Comparison of Flight Ability between Wild and Mass-Reared Melon Fly, Dacus cucurditae COQUILLETT (Diptera

Comparative studies of flight ability were conducted in one wild and two mass-reared strains of the melon fly, Dacus cucurbitae, using a flight mill. A wild strain collected from the field as larvae was reared for 2 generations on pumpkin fruit. Two mass-reared strains, herein called new and old strains, were reared for about 15 and 51 generations, respectively, in a mass-rearing facility. Although there was wide variety in the duration of continuous flights among individual adults, flies of the wild strain flew longer than those of the two mass-reared strains. In the latter, the average duration of continuous flights reached a peak at an earlier adult age than in the wild strain, and then decreased. In the wild strain, the peak average duration was reached later, but the high level was longer than in the mass-reared strains. The flight velocity of the mass-reared strains was higher than that of the wild strain. No difference in flight ability between the new and old mass-reared strains was observed. Artificial rearing over many generations under laboratory conditions seemed responsible for these results.