The role of environmental and genetic factors in shaping the microbiome of a highly olfactory bird species
Many animal species rely heavily on olfaction for self-recognition, mate selection, foraging and predation. The microbiome is hypothesized to play a role in an animal's odor signature by fermenting compounds found in secretions and producing odorous metabolites. Individual microbiomes can be affected by habitat, but individual animal genetics can also shape specific microbial communities. While microbial communities have been shown to influence the social interactions several mammalian studies, no studies have demonstrated this in birds. Procellariiformesare highly olfactory seabirds that rely on odors to locate food, relocate nests, and identify conspecifics and potential mates. In this study, we collected skin swab samples from dorsal and ventral locations from twenty pairs of Leach's storm petrels from a well-established colony at Bon Portage Island in Nova Scotia, Canada. We purified microbial DNA from body swabs and surrounding burrow soil for next-generation sequencing. We hypothesized that birds in mated pairs harbor significantly different microbial communities and potentially exploit these differences to avoid inbreeding and spread of microbial pathogens.
We processed paired-end sequences using mothur v.1.34.4 and visualized multivariate microbial community data using nonmetric multidimensional scaling (NMDS), analysis of similarity and permutational multivariate analysis of variance. Dorsal and ventral samples collected from individual birds clustered separately. Results indicate that petrels in mated pairs carry different microbial communities from their mates, which suggests that these birds may choose mates that diversify the collective microbiome of the pair. However, there was no effect of sex on microbial community, suggesting that the microbiome is not sex-specific in these birds, but may be related to other genetic traits. Additionally, burrow location did not impact bird-associated microbial communities, providing evidence that bird-associated microbial assemblages are influenced more by the individual bird and its mate than by habitat. This study provides the first robust examination of factors that shape the microbiome of a highly olfactory avian species.