CHIRAL SPECIFICITY IN RESPONSES BY THE BARK BEETLE DENDROCTONUS-VALENS TO HOST KAIROMONES

The attraction of the red turpentine beetle, Dendroctonus valens, to the resin volatiles of its host, Pinus ponderosa, is elicited by three chiral monoterpenes. In field assays response was greatest to (S)-(-)-beta-pinene; 92% (S)-(-)-alpha-pinene found in P ponderosa resin was not attractive. However, 75% (R)-(+)-alpha-pinene, which occurs in Pinus lambertiana, a sympatric host of D. valens, was attractive. (S)-(-)-alpha-Pinene interrupted response to (R)-(+)-alpha-pinene. (S)-(+)-3-Carene from both hosts was attractive at the (R)-(+)-alpha-pinene level. Three sympatric coniferous nonhosts each have the same attractive monoterpenes but produce less resin. These studies demonstrate the importance of chirality of host compounds in the host finding behavior of this bark beetle.