Wednesday, March 24, 2010

could ants hold the key to sustainable agriculture?

Wired | Crop monocultures are bad. How, then, has the world’s most successful herbivore thrived by exploiting a single cloned crop?

That conundrum is posed by the leafcutter ant, which harvests more greenery than any other South American animal and uses the vast plantfall to feed the fungi gardens on which they subsist.

But while other ant farmers plant a variety of fungus species, leafcutters sow just one, and they propagate it through cloning. That seems to contradict a tenet of sustainable farming: monocultures are bad, as their lack of genetic diversity leaves them vulnerable to disease and disruption.

How have leafcutters managed this trick? And could they teach us how to make our own agriculture sustainable?

At present, the land provides us with enough to eat — but that might not last. Many agronomists say the clock is ticking on the bounties of the Green Revolution, which depended on fossil fuel-fueled pesticides and fertilizers, as well as soil-wearying techniques and the establishment of vast monocultures.

With the Earth’s population booming and nearly every farm-friendly acre already exploited, keeping our farms running is a looming concern. And for inspiration, says Smithsonian Institution entomologist Ted Schultz, we might look to the leafcutter ant, which despite its reliance on a single crop represents the apex of ant agriculture.

I talked this morning with Schultz, who co-authored a recent Proceedings of the National Academy of Sciences paper on the evolutionary history of ant farming. Schultz described a complex evolutionary dance: the leafcutter fungi is constantly threatened by disease. At the same time, bacteria living on ant exoskeletons produces a disease-killing antibiotic. But somehow the system has stabilized, preventing pathogens from ever raging out of control.