Feeding on Methyl Eugenol and Fagraea berteriana Flowers Increases Long-Range Female Attraction by Males of the Oriental Fruit Fly (Diptera: Tephritidae)

Males of the oriental fruit fly, Bactrocera dorsalis (Hendel), are strongly attracted to methyl eugenol. Recent evidence indicates that treated males fed methyl eugenol have higher mating success and signaling (wing-fanning) activity than control (unfed) males. Chemical analyses have further shown that metabolites of methyl eugenol are incorporated into the male sex pheromone, and laboratory tests revealed that, at least over short distances (<2 m), the pheromonal signals of methyl eugenol-fed males are more attractive to females than those of unfed males. The main goal of the present study was to determine whether feeding on methyl eugenol or flowers of Fagraea berteriana A. Gray that contain a methyl eugenol-like compound increases the long-distance attractiveness of male B. dorsalis under field conditions. Male aggregations, composed of either treated or control males, were established on orange trees, females were released from a central point (12 m from the male groups), and male wing-fanning and female visitation were recorded. For both methyl eugenol and F. berteriana flowers, aggregations of treated males had higher wing-fanning levels and attracted more females on both an absolute (total female sightings per male group) and relative (female sightings per wing-fanning male per group) basis than aggregations of control males. In an additional laboratory experiment, males that fed upon F. berteriana flowers were found to be more attractive to females over short distances (<2 m) than control males, consistent with results from other methyl eugenol-containing plant species.