Meeting Abstract
Host-associated microbiomes are an integral component of host health and function. Recent work elucidates this association and the large variation in microbiome community structure among hosts. Reconciling the extent of community variability with the apparent dependence of hosts on community function, as well as characterizing how functional divergence proceeds across niches, remains challenging. Here, through the study of digestive microbiomes of three insectivorous bat species we characterize how community structure is shaped by functional properties of community members. We use a novel inference framework to show that discordance between levels of community structural and functional variation is influenced by the continuum of shared and derived gene sets across microbial phylogeny. Through multivariate matrix comparisons we demonstrate that while host diet and microbiome community composition do not clearly relate to each other, host diet and metagenome function significantly correlate. We suggest that this discrepancy derives from functional equivalence among microbial lineages. Functional differencs among this set of insectivorous host species disproportionately occurs through selection on abundances of relatively derived microbial functions, as opposed to those that are phylogenetically widespread. Our findings suggest that selection and deterministic processes may influence community assembly, and provide a quantitative foundation for determining community structure-function assembly relationships.
