Biogeographic variation in the composition and social organization of litter-nesting Pheidole communities in the Amazon

Litter-nesting ant communities are useful model systems for testing species assembly rules in complex ecosystems. In particular, the dimorphic and hyperdiverse genus Pheidole, consistently the dominant group in Neotropical litter-ant surveys, provides an opportunity to assess community variation in both the species composition and social organization of worker castes among sites. We surveyed the litter-nesting ant communities in terra firme lowland rainforests at two sites in Ecuador and Peru, and collected Phediole nests to assess colony organization. Overall species composition varied significantly, however the most abundant Pheidole species were consistent between sites. We compare variation in colony size and caste ratios between sites for overlapping species, and discuss the implications of our results in light of the unique hyperdiversity of Pheidole and theoretical models of species assembly.