Scale division graph of the optical analysis tube. Note: L1–L5 represents the direction of the light source. D1–D5 represents the dark direction. S is the distance of the test insect from the release center. L1 indicates 0 < S <= 10 cm, L2 indicates 10 < S <= 20 cm, L3 indicates 20 < S <= 30 cm, L4 indicates 30 < S <= 40 cm, L5 indicates 40 < S <= 50 cm. D1 indicates 0 < S <= 10 cm, D2 indicates 10 < S <= 20 cm, D3 indicates 20 < S <= 30 cm, D4 indicates 30 < S <= 40 cm, D5 indicates 40 < S <= 50 cm.