Temporal and spatial distribution of released Aedes albopictus (Diptera : Culicidae) in Nagasaki, Japan

A mark-release-recapture experiment of Aedes albopictus was carried out in Nagasaki, Japan. A total of 1,478 unfed females of 4-5 days after emergence was sprayed with 0.5% water solution of Rhodamine B and released into an isolated, small, grassy and scrub area. Human bait collections were made for 9 days at 10 fixed collection points to observe the temporal and spatial variations of released females. A total of 348 females was recaptured and the recapture rate was 23.55%. The variations in the number of marked females among 10 collection points were analyzed by multiple log-regression analysis using the number of unmarked females in each collection point and the distance from the release point as independent variables. The relative importance of the distance in explaining the number of marked females at each collection point was the highest just after the release and then became lower according to days post-release, whereas the relative importance of the number of unmarked females became higher with increasing days post-release. The probability of surviving and staying in the release point and in the study area was estimated as 0.299 and 0.429,respectively, by log-regression analysis of the temporal changes in the number of recaptured females.