Ants use bacteria to grow gardens

Ants are definitely most amazing creatures, and there’s so much we could learn from them I wouldn’t even know where to start. But even so, there are many things we have yet to find about them. Leaf cutter ants are one of the most remarkable species, and scientists have recently found a new quality (or ’skill’, if you wish) to add to their list: they use nitrogen-fixing bacteria to make their gardens grow. You know who else does this? Humans.

The finding was reported on 20 November in Science by bacteriologist Cameron Currie from the University of Wisconsin-Madison and analyzes a previously unknown (and awesome) symbiosis between ants and bacteria, and provides a totally new insight on leaf cutter ants and how they managed to be the dominant ant species in the American tropics and subtropics.

“Nitrogen is a limiting resource,” says Garret Suen, a UW-Madison postdoctoral fellow and a co-author of the new study. “If you don’t have it, you can’t survive.”

Indeed, this ‘business relationship’ allows the ants to be impressively successful, while the bacteria thrives too.

“This is the first indication of bacterial garden symbionts in the fungus-growing ant system,” says Currie, a UW-Madison professor of bacteriology.

The fungus growing ants are technically herbivores, but without the bacteria, there is absolutely no way they could get the necessary nutrients.

“Without nitrogen, there is no way these guys could achieve such large colony sizes. These ants are one of the most dominant insects in the Neotropics. The ability to have colonies with millions of ants is predicted to require a tremendous amount of nitrogen.”