ENVIRONMENTAL TEMPERATURE AND THE GUT MICROBIOME IN BATS: CURRENT EVIDENCE AND POTENTIAL IMPLICATIONS FOR HOST HEALTH AND INFECTION SUSCEPTIBILITY: A REVIEW

Abstract

The physiology and gut microbiome of bats could be affected by environmental temperatures but how these factors contribute to susceptibility to infection remains unknown. This narrative review will discuss the direct evidence from bats as well as seasonal studies, hibernation studies and temperature studies in other animals. The only direct evidence available is from a field comparison which revealed no differences in overall community composition of the gut microbiomes from hibernating least horseshoe bats in different winter roosting sites, but did show correlation between winter roost temperature and gut microbiome alpha diversity. Other studies of bats report seasonality and physiological state changes in the microbiome that are also likely a consequence of changes in diet, fasting and host physiology. Individual studies have also been used to correlate bat gut microbiome patterns to immune response or infection. Bat microbiota have also influenced how mice respond to influenza, but this does not imply an effect in bats. For comparative context, experiments in other mammals have demonstrated that temperature effects on microbial communities and host physiology. Collectively, the current evidence is consistent with the possibility of a relationship between environmental temperature, bat gut microbiome and health; however, there is no evidence of any causal pathway nor proof that microbiome changes in response to environmental temperature affect infection susceptibility. Research to quantify microbiome function, immune responses and pathogen levels and bat health is required.