An oviposition-stimulating factor in the male accessory reproductive gland of the locust, Locusta migratoria

The data derived from mating experiments demonstrate that mating has an accelerating effect on oviposition in the female Locusta migratoria. The effect of mating could be mimicked by injection of extracts of the male accessory reproductive gland. The oviposition-stimulating factor was localized in the opalescent gland of the male accessory gland and was transferred to the female via the spermatophore during copulation. Gel filtration of an extract of the opalescent gland revealed a 13,000 Da protein, which, when injected into virgin female locusts, could stimulate the oviposition rate to that seen in mated females. Extracts of the corpus cardiacum also stimulated oviposition when injected into virgin female locusts. This increase was not observably different from that seen after mating. The relevance of these findings will be discussed.