The evolution and biogeography of top Neotropical predators (Eciton spp.)

As keystone predators of Neotropical forests, hundreds of vertebrate and invertebrate organisms associate with the 12 known species of Eciton, which exert strong top-down effects on community structure in the leaf litter. Despite their clear ecological importance and strong history of research, a comprehensive phylogenetic and biogeographic study is lacking for the important clade. This absence of phylogenetic resolution has been a substantial impediment to determining ecological and evolutionary dynamics, and presents an opportunity to investigate broader mechanisms of diversification in the Neotropics. Using the high-throughput method genotyping-by-sequencing (GBS), we harvested SNPs from across the Eciton genome to infer the clade’s phylogenetic history and their colonization of Neotropical habitats. Known to be poor dispersers due to unique life history traits, repeated colonization of Central America across the isthmus of Panamá offers insight into the controversy of the timing of the closure of the Central American Seaway. This work contributes both to a better understanding of the ecological impact of Neotropical army ants as well as the significance of biogeographic processes in macroevolutionary dynamics.