Field responses of the western pine beetle1 and one of its predators to host- and beetle-produced compounds

The responses of the western pine beetle (Dendroctonus brev-icomis LeConte) andTemnochila chlorodia (Mannerheim) to candidate attractants—exo- andendo-brevicomm, frontalin,trans-verbenol, ver-benone, and ponderosa pine turpentine and its major monoterpene components—were quantified by counts of beetles on traps baited with the various attractants, singly and in combinations released simultaneously. Combinations ofexo-brevicomin and frontalin plus a monoterpene or turpentine were the most attractive toD. brevicomis. The responses to these attractant combinations were reduced when verbenone plustrans-verbenol were present. All single compounds and binary mixtures, exceptexo-brevicomin plus frontalin, were much less attractive.exo-Brevicomin was most attractive toT. chlorodia, and this response appeared to decrease when verbenone plustrans-verbenol were present.Coleoptera: Scolytidae.Coleoptera: Trogositidae.This research was supported in part by the Forest Service, U.S. Department of Agriculture, and in part by grants from the Rockefeller Foundation to the University of California. Commercial enterprises and products are mentioned solely for information, and do not imply endorsement by the sponsoring agencies and organizations.