Intra-Annual Variation in Responses by Flying Southern Pine Beetles (Coleoptera: Curculionidae: Scolytinae) to Pheromone Component endo-Brevicomin.

The southern pine beetle Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) is attracted to an aggregation pheromone that includes the multifunctional pheromone component endo-brevicomin. The effect of endo-brevicomin on attractive lures varies from strong enhancement to reduction of beetle attraction depending upon release rate, lure component spacing, and proximity of beetle infestations. Anecdotal observations have further suggested that the effects of endo-brevicomin vary during the year.

Characterization of an aggregation pheromone in Hylesinus pruinosus (Coleoptera: Curculionidae: Scolytinae).

We conducted laboratory and field bioassays to characterize the pheromone system of an ash bark beetle, Hylesinus pruinosus Eichhoff (Coleoptera: Curculionidae: Scolytinae). Solitary females in newly initiated galleries in ash logs produced (+)-exo-brevicomin, whereas male beetles paired with females produced (+)-endo-brevicomin, lesser quantities of (+)-exo-brevicomin, and a third compound that could not be identified. Beetles produced these compounds also after exposure to juvenile hormone III, and they were the sole volatile chemicals isolated from beetles or aerations of infested logs that elicited electrophysiological responses from antennae of either sex.