Trimedlure and the Mating Competitiveness of Irradiated Male Mediterranean Fruit Flies (Diptera: Tephritidae)

Males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), are attracted to trimedlure, a synthetic lure widely used in monitoring and eradication programs. Previous work with wild males revealed that males exposed to trimedlure had a mating advantage over unexposed males under laboratory conditions. Here, I report the results of experiments that examine whether trimedlure increased the mating competitiveness of irradiated males from a long established, laboratory colony (designated Maui-53 for location and year [1953] founders were field-collected) relative to (unexposed) nonirradiated males from a recently established laboratory colony (designated Maui-95). Maui-95 males achieved a disproportionately large number of matings when tested against unexposed Maui-53 males on field-caged host plants. However, in tests conducted 1 d after exposure, Maui-53 males mated significantly more often than Maui-95 males. In tests conducted 3 and 7 d after exposure, Maui-53 males had the same mating success as Maui-95 males. Additional field studies revealed that both unexposed and exposed Maui-53 males spent more time pheromone-calling than Maui-95 males and consequently attracted greater numbers of females. Exposure to trimedlure resulted in a slight, but nonsignificant, increase in the calling activity of Maui-53 males. Implications of these results for control efforts of C. capitata are discussed.