Abstract
The estimate of the summer population density and survival rate of the melon fly, Dacus cucurbitae COQUILLETT, males was carried out by the mark and recapture method in the countryside near Naha City, located in the southern part of Okinawa Island. A single release and repeated recapture system was adopted. The data obtained were analyzed by HAMADA'S z-index method. The density was estimated to be 200-300/ha in a suitable habitat, and about a half of this in an unsuitable one. The survival rate was about 0.8/day in both habitats. The accuracy of these estimates was discussed with respect to seasonal change in the number of flies caught by ‘monitor traps’ baited with cue-lure, a male attractant, and comparison was made with estimates obtained in other islands of Okinawa. It was concluded that the estimates described above are reasonably accurate.
