ウリミバエの交尾継続時間，卵のふ化率および再交尾間隔についての二，三の知見

Abstract

Mating frequencies and hatchability of eggs laid by females which had mated once were investigated using a wild strain (W) and a laboratory strain (L) (ca. 20 gen.) of the melon fly, Dacus cucurbitae. The hatchability of the eggs laid by the L-females whose copulation was interrupted artificially at various times and remating intervals of these females were investigated also. Mean mating frequencies of the L- and W-males were 0.391 and 0.141/day, respectively, while those of the L- and W-females were 0.054 and 0.031/day, respec-tively. Mean remating intervals of the L- and W-females were 18.2 days and 26.4 days, respectively. The hatchability of the females which had mated once in both strains began to decrease at 40 days after the 1st mating. In this experiment, the mean copulation duration was 10h 40min. The mating interruption experiment showed that a copulation lasting more than 30-min was needed to produce fertile eggs, and more than 80-min to maintain a high hatchability of the eggs. Most of the females which copulated for 0-160-min remated in their 1-2 days after the 1st mating, while the females in which the copulation had not been interrupted remated at ca. 13 days after the 1st mating. Thus, it is concluded that a certain length of the copulation duration may be necessary to inhibit the remating of female melon flies.