Female Recognition and Sexual Dimorphism of Cuticular Hydrocarbons in Monochamus galloprovincialis (Coleoptera: Cerambycidae)

Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is the European vector of the pine wilt nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, which causes the pine wilt disease. A series of experiments were carried out to determine the existence of a contact pheromone on the female's cuticle. All males tested tried to copulate with freshly killed females, but none tried to copulate with the same females after they had been washed with hexane. When the hexane extract was reapplied to the extracted females, 50% of the males tried to copulate with them. This shows that females have a contact pheromone on their cuticle that stimulates male copulatory behavior. Cuticular compounds (mainly hydrocarbons) were sampled with solid phase microextraction and solvent extraction. No marked differences between sampling methods were observed. Individual peak analysis revealed that 23 compounds were significantly more abundant in females and eight were more abundant in males. Correspondence analysis found significant differences between the global hydrocarbon profile of male and female M. galloprovincialis. Individually, these compounds represented a small percentage of the total blend. This suggest that males of M. galloprovincialis may distinguish females by a blend of several, not very abundant, compounds that are present in both sexes but in different proportions.