Evidence of an undescribed species of Dendroctonus bark beetle in southern Mexico

The southern pine beetle, Dendroctonus frontalis Zimmermann is a serious pest of pines that occurs throughout the southeastern United States and from Arizona south to Central America. We present evidence that D. frontalis in Chiapas Mexico often cohabits the same trees with a yet-undescribed species that has previously been classified as D. frontalis based on seminal rod morphology. This species is distinguished from D. frontalis by cuticular hydrocarbon composition, pheromone composition, host partitioning, and subtle differences in morphology (including that of the seminal rod). Crossing studies between Dendroctonus sp. nov. and D. frontalis revealed reproductive incompatibilities. Given the apparent capacity of the undescribed species to attack vigorous trees, it may play a role in pine mortality that previously has been attributed solely to D. frontalis.