Abstract
The dispersal rate and longevity of the melon fly, Dacus cucurbitae COQUILLETT, were compared for wild and mass-reared strains under field conditions at Ishigaki Is., Okinawa, Japan from 1978 to 1979. The wild strain was reared with squash for 3 generations, and the mass-reared strain was given an artificial diet for 29-39 generations after colonization. Flies of the wild strain travelled a greater distance than those from the mass-rearing. The longevity of flies in the sild strain was also longer than for those in the mass-reared strain. From these results, it was ascertained that some deterioration in the quality of flies had occurred in the course of mass-rearing.
