Aggregation Pheromone of Pityokteines elegans

In laboratory bioassay experiments, the beetles Pityokteines elegans were attracted to volatiles captured from bolts of grand fir, Abies grandis, colonized by P. elegans males. Male-specific volatiles detected by coupled gas chromatographic–electroantennographic detection (GC-EAD) analysis and by GC–mass spectrometry employing a chiral column were: (S)-(?)-ipsenol, (+)- and (?)-ipsdienol, and ipsenone. Field experiments demonstrated that 1:1 combinations of (?)-ipsenol and (±)-ipsdienol strongly attracted insects of both sexes to multiple-funnel traps. No beetles were attracted to any of these compounds alone, and both enantiomers of ipsdienol were required with (?)-ipsenol to induce attraction. Ipsenol and ipsdienol are now reported as pheromones of five Pityokteines species. Specificity of semiochemical-based communication between sympatric P. elegans and P. minutus appears to be based on host preference and on the composition and chirality of the pheromone blend.