(3E,5Z)-Octadien-2-ol is an Aggregation-Sex Pheromone Produced by Males of the Queensland Longhorned Beetle, Acalolepta aesthetica (Olliff 1890)

Abstract We describe the identification, synthesis, and field testing of an aggregation-sex pheromone produced by male Acalolepta aesthetica (Olliff 1890) (Coleoptera: Cerambycidae: Lamiinae), a cerambycid beetle native to Australia that has recently become established in Hawai‘i. Comparing extracts of headspace volatiles from both sexes revealed that males emitted two sex-specific volatiles, (3 E ,5 Z )-octadien-2-ol and (3 E ,5 Z )-octadien-2-one. Both compounds were synthesized and their bioactivity was tested in field bioassays. Only (3 E ,5 Z )-octadien-2-ol was attractive to beetles of both sexes in these trials, and the corresponding ketone appeared to antagonize attraction when combined with the alcohol. In a dose-response study, traps baited with all doses of (3 E ,5 Z )-octadien-2-ol except 33.3 mg captured more beetles than solvent-control traps, with no significant differences among the effective doses. In a subsequent field trial, beetle capture did not differ between 100 mg of a racemic blend and the insect-produced ( R ) - enantiomer of this compound, indicating that the unnatural ( S )-enantiomer is not antagonistic. No other cerambycid species were captured during our field trials. The structural motif of (3 E ,5 Z )-octadien-2-ol is unique among pheromones identified from lamiines to date. Together, our findings provide a foundation for developing pheromone-based tools to detect, delimit and potentially manage A. aesthetica .