Diet and phylogeny shape the composition, diversity, and structure of the ant-gut bacterial community

The gut bacterial community provides various benefits and maintains a long-term symbiotic relationship with its host. Thus, uncovering its diversity and structure is fundamental for revealing its function in the adaption of its host. The composition, diversity, and structure of the gut bacterial community are affected by various factors including the taxon of the host. To determine the composition of the ant-gut bacterial community and the roles of diet and phylogeny in shaping the composition, diversity, and structure of the bacterial community, we analyzed the composition of the gut bacterial communities of 42 ant colonies (representing 38 species, 28 genera, and 7 subfamilies) using 16S rRNA sequencing. Proteobacteria, Actinobacteriota, and Firmicutes were the dominant bacteria in the ant gut, which was consistent with the composition of the gut bacterial communities of most insects. The alpha and beta diversity of the ant-gut bacterial communities both differed significantly at the OTU and phylum level with respect to all categories according to the diet and phylogeny of hosts at the overall, 75% and 50% core bacterial community, indicating that diet and phylogeny might play important roles in shaping the composition and diversity of the ant-gut bacterial community. Furthermore, CCA and RDA analysis implied that the phylogeny might be more important than the diet of hosts, indicating the host identity could play a more important role than external ecological factors in shaping the composition and structure of the ant-gut bacterial community at the subfamily level. Our results provide insights into the composition of the gut bacterial communities in multiple ant subfamilies and preliminarily reveal the roles of diet and phylogeny in shaping the composition and diversity of the gut bacterial community.