Calibrated funnel trap for quantifying mosquito (Diptera: Culicidae) abundance in wells.

Our article addresses the problems of sampling and quantifying the abundance of immature Aedes aegypti (L.) and other mosquitoes that use subterranean habitats such as wells and service manholes. Two versions of the funnel trap, Austrap and Vietrap, were extremely sensitive for detecting the presence of Ae. aegypti larvae in wells, and the modified version, the Vietrap, sampled on average 20.5% of 3rd and 4th instars when set overnight for 12 h. For both models, regression analyses between trap catch and absolute abundance indicated high coefficients of determination (R2 = 0.932 and 0.992) enabling accurate direct calibration. The effects of immature age, mosquito species, well diameter, and trap size on catch size were investigated. Because of its simplicity, efficacy, and inexpensiveness, the Vietrap will facilitate the comprehensive assessment of key larval habitats for Ae. aegypti, data critical for the development of effective control programs.