Symbiosis and sociality define the evolutionary success of life, but the large-scale synergy between hosts and microbiotas is poorly understood. The present project aims to develop a set of phylosymbiotic approaches to begin to understand how and why hosts have evolved in association with microbiota that shape host ecologies. In principal, microbiota can either evolve phylogenetically with the host diversification or evolve convergently with the host ecological adaptations. Social insects are interesting targets for phylosymbiotic analysis because microbiomes combine functions of nutrient supplementation, individual immunity and colony-level immunity. This applies most explicitly to the ants, which have huge species diversity (>14,000 species), massive ecological footprints (dominant in biomass in most terrestrial ecosystems), and high diversity in life styles (e.g. predatory, omnivory, herbivory). The overall goal of the project is to assemble and analyze metagenomic data for at least 50 ant species to understand 1) The evolutionary and functional dynamics of homologous or analogous microbiota across the family Formicidae (ants), and 2) the functional adaptations that have shaped immune defenses across the ant subfamilies and genera.
I have successfully characterized microbiomes from 60 ant species (50 different genera across 10 out of 12 total existing subfamilies) using 16S amplicon sequencing. The majority of microbiotas does not evolve phylogenetically with the their host diversification. There are two clades of ant species, representing four different genera (Camponotus, Polyrhachis, Myrmecina, Acanthomyrmex), that show significant signs of phylosymbiosis. Preliminary results further suggest that the host symbiotic bacteria belonging to Enterobacteriaceae is likely to be the candidate partners of these phylosymbiotic relationships. Additionally, there is an overall trend that diet specialization correlates with microbiota diversity, albeit insignificant with the present data. In general, the predatory strategies appear to maintain richer microbiota diversity than other diet strategies.
