Many Azteca ant species are obligate or faculative residents in various myrmecophytes throughout the Neotropics. Perhaps the most well known neotropical ant-plant association is that between Azteca ants and Cecropia trees where ants inhabit the internodes of living tree trunks and branches, with some species aggressively defending their host tree. This study is a phylogenetic investigation of the evolution of the associations between Azteca ants and their host plants using molecular sequences from several different loci including Cytochrome c oxidase subunit I, Elongation factor 1a, Wingless, Enolase, and Arginine kinase.