抄録
The relationships between radiation dose and mating competitiveness of gama irradiated melon fly males were studies with two methods; those being FRIED'S method and the method of the direct counting of normal and irradiated flies in copula under the coexistence of normal females, normal males and irradiated males.In the former method, the mating competitiveness of irradiated males did not reduced significantly with doses from 1 to 10 kR, but at 30 kR, reduced significantly.In the latter merhod, the mating competitiveness values of males irradiated with 7 and 12 kR were less than unity, but not significant. At 30 kR, the mating competitiveness reduced significantly. It can be said that the harmful effect of irradiation on the mating competitiveness of the melon flies was negligible with a dose of 7 kR, which was used in the eradication project of melon fly from Kume Island.
