Does the imported cabbageworm,Pieris rapae, use an oviposition deterring pheromone?

Eggs ofPieris rapae (L.) contain a water- and methanol-soluble oviposition-deterring pheromone (ODP) that is avoided by ovipositing females offered treated and untreated cabbage leaves in a choice situation. Water extracts of female accessory glands also deter oviposition. Egg washes and gland extracts stimulate a contact chemoreceptor in sensilla on the fore tarsi. Electroantennogram (EAG) recordings show that antennal receptors respond to volatiles from conspecific eggs, but not to volatiles from eggs ofMamestra brassicae. No differences were detected between North American and European insects with regard to production and perception of ODP. These results differ from conclusions in the literature based upon field observations. It is concluded that this discrepancy in due to methodological differences.