All animals are multi-organismal, meaning that they bear a community of microorganisms. Interactions among the microorganisms and with the animal host comprise the “inner ecosystem”, which via its impact on host traits, can affect the fitness and ecologically-important traits of the host, with population and community level consequences in the “outer ecosystem”. Using Drosophila interactions with its gut microbiome, we are investigating how the composition and diversity of the microbial community interacts with host genotype to influence the fitness and diet utilization traits of the host.
Results/Conclusions
Our analysis comprises two sequential strategies. First, a metagenome/transcriptome analysis of natural Drosophila populations reveals patterns of correlations between functional traits of the host and the composition, diversity and functional traits of the microbiome. We find that some host functional traits are strongly microbiome-dependent, while others appear to be insulated from variation in microbiome traits. Second, the direction of causality (i.e. the contribution of host and microbial factors in driving the correlations) is determined by experimental analysis of Drosophila colonized with different microbial taxa and complex microbial communities. These complementary approaches identify key microbial taxa, host traits and their interactions that shape ecologically-important traits of Drosophila.