Electrophysiological and behavioral responses of Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae) to two candidate pheromone components: frontalin and exo-brevicomin

The Chinese white pine beetle, Dendroctonus armandi Tsai and Li, is considered a serious native pest in the Qinling and Bashan Mountains of China. Relatively few information is available regarding its pheromone characterization, and the functions of its pheromones have not yet been identified. Gas chromatographic and mass spectrometry (GC–MS) analyses of volatiles collected from live D. armandi revealed that (1) virgin female and mated male but not mated female D. armandi produce frontalin and (2) female but not male beetles produce exo-brevicomin. Electroantennography (EAG) and Y-tube laboratory assays indicated that male D. armandi are more sensitive to frontalin and frontalin + α-pinene, whereas female D. armandi are more sensitive to frontalin + α-pinene and exo-brevicomin. These results support frontalin as a virgin female-produced sex pheromone, and frontalin + α-pinene as a virgin female and mated male-produced aggregation pheromone. Furthermore, different concentrations of exo-brevicomin have aggregation and anti-aggregation roles in female D. armandi. This study provides evidence for classifying the two compounds as certain types of pheromones and indicates that these pheromones have clear potential value for monitoring and controlling the outbreak of this serious pest.