Sex Pheromones of Two Melittini Species, Macroscelesia Japona and M. Longipes: Identification and Field Attraction

Two Melittini species, Macroscelesia japona and M. longipes (Lepidoptera: Sesiidae), are native to Japan, but occupy different localities as their host plants seldom grow together. The contents of the sex pheromone gland of adult females of both species, obtained after rearing larvae collected from the field, were investigated by gas chromatograph-electroantennogram detection (GC-EAD) and gas chromatograph-mass spectrometry (GC-MS) analyses. Two GC-EAD-active components were found in a crude extract of M. japona female pheromone gland, and identified as (2E,13Z)-2,13-octadecadien-1-ol (E2,Z13-18:OH) and (2E,13Z)-2,13-octadecadienal (E2,Z13-18:Ald). The average ratio of these two components was about 1:10. In the field, M. japona males were attracted to traps baited with E2,Z13-18:Ald alone, but the strongest attraction was observed with a 1:100 mixture of E2,Z13-18:OH and E2,Z13-18:Ald. The same two components were found in extracts of M. longipes females, but in a markedly different ratio. Male M. longipes were attracted most strongly to lures containing a 20:1 mixture of E2,Z13-18:OH and E2,Z13-18:Ald, although some males were also attracted to lures with E2,Z13-18:OH alone. Although the two species do not generally occur in sympatry, our data indicate that, in the event of overlap, cross attraction of the two species is unlikely.