Effect of different carbon dioxide (CO2) flows on trapping Aedes albopictus with BG traps in the field in Zhejiang Province, China

Carbon dioxide (CO 2 ) attracts host-seeking adult mosquitoes; this fact is exploited for mosquito monitoring, which is important for evaluating the effects of mosquito-control operations. A field experiment was designed to explore the relationship between the CO 2 flow rate and the trapping effect of BG traps. The aim was to select an appropriate flow rate for monitoring Aedes albopictus . Six sampling sites were selected for field experiments in Hangzhou city, Zhejiang Province, China. A total of six CO 2 flow rates (0.00 L/min, 0.075 L/min, 0.15 L/min, 0.30 L/min, 0.60 L/min and 1.20 L/min) were tested to compare their effects on mosquito trapping. The catches were performed in six trapping periods between 15:30 and 18:30, and each catch period lasted 0.5 h. A total of 3068 adult mosquitoes were captured at six sampling sites in six days using BG traps (with BG-Sweetscent), among which 86.96% were Ae . albopictus . The total number of Ae . albopictus (males and females) captured at a flow rate of 0.00 L/min was significantly lower than the numbers captured at 0.075 L/min, 0.15 L/min, 0.30 L/min, 0.60 L/min and 1.20 L/min ( P <0.001, P <0.001, P <0.001, P <0.001, and P <0.001 respectively). The total number of Ae . albopictus captured and the number of Ae . albopictus females captured increased with increasing CO 2 flow and peaked at 0.3 L/min, above which these capture numbers did not increase significantly. In conclusion, the appropriate CO 2 flow rate for monitoring Ae . albopictus with BG traps was 0.3 L/min.