Terpene alcohol pheromone production byDendroctonus ponderosae andIps paraconfusus (Coleoptera: Scolytidae) in the absence of readily culturable microorganisms.

Dendroctonus ponderosae Hopkins andIps paraconfusus Lanier of both sexes produced most of their complement of terpene alcohols at normal to elevated levels in the absence of readily culturable microorganisms. However, there was some evidence that microbial involvement may be required by maleI. paraconfusus to produce ipsenol and ipsdienol at normal levels. Increased levels of certain terpene alcohols found in axenically reared or streptomycin-fed beetles suggest that symbiotic microorganisms may be responsible for breaking down pheromones and other terpene alcohols. There was also evidence for microbial involvement in the production of the antiaggregation pheromone verbenone inD. ponderosae. This compound was not produced in quantifiable levels by axenically reared or streptomycin-fed beetles exposed to α-pinene as vapors or through feeding, but was found in wildD. ponderosae exposed to α-pinene through feeding on bolts of lodgepole pine,Pinus contorta var.latifolia Engelmann.