A Large Male Competitive Advantage in a Lekking Fly, Hermetia Comstocki Williston (Diptera: Stratiomyidae)

This paper describes the mating system of Hermetia comstocki Williston, a stratiomyid fly that, like many other members of the family (Waldbauer, 1984), appears to be a Batesian mimic, in this case of Polistes paper wasps (James, 1935). Little is known about this species other than it occurs in Arizona, New Mexico and Texas (Cole, 1970). In general, not much information exists on the mating behavior of stratiomyids. Females of one species, Inopus rubriceps, which is a pest of sugarcane, have been reported to fly to the lower leaves of the hostplant shortly after emerging; males rush to surround the female although presumably only one male copulates with the female, after which she leaves to oviposit and die (Hitchcock, 1976). In contrast to the scramble competition system exhibited by L rubriceps, I shall document that H. comstocki engages in territorial defense of landmark plants to which females travel to secure a mate. Furthermore, I present data on the role body size plays in the competition among males for possession of mating territories.