Natural history and phylogeny of the fungus-farming ants (Hymenoptera: Formicidae: Myrmicinae: Attini)

Ants of the tribe Attini comprise a monophyletic group of approximately 230 described and many more undescribed species that obligately depend on the cultivation of fungus for food. In return, the ants nourish, protect, and disperse their fungal cultivars. Although all members of this tribe cultivate fungi, attine ants are surprisingly heterogeneous with regard to symbiont associations and agricultural system, colony size and social structure, nesting behavior, and mating system. This variation is a key reason that the Attini have become a model system for understanding the evolution of complex symbioses. Here, we review the natural-history traits of fungus-growing ants in the context of a recently published phylogeny, collating patterns of evolution and symbiotic coadaptation in a variety of colony and fungus-gardening traits in a number of major lineages. We discuss the implications of these patterns and suggest future research directions.