Skin microbiome of a highly olfactory seabird

The microbiome provides multiple benefits to animal hosts that can profoundly impact health and behavior. Microbiomes are well-characterized in humans and other animals in controlled settings, yet assessments of wild bird microbial communities remain vastly understudied. This is particularly true for pelagic seabirds with unique life histories that differ from terrestrial bird species. This study was designed to examine how morphological, genetic, environmental and social factors affect the microbiome of a burrow-nesting seabird species, Leach’s storm-petrel (Oceanodroma leucorhoa). Composition and structure of bacterial communities associated with the uropygial gland and brood patch were assessed using 16S rRNA amplicon-based Illumina Mi-Seq analysis, and compared to burrow-associated bacterial communities. This is the first study to examine microbial diversity associated with multiple body sites on a seabird species. Results indicate that sex and skin site contribute most to bacterial community variation, and that major histocompatibility complex (MHC) genotype impacts the composition of bacterial assemblages in males. In contrast to terrestrial birds and other animals, environmental and social interactions do not significantly influence storm petrel-associated bacterial assemblages. Thus, individual morphological and genetic influences outweighed environmental and social factors on microbiome composition, suggesting a dependence on individual genetics in mate selection potentially through microbiome-mediated odor cues for this highly olfactory species.