Fungus farming is a fascinating symbiosis that has evolved multiple times in social insects: once in ants, once in termites, and several times in weevils (beetles) from the subfamilies Scolytinae and Platypodinae. The behavior of these "ambrosia beetles"—over 3,000 species—is poorly known, because they live inside galleries in wood, making observation hard. Here, a study focuses for the first time on the division of labor within colonies of ambrosia beetles. The author shows that in Xyleborus affinis, unlike in ants and termites, social behavior such as brood and fungus care is mostly by fertile "helper" females who reproduce alongside their mother, the colony foundress. He also shows that a specialized fungus in the genus Raffaelea is probably the only food source for the larvae.
