Farmer ant species may have lost all its males

From Oaxaca, Mexico, at a meeting of the Animal Behavior Society

Minuscule gardeners that grow fungus for food may be the first ant species that scientists have discovered to have no power of sexual reproduction. Several lines of evidence suggest that the species Mycocepurus smithii consists only of females that produce daughters from unfertilized eggs, says Anna Himler of the University of Texas at Austin.

Even standard ant reproduction has some asexual aspects. Worker ants typically don't reproduce but care for the offspring of their queen. The queen lays both fertilized and unfertilized eggs, the latter turning into males.

Scientists already knew of five unusual ant species that produce females from unfertilized eggs, says Himler. In these species, however, occasional males still appear.

In Himler's studies of M. smithii, she collected more than 100 nests without finding a male. A colleague likewise collected some 200 nests but