Assessing the drivers of gut microbiome composition in wild redfronted lemurs via longitudinal metacommunity analysis

Abstract

The gut microbiome influences host’s immunity, development, and metabolism and participatesin the gut–brain axis, thus impacting the health of the host. It is a dynamic community varyingbetween individuals and within individuals at different time points. Hence, determining the factorscausing this variability may elucidate their impact on host’s health. However, understanding thedrivers of variation has proven difficult particularly as multiple interactions occur simultaneouslyin the gut microbiome. We investigated the factors shaping the gut microbiome by applying themetacommunity concept where the gut microbiome is considered as a microbial community shapedby the interactions within the community, with the host and microbial communities outside the host,this through a longitudinal study in a wild primate. Focal behavioral data were collected for 1 year infour groups of redfronted lemurs to determine individual social and feeding behaviors. In addition,regular fecal samples were collected to assess bacteria, protozoa, and helminths through markergene analysis and to measure fecal glucocorticoid metabolite (fGCM) concentrations to investigatethe impact of physiological stress on the gut microbiome. Higher consumption of leaves and elevatedfGCM concentrations correlated with higher alpha diversity, which also differed among groups.The major drivers of variation in beta diversity were group membership, precipitation and fGCMconcentrations. We found positive and negative associations between bacterial genera and almostall studied factors. Correlations between bacterial indicator networks and social networks indicatetransmission of bacteria between interacting individuals. We detected that processes occurring insidethe gut environment are shaping the gut microbiome. Host associated factors such as, HPA axis,dietary changes, and fluctuations in water availability had a greater impact than interactions withinthe microbial community. The interplay with microbial communities outside the host also shape thegut microbiome through the exchange of bacteria through social relationships between individualsand the acquisition of microorganisms from environmental water sources.