Mechanism of Egg Recognition by the Cowpea Weevil Callosobruchus maculatus

Several experiments were conducted to determine the mechanism by which ovipositing cowpea weevils, Callosobruchus maculatus (F.), avoid egg-laden seeds. Deterrence was associated with the egg itself and not with other adult activities on the host. Both chemical and physical (tactile) stimuli appear to be involved in egg recognition; the chemical deterrent was more soluble in methanol than in ether or water. Contrary to a previous study using C. chinensis (L.), we found that females were not deterred from ovipositing on seeds that had been exposed to high densities of males