Site fidelity and long-distance homing by males of solitary parasitic wasps (Hymenoptera: Scoliidae)

Site fidelity and long-distance homing are known to occur in nesting female Hymenoptera. We report here on the site fidelity and homing ability in males of five species of scoliid wasps (Hymenoptera: Scoliidae), a group whose females do not make nests but are ectoparasitoids of scarabaeid beetles (Coleoptera: Scarabaeoidea). The males of these wasp species patrol female emergence areas searching for mates. Based on mark-recapture data, we found that between 40% and 100% of marked males left the release area and travelled 50-800 m from the point of capture returning to their original patrol area. We discuss the adaptive significance of site fidelity and homing behaviour in Scoliidae, and propose hypotheses about the evolution of the homing behaviour in Hymenoptera. The homing ability of these primitive Aculeata may represent a case of convergent evolution with other Hymenoptera in which males patrol emergence areas in search of females. Additionally, this homing ability may serve as a preadaptation for the evolution of nest-provisioning and nesting habits in Hymenoptera.