Tag Archives: bat

Fossil Friday: the oldest kind-of-bat species seen so far, described from set of teeth found in China

Asian bats — I think we’ve all heard more about them than we’d like, these past two years. But new research comes with a twist on that subject. Researchers from the US and China have identified the oldest known bat fossil from the Asian record.

The upper molars of Altaynycteris aurora, from which the species was described. Image credits Matthew F. Jones et al., (2021), Biology Letters.

The discovery helps us better understand the evolutionary history of the only true mammalian flyers, pushing their story back to the Eocene — as far as we know. It also raises the possibility that the bat family originates in Asia entirely, although it’s too soon to say for sure.

Whence bats come from

“Bats show up in the fossil record out of the blue about 55-ish million years ago — and they’re already scattered on different parts of the globe,” said lead author Matthew Jones, a doctoral student at the KU Biodiversity Institute and Department of Ecology & Evolutionary Biology. “Before this, the earliest bats are known from a couple of places in Europe — Portugal and southern France — and Australia. So, when they show up early in the fossil record as these fragmentary fossils they’re already effectively worldwide.”

“By the time we get their earliest known full skeletons, they look modern — they can fly, and most of them are able to echolocate. But we don’t really know anything about this transitional period from non-bats to bats. We don’t even really know what their closest living relatives are among mammals. It’s a really big evolutionary mystery where bats came from and how they evolved and became so specialized.”

The team comprised members from the University of Kansas and the Chinese Academy of Sciences. The fossil they describe was unearthed at a remote field site in the Junggar Basin, China, after quite a long digging effort. Although they suspected that the sites would be rich in Paleocene and Eocene fossils, Jones explained, various members of the team worked here for several years, sifting the sediment, before finding any actual fossils.

“We’ve been fortunate enough to be able to host our Chinese colleagues here in Lawrence for extended research visits, and they’ve more than reciprocated by hosting us for research and fieldwork in China. This work in the Junggar Basin is really trailblazing work because the fossil record in this part of China is only just barely beginning to emerge, and this area is very removed and isolated. It’s just a giant empty place. There are some camels, some snakes and lizards, but you don’t see many people there. That remoteness makes the logistics to do fieldwork there quite difficult and expensive because you’ve got to bring in all your food and water from far outside — all of that hindered research in this area previously.”

Residues from the sieving were sent to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing for sorting. Back in 2017, they got the first sign that their work would pay off: a possible fragment of a fossilized bat — a tooth. One year later, a second tooth was found amid the sieved dirt. Their structure was distinctive enough to suggest they belonged to a yet-undescribed species; the team christened it Altaynycteris aurora.

Residue from the sifting was sent to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing for sorting. Back in 2017, they got the first sign that their work would pay off: a possible fragment of a fossilized bat — a tooth. One year later, a second tooth was found in the dirt. Their structure was distinctive enough to suggest they belonged to a yet-undescribed species; the team christened it Altaynycteris aurora.

Still, the teeth leave us with more questions than answers. The morphological details of the species remain unknown; we can’t even say for sure whether it was able to fly, or echolocate, like bats today do. According to Jones, they look to be “in between what we would expect a bat ancestor to look like […] and what true bat looks like”.

“So, they have some features that are characteristic of bats that we can point to and say, ‘These are bats.’ But then they have some features that we can call for simplicity’s sake ‘primitive,'” he adds.

The paper “The earliest Asian bats (Mammalia: Chiroptera) address major gaps in bat evolution” has been published in the journal Biology Letters.

Leaf Nose Bat.

Bats can use leaves as ‘mirrors’ to spot hiding prey — but it only works at an angle

Bats use leaves as sound ‘mirrors’ to find (and eat) sneaky insects according to new research.

Leaf Nose Bat.

A Leaf Nosed Bat.
Image via Pixabay.

Even on moonless nights, leaf-nosed bats are able to snatch up insects resting still and silent on leaves. New research from the Smithsonian Tropical Research Institute (STRI) shows that bats pull off this seemingly-impossible feat by approaching packs of leaves from different directions. This gives them the chance to use their echolocation to find camouflaged prey — even prey that specifically tries to hide from the acoustic surveys.

I spy with my little ear… a bug

“For many years it was thought to be a sensory impossibility for bats to find silent, motionless prey resting on leaves by echolocation alone,” said Inga Geipel, Tupper Postdoctoral Fellow at STRI and the paper’s lead author.

Combining data from an experiment using a biosonar with video footage from high-speed video cameras of bats approaching prey, the team found how critical approach angle was to the leaf-nosed bats’ hunting prowess.

Bats can drench an area in sound waves and then listen in on the returning echoes to survey their environment. It works much like a radar that uses sound instead of radio waves, and is undoubtedly a very cool trick to pull off. However, it’s not infallible: leaves are very good sound reflectors, so they drown out the echoes produced by any insect hiding in a patch of leaves. This natural cloaking mechanism is known as acoustic camouflage and makes the insects, for all intents and purposes, undetectable for the bats.

At least, that’s what we thought. To understand how bats pick out prey through the acoustic camouflage, the team aimed sound waves at a leaf (with and without an insect) from over 500 different angles. Using this data, they created a three-dimensional representation of the echoes it generates. For each direction, the team also calculated how intense the echo was over the five different frequencies of sound present in a bat’s call.

As expected, leaves both with and without insects were very good sound reflectors if the sound approaches at an angle under 30 degrees (more-or-less from straight ahead). For a bat approaching at these angles, any echoes generated by an insect will be drowned out by the leaf’s echo. However, Geipel and colleagues found that for angles greater than 30 degrees, incoming sound waves bounce off the leaf much like light on a mirror or a lake. An approach at this angle makes the insect’s echo stand out clearly against the quiet backdrop provided by the leaf.

The optimal angle for bats to approach resting insects on leaves ranges between between 42 and 78 degrees, the authors conclude.

To verify their results, Geipel recorded actual bats at STRI’s Barro Colorado Island research station in Panama as they hunted insects positioned on artificial leaves. Their approaches were filmed using two high-speed cameras, and Geipel used the footage to reconstructed the flight paths of the bats as they closed in on the insects. Almost 80%of the approach angles were within the range of angles that makes leaves act as reflectors, she reports, suggesting that the findings are sound.

“This study changes our understanding of the potential uses of echolocation,” Geipel said. “It has important implications for the study of predator-prey interactions and for the fields of sensory ecology and evolution.”

The paper “Bats Actively Use Leaves as Specular Reflectors to Detect Acoustically Camouflaged Prey” has been published in the journal Cell Biology.

Deaf moths use acoustic camouflage to escape bats

A new study has found that moths have developed a remarkable type of camouflage — it’s acoustic rather than visual.

This image shows a Madagascar bullseye (Antherina suraka), one of the moth species used in Thomas Neil’s research. Image credits: Thomas Neil.

When we think of camouflage, we picture a visual image — something that blends in with the surroundings. That’s because when most creatures are hiding, they want to be out of sight. But if you were hiding from a bat, for instance, that wouldn’t make much sense: bats don’t “see” with their eyes, but rather with their distinct echolocation ability (think of it like a biological sonar). So to hide from a bat, you’d need a different mechanism.

That’s what some moths figured out a long time ago.

Moths are a mainstay on bats’ menu and, naturally, they’d like to avoid being eaten. So in response, some moths have developed ears that detect the ultrasonic calls of bats, but others have remained deaf — and seemingly helpless. But that’s not quite true: a new study has revealed that these insects developed a type of “stealth coating” that serves as acoustic camouflage to evade hungry bats.

Thomas Neil, from the University of Bristol, UK explains how the fur on a moth’s thorax and wing joints provide acoustic stealth by reducing the echoes of these body parts from bat calls.

“Thoracic fur provides substantial acoustic stealth at all ecologically relevant ultrasonic frequencies,” said Neil, a researcher at Bristol University. “The thorax fur of moths acts as a lightweight porous sound absorber, facilitating acoustic camouflage and offering a significant survival advantage against bats.” Removing the fur from the moth’s thorax increased its detection risk by as much as 38 percent.

Neil used acoustic tomography to quantify echo strength of two deaf moth species subjected to bat predation and two butterfly species that are not. He was able to show that acoustic camouflage appears in both moth species, but is absent in the butterflies.

“We found that the fur on moths was both thicker and denser than that of the butterflies, and these parameters seem to be linked with the absorptive performance of their respective furs,” Neil said. “The thorax fur of the moths was able to absorb up to 85 percent of the impinging sound energy. The maximum absorption we found in butterflies was just 20 percent.”

A rotating 3D image of a moth scale. This type of structure is responsible for the acoustic camouflage. Credits: Thomas Neil.

It’s not clear when this mechanism would have emerged. The hairs on the thorax are basically just elongated scales (as you find on the wing), which emerged around 200 million years ago, long before bats evolved (65 million years ago), Neil told me in an email. It’s very hard to say whether the emergence of bats made the moths become hairier.

But what does seem clear is that bats and moths are in a sort of arms race — as the moths develop their camouflage structure, bats try to overcome it — but it’s not that easy.

“Whereas some bats have shifted the frequency of their calls to try and hide from moths that have developed hearing, shifting the frequency to try and overcome the acoustic camouflage of moths would not work,” Neil told ZME Science.

“This is because the absorption is broadband, with the effect being consistent over the frequencies that we measured (20 -160 kHz, the range which most bats use). One thing bats could do would be to simply emit louder echolocation calls to try and get stronger echoes back from the moth, but we have not done any field testing yet to see if this is the case.”

Further research will try to establish how common this occurrence is, and whether there is a difference between deaf and non-deaf moths. There’s no reason why stealth coating and the ability to hear are mutually exclusive; although deaf moths have more evolutionary pressure on them to evolve this type of ability, it would still be a benefit for them to be able to camouflage acoustically, Neil adds.

“We only tested two moths in this study from the family Saturniidae (Antherina suraka and Callosamia promethea). The study is a sort of a proof of concept, we’ve shown that the fur on the thorax can absorb ultrasound, but the extent to which it is present amongst the many moth species is currently unknown.”

“We’re currently working on quantifying to ‘furriness’ of moths across different families to see if there is any relationship between the different forms of defence against bats, he concludes”.

Neil will describe his work during the Acoustical Society of America’s 176th Meeting.

An artist's impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. Credit: Gavin Mouldey.

Giant, ancient bat discovered in New Zealand could walk on all fours

Fossils of a giant burrowing bat, about three times larger than today’s average bat, were discovered by paleontologists in New Zealand. The ancient species belongs to a lineage that used to flourish in the southern landmasses of Australia, New Zealand, South America and possibly Antarctica.

An artist's impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. Credit: Gavin Mouldey.

An artist’s impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. Credit: Gavin Mouldey.

Judging from its teeth and bones, Vulcanops jennyworthyae — named so after researcher Jenny Worthy who found the fossils — likely weighed an estimated 40 grams. Even at this modest weight, it’s the biggest burrowing bat that we know of.

Burrowing bats not only fly but also scurry about on all fours. It’s common to see them foraging for animal and plant food on the forest floor and along tree branches. Although they also lived in Australia, nowadays, burrowing bats can only be found in New Zealand.

If it was anything like today’s burrowing bats, Vulcanops j. must have had a broad diet comprising of both plants and animals. Burrowing bats commonly chase down insects and other invertebrates like weta and spiders, but also consume fruit, flowers, and nectar. Due to its large size and specialized teeth, Vulcanops j. should have been capable of eating even more plant food as well as small vertebrates — a diet more like that of its South American cousins.

Vulcanops jennyworthyae

Vulcanops jennyworthyae likely enabled the giant extinct bat to eat a broader diet than its cousins. Perhaps it also munched on small vertebrates. Credit: Scientific Reports.

“Burrowing bats are more closely related to bats living in South America than to others in the southwest Pacific,” says study first author and University of New South Wales Professor Sue Hand.

“They are related to vampire bats, ghost-faced bats, fishing and frog-eating bats, and nectar-feeding bats, and belong to a bat superfamily that once spanned the southern landmasses of Australia, New Zealand, South America and possibly Antarctica.”

Around 50 million years ago, all of these landmasses were part of the same giant continent called Gondwana. The climate was also wildly different with average global temperatures up to 12 degrees Celsius higher than today. Antarctica, for instance, was covered in lush forests and was ice-free. After tectonic activity fragmented these landmasses, Australasia’s burrowing bats became isolated from their South American relatives.

“The fossils of this spectacular bat and several others in the St Bathans Fauna show that the prehistoric aviary that was New Zealand also included a surprising diversity of furry critters alongside the birds,” said study co-author, Associate Professor Trevor Worthy of Flinders University.

The fossil dig site at St Bathans in New Zealand. Credit: Trevor Worthy.

The fossil dig site at St Bathans in New Zealand. Credit: Trevor Worthy.

Vulcanops’ lineage became extinct not long after the early Miocene, when the climate in New Zealand took a sudden swing, becoming far colder and drier. The environmental changes left many species vulnerable — and Vulcanops was not alone. Numerous species couldn’t adapt, including crocodiles, terrestrial turtles, flamingo-like palaelodids, swiftlets, several pigeon, and non-flying mammals.

Today, only two bat species comprise the entire native land mammal fauna in New Zealand. All other land mammals in the country have been introduced by humans over the past 800 years.

The findings appeared in the journal Scientific Reports. 

A diseased bat infected with White Nose syndrome. Image: Wisconsin Watch

Pest-controlling Bats provide a service worth at least $1 billion to farmers

Corn farmers around the world owe bats at least $1 billion, seeing how they ward off pests like insects. The findings were made by a group at Southern Illinois University who devised an experimental exclosure in order to estimate bats’ contribution to pest control.

A diseased bat infected with White Nose syndrome. Image: Wisconsin Watch

A diseased bat infected with White Nose syndrome. Image: Wisconsin Watch

The researchers built a series of exclosures measuring 20 by 20 meters and seven meters high. The netting was enough to keep bats outside, but loose enough to allow insects to wander about freely. Additionally, the netting was slid to one end during the day to allow birds to forage in the area. This way, they reached an estimate of how much control bats exert on insects, their favorite food. Extrapolating these figures on a global level, the team found “the suppression of herbivory by insectivorous bats is worth more than US$1bn globally on this crop (corn) alone.” A different study published in 2011, warned that  the loss of bat species in North America could lead to agricultural losses in the region of US$3.7bn.

These sort of numbers are very difficult to gauge, so the estimates should be taken with a grain of salt. In this particular case, they may be way off, as in too conservative. Bats, like bees, are pollinators so their value and contribution to the ecosystem is far reaching. It’s not just corn we’re talking about. Entire species may depend on bats.

Unfortunately, bat populations have steeply declined since 2006 at the hand of White Nose Syndrome – a bat-killing disease more virulent than any other disease in the known history of mammals. The disease is caused by a fungus called Geomyces destructans which makes bats’ noses turn white when they hibernate and is easily transmissible from individual to individual.  Within a year, the disease had spread from its epicenter of upstate New York to as far as Texas. Numerous caves and bat populations have been quarantined, but the disease could spread to other parts of North American and eventually the whole world. In the eastern United States, at least, bats could be come extinct in only 20 years considering current mortality rates.

Map of White-Nose Syndrome spreading in North America. Image: whitenosesyndrome.org

Map of White-Nose Syndrome spreading in North America. Image: whitenosesyndrome.org

That’s, of course, if we don’t do anything about it. Hope might lie in a new treatment developed  in Missouri by Forest Service scientists. The treatment is based on a bacteria, Rhodococcus rhodochrous, which lives practically everywhere and is pretty much harmless. After they grew the bacteria on cobalt, the researchers collected volatile organic compounds generated by the bacteria which they found could annihilate the white nose-causing fungus. “Many of the bats in those trials experienced increased health and survival,” the researchers said for Discovery News.

[MORE] Check out the first man-made bat cave

Bats could use help from everyday people, as well. Unfortunately bats are wrongfully stigmatized as rabies-carrying flying rodents or pests, when in fact these mammals are vital to the ecosystem. By raising awareness surrounding this very delicate issue, local authorities might step up their game to address the challenge.

Fungal Disease Kills 5 million North American bats in only Seven Years

In just 7 years, a disease called white-nose syndrome has killed more than 5 million North American bats, almost wiping out entire colonies. The disease has been reported in caves and mines of 25 states throughout the Northeastern U.S. and no treatment or practical way of halting the disease has been proposed.

The disease is caused by a fungus, Pseudogymnoascus destructans, which colonizes the bat’s skin. The disease is responsible for killing somewhere between 5 and 7 million bats. Even though several compounds (antifungals, fungicides, and biocides) where shown to effectively inhibit the growth of the fungus, there is no plan to actually fight the disease. The fungus was first described in 2006.

Bat suffereing from white nose syndrome. Image via Caving News.

A new study has quantified the damage done to bat colonies by the fungus, and their findings are extremely worrying. Before the emergence of the disease, colonies in the US were approximately 10 times more numerous than their European counterparts – but now, it’s almost the other way around, with population decline ranging between 60 and 98 percent.

To make this even more disturbing, bats also provide valuable environmental services; as nighttime insect predators, they are considered some of the most valuable non-domestic creatures from an economic point of view. A drop in the number of bats will lead to a rise in the number of mosquito and pests, ultimately leading to financial damage and human diseases. There is also a risk of the spores contaminating humans as well.

The US Fish & Wildlife Service (USFWS) has called for a moratorium on caving activities in affected areas and strongly recommends to decontaminate clothing or equipment in such areas after each use. Cave management and preservation organizations have been requesting that cave visitors limit their activities and disinfect clothing and equipment that has been used in possibly infected caves.

If you are visiting a cave with a bat colony, please pay extra attention to decontaminating your clothes, or, if not possible, don’t visit it at all.

Source: Science Mag

Golden bat discovered in Bolivia

The bat species was known to science previously, but scientists misclassified it – so technically, it’s still a discovery.

Myotis midastactus had previously been classified as another bat found in South America called Myotis simus. However, after analyzing a collection of museum specimen researchers found that it was in fact a different species, which lives only in Bolivia. The characteristic bright gold color earned it the name midasactus – after the mythological Greek king Midas, who turned to gold everything he touched.

Dr Ricardo Moratelli and Dr Don Wilson, from Fundacao Oswaldo Cruz (Oswaldo Cruz Foundation), Rio de Janeiro, Brazil and the Smithsonian Institution in Washington, US respectively conducted the study. They were unable to catch any specimens even after spending two months trying to do so. However, he was able to classify it with museum specimens, also emphasizing their importance.

“I can confidently say that many new species from different zoological groups are in museum cabinets around the world, awaiting recognition and formal description.”

He also adds that finding (or re-finding) a species is one of the most exciting things a biologist can do.

“Discovering new species is the most exciting part of my research, and in some cases describing a new species can be the first step to preserve others.”

 

Light pollution impeding rainforest regeneration: Seed dispersing bats avoid feeding in light polluted areas

When you think about pollution, usually dirty chemical substances pop to mind; maybe some petroleum, or waste water – light pollution doesn’t usually take the first places. But a new study conducted by scientists from the German Leibniz Institute for Zoo and Wildlife Research Berlin (IZW) showed that light pollution can also have a significant effect.

What is light pollution, anyway?

batsWell, as the name pretty much explains it, light pollution is excessive, misdirected, or obtrusive artificial light. It is introduced by humans directly or indirectly, and it generally occurs in or near big cities – but this is not always the case. Light pollution is basically a side-effect, a by-product if you will of human development; where humans thrive, like for example in Europe, or the US or the developed parts of Asia, we start using more and more light, until it has a negative effect.

Working with Sowell’s short-tailed bats (Carollia sowelli), Daniel Lewanzik from the IZW first built simple flight cages, and then gave the bats a simple choice. He divided the cages into two compartments: one was naturally dark and the other was illuminated by a sodium street lamp, the most common form of street lighting in the world. Inside both parts of the cage, bats were offered some of their favorite snacks: pepper plants, nightshade and figs. The results were pretty clear: bats flew into the darker compartments twice more often than in the illuminated ones.

In a second experiment, Lewanzik illuminated pepper plants growing in the wild with a street light and measured the percentage of ripe fruit which bats harvested from plants in a dark location and from lit plants. Naturally, 100 percent of the naturally dark plants were harvested – it’s not like bats to give up on a tasty meal. However, only three quarters of the illuminated plants were harvested, which shows that even when offered the possibility of a feast, they sometimes still turn it down, if there’s light involved. Although insect-eating bats have been shown to avoid foraging in light-polluted areas, this is the first study to show that fruit-eating bats also avoid areas with light – and this is significantly more important, because bats play a key role in pollinating plants and spreading their seeds, especially the seeds of species that are first to recolonise cleared land.

“In tropical habitats bat-mediated seed dispersal is necessary for the rapid succession of deforested land because few other animals than bats disperse seeds into open habitats”, says Daniel Lewanzik, doctoral candidate at the IZW and first author of the study.

Basically, bats eat fruits and then defecate while flying, spreading the seeds all around. This is a very natural process, and it helps plants regenerate. If they avoid some areas, then those areas will regenerate considerably slower.

If we want to prevent this, there are some things we can do:

“The impact of light pollution could be reduced by changes in lighting design and by setting up dark refuges connected by dark corridors for light-sensitive species like bats,” Lewanzik says.

Full bibliographic informationLewanzik D, Voigt CC (2014): Artificial light puts ecosystem services of frugivorous bats at risk. Journal of Applied Ecology.

(c) EcoHealth Alliance

Deadly Mers virus found in tomb bat – not the one spreading it to humans

Many months later after scientists isolated thousands of samples taken from different bat species found close to the home of the first known victim of the Mers coronavirus – a deadly virus which first emerged in the Middle East last year, killing 47 so far (~50% fatality among infected) – scientists found the evidence of the presence of the virus in one species only: the Egyptian tomb bat.

Dr Ian Lipkin, director of the Center for Infection and Immunity from Columbia University and a co-author of the study, said: “In this case we have a virus in an animal that is identical in sequence to the virus found in the first human case.”

(c) EcoHealth Alliance

(c) EcoHealth Alliance

The Mers virus has well proven its potential for being deadly, and naturally scientists have been taking measures not only to contain the virus, but also understand how it works and keep it stable so that it may not evolve into something truly pandemic. We still know little about it – far too little considering the threats it may pose.

The virus can indeed spread from human to human, however it was observed that the likeliest source of infection is of animal origin. Since this claim has been made, scientists have been scouring feverishly on the prowl for the contact zero animal.

This latest lab confirmation hints that the Egyptian tomb bat may be the origin of the plague. It wouldn’t be that surprising considering they are a source of lots of human virus infections, like Ebola, henipahvirus, rabies and Sars. However, in this case, while they may be the original bearers of the virus, bats most likely aren’t the one actively spreading the virus to humans.

“Even if this proves to be the case, bats are unlikely to be the source of the continuing Mers outbreaks. Humans and bats just don’t interact very much. It’s much more likely that an intermediate animal is involved – and finding out what this animal is is key if we are to eradicate this virus before it becomes a bigger problem,” the researchers write.

This intermediate animal is currently sought after, and samples  taken from camels, sheep, goats and cattle are now being analysed. Researchers bet their money on the dromedary camel, which was incriminated in an earlier study published in the Lancet Infectious Diseases journal. However, only antibodies – the proteins produced to fight infections – were detected in camels, rather than the virus itself, and more work needs to be done to confirm this finding.

Prof Ian Jones from the University of Reading added: “The surprising overall message is that the bats of (Saudi Arabia) are not awash in the virus, quite the opposite as only one example was found and that appeared to be incomplete.”

“The main reservoir for this virus and how it gets to infect people remains unclear at this stage.”

 

Hawk moths jam the bat sonar signals by rubbing their genitals

It’s a dog eat dog out there, and any advantage you can get is more than welcome – as strange as it may be. According to a research published in Biology Letters on 3 July, Hawk moths create an ultrasonic noise that could be used to scare off an attacking bat and to jam the bat’s sonar.

Hawk moth. Picture source.

Hawk moth. Picture source.

Radar jamming is by now a very common technique in human warfare, but not really often seen in the animal world. It’s well known that bets rely on ultrasonic echolocation to get around and find prey – but their prey has adapted as well. Several species of moths have developed ways of hearing this echolocation and, as this study shows – even counter it.

Researchers at Boise State University and the Florida Museum of Natural History pre-recorded the bats’ attack sequence, and then studied what Hawk moths did when they heard this sound. What they did was quite surprising: they created an ultrasonic response by rubbing their genitals against their abdomens; both male and female members did this, albeit using different techniques. They also created the sound when touched. Three species have exhibited this behaviour: Cechenena lineosa, Theretra boisduvalii and Theretra nessus.

“The […] anti-bat ultrasound production in hawkmoths […] might play a similar role as in tiger moths — to startle, warn of chemical defense or jam biosonar,” write the authors, Jesse Barber and Akito Kawahara.

Interestingly enough, moths only exhibited this behaviour near the end of the bat attack sequence, suggesting that this is probably their last line of defense – a last minute “pocket strategy” against their predators.

Scientific article.

Spiders eat bats – almost everywhere [shorties]

Yep, spiders eat bats all across the world – except for Antarctica that is. Bats rank among the most successful groups of mammals, with the more than 1,200 species of bats comprising about one-fifth of all mammal species; aside for humans, they have very few natural enemies, and usually, their numbers are large enough to survive even amidst several predators. However…

OLYMPUS DIGITAL CAMERA

For some invertebrates, bats are often on the menu. Not only spiders, but also giant centipedes and even some cockroaches sometimes feast on bats (or their young ones).

This was a known phenomena, but was thought to occur pretty rarely. Recent studies of a web-building spider species (Argiope savignyi) and a tarantula species (Poecilotheria rufilata) both killing small bats led researchers to suggest that bat captures and kills due to spiders might be more frequent than previously thought.

Rainforest plant evolved beacon for pollinating bats

A lot of attenton has been given to plants that visually attract pollinating bees, through bright colours and spectacular designs, but bats play a very important role for pollinating as well, and there is much we have yet to understand about how they can be attracted by plants.

Researchers have now discovered that a species of rainforest vine, pollinated by bats, has evolved special shaped leaves with such conspicuous echoes that bats can find it twice as fast using echolocation.

Located in Cuba, Marcgravia evenia has developed a distinctively shaped concave leaf located close to the flower which has amazing acoustic properties. Scientists discovered that it acts as an ideal echo beacon, sending back strong and clear echoes in all directions, practically creating its own signature that bats can easily notce and follow.

Scientists trained bats to search for a small plant located in an artificial background, and the results were conclusive. Dr Marc Holderied of Bristol’s School of Biological Sciences, co-author of the paper, said:

“This echo beacon has benefits for both the plant and the bats. On one hand, it increases the foraging efficiency of nectar-feeding bats, which is of particular importance as they have to pay hundreds of visits to flowers each night to fulfill their energy needs. On the other hand, the M. evenia vine occurs in such low abundance that it requires highly mobile pollinators.”