Flower-feeding affects mating performance in male oriental fruit flies Bactrocera dorsalis


Dr T. E. Shelly, Hawaiian Evolutionary Biology Program, 3050 Maile Way, University of Hawaii, Honolulu, HI 96822, U.S.A.
E-mail: tshelly@hawaii.edu


1. Males of the oriental fruit fly Bactrocera dorsalis are attracted to and feed on flowers of the golden shower blossom Cassia fistula. Flowers of this plant contain methyl eugenol, the metabolites of which apparently function in the synthesis of male sex pheromone.

2. The goal of the study reported here was to determine whether feeding on C. fistula flowers enhanced male mating success. Mating frequencies of unfed (control) and fed (treated) males were compared in trials conducted 0 (same day), 2, 7, or 21 days after treated males were exposed to the flowers. Trials were performed using flowers from three trees of C. fistula to investigate whether the effects of floral feeding were similar among different plants.

3. For all three trees, treated males accounted for a disproportionately large number of matings in trials performed 0, 2, and 7 days after floral feeding by the treated males. For two of the trees, treated males also had a mating advantage 21 days after flower-feeding.

4. Additional tests were conducted to compare female attraction to perch sites of control and treated males. When at a lek, males exhibit rigorous wing-fanning behaviour, presumably to increase dispersal of the sex pheromone. Floral feeding had no significant effect on the level of wing-fanning. Significantly more female sightings were recorded for perches of treated than control males, however, suggesting that the treated males produced a pheromone more attractive to females than did control males.