Attraction of released male Mediterranean fruit flies to trimedlure and an α-copaene-containing natural oil: effects of lure age and distance

Abstract Fruit flies (Diptera: Tephritidae) pose a serious threat to global agriculture, and many countries operate trapping programs to detect incursions of pest tephritids. Surveillance relies heavily on male-specific attractants, termed male lures. Trimedlure is a widely used male lure that targets the genus Ceratitis , which includes the Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann). However, trimedlure is not a potent lure, and alternatives are being developed. Recent trapping studies have shown that a natural oil with an elevated concentration of the sesquiterpene α-copaene is significantly more attractive than trimedlure. The present study further compares the relative attractiveness of trimedlure and this natural oil via release-recapture trials of C . capitata males in a macadamia nut orchard in Hawaii. The experimental design involved the release of male medflies from different distances around a single, centrally located trap. Comparisons of the two lures were based on captures of males released near or far (15 or 30 m) from fresh or aged (weathered < 2 weeks or 10–12 weeks, respectively) lures. For the 15 m releases, fresh trimedlure and fresh natural oil attracted similar numbers of male medflies, whereas traps baited with aged natural oil captured significantly more medflies than traps baited with aged trimedlure. For the 30 m releases, both fresh and aged natural oil-baited traps captured significantly more male medflies than traps baited with comparably weathered trimedlure. Together with the trapping data from wild populations, these release-recapture results suggest that the natural oil lure is a viable replacement for trimedlure.