Figure 1.

The dual-choice experimental setup. The fan (a) drew air (~130 L/min/tent) from the two tents (b) to the outside environment via PVC pipes (c), trap chambers (d) and central choice chamber (e). An exit trap (f) opened into each trap chamber. The fan pipe and the release cup (h) were fitted on top and on the bottom of the choice chamber, respectively, through circular holes. The trap and choice chamber measured 30 × 15 × 20 and 30 × 20 × 20, respectively. Diagrams are not drawn to scale; all dimensions are in centimeters.