Analysis of survival of young and old Aedes aegypti (Diptera : Culicidae) from Puerto Rico and Thailand

It generally is assumed that the daily probability of survival of wild adul t mosquitoes is independent of age. To test this assumption we conducted ma rk-release-recapture studies in Puerto Rico and Thailand to determine if es timated. daily survival rates between two different age cohorts of the deng ue vector Aedes aeglipti (L.) were the same. Survivorship was estimated wit h nonlinear regression analysis using bootstrapping to obtain estimates of errors. Initial recapture success of the younger cohort was greater than th e older cohort at both locations. Our analysis revealed a significantly gre ater survival rate for the younger cohort of females in Puerto Rico, and no significant differences between age cohorts in Thailand. For comparison, a traditional approach for analyzing these type of data, linear regression o f log -transformed captures over time (exponential model), was used to calc ulate the probability of daily survival based on slopes of linear regressio n lines for recaptured mosquitoes. With this method, the estimated daily su rvival rate of older females (13-33 d old) was significantly greater than s urvival of younger ones (3-13 d old) in Puerto Rico and Thailand. In additi on, short-range movement of mosquitoes was observed in Puerto Rico; maximum dispersal distance detected was 79 m. Survival rates of adult Ae. aegypti may be age dependent and nonlinear regression analysis is a sensitive appro ach for comparing patterns of mosquito survival based on mark, single relea se, multiple recapture data.