Gut microbiome in two high-altitude bird populations showed heterogeneity in sex and life stage

Abstract

Gut microbiotas have important impacts on host health, reproductive success, and survival. While extensive research in mammals has identified the exogenous (e.g. environment) and endogenous (e.g. phylogeny, sex and age) factors that shape the gut microbiota composition and functionality, yet avian systems remain comparatively less understood. Shorebirds, characterised by a well-resolved phylogeny and diverse life-history traits, present an ideal model for dissecting the factors modulating gut microbiota dynamics. Here, we provide an insight into the composition of gut microbiota in two high-altitude (ca. 3200m a.s.l.) breeding populations of Kentish plover (Charadrius alexandrinus) and Tibetan sand plover (Charadrius altrifrons) in Qinghai-Tibetan Plateau, China. By analysing faecal bacterial communities using 16S rRNA sequencing technology, we find a convergence in gut microbial communities between the two species, dominated by Firmicutes, Proteobacteria and Bacteroidetes. This suggests that the shared breeding environment potentially acts as a significant determinant shaping their gut microbiota. We also show sex- and age-specific patterns of gut microbiota: female adults maintain a higher diversity than males, and juveniles are enriched in Rhizobiaceae and Exiguobacterium due to their vegetative food resource. Our study not only provides a comprehensive descriptive information for future investigations on the diversity, functionality and determinants of avian microbiomes, but also underscores the importance of microbial communities in broader ecological contexts.