MSB: Experimental Coevolutionary Genetics of the Attine Ant-Microbe Symbiosis

University Of Texas At Austin, Austin TX

Investigators

Abstract

Certain ants cultivate fungi as their major food source. The ants collect and transport vegetable substrate to a "garden," usually a sheltered chamber excavated in the ground, then plant fungus on this new substrate. Gardens of fungus-growing ants are foci of interactions within a community of ants, the cultivated fungus, and a great diversity of additional microbes. Specifically, pathogens attacking the ants or the fungal gardens can cause the death of the nest community, but a variety of auxiliary microbes contribute disease-suppressing properties that control such pathogens. Disease resistance to pathogens is shaped by the genetic identity of both the ant and the fungus and the interaction of these two dominant community members with the auxiliary microbes. This research will elucidate how these nest community members interact and co-evolve in response to pathogen presence. To understand disease dynamics, the research will (a) characterize the inheritance of assemblages of auxiliary microbes from maternal to offspring ant nest; (b) determine the importance of co-inheritance of ant-fungus-microbe combinations to disease resistance of the community; and (c) evaluate the relative contribution to disease-resistance by ant, fungus, and auxiliary microbes. The research integrates a variety of experimental approaches within an ecological-genetics and quantitative-genetics framework, contributing towards a unification of ecology and evolutionary biology. Inheritance of auxiliary microbes between generations occurs in diverse hosts, including humans, but the importance of communities of auxiliary microbes in their contribution to the health of a host is incompletely understood. This research develops novel experimental approaches to elucidate the role of auxiliary microbe communities in disease suppression. Because microbial communities also confer disease resistance for humans (e.g., the microbiome of human skin or gut) and for crops (e.g., the microbiome of roots), this research on fungus-growing ants will contribute to the understanding of general microbial principles with applications to human and agricultural disease management. Fungus-growing ants and their microbes will also be used to promote education of students and the public on the importance of ecological, evolutionary, and all biological processes. A postdoctoral researcher and multiple undergraduates will be trained and mentored in this research project.