| Abstract: | Summary. Nine compounds identified from capturedvolatiles of the Douglas-fir beetle, Dendroctonus pseudotsugae,the mountain pine beetle, D. ponderosae, and thespruce beetle, D. rufipennis, that elicited antennal responsesin males and females of one or more of these species weretested in the field to determine behavioural activity.1-Octen-3-ol, found in the volatiles of females of all threespecies decreased the response of male and female coastaland male interior D. pseudotsugae and both sexes of D. ponderosaeto their aggregation pheromones. Acetophenone,identified in the volatiles of females of all three species,significantly decreased the response of interior femaleD. pseudotsugae. trans-Verbenol, a potent aggregationpheromone of D. ponderosae, decreased the response of bothsexes of D. pseudotsugae, while 3-methyl-2-cyclohexen-1-one (MCH), the antiaggregation pheromone of D. pseudotsugae and D. rufipennis decreased the response of both sexesof D. ponderosae. While it has been demonstrated that semiochemicalmediated interspecific communication occursamong bark beetles infesting the same host, this studydemonstrates that beetles can perceive signals emitted byheterospecifics attacking nonhosts and can potentially usethem to avoid attacking the wrong species of conifer. |
