the animal's location. As a bat flew toward a landing spot, the firing of place neurons also contained information about the presence or absence of another bat at that spot. And when another bat was present, the activity of these neurons indicated the identity of the bat they were flying toward.

"This is one of the first papers to show identity representation in a non-primate brain," said study senior author Michael Yartsev, an associate professor of bioengineering and neuroscience at UC Berkeley. "And surprisingly, we found it in the hub of what was supposed to be the brain's GPS.We found that it still acts as a GPS, but one that is also tuned to the social dynamic in the environment."

While not as visually stunning as a school of fish or a murmuration of birds, highly social animals like humans and bats also exhibit forms of collective behavior, said study first author Angelo Forli, a postdoctoral fellow in Yartsev's NeuroBat lab.

"Social animals, like humans, will coordinate in space to achieve different goals," Forli said. "It might be just visiting others. It might be moving together, as in the case of classical collective behaviors or playing a soccer match. Or it might be other forms of cooperation or conflict."

Due to the complexity of the experiment, Forli initially had doubts about whether allowing groups of bats to fly and interact freely would yield results about the neural basis of collective behavior. He was concerned that the movements of the bats and their social interactions might be too random to uncover robust relationships between their neural activity and their behavior.

So he was pleasantly surprised when the bats spontaneously established a handful of specific resting spots within the flight room and followed very similar trajectories when traveling among them. The bats also showed strong preferences for flying toward specific "friend" bats, often landing very close to or even on top of each other.

"We found that if you put together a small group of bats in a room, they would not actually behave randomly, but would show precise patterns of behavior," Forli said. "They would spend time with specific individuals and show specific and stable places where they liked to go."

These precise patterns of behavior allowed Forli to identify not only the neural activity associated with different flight trajectories, but also how the neural activity changed depending on the identity of the bat present at the target location and the movements of other bats.

"By recording just a handful of those neurons from this brain structure, we can really know what the bats were doing in their social space," Yartsev said. "We could find out if they were going to an empty location or to a location where there were other individuals, which is really surprising."

In recent years, Yartsev and his NeuroBat Lab have used a variety of wireless neural recording devices and flight tracking technologies to uncover a number of surprising details about the brain, including how bats' neural activity syncs up while they socialize; how activity in the frontal cortex helps bats identify self vs. others during vocal interactions; how bats' hippocampus maps not only specific locations, but full flight trajectories; and even how stable spatial memories might be stored in the brain.

This new study brings together the team's work on navigation and social behavior, showing how these two things are fundamentally intertwined within the brain. The findings also help illuminate why damage to the hippocampus in humans has been linked to both social and spatial aspects of memory loss in neurodegenerative diseases like Alzheimer's.

"Our episodic memories are a combination of the environment where we are located and our experiences within it -- including, of course, our social experiences," Yartsev said. "Our results are surprising, in the sense that no one has observed this connection before in groups of animals and at the individual neuron level. But they also make sense in that they are very consistent with deficits that people with damage to the hippocampus experience."

Finally, this study highlights a very important point, Yartsev said. While most of the neuroscientific community examines the brain under "simplified" or "artificial" conditions that are often far removed from the natural behavior the brain has evolved to promote, this work demonstrates the power of the natural approach to neuroscience research.

"For half a century, people have been studying place neurons, but 99% of that work has been done in single animals moving in an empty box," Yartsev said. "Our findings suggest that there is a lot that can be learned when neuroscience research focuses on natural behavior."

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Oldest bat skeletons ever found described from Wyoming fossils

Scientists have described a new species of bat based on the oldest bat skeletons ever recovered. The study on the extinct bat, which lived in Wyoming about 52 million years ago, supports the idea that bats diversified rapidly on multiple continents during this time. Led by researchers at the American Museum of Natural History and Naturalis Biodiversity Center in the Netherlands, the study is published today in the journal PLOS ONE.

There are more than 1,460 living species of bats found in nearly every part of the world, with the exception of the polar regions and a few remote islands. In the Green River Formation of Wyoming -- a remarkable fossil deposit from the early Eocene -- scientists have uncovered over 30 bat fossils in the last 60 years, but until now they were all thought represent the same two species.

"Eocene bats have been known from the Green River Formation since the 1960s. But interestingly, most specimens that have come out of that formation were identified as representing a single species, Icaronycteris index, up until about 20 years ago, when a second bat species belonging to another genus was discovered," said study co-author Nancy Simmons, curator-in-charge of the Museum's Department of Mammalogy, who helped describe that second species in 2008. "I always suspected that there must be even more species there."

In recent years, scientists from the Naturalis Biodiversity Center started looking closely at Icaronycteris index by collecting measurements and other data from museum specimens.

"Paleontologists have collected so many bats that have been identified as Icaronycteris index, and we wondered if there were actually multiple species among these specimens," said Tim Rietbergen, an evolutionary biologist at Naturalis. "Then we learned about a new skeleton that diverted our attention."

The exceptionally well-preserved skeleton was collected by a private collector in 2017 and purchased by the Museum. When researchers compared the fossil to Rietbergen's expansive dataset, it clearly stood out as a new species. A second fossil skeleton discovered in the same quarry in 1994 and in the collections of the Royal Ontario Museum was also identified as this new species. The researchers gave these fossils the species name Icaronycteris gunnelli in honor of Gregg Gunnell, a Duke University paleontologist who died in 2017 and made extensive contributions to the understanding of fossil bats and evolution.

Although there are fossil bat teeth from Asia that are slightly older, the two I. gunnelli fossils represent the oldest bat skeletons ever found.

"The Fossil Lake deposits of the Green River Formation are simply amazing because the conditions that created the paper-thin limestone layers also preserved nearly everything that settled to the lake's bottom," said Arvid Aase, park manager and curator at the Fossil Butte National Monument, in Wyoming. "One of these bat specimens was found lower in the section than all other bats, making this species older than any of the other bat species recovered from this deposit."

While the I. gunnelli skeletons are the oldest bat fossils from this site, they are not the most primitive, supporting the idea that Green River bats evolved separately from other Eocene bats around the world.

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What is it good for? Absolutely one thing: Luna moths use their tails solely for bat evasion

In a pair of complementary studies, researchers took a close look at Luna moth (Actias luna) tails through the eyes of birds and female moths to test the tails' role in predation and sexual selection. Scientists have known for about a decade that Luna moths -- and other related silkmoths -- use their long, trailing tails to misdirect bat attacks.

"They have projections off the back of the hindwing that end in twisted, cupped paddles," said Juliette Rubin, a doctoral student at the Florida Museum of Natural History and lead author of both studies. "From experimental work with bats and moths in a flight room, we've found that these structures seem to reflect bat sonar in such a way that bats often aim their attacks at the tails instead of the main body."

Traits that evolve for one specific function can often be co-opted by natural selection for another, and Rubin wondered whether the twisted tails of Luna moths might come with any additional benefits or hidden costs.

Male Luna moths doff their tails, retain their charm

Silkmoths have independently evolved tails on multiple occasions across three continents, and the appendages can vary significantly in length. Hind wings in some species can extend to more than twice the size of the moth's wingspan, and the longer the tail, the more likely a moth will successfully thwart a prowling bat.

But far from being drab, utilitarian decoys meant only for sonar-sensing bats, silkmoth tails are often visually stunning, like decorative streamers trailing behind a kite. Across the animal and plant kingdoms, many of the most colorful and alluring structures are used to attract mates or pollinators, and scientists suspected the same might be true of silkmoth tails.

This type of dual function for a single trait isn't without precedent. The vivid colors of strawberry poison dart frogs (Oophaga pumilio) both deter predators and help males attract mates; male deer and other ungulates use their antlers to fight off rivals and signal their vigor to females; and moths that use clicks or chirruping sounds to disrupt bat echolocation can compose duets using the same sounds during courtship.

Luna moths have neither mouths to produce sound nor ears to hear it, but they do have sensitive eyes and powerful scent-detecting antennae. When female Luna moths are ready to mate, they perch in one place and emit a pheromone, a single molecule of which is enough to trigger a male antenna. The males of closely related Indian moon moths (Actias selene) can find females from more than six miles away by following the pheromone plume to its source.

"We don't know how many males are traveling to a female each night," Rubin said. "It's entirely possible she's able to call in multiple suitors and potentially have her pick."

Rubin put this idea to the test, setting up mating experiments in which a female Luna moth was enclosed in a flight box with two males: one with normal hind wings, and one with its tails removed.

Initially, the data seemed to suggest that females preferred males whose wings remained intact, but additional controlled experiments demonstrated that this was more likely an incidental effect of the tail removal. During trials in which both males had their wings clipped, and one had the tails glued back on, there was no difference in their mating success.

Do tails make Luna moths invisible to bats but conspicuous to birds?

Having demonstrated tail wings likely weren't conferring any additional benefits beyond survival, Rubin wanted to see whether they had any obvious drawbacks. Their long tails effectively throw off pursuing bats by creating a decoy target, but bats aren't the only adversaries Luna moths have to avoid. Their electric green tails with bright, pink parfait borders might make Luna moths noticeable to birds and other visually oriented predators that hunt during the day.

Other organisms contend with similar tradeoffs. The bioluminescent displays of fireflies make it easier for males to locate potential mates, but it also makes them stand out to nocturnal frogs and geckoes.

Luna moths live incredibly short lives, during which they can afford to lose a tail or two. Once they emerge from their cocoons, the moths have about a week to find a mate and reproduce before dying. "This creates a very intense period of adulthood, where surviving the night is of the utmost importance," Rubin said.

Luna moths are mostly inactive during the day, reducing their chances of being nabbed midair. If they don't do a good enough job concealing themselves, however, they run the risk of not surviving to nightfall.

Rubin wanted to know if their visually elaborate tails put Luna moths at a disadvantage in this high-stakes game of hide-and-seek. To find out, she and her colleagues wrapped mealworms in pastry dough in the shape and size of Luna moth bodies, to which they attached real wings, half of which had tails. They partially hid these moth replicas among branches and leaves in an aviary, then introduced a succession of Carolina wrens (Thryothorus ludovicianus), recording how many of the snacks the birds located and ate.

The results conclusively indicate that the tails had no effect on the birds' ability to locate the fake moths. This might seem odd to us, Rubin said, because we're such visually oriented animals. But there's evidence that suggests birds might rely on search images when trying to distinguish food items from patterns in the background.

Humans do this too. When trying to complete a Where's Waldo puzzle, people often look for the characteristic red, horizontal lines of Waldo's shirt while scanning across the page. It's possible that Luna moth tails don't match the typical moth and butterfly mold that birds expect to see while foraging, the equivalent of Waldo wearing a solid red shirt rather than his signature stripes.

While not indicative of all silkmoths, the studies suggest that these stunning and complex structures evolved for a single function in Luna moths.

"When we see these really obvious physical features in animals, we're often drawn into stories we've heard about them," Rubin said. "One is that conspicuous traits are for attracting mates or competing with rivals, and another is that these very showy traits must come with a cost. Both of these studies show it's really important to test those assumptions. A trait that's obvious to us, as visual creatures, might not stand out to the predators that hunt them, and the traits that we think are dynamic and alluring might not seem that way to a potential mate."

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Bigger flowers, greater rewards: Plants adapt to climate disruptions to lure pollinators

There's been a well-documented shift toward earlier springtime flowering in many plants as the world warms. The trend alarms biologists because it has the potential to disrupt carefully choreographed interactions between plants and the creatures -- butterflies, bees, birds, bats and others -- that pollinate them.

But much less attention has been paid to changes in other floral traits, such as flower size, that can also affect plant-pollinator interactions, at a time when many insect pollinators are in global decline.

In a study published online in the journal Evolution Letters, two University of Michigan biologists and a University of Georgia colleague show that wild populations of the common morning glory in the southeastern United States increased the size of their flowers between 2003 and 2012.

Increased flower size suggests a greater investment by the plants in pollinator attraction, according to the researchers. The changes were most pronounced at more northern latitudes, in line with a broad range of previous work showing that northern plant populations tend to show more dramatic evolutionary responses to climate change.

A shift to earlier flowering was also observed among those morning glory populations. In addition, there were tantalizing indications that the plants have increased their investment in floral rewards -- the nectar and pollen obtained by the bees, syrphid flies and wasps that pollinate the white, pink and blue morning glory flowers.

"There is a major gap in our understanding of how traits that are crucial for plant-pollinator interactions may be evolving over time as a response to a changing climate," said study lead author Sasha Bishop, a doctoral student in the U-M Department of Ecology and Evolutionary Biology.

"We show that -- in addition to well-documented shifts to earlier flowering -- floral architecture and rewards can also play significant roles in the evolutionary response to contemporary environmental change."

The common morning glory is an annual weedy vine found across the eastern, midwestern and southern United States. It is frequently seen along roadsides and crop fields.

The U-M-led study used a "resurrection" approach that involved germinating morning glory seeds collected from the edges of agricultural soy and corn fields in Tennessee, North Carolina and South Carolina in two years: 2003 and 2012.

During that nine-year span, the region experienced rising temperatures -- particularly rising minimum and nighttime temperatures -- and an increase in the number of extreme rainfall events interspersed with more extreme drought.

To look for changes in floral morphology, the researchers planted field-collected seeds from both years in a greenhouse at U-M's Matthaei Botanical Gardens. When the flowers bloomed, various floral traits were measured with digital calipers.

Measurements showed that morning glory corollas became significantly wider during the nine-year interval -- 4.5 centimeters (1.8 inches) in diameter in 2003 and 4.8 centimeters (1.9 inches) in 2012, and the change in corolla width was greatest in populations at more northern latitudes. The petals of a flower are collectively known as the corolla.

The study also revealed a shift to earlier flowering times between 2003 and 2012, driven primarily by populations at more northern latitudes. The start of flowering occurred an average of four days earlier for the plants grown from seeds collected in 2012.

Interestingly, the researchers also observed a latitude-influenced trend toward greater investment in floral rewards (pollen and nectar) over time. On average, morning glory flowers grown from 2012-collected seeds produced more pollen grains and more nectar sucrose than the flowers from the 2003-collected seeds.

However, the pollen and nectar analyses involved only four populations of morning glory plants. Due to the low number of populations examined, the floral rewards findings were not included in a statistical test to look for evidence that adaptation through natural selection is occurring in the plants.

"Nonetheless, it appears likely that there is a temporal increase in investment in pollinator attraction and that this result is driven by populations at northern latitudes," said study senior author Regina Baucom, an associate professor in the U-M Department of Ecology and Evolutionary Biology.

The study found no evidence that morning glories are increasing the rate at which they self-pollinate. Evidence from some previous studies pointed to increased "selfing" as a possible response to climate change and/or pollinator declines associated with land-use change.

"This is the first article to use the resurrection approach to examine the potential that traits responsible for plant-pollinator interactions may be evolving over time, concomitant to decreases in pollinator abundance and dramatic environmental changes due to changing climate and land-use regimes," Bishop said.

Fifteen morning glory populations were included in the resurrection experiment looking at changes in floral morphology. Twenty-three populations were included in the study of earlier springtime flowering. In total, 2,836 flowers were measured from 456 plants.

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Whiskers help nectar-eating 'acro bats' hover like hummingbirds

From dragonflies to hummingbirds, hovering flight is among the most complex and captivating forms of animal movement -- a physiological feat of size, musculature and wing development.

For nectar-feeding bats that hover as they feed from flowers, this aerial maneuver also depends on extra-long whiskers unlike those of most other bat species, according to a Dartmouth College-led study in the journal Proceedings of the Royal Society B. The researchers used high-speed cameras to capture how the stiff hairs jutting forward from the face of nectar-eating bats provide enhanced spatial information that guides the animals as they swoop in to quickly feed -- within a second or less -- on succulent flowers without landing.

"The whiskers of nectar-feeding bats are critical sensory organs that provide high-quality input the brain works with to optimize hovering. It's a cool junction between sensory biology and bio-kinematics, between form and function," said lead author Eran Amichai, a postdoctoral researcher in biological sciences at Dartmouth who studies echolocation in bats. Co-authors are postdoctoral fellow David Boerma from the American Museum of Natural history, animal behavioralist Rachel Page at the Smithsonian Tropical Research Institute in Panama, Sharon Swartz, a professor of biology and engineering at Brown University, and Hannah ter Hofstede, a past assistant professor of biological sciences at Dartmouth now at the University of Windsor in Canada.

The researchers worked at the Smithsonian Tropical Research Institute recording Pallas's long-tongued bats -- a South and Central American bat that has the fastest metabolism of any mammal -- as they drank from hand-blown glass flowers designed for the study to replicate the plants the animals feed from. High-speed infrared cameras captured photos and video of the bats as they descended upon the glass flowers and navigated their muzzles and tongues into the "bloom" to eat the nectar. Feedings typically lasted between a half- to one second.

The researchers found that bats with clipped whiskers were less agile and accurate during feeding and flight than animals with untouched whiskers. The animals with clipped whiskers were held for a few days until the hairs regrew, then released back into the jungle. "Clipping the whiskers doesn't reduce the bats' ability to feed, they just do it a little less gracefully," Amichai said. "If it were gymnastics, they'd get an 8.5 instead of a 9.8."

The role of long whiskers in nectar-feeding bats' flight control provides new insight into the coevolution of the bats with the flowers they feed on, Amichai said. The majority of bats possess short whiskers not arranged in any particular pattern or direction. But the researchers found that whisker length in nectar-eating bats evolved at least twice to -- along with long tongues and faces -- potentially help them better navigate the deep chambers of the flowers they prefer. In turn, the long reach these flowers require results in more pollen sticking to their pollinators and thus the broader proliferation of their kind.

The researchers plan to continue their work using higher-resolution images, flowers that move, interactions with predators and other expansions on the experimental model, Amichai said.

In the meantime, the latest study offers a fascinating glimpse into how nectar-feeding bats combine various forms of sensory information to navigate the world around them, Amichai said. Their world is a combination of scent, echolocation, spatial memory, knowledge of the seasons and the physical sensation and equilibrium provided by their whiskers.

"I find thinking in these terms of switching back and forth between completely different ways to perceive the world -- and seamlessly integrating their input -- to be a mind-blowing concept," Amichai said. Understanding how animals perceive and interact with their surroundings helps scientists develop better conservation strategies, he said.

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Hibernation slows biological aging in bats

The most common bat in the United States, the big brown bat, boasts an unusually long lifespan of up to 19 years. A new study led by University of Maryland researchers identifies one of the secrets to this bat's exceptional longevity: hibernation.

"Hibernation has allowed bats, and presumably other animals, to stay in northerly or very southerly regions where there's no food in the winter," said the study's senior author, UMD Biology Professor Gerald Wilkinson. "Hibernators tend to live much longer than migrators. We knew that, but we didn't know if we would detect changes in epigenetic age due to hibernation."

The researchers determined that hibernating over one winter extends a big brown bat's epigenetic clock -- a biological marker of aging -- by three-quarters of a year. The study, published in the journal Proceedings of the Royal Society BonAugust 10, 2022, also included scientists from McMaster University and the University of Waterloo, both in Ontario, Canada.

They analyzed small tissue samples taken from the wings of 20 big brown bats (Eptesicus fuscus) during two periods: in the winter when they hibernated and in the summer when they were active. The bats, kept in a research colony at McMaster University, ranged in age from less than 1 year old to a little over 10 years old.

Once the samples were collected, the researchers measured changes in DNA methylation -- a biological process associated with gene regulation -- between samples taken from the same animal during active and hibernating periods. They discovered that changes in DNA methylation occurred at certain sites in the bat's genome, and these sites appeared to be affecting metabolism during hibernation.

"It's pretty clear that the sites that decrease methylation in the winter are the ones that appear to be having an active effect," Wilkinson said. "Many of the genes that are nearest to them are known to be involved in regulating metabolism, so they presumably keep metabolism down."

Some of these genes are the same ones that Wilkinson and fellow researchers identified as "longevity genes" in a previous study. Wilkinson said that there is significant overlap between the hibernation genes and the longevity genes, further highlighting the link between hibernation and longer lifespans.

The earlier study also established the first epigenetic clock for bats, capable of accurately predicting the age of any bat in the wild. That clock was applied to this latest study, enabling the researchers to demonstrate that hibernation reduces a bat's epigenetic age in comparison to a non-hibernating animal of the same age.

Studies like this help explain why bats have longer lifespans than expected for a small mammal about the size of a mouse. However, they also raise new questions.

"We still don't have a very good understanding of why some bats can live a really long time and other ones don't," Wilkinson said. "We've shown that the ones that live a really long time all share the ability to hibernate, or to go into torpor frequently. That seems to be a corollary, but it's not sufficient because hibernating rodents don't live 20 years."

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Researchers find why bat cells do not get infected by SARS-CoV-2

Bat cells have specific molecular barriers to deal with SARS-CoV-2 replication, according to a study published in the Journal of Virology -- a publication of the American Society of Microbiology -- which includes the participation of Jordi Serra-Cobo, lecturer of the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona and expert on ecoepidemiological studies.

The study was carried out on primary cells of bat species which had been little studied and which circulate around Europe and Asia (specifically, Rhinolopuhs ferrumequinum, Myotis myotis, Eptesicus serotinus, Tadarida brasiliensis and Nyctalus noctula). These cellular lines were obtained through small biopsies carried out on the wings of the bats -- for instance, in bat colonies of Myotis myotis in Majorca and other cell lines brought by some research teams that took part in the study. As stated in the conclusions, these cellular models defined in chiropterans are shaped as tools of scientific interest to study the evolutionary relationship between bats and coronaviruses.

The study, led by the experts Nolwenn Jouvenet and Laurent Dacheux, from the Institute Pasteur in Paris, includes the collaboration of experts from research institutions in France, the Czech Republic and Switzerland.

How do bats protect themselves from viral infections?

Coronaviruses are present in many animal species worldwide, such as bats (chiropteans). In this context, the scientific literature has described for years the great resistance of some chiropteran species towards the viral infection. In these flying mammals, the immune system is on a pre-alert stage, a condition that allows a faster response to viral infections. For most mammals, having an immune system on a constant pre-alert state would involve inflammation problems but this is not the case for bats, which is why they are the focus of many international epidemiological and immunological studies.

As part of the study, the team analysed the ability of primary cells from different bat species to support SARS-CoV-2 replication. "The results reveal that none of these cells was permissive to the infection, not even those expressing detectable levels of angiotensin-converting enzyme 2 (ACE2), a metallopeptidase that serves as a viral receptor in many mammal species," says Jordi Serra-Cobo, member of the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB and the only expert in Spain to take part in this study.

"The cells did not allow the infection in the species Rhinolophus ferrumequinum, a chiropteran from the same genus as the Asian bat in which the BANAL-52 virus was found, a potential ancestor of SARS-CoV-2. Specifically, the genetic sequences of the BANAL-52 virus is 96.8% similar to that of SARS-CoV-2," says Serra-Cobo, distinguished expert in studies with bats as natural reservoirs of infectious agents like coronaviruses.

Humans and chiropterans vs. SARS-CoV-2 infection

Regarding the human species, it is known that the SARS-CoV-2 spike protein binds to the cell membrane receptor ACE2 and then the virus infects the cell. "In the case of the chiropteran cells, either the amount of ACE2 enzyme is small and it no longer enters the cell or, if the virus binds to ACE2, it cannot infect the cell," highlights Serra-Cobo.

From a global perspective, this study contributes to a better understanding of the fighting mechanisms against viral infections. This is a line of research that has been carried out for years by the team led by Serra-Cobo at the UB and IRBio and which is now gaining strength within the framework of the EvoDevo-Cat research group at the Faculty of Biology of the UB.

"Specifically, our team is working to understand the adaptations of the chiropterans regarding viral infections. An important number of zoonotic viruses circulate in chiropter populations without causing symptoms of the disease in the carriers," notes the researcher.

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A rare discovery of long-term memory in wild frog-eating bats

Frog-eating bats trained by researchers to associate a phone ringtone with a tasty treat were able to remember what they learned for up to four years in the wild, new research has found.

The study acquainted 49 bats with a series of ringtones that attracted their attention, and trained them to associate flying toward just one of the tones with a reward: a baitfish snack.

Between one and four years later, eight of those bats were recaptured and exposed again to the food-related ringtone. All of them flew toward the sound, and six flew all the way to the speaker and grabbed the food reward, meaning they expected to find food. Control bats without previous training on the sounds were comparatively unmoved by the exposure to the unfamiliar tones.

"I was surprised -- I went into this thinking that at least a year would be a reasonable time for them to remember, given all the other things they need to know and given that long-term memory does have real costs. Four years strikes me as a long time to hold on to a sound that you might never hear again," said lead author May Dixon, a postdoctoral scholar in evolution, ecology and organismal biology at The Ohio State University.

Dixon led this study at the Smithsonian Tropical Research Institute in Panama while she was a graduate student at the University of Texas at Austin.

"The environment that previous generations experienced can be extremely different from the environment an animal is born into -- and it may also change throughout an animal's life," she said. "Trying to figure out how animals use learning and memory is one way to figure out how they're going to make it in a life full of change in the modern world."

The study is published today (June 20, 2022) in Current Biology.

In the first phase, individual frog-eating bats captured for a series of cognition tests were exposed to a highly attractive sound in the lab: the mating call of the male túngara frog, one of this species of bats' preferred prey. Flying to that sound was rewarded with a piece of baitfish placed on mesh above the speaker.

Over time, the sound was mingled with and gradually replaced by a ringtone, but the reward was the same. Researchers then introduced three other ringtones, none of which was connected to a food reward. Bats were trained to discern the differences and eventually no longer flew toward the unrewarded sounds. Each bat secured at least 40 snacks by flying to the trained ringtone over 11 to 27 days. All bats were microchipped and returned to the wild.

Beginning a year later and for three additional years, Dixon captured bats and identified eight from the initial trial by their microchips. In a follow-up test of their response to the original rewarded ringtone, all eight trained bats quickly flew to the sound and were able to tell the difference between that ringtone and a new, steady tone, though many of the bats did fly to an unrewarded sound from the initial training.

When 17 untrained bats were exposed to these sounds, they mostly twitched their ears in response to the sounds, but didn't fly toward them.

"The study taught us a lot because there are relatively few studies of long-term memory in wild animals and we don't have systematic understanding of long-term memories in nature yet," Dixon said. "If we can collect additional data on different species of bats, we could pick this apart and see what life histories select for long memories."

The paper lists 39 previous studies that have documented memory in species ranging from fish, birds and bats to goats and primates. Some of the longest of those experiments -- documenting memory in sea lions for 10 years, tortoises for nine years and dolphins for 20 years -- were all conducted on animals that lived in captivity the entire time.

"Being able to study memory in the wild is important," said study co-author Gerald Carter, assistant professor of evolution, ecology and organismal biology at Ohio State. "You can't necessarily extrapolate from the wealth of data we have on animals in the lab to what they're facing in the wild, where there are many more things they have to remember. The environment is different and the brain is different in the wild versus captivity."

Despite the human tendency to assume a long memory gives our species the intelligence advantage, nature shows us that memory flexibility -- also called adaptive forgetting -- may be important for survival.

"It's not always true that being the smartest or having the longest memory is actually advantageous. Research has shown that fruitflies selected for improved memories can't compete as well against other fruitflies," Dixon said. "Just because it's useful for humans to be so smart and have such good memories doesn't necessarily mean it's going to be the best thing for other animals.

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Hundreds of new mammal species waiting to be found, study says

At least hundreds of so-far unidentified species of mammals are hiding in plain sight around the world, a new study suggests.

Researchers found that most of these hidden mammals are small bodied, many of them bats, rodents, shrews, and moles.

These unknown mammals are hidden in plain sight partly because most are small and look so much like known animals that biologists have not been able to recognize they are actually a different species, said study co-author Bryan Carstens, a professor of evolution, ecology and organismal biology at The Ohio State University.

"Small, subtle differences in appearance are harder to notice when you're looking at a tiny animal that weighs 10 grams than when you're looking at something that is human-sized," Carstens said.

"You can't tell they are different species unless you do a genetic analysis."

The study was published today (March 28, 2022) in the Proceedings of the National Academy of Sciences.

The team, led by Ohio State graduate student Danielle Parsons, used a supercomputer and machine-learning techniques to analyze millions of publicly available gene sequences from 4,310 mammal species, as well as data on where the animals live, their environment, life history and other relevant information.

This allowed them to build a predictive model to identify the taxa of mammals that are likely to contain hidden species.

"Based on our analysis, a conservative estimate would be that there are hundreds of species of mammals worldwide that have yet to be identified," Carstens said.

That finding, in itself, would not be surprising to biologists, he said. Only an estimated 1 to 10% of Earth's species have been formally described by researchers.

"What we did that was new was predict where these new species are most likely to be found," Carstens said.

Results showed unidentified species are most likely to be found in the families of small-bodied animals, such as bats and rodents.

The researchers' model also predicted hidden species would most likely be found in species that have wider geographic ranges with higher variability in temperature and precipitation.

Many of the hidden species are also likely to occur in tropical rain forests, which is not surprising because that's where most mammal species occur.

But many unidentified species are also likely living here in the United States, Carstens said. His lab has identified some of them. For example, in 2018, Carstens and his then-graduate student Ariadna Morales published a paper showing that the little brown bat, found in much of North America, is actually five different species.

That study also showed a key reason why it is important to identify new species. One of the newly delimited bats had a very narrow range where it lived, just around the Great Basin in Nevada -- making its protection especially critical.

"That knowledge is important to people who are doing conservation work. We can't protect a species if we don't know that it exists. As soon as we name something as a species, that matters in a lot of legal and other ways," Carstens said.

Based on the results of this study, Carstens estimates that somewhere near 80% of mammal species worldwide have been identified.

"The shocking thing is that mammals are very well described compared to beetles or ants or other types of animals," he said.

"We know a lot more about mammals than many other animals because they tend to be larger and are more closely related to humans, which makes them more interesting to us."

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Noble false widow spider captures bats in the attic

Scientists from the Ryan Institute in NUI Galway have published the first record of a Noble False Widow spider feeding on a protected species of Pipistrelle bats in the UK.

The new study, published today in the international journal Ecosphere,demonstrates that False Widow spiders continue to impact native species.

It is the first time a member of this family of spiders, called Theridiidae, has been recorded preying on a bat anywhere in the world, or any vertebrate in Britain.

It is also the first time for any species of false widow spider to be recorded preying on mammals.

The extraordinary discovery was made by wildlife artist Ben Waddams at his home in north Shropshire, England. On two consecutive days, bats living in the attic were found entangled on the spider's web below the entrance to the roost.

The first bat, a young pup, was completely immobilised with its limbs pinned tightly to the torso with silk. It was slightly shrivelled and discoloured from the spider feeding off the remains.

A second, much larger adult bat, was also captured and entangled in the web but as it was still alive, the bat was rescued from the web and released.

In Britain, the Pipistrelle bats are protected under the Wildlife and Countryside Act, 1981, and the Conservation of Habitats and Species Regulations 2017.

The rather grisly event is not as uncommon as people might expect, three years ago the Noble False Widow spider was reported feeding on a protected species of native lizard in Ireland.

Originating from Madeira and the Canary Islands, the Noble False Widow spider Steatoda nobilis has the potential to become one of the world's most invasive species of spider.

It was first reported in southern England in 1879 and has increased its range and population density in recent decades, spreading northwards towards Scotland and westward through Wales and Ireland. In that time the species has also spread globally from across Europe, East Asia, North America, and South America.

The species is known for its medical significance, having the ability to cause a range of mild to severe symptoms in people who are bitten, but little is known about its impact on native species.

Over the past five years, the team led by Dr Michel Dugon in NUI Galway's Ryan Institute, have been studying a wide range of characteristics specific to the species including its venom, symptoms after envenomation, ecology and behaviour.

Dr Michel Dugon, Head of the Venom Systems Lab, Ryan Institute, NUI Galway and senior author of the study, said: "We have been working on the Noble False Widow for the past five years, and have learnt a great deal about this species -- yet, we are still surprised by its ability to adapt to new environments and make the most of the resources available. It is a truly remarkable species."

Dr John Dunbar, Irish Research Council Post-Doctoral fellow, Venom Systems Lab, Ryan Institute, NUI Galway and lead author of the study, said: "In more exotic parts of the world, scientists have been documenting such predation events by spiders on small vertebrates for many years, but we are only beginning to realise just how common these events occur. Now that this alien species has become well established in Ireland and Britain, we are witnessing such fascinating events on our very own doorstep.

"Even other, much smaller, species of false widows are known to capture and feed on snakes and lizards. This study presents yet another example of the invasive impact by the Noble false widow spider on native species. We know they are much more competitive than native spiders, and this further confirms their impact on prey species."

They possess a fast-acting neurotoxic venom with a very similar composition to true black widows that can cause neuromuscular paralysis in terrestrial vertebrates which allows them to occasionally feed on small reptiles and mammals.

Aiste Vitkauskaite, researcher at the Venom Systems Lab, Ryan Institute, NUI Galway, said: "False widow spiders, just as their close relatives' black widow spiders, have extraordinary prey capture techniques and remarkably potent venom which allows them to capture small vertebrate prey many times larger than the spider itself with surprising ease.

"In the last three years alone, we have observed two occasions of the alien Noble False Widow capturing and feeding on protected species of vertebrate animals in Ireland and Britain. As the Noble False Widow continues to expand its range and increase populations across Ireland and Britain, we should expect to observe similar predation events on small vertebrate animals by this spider, including protected species."

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