Preemergence mating in the mass-attacking bark beetle,Dendroctonus ponderosae(Coleoptera: Curculionidae)

Abstract

AbstractThe mountain pine beetleDendroctonus ponderosaeHopkins (Coleoptera: Curculionidae) kills its hosts by attackingen masseand overwhelming tree defences. Young adult beetles completing development under the bark may have the opportunity to mate with siblings or with brood from adjacent galleries prior to emerging from the natal host tree. We investigated the incidence of preemergence mating among female beetles at two locations in the recently expanded range of the insect in northern Alberta, Canada. Female beetles emerging from under the bark late in the emergence period were more likely to be mated upon emergence than beetles that emerged earlier. Delaying emergence of brood adults once they were at the teneral adult stage had little effect on the incidence of preemergence mating. The frequency of preemergence mating varied from 3–12% among female beetles. This is higher than the 1–2% reported in other studies within the historic range of the mountain pine beetle. Reasons for these differences are discussed.