AGGREGATION PHEROMONE OF THE AFRICAN RHINOCEROS BEETLE, ORYCTES MONOCEROS (OLIVIER) (COLEOPTERA, SCARABAEIDAE)

Ethyl 4-methyloctanoate is a male-produced aggregation pheromone of th e African rhinoceros beetle, Oryctes monoceros (Olivier). It was ident ified by coupled gas chromatographic-electroantennographic detection ( GC-EAD) and coupled CC-mass spectrometry (MS) of Porapak Q-trapped mal e-produced volatiles. Natural and synthetic ethyl 4-methyloctanoate el icited comparable antennal responses. In a field experiment (La Me Res earch Station, Cote d'Ivoire), synthetic ethyl 4-methyloctanoate relea sed at 30 mg/day attracted both male and female Oryctes, whereas the k nown, non-beetle-produced attractant, ethyl chrysanthemate, did not at tract any Oryctes. Upon improvement of trap design and placement, and the identification of synergistic (plant) volatiles, pheromone-based m ass trapping may become an alternative and/or additional strategy to m anage O. monoceros, one of the most destructive pests of commercial co conut, oil, and date palms in Africa.