Pheromone components and diel periodicity of pheromonal communication in Lymantria fumida

Extracts of pheromone glands from female Lymanitria furnida were analyzed b y coupled gas chromatographic-electroantennographic detection (GC-EAD) and by coupled GC-mass spectrometry (MS). The two compounds that elicited respo nses from male L. furnida antennae were identified as cis-7,8-epoxy-2-methy loctadecane (disparlure) and 2-methyl-Z7-octadecene (2me-Z7-18Hy). Field ex periments in northern Japan demonstrated that synthetic (7R,8S)-cis-7,8-epo xy-2-methyloctadecane [(+)-disparlure] and 2me- Z7-18Hy are synergistic sex pheromone components of L. fumida. (7S,8R)cis-7,8-Epoxy-2-methyloctadecane [(-)-disparlure] had no behavioral effect on male L. fumida. Traps baited with (+)-disparlure and 2me-Z7-18Hy captured male L. fumida between 21:00 a nd 24:00 hr, whereas traps baited with (+)-monachalure [(7R,8S)-cis-7,8-epo xy-octadecane],(+)-disparlure and 2me-Z7-18Hy attracted males of the nun mo th, L. monacha L., between 02:00 and 04:00 hr. Both temporal separation of pheromonal communication and specificity of pheromone blends seem to contri bute to the reproductive isolation of sympatric and coseasonal L. fumida an d L. monacha.