Evolution of attine ant symbioses
Attine ants are major herbivores in the neotropics. The ants cultivate homobasidiomycete fungi in the genus Leucocoprinus (and related taxa), to which they feed leaf material.
Studies by Chapela at al. and Mueller et al. used rDNA sequences to show that there are several lineages of cultivars among the homobasidiomycetes—implying that there have been multiple instances of domestication.>
Free-living forms nested within cultivar clades may represent “escapes” from domestication.
Escovopsis is an ascomycetous fungal pathogen of the ant gardens. A study by Currie et al. suggested that the phylogeny of Escovopsis, the associated ant fungi, and the ants are all congruent. This suggests that the three lineages are co-speciating.
Chapela, I. H., S. A. Rehner, T. R. Schultz, and U. G. Mueller. 1994. Evolutionary history of the symbiosis between fungus-growing ants and their fungi. Science 266:1691-1694.
Currie, C., B. Wong, A. E. Stuart, T. R. Schultz, S. A. Rehner, U. G. Mueller, G.-H. Sung, J. W. Spatafora, and N. A. Strauss. 2003. Ancient tripartite coevolution in the attine ant-microbe symbiosis. Science 299: 386-388.
Mueller, U. G., S. A. Rehner, and T. R. Schultz. 1998. The evolution of agriculture in ants. Science 281: 2034-2038.