So…you think humans are the only critters who farm and garden? Think again. From a Science in Brief column in yesterday’s LA Times comes this about ants:

Study finds ants longtime farmers

Ants took up farming some 50 million years ago, according to researchers who traced the ancestry of farmer ants.

An analysis of the DNA of farmer ants traced them back to an original ancestor — a sort of Adam ant, at least for the types that raise their own food, according to a paper published in the online edition of Proceedings of the National Academy of Sciences.

In the last 25 million years, ants have developed different types of farming, including the well-known leaf-cutter ants. Leaf-cutter ants don’t eat the leaves they collect. Instead, they grow fungus on the leaves and eat the fungus.

Only four types of animals are known to farm for food — ants, termites, bark beetles and, of course, humans. All four cultivate fungi.

If you have online access to that journal, you can read the full article at: http://www.pnas.org/cgi/reprint/0711024105v1. There’s no research on whether ants prefer to create formal gardens or naturalistic ones, though I’d guess aesthetics aren’t hight on their list of concerns.

To that, I’d also add that some ants are also livestock farmers in that they cultivate other animals. Aphids and ants have a symbiotic relationship, with ants tending aphids to share in the sweet nectar they exude. And all last year we had a major ant trail leading from the ground into the grapefruit tree, where ants and scale insects had set up shop on the skins of the young grapefruits. It didn’t seem to affect the grapefruits too much, though we always had to remember to scrub them clean before serving them up. Here’s a link to a related story on ants and scale insects in tropical coffee plantations.