Infanticide Avoidance by the Granary Weevil, <Emphasis Type="Italic">Sitophilus granarius</Emphasis> (L.) (Coleoptera: Curculionidae): The Role of Harbourage Markers,Oviposition Markers,and Egg-Plugs

In dual choice experiments, adult female granary weevils, Sitophilus granarius L. (Coleoptera: Curculionidae), demonstrated no feeding preference for wheat that had been previously exposed to male and female conspecifics but avoided feeding on grain parasitized with related or unrelated conspecific eggs. Feeding avoidance was lost if egg-parasitized grains possessed an additional unsealed oviposition cavity. Females also preferred to consume artificially damaged grains over undamaged grains. These results suggest that a harbourage-derived feeding deterrent does not exist but an oviposition-derived feeding deterrent does, and that this deterrent protects S. granarius conspecifics from infanticide regardless of their relationship to the adult insect. Egg-plugs may also serve to reduce infanticide by preventing the release of phagostimulatory compounds from oviposition-damaged wheat.