Secondary attraction and field activity of beetle-produced volatiles inDendroctonus terebrans

Controlled infestation ofDendroctonus terebrans (Olivier) on bolts of slash pine,Pinus ellionii Engelm. var.elliottii, elicited greater attraction of wild conspecifics than uninfested bolts. Secondary attraction was not apparent, however, to standing slash pines that had received volunteer attacks, when compared with attraction to unattacked but susceptible trees. Hindguts from in-flight or attacking femaleD. terebrans contained frontalin, and those from in-flight or attacking males containedexo-brevicomin.Trans-pinocarveol,cis-verbenol,trans-verbenol, myrtenal, verbenone, myrtenol, and other compounds were produced by both sexes during gallery construction in host trees. Synthetic frontalin, when deployed with a standard host odor mixture of turpentine and ethanol, was very attractive to maleD. terebrans in field-trapping experiments. The addition of eitherexo-brevicomin orendo-brevicomin to the frontalin-turpentine combination negated the attractive effect of frontalin for males.Trans-verbenol, myrtenol, and verbenone had little effect onD. terebrans behavior. Responses of females did not differ among treatments in any of the 11 field experiments.