Pallas's long-tongued bat (Glossophaga Soricina) is seen eating nectar from Costa Rican banana trees. Credit: Julian Schneider
New research in Frontiers of Ecology and Evolution has revealed that nectar-feeding bats found in Costa Rican banana plantations have a smaller variety of gut microbes than those who eat in natural forest habitats or organic plantations. This is the first study to demonstrate a link between habitat alteration and sustainable agriculture, as well as the gut microbiotas of wildlife.
"Both conventional monoculture banana plantations and organic banana plantations provide reliable food sources for some nectar-feeding bats." However, the bats that foraged in intensively managed plantations showed a decreased diversity of gut microbes. This could indicate gut dysbiosis or an unhealthy imbalance of its microbial symbionts. Priscilla Alpzar is the first author of this study and a doctoral student at Institute of Evolutionary Ecology and Conservation Genomics of University of Ulm, Germany.
"Bats who foraged in organic banana plantations, on the other hand, had varied and individual gut microbiotas more like their natural forest-foraging peers."
Fast food lowers bacterial diversity
A persistent imbalance in the microbe community of the gut is known as gut dysbiosis. It has been linked to poor health and increased susceptibility for illness. Studies on humans have shown that dysbiosis can be caused by eating a low-quality diet. This is due to a reduction in the number of bacteria in the gut. This is the first study to demonstrate that similar effects can occur in wildlife.
"We wanted to examine the effects that intensive plantations of only banana plants on local wildlife and to understand if sustainability agriculture has the same effect," says Alpizar.
Pallas's long-tongued bat (Glossophaga Soricina) is seen eating nectar from Costa Rican banana trees. Credit: Julian Schneider
To determine which bacteria groups are present in feces from bats that forage in intensive and organic banana plantations as well as bats that feed in their natural habitats, the researchers examined samples taken from these bats to identify whether they were more common or less common. The researchers also measured the body condition of each bat, including their size and weight.
"Both the organic and conventional banana plantations provided a reliable food source for bats," reports Alpzar.
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"We discovered a fascinating link between the microbiome composition of the gut and the condition in bats. Some gut bacteria was only found in bats with higher residual bodies mass than those from natural forests. This suggests that these microbes may play a role fat deposition. Because bats that forage in banana plantations do not need to travel long distances to find food, it is understandable that they don't require special bacteria to store fat. Fat deposition is essential for forest-foraging bats because food is seasonal and distributed in large numbers in patches.
Further research is required to determine if pesticides (or the provision of a single, abundant food source) cause changes in the bat's microbiota and if long-term effects on the bat's health.
"Our study showed that more sustainable agricultural practices can have a lower impact on wildlife. Alpzar concluded that the findings of our study can help producers and consumers work together to develop more sustainable and bat-friendly agricultural practices.
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More information: Priscilla Alpzar et. al., Agricultural Fast Food - Bats Feeding in Banana Monocultures are Heavier but have Less Diverse gut Microbiota Frontiers in Ecology & Evolution (2021). Information from Frontiers in Ecology and Evolution Priscilla Alpzar et. al., Agricultural Fast Food - Bats Feeding in Banana Monocultures are Heavier but have Less Diverse gut Microbiota (2021). DOI: 10.3389/fevo.2021.746783
