Dose-dependent and species-specific responses of pine bark beetles (Coleoptera: Scolytidae) to monoterpenes in association with pheromones

Monoterpenes affected the attraction of three sympatric species of bark beetles (Coleoptera: Scolytidae) to pheromone-baited multiple-funnel traps in stands of lodgepole pine. Catches of Ips pini (Say) in traps baited with its pheromone, ipsdienol, were directly related to the release rates of 3-carene, pphellandrene, and ppinene. Catches of Dendroctonus ponderosae Hopkins in traps baited with exo-brevicomin and cis- and trans-verbenol were directly related to the release rates of 3-carene, myrcene, and pphellandrene. Zps Zatidens (LeConte) exhibited prefer-ences for traps baited with ipsenol and Pphellandrene or P-pinene but not in a dose-dependent fashion. Catches of I. latidens in traps baited with its pheromone, ipsenol, were inversely proportional to the release rates of 3-carene, myrcene, and terpinolene. Similarly, catches of I. pini in traps baited with its pheromone, ipsdienol, were inversely proportional to the release rates of myrcene and terpinolene. These results demonstrate a degree of species specificity among three phloeophagous species with respect to preferred host odours. The bark beetle preda-tors-associates Lusconotus complex LeConte (Coleoptera: Colydiidae) an