Relationship of sexual maturation rate to response of oriental fruit fly strains (Diptera: Tephritidae) to methyl eugenol

Laboratory-reared and wild, fruit-reared adults of the Oriental fruit fly,Dacus dorsalis Hendel, were tested for response to methyl eugenol at various ages. Virgin laboratory (2, 4, 6, 8, and 10 days old) and wild (7, 11, 15, 19, and 23 days old) flies were released into an outdoor field cage and trapped over a two-day period. Response of males increased with age as ca. 32% and 22% of laboratory and wild males responded at 2 and 7 days of age, respectively, while ca. 93% of both strains responded at 10 and 23 days of age, respectively. These correspond approximately to the ages at which they reach sexual maturity. Female response did not increase with age and fluctuated between 15% and 29% for the laboratory strain and 10% and 45% for the wild strain. The age-related response profiles, when integrated with sexual maturation curves, indicate that one of the major reasons the male-annihilation technique is effective is because methyl eugenol is able to attract 40–50% of male flies prior to the onset of sexual maturation.