Behavioral responses of eastern larch beetle (Coleoptera: Curculionidae: Scolytinae) to pheromone components and selected host-produced compounds in the Great Lakes region.

This article focuses on the chemical ecology of the eastern larch beetle (Dendroctonus simplex LeConte) and its natural enemies, particularly examining how host resin odors and pheromone components influence beetle and predator behavior during outbreaks in Minnesota. Field assays demonstrated that the host monoterpene ∆-3-carene combined with the female-produced pheromone seudenol significantly increased eastern larch beetle captures, while α-pinene enhanced attraction of their predators, Thanasimus dubius and Thanasimus undulatus. Varying release rates of the pheromone frontalin affected beetle attraction biphasically, with high concentrations reducing beetle captures but increasing predator attraction; laboratory olfactometer assays showed that walking male beetles were arrested by a combination of frontalin and seudenol, whereas females showed no such response. These findings suggest that pheromone and host volatile interactions mediate host and mate location in eastern larch beetles and may inform management strategies by exploiting semiochemical cues.