Evaluation of five trapping systems for the surveillance of gravid mosquitoes in Prince Georges County, Maryland.

Five mosquito trapping systems were evaluated in a large wildlife research center containing extensive and diverse mosquito-breeding habitat. The systems evaluated included Centers for Disease Control (CDC) New Standard Miniature Light traps with and without CO2 (dry ice), CDC gravid traps, partially open 1.8-m3 cages, and Fay-Prince traps baited with CO2. The first 4 trap systems were evaluated for 17 periods, while the Fay-Prince trap was evaluated on 5 trapping dates. Parameters recorded for each species were total catch, percent males, total females, and whether blood-fed/gravid. Fourteen of the 23 species caught yielded over 50 individuals in the 5 trapping systems (range of 71-2,524 specimens per species). Both light and CO2 were powerful attractants for 12 of the 14 commonly caught species. However, for most species, the majority of captured females were nongravid. Gravid traps caught fewer mosquitoes than did light- or CO2-baited traps, but the catch consisted of a higher percentage of gravid females. The open cages caught substantial numbers (>100 individuals) of 5 species, and for 2 species, this was the most productive trap. While light- and CO2-baited traps tended to catch few males or gravid females, the open cages caught an eclectic mixture of males, gravid females, and nongravid females, perhaps representative of the true percentages of each in nature.