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Ants make up a substantial fraction of Earth’s animal biomass, particularly in tropical forests, where they may account for a plurality of animal biomass in the canopy. But how does an ancestrally omnivorous lineage become dominant in a nitrogen- and amino-acid-limited environment? While anecdotal evidence exist suggesting that bacteria, which have facilitated dietary flexibility in so many other insects, may have played an important role in the evolution of functional herbivory in ants, to date there has been no systematic investigation of the diversity and abundance of potentially symbiotic bacteria in ants. Currently, for this evolutionarily diverse and ecologically dominant insect family, we don’t understand what constitutes a “typical” gut microbiome. The proposed project seeks to begin answering this question, starting with a diverse set of carefully collected specimens from the Peruvian Amazon rainforest. The collection site hosts one of the most diverse assemblages of ant species in the world, and specimens from this region formed the basis for the landmark stable isotope study by Davidson et al. indicating the dietary breadth of tropical ants. Thus, samples from this region represent an ideal first case study that addresses a specific unanswered ecological question, while simultaneously generating data covering a broad swath of the total ant phylogeny. To facilitate these goals, we have collected an initial sample set consisting of many individuals from over 100 ant species in the Madre de Dios region of Peru. For each colony collected, some specimens have been preserved whole, and some dissected according to previously-established protocols for separate preservation of the GI tract; this has proven important to bias analyses towards gut-relevant microbes and reduce the impact of surface contaminants. For most collections, dissected guts have been preserved both for molecular analysis and fixed for FISH microscopy / morphometric analysis. Additionally, a gut from most of the collected colonies was observed in the field using fluorescence microscopy, yielding a preliminary visual index of the morphology, distribution, and abundance of microbial cells present. Additional metadata include location, habitat, and collection methodology. |