The team of scientists who collaborated on this analysis includes Ted Schultz of the Smithsonian's National Museum of Natural History, Bess Wong of the Smithsonian Tropical Research Institute, Cameron Currie and Alison Stuart of the University of Kansas, Stephen Rehner of the U.S. Department of Agriculture, Ulrich Mueller of the University of Texas at Austin, Gi-Ho Sung and Joseph Spatafora of Oregon State University, and Neil Strauss of the University of Toronto.

"The ants, garden fungi, and weeds have all been co-evolving since ant agriculture first got started -- that's around 50 million years of symbiosis," said Dr. Ted Schultz, research entomologist in the Entomology Section of the Smithsonian's National Museum of Natural History.

By studying DNA sequences from ants, garden fungi and fungal weeds, the research team was able to peer millions of years into the past to see how this co-evolutionary system evolved. The researchers learned that the ants, their garden fungi and the parasitic fungal weeds have been living in a co-evolved, complex system for a very long time, probably 50 million years or longer. During that time, they have been locked in a never-ending evolutionary "arms race," in which the ants and garden fungi are perpetually evolving new ways to control the parasitic fungal weeds, and the weeds are perpetually developing new ways to continue to infect fungus gardens.

There is a fourth factor in the ant colonies, a kind of bacteria that the ants cultivate on the outsides of their bodies. These bacteria produce an antibiotic that specifically suppresses the growth of the weed fungi, and the ants use this antibiotic to keep
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Contact: Michele Urie
urie.michele@nmnh.si.edu
202-786-2950
Smithsonian Tropical Research Institute
17-Jan-2003