Kairomonal response by four Monochamus species (Coleoptera : Cerambycidae)to bark beetle pheromones

We investigated the hypothesis that wood-boring beetles in the genus Monoch uamus (Cerambycidae) utilize pheromones of sympatric bark beetles as host-f inding kairomones. All nine bark beetle pheromones tested electrophysiologi cally were antenally active for both sexes of M. scutellatus M. clamator an d M. obtusus from British Columbia. When held-tested with multiple-funnel t raps (British Columbia) or cross-vane traps (Ontario), a blend composed of frontalin, ipsdienol, ipsenol, and MCH, in combination with a blend of host volatiles attracted significant numbers of M. clamator, M. obtusus, M. not atus, and M. scutellatus to baited traps. Traps baited with host volatiles in combination with a second blend composed of endo-brevicomin, exo-brevico min, cis-verbenol, trans-verbenol, and verbenone caught no more beetles tha n unbaited traps or traps baited with the host blend alone. In British Colu mbia, tmp baited with the first blend alone or both blends together capture d more M. scutellatus and M. clamator than unbaited traps, demonstrating a response to bark beetle pheromones in the absence of host volatiles. These results suggest that Monochamus spp, are minimizing foraging costs by using the pheromones of sympatric bark beetles as kairomones.