a1 School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
a2 Tan Hak Heng Co., 20 Jalan Tan Jit Seng, 11200 Tanjong Bungah, Penang, Malaysia
Sex pheromonal components of the tephritid fruit fly Bactrocera dorsalis (Hendel), 2-allyl-4,5-dimethoxyphenol and (E)-coniferyl alcohol, are biosynthesized from a highly potent male attractant, methyl eugenol, then sequestered and stored in the rectal gland prior to their release during courtship at dusk. These sex pheromonal components have been detected in the haemolymph and crop organ. Hence, attempts were made to separate and identify the haemolymph fractions which contained the sex pheromonal components. Identification of these bioactive fractions in methyl eugenol-fed male flies using gel filtration column chromatography and biodetection using live male flies showed two fractions as highly attractive to conspecific males. These fractions show a significant increase in protein absorbance in the elution profile of haemolymph from methyl eugenol-fed males compared with that from methyl eugenol-deprived males. The molecular mass of these bioactive fractions as determined by using gel filtration was in the peptide range of 3.3 to 5.5 kDa. Subsequent gas chromatography–mass spectrometry analyses further confirmed the presence of the pheromonal components in the bioactive fractions. The presence of these methyl eugenol-derived sex pheromonal components in specific haemolymph fractions suggests the involvement of a sex pheromone binding complex.
(Accepted August 05 2005)
c1 *Current address: National Centre for Advanced Bio-Protection Technologies c/o HortResearch, Canterbury Agricultural and Science Centre, Gerald Street, PO Box 51, Lincoln 8152, Canterbury, New Zealand, Fax: +64 3325 6063 E-mail: email@example.com