Singapore fruit bats suffer from environmental degradation


This July 2018 video is called Lesser short-nosed fruit bat (Cynopterus brachyotis).

From the National University of Singapore:

Even resilient common species are not immune to environmental crisis

Measures of genetic diversity of a fruit bat common in Singapore decreased 30-fold over the last 90 years

December 18, 2019

A recent study by scientists from the National University of Singapore (NUS) revealed that the current biodiversity crisis may be much broader than widely assumed, and may affect even species thought to be common and tolerant of fragmentation and habitat loss.

Specifically, the research team found that the effective population size and genetic diversity of a common fruit bat species — the Sunda fruit bat (Cynopterus brachyotis) — that was believed to remain widely unaffected by urbanisation, has shrunk significantly over the last 90 years. By comparing historic DNA from museum samples collected in 1931 and modern samples collected in 2011 and 2012, the NUS team found a nearly 30-fold reduction in effective population size and corresponding levels of decline in genetic diversity estimates.

“This bat species carries a genomic signature of a steep breakdown in population-genetic diversity. The extreme bottleneck event that led to a reduction in genetic diversity happened some time in the early Anthropocene (around the 1940s) when humans’ impact on this planet became dominant,” explained first author Dr Balaji Chattopadhyay, who recently finished a postdoctoral fellowship at the NUS Department of Biological Sciences at the Faculty of Science.

Understanding the decline in population-genetic diversity of the Sunda fruit bat

An effective pollinator and seed disperser, Cynopterus brachyotis represents an important keystone bat species in Singapore’s ecosystem. This bat species is also widely distributed in human-dominated landscapes across tropical Southeast Asia.

In order to understand the effects of human-mediated changes such as urbanisation on the evolutionary trajectory of Singapore’s population of Cynopterus brachyotis, the NUS team reconstructed and compared diverse models of historic demography. The researchers sequenced and examined over 634 million DNA reads of Cynopterus brachyotis genome and generated multiple datasets for the study.

Their findings suggest that Singapore’s Cynopterus brachyotis population underwent a continuous decline that started approximately 195 generations ago (i.e. 1,600 years ago), and experienced a recent genetic bottleneck — or a sharp reduction in population size — nine generations ago, roughly in 1940. Genetic bottlenecks increase the vulnerability of a species to unpredictable events and can accelerate extinction of small populations. While bottlenecks following human interference have been documented in many endangered species, this study suggests that even common human commensals may not be immune to the effects of bottlenecks.

“Cynopterus brachyotis is a generalist fruit bat that tolerates urbanised settings. As such, it is an unlikely victim of habitat degradation and fragmentation. The unexpected loss in genetic diversity in this common species, largely due to urbanisation and human-mediated changes, indicates that the modern environmental crisis can generate adverse silent effects that only become apparent much later, when the impact of low genetic diversity may take hold in a population,” explained Assistant Professor Frank Rheindt from the NUS Department of Biological Sciences, leader of the laboratory group that conducted the study.

“This phenomenon has been characterised as extinction debt, when actual extinction occurs with a time lag, long after the critical damage was done. Hence, an increased understanding of baseline levels and rates of loss of genetic diversity across organismic groups like Cynopterus brachyotis bats and habitats may, in the future, become imperative for informed conservation action,” he added.

This research was conducted in collaboration with the National Parks Board (NParks) Singapore which supported the sampling of contemporaneous populations of the bats. The findings were published in the journal Current Biology on 16 December 2019.

“Our research also underscores the importance of strong museum collections facilitating the DNA-sampling of time series. More global support is needed for modern cryo-collections, which are generally under-funded,” said Asst Prof Rheindt.

Asst Prof Rheindt is looking to extend the research by investigating multiple other animal species in Singapore and Southeast Asia to better characterise extinction risk.

New nature reserve for Bonaire island bats


This 5 September 2019 video says about itself:

Safeguarding Nature Projects – Bonaire – Caves & Karst Nature Reserve

Julianka Clarenda is visiting Fernando Simal of WILDCONSCIENCE and The Caribbean Speleological Society (CARIBSS) to see the Caves & Karst Nature Reserve.

This project of the Public Entity Bonaire in cooperation with WILDCONSCIENCE and The Caribbean Speleological Society (CARIBSS) is funded by the Ministry of Agriculture, Nature and Food Quality (LNV).

Movie commissioned by DCNA, on behalf of Ministry of LNV, produced by B-onair.

Local authorities of Bonaire island in the Caribbean reported, 17 December 2019 (translated):

Caves & Karst Reserve on Bonaire. The 31-hectare park that comprises a special cave system with a colony of bats is an initiative of the local organization Wild Conscience and the Caribbean Speleological Society. …

Bonaire has around 200 caves, some of which are delivery rooms for the 7 bat species. They contribute significantly to the biodiversity of the island that has been a special municipality of the Netherlands since 2010.

American little brown bat conservation


This 2017 video from Canada is called Endangered Ontario: Little brown bat.

From the Ecological Society of America in the USA:

Bats in attics might be necessary for conservation

Buildings are vital summer roosting places for little brown bat maternity colonies in Yellowstone National Park

November 19, 2019

For the little brown bat — a small mouse-eared bat with glossy brown fur — a warm, dry place to roost is essential to the species’ survival. Reproductive females huddle their small furry bodies together to save thermal energy during maternity season (summer), forming “maternity colonies.” In the face of severe population losses across North America, summer access to an attic or other permanent sheltered structure, as opposed to just trees or rock crevices, is a huge benefit to these bats.

In a new study published in the Ecological Society of America’s journal Ecosphere, researchers with Ohio University, University of Kentucky, and the US National Park Service investigate and describe the conservation importance of buildings relative to natural, alternative roosts for little brown bats (Myotis lucifugus) in Yellowstone National Park.

Yellowstone’s iconic high-elevation landscape provides abundant natural roosting places but not many buildings. The study involved four visitor areas with several buildings that are known to host bold little brown bats, which are among the few bat species that will make their homes in structures that are actively used by people, allowing humans to get up close and personal. Sometimes, the investigation even involved researchers capturing them by hand.

“We occasionally entered attics to look to see if they were occupied by bats,” says lead study author Joseph Johnson, an assistant professor of vertebrate biology at Ohio University. “On these occasions we sometimes took the opportunity presented by inactive bats… We would gently pluck them from the walls and glue a transmitter on them in order to study their thermoregulation, but also to let them lead us to additional roosts.”

Over the summers of 2012-2015, researchers tracked individual bats in the park. Using temperature-sensitive radio-transmitters, the researchers measured roost preferences and body temperature regulation in adult male and female bats roosting in buildings, trees, and rocks.

Their results show that reproductive females roost in attics in the study area on 84% of all days for which they collected data, while males roost exclusively in rock crevices or trees. It appears then that outside of maternity colonies, adult males and non-reproductive females will roost by themselves or in small aggregations.

The idea and study of bats using buildings is not new; people have probably seen bats in buildings ever since humans first started building them. What is new is comparing the benefits buildings provide bats with the benefits of alternative natural roosts. “That was what we did in our research,” Johnson says, “using the challenging environment of Yellowstone National Park as a lens through which to view these benefits. As populations of bats continue to decline in North America, we believe that highlighting the importance of buildings to bats is important for conservation.”

Outside Yellowstone and national parks, people frequently evict bats from their buildings. The removal of bats, especially maternity colonies that allow females to conserve warmth and energy, is a conservation concern as white-nose syndrome (WNS) continues to devastate populations in cave-hibernating bat populations across the continent.

WNS is named for a distinct white fungal growth around the muzzle and on wings of hibernating bats — it is the first known pathogen that kills a mammal host during hibernation. The fungus erodes skin and membranes and causes infected bats to burn through energy and fat reserves twice as fast as healthy individuals, and it essentially results in starvation. WNS fungus only thrives in the cold, damp environments typically associated with underground hibernation sites such as caves and mines, and it only grows on bats when they hibernate during winter. Bats that do survive WNS are particularly weak come spring and summer.

“To date, there have been no signs of WNS in these buildings or in Yellowstone, although the fungus has now been documented both east and west of the Park,” says Johnson. If WNS is present in the study area, the researchers expect to see a sharp reduction in the number of bats present during the summer. “Thankfully,” he says, “we have not seen any such decline as of yet.”

Another complication for little brown bats is a state of body temperature regulation called “torpor.” It can be thought of as a form of hibernation, but on a daily scale. In spring through fall, the little brown bat enters a state of decreased physiological activity. Torpor saves energy for the bat when the ambient temperature gets too cool (yes, even in summer). Instead of expending energy and fat reserves to maintain a constant body temperature, torpor allows the body to cool close to their roost temperature and physiological activity to slow. While in torpor, a bat’s heart rate drops from up to 210 beats per minute to as few as 8 beats per minute.

For a pregnant bat, however, their ability to regulate body temperature decreases. Torpor also slows gestation and delays the birth of offspring, potentially forcing juvenile bats to mature quickly before winter arrives, and therefore decreasing survival rates of new generations.

The study confirms that male bats roosting in rocks and trees largely allow their body temperature to dip close to the ambient temperature. Female bats in buildings, on the other hand, sustain higher body temperatures than males throughout the day, thanks to buildings being more insulated from low ambient temperatures during the middle of the maternity season.

Ultimately, the importance of buildings to bats may be especially great at high elevations and latitudes. The researchers believe that buildings allow for larger populations of little brown bats than would be possible without buildings in these landscapes, and that conservation managers need to evaluate the conservation value of buildings for bat populations as WNS continues to grow and spread.

“This warmth is important for bats during the summer months to help with their reproductive efforts,” emphasizes Johnson. “Bats surviving WNS and trying to recover might benefit from a warm roost tremendously.”

Freed bats keep friends from captivity days


Thus 2012 video says about itself:

When it comes to feeding, this thumb-sized bat definitely sides with Dracula. Vampire bats are the only mammals on an all-blood diet — and an unsuspecting cow is the perfect prey.

From ScienceDaily:

After release into wild, vampire bats keep ‘friends’ made in captivity

October 31, 2019

Vampire bats that share food and groom each other in captivity are more likely to stick together when they’re released back into the wild, find researchers in a study reported on October 31 in the journal Current Biology. While most previous evidence of “friendship” in animals comes from research in primates, these findings suggest that vampire bats can also form cooperative, friendship-like social relationships.

“The social relationships in vampire bats that we have been observing in captivity are pretty robust to changes in the social and physical environment — even when our captive groups consist of a fairly random sample of bats from a wild colony,” said Simon Ripperger of the Museum für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Science in Berlin. “When we released these bats back into their wild colony, they chose to associate with the same individuals that were their cooperation partners during their time in captivity.”

He and study co-lead author Gerald Carter of The Ohio State University say their findings show that repeated social interactions they’ve observed in the lab aren’t just an artifact of captivity. Not all relationships survived the transition from the lab back into the wild. But, similar to human experience, cooperative relationships or friendships among vampire bats appear to result from a combination of social preferences together with external environment influences or circumstances.

Carter has been studying vampire bat social relationships in captivity since 2010. For the new study, he wondered whether the same relationships and networks he’d been manipulating in the lab would persist or break down after their release in the wild, where the bats could go anywhere and associate with hundreds of other individuals.

Studying social networks in wild bats at very high resolution hadn’t been possible until now. To do it, Simon Ripperger and his colleagues in electrical engineering and computer sciences developed novel proximity sensors. These tiny sensors, which are lighter than a penny, allowed them to capture social networks of entire social groups of bats and update them every few seconds. By linking what they knew about the bats’ relationships in captivity to what they observed in the wild, they were able to make this leap toward better understanding social bonds in vampire bats.

The researchers found that shared grooming and food sharing among female bats in captivity over 22 months predicted whom they’d interact with in the wild. While not all relationships survived, the findings suggest that the bonds made in captivity weren’t just a byproduct of confinement and limited options. The researcher report that the findings are consistent with the idea that both partner fidelity and partner switching play a role in regulating the bats’ relationships.

“Our finding adds to a growing body of evidence that vampire bats form social bonds that are similar to the friendships we see in some primates,” Carter said. “Studying animal relationships can be a source of inspiration and insight for understanding the stability of human friendships.”

The researchers say they’ll continue to work on individual differences in cooperativeness among vampire bats and exploring how individuals go from being strangers to cooperation partners. Taking advantage of their newfound abilities to measure relationships in the wild, they’re also looking into social foraging and whether bats that cooperate within their day roost also go hunting together at night.

This work was supported by the Deutsche Forschungsgemeinschaft, a Smithsonian Scholarly Studies Awards grant, and a National Geographic Society Research Grant.

See also here.

Bats face many threats — from habitat loss and climate change to emerging diseases, such as white-nose syndrome. But it appears that wildfire is not among those threats, suggests a study from the University of California, Davis, published today in the journal Scientific Reports. It found that bats in the Sierra Nevada appear to be well-adapted to wildfire: here.

Butterfly, plant, moth, bat evolution, new research


This October 2016 video from the USA says about itself:

Find out how butterfly pollination behavior influences plant evolution! Drs. Robin Hopkins & Heather Briggs take us through their research into the effects of pipevine swallowtail behavior on the evolution of flower color in the wildflower Phlox.

From the Florida Museum of Natural History in the USA:

Butterflies and plants evolved in sync, but moth ‘ears’ predated bats

October 21, 2019

Summary: A new study cross-examines classic hypotheses about the coevolution of butterflies with flowering plants and moths with bats, their key predators. The findings show flowering plants did drive much of these insects’ diversity, but in a surprise twist, multiple moth lineages evolved ‘ears’ millions of years before the existence of bats, previously credited with triggering moths’ development of hearing organs.

Butterflies and moths rank among the most diverse groups in the animal kingdom, with nearly 160,000 known species, ranging from the iconic blue morpho to the crop-devouring armyworm.

Scientists have long attributed these insects’ rich variety to their close connections with other organisms. Butterflies, they hypothesized, evolved in tandem with the plants they fed on, and moths developed sophisticated defense mechanisms in response to bats, their main predators.

Now, a new study examines these classic hypotheses by shining a light on the early history of Lepidoptera, the order that includes moths and butterflies. Using the largest-ever data set assembled for the group, an international team of researchers created an evolutionary family tree for Lepidoptera and used fossils to estimate when moths and butterflies evolved key traits.

Their findings show that flowering plants did drive much of these insects’ diversity. In a surprise twist, however, multiple moth lineages evolved “ears” millions of years before the existence of bats, previously credited with triggering moths’ development of hearing organs.

“Having a fossil-dated family tree gives us our most detailed look yet at the evolutionary history of moths and butterflies,” said the study’s lead author Akito Kawahara, University of Florida associate professor and curator at the Florida Museum of Natural History’s McGuire Center for Lepidoptera and Biodiversity. “We’ve thought for a long time that flowering plants must have contributed to the extraordinary number of moth and butterfly species we see today, but we haven’t been able to test that. This study helps us see if prior hypotheses line up, and what we find is that the plant hypothesis does, but the bat hypothesis does not.”

The research also suggests lepidopterans are much older than previously thought, with the shared ancestor of today’s butterflies and moths likely appearing about 300 million years ago — roughly 100 years earlier than previous estimates.

A seminal 1964 paper by Paul Ehrlich and Peter Raven used the tightly interwoven relationships between butterflies and flowering plants as the foundation for the theory of coevolution — the idea that different organism groups evolve in response to one another.

As plants developed toxins to ward off hungry caterpillars, they reasoned, butterflies evolved ways of tolerating them. Plants, in turn, would ramp up their weaponry, and the cycle of one-upmanship continued.

Similarly, scientists, including Kawahara, have cited bats as the driving force behind moths’ evolution of special defenses, including ultrasonic-sensitive hearing organs, sonar jamming and long, twisted tails that can deflect an attacker in flight.

Cross-examining these hypotheses requires a trip back in deep time — no easy task with a group of insects that is notoriously rare in the fossil record. Further complicating matters, fossils are often tricky to identify accurately as a moth or butterfly, Kawahara said. One originally labeled as Lepidoptera was later revealed to be a leaf.

Kawahara’s team used two analytical approaches to avoid making the same mistake. They examined previous studies of Lepidoptera fossils, tossing out any examples that seemed questionable. They vetted the 16 remaining fossils with other lepidopterists, looking for consensus that they really represented moths and butterflies. They then used these fossils to date their evolutionary tree, built from more than 2,000 genes from 186 existing moth and butterfly species. To double-check those dates, they carried out the same analysis using just three fossils, each displaying all the hallmark characteristics of a particular Lepidoptera group.

Journeying into moth ‘ears’

A major shocker was the fossil-dated tree’s revelation that nocturnal moths evolved hearing organs nine separate times, four of which occurred around 91 million years ago — about 30 million years before bats dominated the night sky.

What could moths have been listening to in a pre-bat world?

Small pterosaurs, Cretaceous birds, maybe?

“We don’t know,” Kawahara said. He and study co-author Jesse Barber, a bat expert and associate professor at Boise State University, hypothesize that “they probably used these hearing organs to detect the sounds made by other predators, like footfall, flight or rustling, and later co-opted them to pick up on bat sonar.”

Many moths and a few butterflies have “ears” on various parts of the body, depending on the family. The majority of hearing organs, however, are near the wings, the optimal location for swiftly cueing an insect to move toward or away from a sound, said study co-author Jayne Yack, a professor of neuroethology at Carleton University in Ottawa, Ontario.

“It makes sense to have your ears close to flight machinery, if your response to sound is to escape by flight,” she said.

While the finding that some of these organs predated bats came as a surprise, Yack cautioned against jumping to the conclusion that there is no connection between bats and moths’ ability to hear. She pointed out that many species with ears appear just prior to the proposed time when bats developed echolocation, “so something around that time period appears to have been an important selection pressure.”

“The vast majority of ears in today’s Lepidoptera are sensitive to ultrasound, and at least some of them have been shown to function in evading bats,” she said. “Some also evolved after bats first used echolocation. But the evidence does require that we reconsider the currently held assumption that all ears in nocturnal Lepidoptera evolved in response to bat echolocation.”

Nectar straw was a game-changer

The earliest moths likely tunneled and fed inside non-vascular plants such as bryophytes as larvae and had chewing mouthparts as adults. The development of the proboscis, a coiled straw-like mouthpart that can suck up nectar, plant sap and other fluids, helped moth diversity rocket off, Kawahara said. More than 99% of today’s moths and butterflies have a proboscis.

The fossil-dated tree puts the origin of the proboscis around 241 million years ago, coinciding with the time when flowering plants were quickly diversifying. The proboscis helped early moths access nectar and may have enabled them to fly farther and colonize new host plants.

Butterflies, a much younger and less diverse group than moths, did not originate until about 100 million years ago and are just day-flying moths, Kawahara said.

“This study underscores previous studies that show butterflies really belong in the much bigger group of moths,” he said. “We tend to appreciate butterflies because they’re often flashy and charismatic, but we shouldn’t forget about moths, which can be just as striking. Moths and plants were interacting some 50 million years before the first dinosaur roamed the Earth, and those interactions helped lead to the diversity we see on our planet today.”

The origin of bats


This 11 September 2019 video says about itself:

Bats pretty much appear in the fossil record as recognizable, full-on, flying bats. And they show up on all of the continents, except Antarctica, around the same time. So where did bats come from? And which of the many weird features that bats have, showed up first?