Douglas-fir beetle (Coleoptera: Curculionidae) response to single-point-source 3-methylcyclohex-2-en-1-one (MCH) releasers

The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (Coleoptera: Curculionidae) antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), has been used since 2000 to protect high-value trees and stands throughout western North America. Operational treatments involve placing individual releasers on a 12 m × 12 m grid throughout the area to be protected. In this study, six widely spaced trap lines were established with aggregation attractant–baited traps located 1, 3, 9, 27, and 81 m from a location where an operational MCH release device was alternately either present or absent, and changes in catches caused by the MCH device were assessed at all distances. Trap catches were suppressed by about 70% at one and three metres, by 50% at nine metres, by 30% at 27 m, and not at all at 81 m. Inhibition by the MCH device varied with distance (m) from the source according to the function 0.79 − 0.092x0.51 (R 2 = 0.986). Decline of attractant inhibition with distance from the MCH device was much less steep than would have been expected if catch inhibition had varied directly with the average airborne concentration of MCH.

Field Screening of Known Pheromone Components of Longhorned Beetles in the Subfamily Cerambycinae (Coleoptera: Cerambycidae) in Hungary

Five compounds known to be pheromone components of longhorned beetles (Coleoptera: Cerambycidae) in the subfamily Cerambycinae were fi eld-tested as attractants and possible pheromones for the cerambycid fauna of Hungary. Nine cerambycid species were caught in baited traps. Large numbers of both sexes of the cerambycine species Molorchus umbellatarum Schreb. were caught in traps baited with (2R*,3S*)-octanediol, while the diastereomeric (2R*,3R*)-octanediol was to some extent attractive as well. This is the fi rst report on an aggregation attractant and a likely pheromone for a species in the cerambycine tribe Molorchini. The results of our study support the hypothesis that the diol/hydroxyketone pheromone motif is characteristic of and highly conserved within the subfamily Cerambycinae. Intraspecifi c chemical communication is summarized for the subfamily Cerambycinae, and possible links between taxonomy, insect behaviour, and pheromone structures are described