Phanaeus Behavior:2 Food Transportation and Bisexual Cooperation1

Abstract

Food collection and pairing habits of 3 Mexican species of Phanaeus are examined. In Phanaeus, dung is usually buried near the animal dropping, but P. daphnis Harold, P. mexicanus Harold and P. palliatus Sturm very often reduce the effects of inter-specific competition with other Scarabaeinae by rolling a piece of dung a considerable distance away from the animal dropping. This behavior assists in the formation of bisexual couples because males are attracted to females who are rolling a ball of dung. The newly formed couple works together in the construction and provisioning of a burrow, but their relationship is not sexual until ovarian maturation occurs. Most individuals of P. palliatus and many of the other 2 species dig burrows under or near the edge of the dropping; such burrows are usually occupied by a single individual of either sex, not by a bisexual couple. Nidification is always distinct from the formation of burrows for shelter and food storage and seems to be stimulated solely by ovarian maturation. The construction of a burrow (“home”) by a bisexual couple in either P. daphnis of P. mexicanus is considered an example of incipient subsocial behavior. With the concurrent reduction in competition, more individuals can feed on a single dropping, the excrement is dispersed more rapidly and over a wider area, and flies do not have a chance to breed in the dung.