Pheromone communication and mating behaviour of coffee white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae).

This study investigated pheromone communication and mating behaviour of the coffee white stem borer (CWSB), Xylotrechus quadripes (Coleoptera: Cerambycidae), in South Yunan, China. Coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric (MS) analyses of volatiles released by male and female CWSB identified 2-hydroxy-3-decanone and 2,3-decanedione as male-specific candidate pheromones. Further GC-EAD and GC-MS analyses confirmed that only (S)-2-hydroxy-3-decanone is produced by male CWSB and elicits antennal responses by male and female CWSB. In field experiments, 2-hydroxy-3-decanone as a trap bait afforded capture of one female CWSB, and in laboratory experiments it weakly attracted female but not male CWSB. Complex mating behaviour in CWSB includes: 1) attraction of potential mates by both sexes; 2) repeated landings (with ever decreasing distance) of a female next to a male; 3) males dashing to a nearby female; 4) rejection of mating attempts by females; 5) post-mating female guarding by males; and 6) size-dependent mating success of males. Considering this complex mating behaviour, lack of direct flight towards pheromone sources, mating near pheromone-baited traps, and only moderate attractiveness of (synthetic) pheromone, pheromone-based trapping of females does not seem to be a viable strategy for managing CWSB populations in China.