|Pallas’s long-tongued bat (Glossophaga soricina), feeding on nectar from banana trees in Costa Rica
Nectar-feeding bats have a diverse diet and a diverse gut microbiome too. When these bats get an easy and quick supply of food, in their case banana plantations, they take to this ‘fast-food’ since it is reliable. Just like humans, how this food is grown determines the nature of their gut microbiome, says a recently published study
The researchers collected fecal samples from bats that had foraged for an hour after sunset in intensive banana plantations, organic plantations as well as from bats feeding in their natural habitat. They used DNA sequencing to determine which bacterial groups were present, absent, more common, or they were linked to a specific habitat. They also measured the bat’s body condition, which included their size and weight.
Bats feeding in plantations also had higher body mass and size, a result of the ready availability of food. While bats in natural environments and organic cultures resulted in a diverse microbiome in the bats, those foraging in intensely managed monocultures had less microbiome diversity.
“We found an interesting link between the gut microbiome composition and the condition of the bats,” said Priscilla Alpízar, a doctoral student at the Institute of Evolutionary Ecology and Conservation Genomics of the University of Ulm in Germany and also the first author of the study. “Some gut bacteria were only associated with bats of higher residual body mass and those from the natural forests, suggesting these microbes could play a role in fat deposition. Since bats foraging in banana plantations don’t need to fly long distances to look for food, it makes sense that these bats don’t need special help from bacteria to store fat. However, for forest-foraging bats, fat deposition is important because food is seasonal and widely distributed in patches.”
Less diversity in the gut microbiome is known as gut dysbiosis, often seen in humans who consume a ‘fast-food diet’ and are also more prone to illness. However, this is the first study to show that a similar effect is seen in wildlife too. Interestingly, it is the human desire for mass production that has caused dysbiosis in the bat.
“Our study shows that more sustainable agricultural practices can have less of an impact on wildlife,” Alpizar adds. “Hopefully, our findings can lead the efforts to work together with producers and consumers to find more sustainable and bat-friendlier agricultural practices.”