(A) EAG response recording from female antennae showed a dose-dependent manner. Doses of selected ligands: 25 ug (green), 50 ug (purple) and 100 ug (blue), n = 6–8; mean ± std. (B) Doses of four compounds, 100 ug; n = 6–8; mean ± std, mosquito age: 4–5 days old. EAG response of 1-octen-3-ol was used as a standard (100%) to normalize those elicited by other chemicals. Indole and skatole elicited more than 50% of the 1-octen-3-ol response. (C) EAG response post-RNAi-treatment. Compound: indole, 100 ug, n = 6–8; mean±std; mosquito: 4–5 day post RNAi treatment. Detection was separated into non-injected group, dsRNA-dsRED injected group, dsRNA-OBP37 injected group and dsRNA-OBP39 injected group. Hexane (10 ul) was used as a control in this study.