WASHINGTON (AP) -- 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 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, according to entomologists Ted Schultz and Sean Brady at the Smithsonian's National Museum of Natural History.
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, people. All four cultivate fungi.
By studying the fungus-growing ants the researchers hope to learn more about the development of ant agriculture.