Electrophysiological and Behavioral Responses of Dendroctonus valens (Coleoptera: Curculionidae: Scolytinae) to Candidate Pheromone Components Identified in Hindgut Extracts

The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a serious, exotic pest of pines in China that was introduced from North America during the 1980s. Relatively little is known of its pheromone biology. In our studies, gas chromatographic and mass spectral (GC-MS) analysis of hindgut volatiles revealed the presence of trans-verbenol, cis-verbenol, myrtenol, myrtenal, and verbenone, which are frequently reported pheromone compenents of Dendroctonus spp. Subsequently, bioactivity trials were conducted in the laboratory and field for three oxygenated monoterpenes: trans-verbenol, myrtenol, and myrtenal. Electroantennogram tests indicated that D. valens possess olfactory sensitivity for these three compounds. Additionally, walking D. valens displayed anemotaxis toward all three compounds in a Y-tube olfactometer. In field tests, both trans-verbenol and myrtenol significantly increased catches of beetles in traps baited with host kairomone [a blend of three host monoterpenes: (+)-α-pinene, (−)-β-pinene and (+)-3-carene]. These conspecific-produced attractants may have a role in D. valens chemical communication. Although the appropriateness of classifying these compounds as pheromones is still uncertain, these compounds clearly have potential for use in management of this serious pest.