Western pine beetle: specificity among enantiomers of male and female components of an attractant pheromone.

The flight response of both sexes of Dendroctonus brevicomis to the mixture of myrcene, racemic frontalin, and (1R,5S,7R)-(+)-exo-brevicomin and to the mixture of myrcene, (1S,5R)-(-)-frontalin and racemic exo-brevicomin was significantly greater than the response to the same mixtures in which the antipodes were substituted. The flight response to these two mixtures was also greater than the response to the ternary mixture of myrcene, racemic frontalin, and racemic exo-brevicomin (MFE). The walking response of both sexes to the mixture of myrcene, racemic frontalin, and (+)-exo-brevicomin was not different from the response to MFE. Substitution of the antipode lowered the response when compared to that of MFE. When evaporated with ponderosa pine turpentine, (-)-frontalin was active in the field while its antipode was not.