Aedes aegypti survival and dispersal estimated by mark-release-recapture in northern Australia

Abstract

The survival and dispersal of adult Aedes aegypti were estimated in northern Australia where sporadic outbreaks of Ae. aegypti-borne dengue viruses have occurred in recent years. Standard mark-release-recapture methods were used. In addition, a new sticky trap was used to capture the mosquitoes. Prior to the field study, the survival and effect of marking Ae. aegypti with fluorescent powder were determined in the laboratory. Mortality was age-dependent and the marked cohorts had higher survival rates than the untreated cohorts. Recapture rates of 13.0% and 3.6% over a seven-day period were achieved for two batches of marked Ae. aegypti released simultaneously at the field site. More males than females were recaptured although the proportion of females increased with time. The probability of daily survival was 0.91 and 0.86 for the blue- and pink-marked females, respectively, and 0.57 and 0.70 for the blue- and pink-marked and males, respectively. The mean distance traveled of recaptured Ae. aegypti was 56 m and 35 m for females and males, respectively. The maximum observed distance traveled of 160 m was the same for both sexes. The warm to hot and dry climatic conditions may have restricted the dispersal of released mosquitoes in this study. The frequency of recaptures at certain trap locations suggested that shade, wind, and the availability of hosts affected the distribution of Ae. aegypti within the study site.