9728555 Seybold Bark beetles, which aggregate in large numbers and feed in the living, sugar-transporting tissue of many of our most valued tree species, are the predominant insect pests of conifers in western North America. These insects use odor attractants (pheromones) to gather on and infest the trees. In this project the PIs propose to study how two economically important species of bark beetles, the mountain pine beetle, Dendroctonus ponderosae, and the Jeffrey pine beetle, Dendroctonus jeffreyi, synthesize the mixtures of relatively small lipid molecules that they use as pheromones. The research will utilize a variety of standard biochemical and physiological techniques to reveal the pathways that these insects use as well as how these pathways are hormonally regulated. Key objectives of the study are to determine when in the life cycle the chemicals are biosynthesized and in what region of the body the synthesis occurs. Furthermore, the relationship of pheromone synthesis to the olcorcsin chemistry of the host pines will be examined. Ultimately, this fundamental research on the origin of bark beetle pheromones may identify unique susceptible target points in projection or regulation that could be used for insect control techniques. While it is impossible to predict with any accuracy practical outcomes of this research, it should be emphasized that the only time that the beetles leave their galleries beneath the bark is for the short-duration, pheromone-mediated flight to new hosts.
