Patterns of bacterial community composition and nutrient content across Azteca trigona ants, their nest, refuse and surrounding soil

Background/Question/Methods

Microbial life is ubiquitous, yet we are just beginning to understand how microbial communities are assembled. Built environment microbiomes are useful systems to explore community assembly, as the microbial community of the structure is so closely tied to that of its inhabitants and its surroundings. Our study tests whether relationships between ant microbiomes and their environments resemble patterns identified in the microbiome of the human home. We predict that the microbiome of the canopy ant Azteca trigona represents a distinct community compared to its surroundings, similar to human microbiomes and their environment. Similarly, we predict that chemical composition should vary across sample types due to the varying metabolic needs of distinct microbial communities. Due to the intimate nature in which ants macerate and regurgitate plant material for nest construction, we predict that the nest microbiome should resemble the microbiome of ants more than the surrounding environment. Finally, we also expect little variation among ant colonies due to the importance of core microbiota. 

Results/Conclusions

As predicted ant microbiomes were distinct from their environment, as was the chemical composition. Nest bacterial composition was similar to the surrounding soil, resembling the pattern seen in outdoor human home microbiomes. However, contrary to initial predictions, ant microbiomes varied dramatically across colonies. This variation was largely driven by the relative abundance of Lactobacillus, a genus frequently associated hymenopteran diets. The distinct microbiome associated with ants, relative to their nests and surrounding environment, supports the common hypothesis that ants are capable of filtering and maintaining microbiota.