For approximately 50 million years, fungus-growing ants have been farming fungus for food. Over the evolutionary history of this ancient agricultural association, the ants have diversified into more than 200 species. These ants are divided into five distinct phylogenetic and ecological groups, each with their own favored fungal crops. The evolution of agriculture in ants culminates in the leaf-cutters, which form massive colonies, and have some of the most complex societies of any social insect. This ant-fungus mutualism is also one of the most intricate systems described in nature. As in human agriculture, the ants’ fungal crops are plagued by specialized and coevolved microfungal pathogens. To combat these pathogens, the ants engage in another mutualism with antibiotic-producing actinobacteria. This mutualism, in turn, is exploited by specialized black yeast. Furthermore, just as humans have used bacteria-derived nitrogen to fertilize soils for thousands of years, the ants' gardens also contain nitrogen-fixing bacteria. This ancient association of farmers, crops, pathogens and N-fixers is one of the clearest examples of the ecological and evolutionary dynamics of coevolution and species interdependence.
The Currie Lab is interested in studying the dynamics of this symbiosis, with a particular focus on the interactions that occur between players in the system. We have a number of different ongoing research areas ranging from symbiont interaction studies (e.g., symbiont switching studies, paired symbiont interaction assays, etc.); exploring microbial diversity in the system using metagenomics; understanding the molecular interactions that occur between symbionts (e.g., antibiotics arms race); comparative genomics of coevolution; host-pathogen dynamics; studying the origins of ancient agriculture; behavioral ecology; and population genetics.
Click on an area to learn more about the research in our laboratory.