by Emanuela Barbiroglio
Alternately admired and vilified, bats are one of the most mysterious living mammals. Their nocturnal habits and unique adaptations mean that bat biology still holds many secrets. Bats may hold the key to understanding diabetes.
When the pandemic began in 2020 and speculation began that a notorious zoonotic “spillover” seemed to have started it all, one specific animal was identified almost immediately as a threat to humans: bats. People feared them and in some cases even killed them in a vain attempt to stop the virus from spreading.
Then the perception of nature’s only flying mammal reversed again and scientists’ understanding of ecosystems advanced precisely as a result of covid-19.
“The pandemic has highlighted the importance of better understanding bat species as well as their habitats,” said Elise Sivault, “and, more generally, of avoiding any type of process that brings wildlife closer to the environment,” said Elise Sivault. ‘man.” She has been catching bats in Papua New Guinea for BABY project led by Dr. Katerina Sam, from the Biology Center of the Czech Academy of Sciences.
The BABE project analyzes how bats and other predators help keep the world green. And with over 1,450 species and representing 20% of our planet’s mammals, bats are one of the most diverse and geographically dispersed species. As such, they play a valuable role in the global ecosystem by pollinating crops and maintaining plant diversity.
“They are also one of the most misunderstood mammals, due to their cryptic, nocturnal lifestyle,” Sivault added.
Although widely accepted as predators of arthropods (insects, spiders, and other invertebrates), bats are often absent from insect studies compared to birds. “We don’t know much about their impact on arthropod populations or their indirect consequences on plants,” Sivault said.
What we do know is that bats are excellent at gobbling up insects and other arthropods. Sivault and his team are looking at what individual species eat and how much. So far, the results have indicated the difference in the strength of arthropod control by bats along different latitudes.
“In Europe, most bat species have legal protection, but elsewhere many don’t,” Sivault said. “Much more needs to be done to understand their needs, habitats and behaviors in order to find an effective way to protect them.”
Few people know it, but bats help us study and prevent human diseases such as diabetes. Some species of winged mammals have genes that allow them to survive on a super sweet diet of nectar. What this tells us about diabetes in humans is part of research conducted by the Chiroglu project.
Because fruit bats feed on fruit or nectar, researchers have sequenced more than 1,000 genes in a wide range of fruit bat species. They identified a series of molecular adaptations in genes involved in carbohydrate metabolism. To analyze the genetic sequences of more than 100 species of fruit bats, they used a technique called “sequence capture.”
The results show that several distant fruit bat species, having independently evolved to feed on nectar, underwent identical molecular adaptations in the genes responsible for their sugar metabolism. This indicates that evolution seems to have followed the same path more than once to solve a particular problem.
“Our research is driven by curiosity, but it has potentially important implications for humans,” said Stephen Rossiter, professor of molecular ecology and evolution at Queen Mary University of London. “We, like laboratory animals, develop diabetes if we live on high sugar diets. Nectar-eating bats appear to have developed unique changes in metabolic enzymes that may allow them to ward off diabetes and other metabolic diseases.
On the other hand, the life of a bat is not easy. They are threatened by human encroachment and hunting, climate change and habitat loss. Some species of bats in North America are also affected by white-nose syndrome (WNS), a disease caused by a fungal pathogen that infects bats during hibernation. Researchers from the EVOL-WNS are trying to understand why the WNS pathogen is not lethal to European bats but kills their American counterparts.
In 2015, Thomas Lilley, then a Marie Skłodowska-Curie Actions (MSCA) fellow at the University of Liverpool, discovered that the disease-causing fungus originated in Europe, where the bats were actually infected but did not die. . “That meant they must have developed resistance or tolerance at some point in their history,” Lilley said.
He wanted to see if this process towards tolerance had already started in North America after 10 years of exposure to the fungus. This would be evidenced by examining the differences in the genomes of bats sampled before the fungus arrived and bats coexisting with it. Compared to bat genomes sampled before the fungus arrived, Lilley would have expected to see reduced genetic diversity in bats sampled 10 years later. This would have indicated some sort of selection towards resistance or tolerance. However, he found no evidence for this, meaning that bat populations used mechanisms other than genetic immunity to survive infection.
“I thought I would find a signal for emerging selection in bats in North America, because that’s what should be happening in theory,” Lilley said. “But in reality, there are so many factors at play that it’s hard to identify causality.” This discovery helped Lilley see the ecosystem in a much more holistic way. “It’s all connected and it’s a super interesting thought,” he said.
Lilley is currently working on a project at the Finnish Museum of Natural History (Luomus). He studies how bats in Europe cope with fungal infections. To better protect bats, Lilley says the first thing we need to do is learn more about them. The work undertaken so far shows that they are quite difficult to study. This means that there are many aspects of their life cycle that even scientists know very little about.
“For example, here in Finland, we don’t really know where the bats hibernate during the winter,” Lilley said. “And winter is long here in the North, so not knowing where these protected species reside for most of the year is a huge problem for conservation.”
Successfully protecting bats also means involving the public. Bats often reside and breed in buildings during the summer, so they are often considered pests although in fact they keep mosquitoes away from surrounding areas. “It’s important to make sure the public understands that coexistence, and more importantly, even cohabitation is possible with bats and makes it easier to protect these animals,” Lilley said.
The research in this article was funded by the European Research Council of the EU and the Marie Skłodowska-Curie Actions (MSCA). This article was originally publishedin Skylinethe European magazine for research and innovation.