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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Three's Company Down on the Ant Farm
17 January 2003 (All day)
One of nature's oddest partnerships exists between certain ants and the fungi they cultivate. Now, researchers have found a third player in this collaboration, a pathogen that infects the fungi. Moreover, the pathogen has been associated with the two for as long as the ants have tended their moldy crop. This is one of the first demonstrations of a long-term, three-way relationship.
Attine ants, which include leaf-cutters that can defoliate a tree in one night, can't digest plant matter themselves and instead retrieve it as fodder for the fungi. In return, the fungi supply the ants with nutrient-filled threads. But infection by a microfungus called Escovopsis can reduce the size of the “farm” and of the ant workforce. Sometimes it can even destroy an entire colony.
The ants and fungi have been together for 50 million years, maintaining their tight association even as new ant species arose. Cameron Currie of the University of Kansas, Lawrence, has now shown that over that same time, the pathogen has been as tightly entwined with the ant and the fungi as they have been with each other.
To trace the pathogen's history, Currie and his colleagues analyzed DNA from 17 strains. The resulting evolutionary tree pointed to a common ancestor that dated back to the days of the first cultivation of fungi by ants, he reports in the 17 January issue of Science. Today, there are four lineages of the microfungus, and each is associated with a particular ant-fungi system.
“It looks to me as if the pathogen was locked into the relationship” early on, notes Daniel Janzen, an evolutionary biologist at the University of Pennsylvania in Philadelphia. All in all, Janzen adds, “it's a nice, clean example” of coevolution.