Variation of reproductive characters in wild and mass-reared melon flies, Dacus cucurbitae Coquillett (Diptera: Tephritidae)

From the stand point of quality control, experiments were conducted to compare several reproductive characters in wild and mass-reared melon flies, Dacus cucurbitae COQUILLETT. The mass-reared strain used in these experiments was obtained from the mass-rearing culture maintained on artificial diet at the mass-production facility of Okinawa Prefectural Fruit Flies Eradication Project Office. This culture had been reared through about 20 generations from initial laboratory colonization. Individuals of the wild strain were obtained as larvae from infested fruits in fields. The characters compared in these experiments included the pre-oviposition period, total number of eggs oviposited per female flies throughout the lifespan, frequency of oviposition, rate of oviposition (number of flies which oviposited/time when the artificial egging device was set), post-reproductive period, frequency of mating and longevity in male and female flies. The pre-oviposition period, post-reproductive period and longevity in the male and female flies of the mass-reared strain were shorter than those of the wild one. The total number of eggs oviposited throughout the lifespan and the rate of oviposition of the mass-reared strain were higher than those of the wild one. Frequency of oviposition and mating for the mass-reared strain were higher than those for the wild one. The coefficient of variation of the pre-oviposition period, total number of eggs oviposited per female throughout the lifespan, rate of oviposition, post-reproductive period and frequency of mating for the wild strain were higher than those for the mass-reared one. But the coefficient of variation of the pre-mating period, longevity in males and females for both strains showed approximately similar values. It was concluded that the mass-reared strain shows a shorter maturation period, higher fertility, shorter longevity and lower variation in reproductive characters when compared with the wild one.