Chemical Composition of Gum Turpentines of Pines XXIX. * *Institute of Forest Genetics, California Forest and Range Experiment Station, maintained by the Forest Service, U. S. Department of Agriculture, in cooperation with the University of California, Berkeley

Composition of Attractant Semiochemicals of North American Species of Dendroctonus Bark Beetles: A Review

“…Host compounds found to influence Dendroctonus attraction (Figure 2) have predominantly been the volatile constituents of host resin, including the monoterpenes alpha-pinene, beta-pinene, 3-carene, terpinolene, limonene, myrcene, and camphene; the phenylpropanoid 4-allylanisole; and n-heptane (produced by Jeffrey pine, Pinus jeffreyi Balf.). Typically, conifer resin contains a blend of volatile compounds, with compound identities and proportions having specific associations with tree species, population, and susceptibility to insect colonization [84,[228][229][230][231][232][233][234]. Ethanol is a general attractant for bark and ambrosia beetle species that require weakened hosts for reproduction [235][236][237][238], and of the three Dendroctonus species that respond to ethanol (D. valens, D. terebrans, and D. pseudotsugae) only the final is considered aggressive within its native range.…”

“…Typically, certain, individual host resin constituents have stronger attractive effects than others, but there may be limited correspondence between attractiveness and the predominance of the compound in the resin of host species of the beetle [82,118,193,197,201,244]. The lack of a clear pattern in monoterpene preferences among different Dendroctonus species may be due to the substantial intraspecific variation in resin compositions of conifers [228]. As with the pheromone components, Dendroctonus responses to individual host odors may be influenced by their chirality (as demonstrated with alpha-pinene in several Dendroc-tonus species), with attractive responses sometimes being primarily, or only, to a single enantiomer [201,245,246].…”