Slanted Science

Hot on the heels of the news that bacteria in human guts make us fat comes this: scientists have shown that leafcutter ants also use the single-celled critters to give them some otherwise inacessible nutrients. They apparently use the bacteria’s ability to fix atmospheric nitrogen into a biologically usable form. Clever little fellas, eh?
The element nitrogen is absolutely indispensable to life; it’s a part of every protein, for starters. It’s also the most abundant elemnt in the atmosphere, accounting for almost 80% of air. But multicellular organisms – plants, fish, birds, you and me – cannot use the massive amounts of nitrogen which we take in with each breath. To get ours, we have to eat things which have already incorporated the gas into their bodies. As the authors of this study put it:

“Nitrogen is a limiting resource. If you don’t have it, you can’t survive.”

Well, it’s been known for some time that leafcutter ants rely on fungi to feed them. The ants bring foliage back to their nest, but are unable to digest it. They then act as farmers, cultivating a fungal species which will break down the indigestable leaves into a mush which the ants can eat.

What wasn’t known was where the fungal farmhands get their nitrogen from (as they can’t fix it from atmospheric sources). These boffins have shown that the fungi are fed nitrogen by their bacterial neighbors in the big, mushy leaf piles which are the ants’ underground cropfields.

When scientists traced the fate of labeled nitrogen which they fed into a carefully controlled ant colony, they found that the bacterially-fixed nitrogen turned up in the ants’ bodies. Proof that not only did the fungi utilize the bacteria as a nitrogen source, but that the ants themselves were reliant on this system.

Don’t Hold Your Breath, But This Might Lead To: almost certainly some kind of Hollywood health food. We’re picturing celebrities gorging on leafcutter ant mulch, convinced by some charaltan that it is imbued with concentrated nitrogen healing powers.