INSECT AND HOST ODORS IN THE AGGREGATION OF THE WESTERN PINE BEETLE

Abstract

AbstractDendroctonus brevicomis Lec. responded in flight to combinations of insect- and host-produced volatiles. Emergent female beetles crushed at −70 °C, as well as synthetic exo-7-ethyl-5-methyl-6, 8-dioxabicyclo [3.2.1] octane (“brevicomin”) attracted both sexes of the western pine beetle when offered with oleoresin freshly tapped from the host, Pinus ponderosa Laws. Offered separately, these materials were inactive. Crushed emergent Dendroctonus ponderosae Hopk. males per se, however, attracted flying D. brevicomis in appreciable numbers. Dominance of either host odor or insect pheromone appeared to govern the sex ratio of the responding insects.