Notebook

ANTSY ANTIBIOTICS Humans didn't invent self-medication. Ants got into the act 50 million years ago. The attine ants are expert gardeners, cultivating edible fungi in subterranean "mushroom farms" on food harvested above ground. The most famous attines are the leaf cutters, whose superorganismlike colonies of several million ants are organized into functional castes led by a queen (B. Hölldobler and E.O. Wilson, Journey to the Ants, Harvard University Press, 1994). Their prodigious harvesting of leaves to feed the fungi, and the soil they turn over building the colony, are important in tropical ecosystem dynamics. But there's a fly in the ointment: Another fungus, called Escovopsis, parasitizes the farms. What's a poor ant queen to do? According to graduate student Cameron Currie and colleagues at the Smithsonian Tropical Research Institute, Panama, and the University of Toronto, Canada, like many a parent she insists on antibiotics (C.R. Currie et al., "Fungus-growing ants ...