Gustatory Cues in the Orientation of Dendroctonus Ponderosae (Coleoptera: Scolytidae) to Host Trees

Female mountain pine beetles, Dendroctonus ponderosae Hopkins, were exposed to papers soaked in outer bark extracts of lodgepole pine, Pinus contorta Douglas var. latifolia Engelmann. Both benzene and methanol–water extracts elicited greater feeding activity than did controls. Non-polar host compounds exhibited greater incitant (initiation of feeding) properties, while polar compounds were more powerful stimulants (continuation of feeding). No differences were detected in feeding on extracts from resistant or susceptible trees. Repellency appears to be associated with beetle responses to active host metabolism.