Figure 1.

The field trapping device with different odorant chemicals. (A) Four independent traps (including one basic trap) about 10 m apart were set simultaneously on 1 day. The basic trap: four metal blocks were heated to 37.0°C, a petri dish of water was placed directly above the blocks, and then a faint-yellow 15 cm × 15 cm sticky plate with four 1 cm diameter holes was placed above. A simple carbon-dioxide generator with sodium citrate and sodium bicarbonate was placed on the left side of the sticky plate. A black polyethylene bag (60 cm × 60 cm) was placed adjacent to the right side of the sticky plate. The mosquito traps were placed in a ventilated corridor near the building (0.3 m to the wall of the building; 0.5–0.6 m to the bushes adjacent next to a drainage channel). (B) Top view of the basic trap. (C) Lateral view of the basic trap. (D) Effects of odorant chemicals on mosquito capture rate. Water refers to the basic trap presenting in addition a Petri dish with water. (E) Cyclopentanone and pyridine treatments in the absence of CO₂ resulted in a zero capture rate. Error bars show standard deviations (n = 20 for the basic trap; n = 5 for the others). Significant differences are indicated by different lowercase letters.