Fruit bats living in colonies share the same microbial communities in their fur that change in parallel with each other over time, reports a study published online this week in Nature Ecology & Evolution. The findings suggest that fruit bat colonies form a single fur microbiome, in contrast to their gut microbiomes, which differ between individuals.
Microbial communities that live in and on animals are influenced by environmental and social factors and are known to affect host behaviour and health. These factors may alter how both individuals and populations respond to environmental changes. However, most studies investigating how microbiomes change over time have been restricted to either humans or model organisms in the laboratory.
Oren Kolodny, Maya Weinberg and colleagues analysed the fur and gut microbiomes of two Egyptian fruit bat colonies - one a captive colony, the other free-living. Taking weekly fur and anal swabs of the bats for 13 weeks, they found that the sampled fur microbiomes of different individuals on a given day are more similar than those sampled from the same bat on different days. The authors also found the same effect in the volatile compounds found on the bats’ fur.
These shared changes in the bats’ fur microbiome suggest that colony-level processes - such as roosting together - act to coordinate microbial changes across whole colonies. In contrast, the authors found that the bats' gut microbiomes change most prominently at the individual level, and are likely driven by host immunity and physiology.