Sampling biases of the BG-sentinel trap with respect to physiology, age, and body size of adult Aedes aegypti (Diptera: Culicidae)

Abstract

Currently, Aedes aegypti (L.) control strategies are being developed that involve manipulation of the vector at the adult stage (e.g., the use of the bacterial endosymbiont Wolbachia to shorten the life span of the vector population). These novel strategies demand adult sampling methods to measure changes in population size, structure (age, sex ratio), and, ultimately, the success of the program. Each sampling method presents certain biases. Once these biases are defined, methods used to estimate population size and structure can be calibrated accordingly, resulting in more accurate and complex estimates of the vector population. A series of mark-release-recapture experiments with adult Ae. aegypti were conducted in a large outdoor flight cage and an indoor setting in far north Queensland, Australia. The biases of the BG-Sentinel trap (BGS) were investigated across several categories, as follows: 1) mosquito age; 2) sex; 3) physiological status; and 4) body size. Biases were not detected across age groups or body sizes. A significant bias was detected across physiological groups: nulliparous females were recaptured at a significantly lower rate than all other groups except blood-fed parous females, which were also recaptured at a low rate by the BGS. Males were recaptured at a higher rate than all groups, but only a significant difference in recapture rates was observed between males and nulliparous females. Previous studies show that the BGS is a highly effective tool for Ae. aegypti surveillance. The BGS proves to be a reliable tool in Ae. aegypti surveillance with consistent sampling outcomes. The sampling bias of the BGS is measurable and can be used to generate more accurate estimates of the adult population and its attributes.