A major goal of ecology is to understand the factors promoting coexistence among competing species. Chief among the hypothesized mechanisms is habitat heterogeneity, but alternatives include temporal fluctuations in resource availability, spatially restricted dispersal, and tradeoffs among fecundity, dispersal, and competitive ability. Only a handful of these mechanisms have ever been shown to operate in the field, and experimental tests simultaneously evaluating multiple mechanisms are rare. The proposed study will evaluate alternative coexistence mechanisms in an emerging model system in community ecology - ants that compete to establish colonies in specialized plant structures known as domatia. Three species of ants colonize the domatia of the Amazonian trees Tococa bullifera and Maieta guianensis. Using this system, non-mutually exclusive mechanisms that may promote ant coexistance will be tested with a combination of field observations, manipulative experiments, and mathematical models. Because this system is composed of two specialists that coexist with a generalist on two resources, our results could provide unique insights into the evolution of specialization in ecological communities. The project will provide ample opportunities for students at multiple stages of their academic careers to develop research, modeling, and mentorship skills. Furthermore, the collaborating PI's are at institutions with large minority enrollments, which will allow them to continue mentoring students from underrepresented groups. Finally, this project will strengthen a dynamic and productive international collaboration, and allow US students to gain their first experience working in Amazonian ecosystems.
