Movement and oviposition of released Aedes albopictus (Diptera : Culicidae) in Nagasaki, Japan

The movement and oviposition of Aedes albopictus were examined by a combination of mark-release-recapture experiment and an ovi-trap survey of egg numbers in Nagasaki, Japan. Fed mosquitoes were marked with fluorescent dye and released into an isolated, small, grassy and scrub area on the campus of Nagasaki University School of Medicine. Twenty ovi-traps were distributed evenly in the study area and the number of eggs was examined for 2 weeks and 9 days before and after the release, respectively. Human bait collections were made at 10 collection points also in the same period. The multiple regression analysis was applied to the observed differences in egg density among ovi-traps after the release and those in recaptured mosquitoes. The baseline data collected before the release were used as independent variables. The results showed a high correlation between the number of eggs deposited in an ovi-trap and the distance from the release point to the ovi-trap. The number of recaptured females in a collection site showed a high correlation with the distance from the release point during the first 2 days after the release. However, on the 4-5th day after the release, the number of recaptured females showed a higher correlation with the number of unmarked females.