Caojinge Li, Tantan Gao, Lifeng Meng, J Huang
Gut microbiota plays a crucial role in nutrition acquisition and environmental adaptation in social hornets ( Vespa spp.), yet how host phylogeny correlates with dietary niche partitioning and gut microbial community in sympatric species remain poorly understood. Here, we combined mitochondrial COI phylogenetics, multi-locus metabarcoding ( COI / trnL -P6) dietary profiling, and 16S rRNA-based gut microbiota characterization across four sympatric Vespa species. COI phylogeny revealed two distinct clades: ( Vespa tropica + V. basalis ) and ( V. velutina + V. bicolor ). Dietary preferences and gut microbiota composition matched host phylogeny: the first clade was characterized by Fagales consumption and variable insect prey ( V. basalis : Coleoptera; V. tropica : Hymenoptera) and Pseudomonadota dominance, the second specialized in Hymenoptera/Ericales and Bacillota. This pattern suggests that host evolutionary history may shape microbial community and dietary niches. Functional prediction suggested enhanced secondary metabolite biosynthesis in the V. tropica clade versus upregulated carbohydrate metabolism in the V. velutina clade, highlighting the influence of food niches on gut microbiota function. Within clades, fine-scale dietary partitioning (e.g., V. velutina prefers Apis , while V. bicolor specializing on Megachilidae bees) minimizes interspecific competition, revealing the coexistence strategies of sympatric Vespa species. Our findings suggest a potential interaction between host phylogeny and dietary adaptation in shaping gut microbiota, which requires further validation with larger sample sizes.