Mean response of An. gambiae to skin microbiota in an olfactometer. Microbiota were grown on blood agar and tested at different times of incubation (A) and in different dilutions of the most attractive treatment (12 h incubation) (B). Six times 30 mosquitoes were released per treatment. Error bars represent standard errors of the mean; ***: χ2-test P < 0.001; **: χ2-test P < 0.01. R = The trap entry response expressed as the number of female mosquitoes caught in both trapping devices divided by the number of mosquitoes that flew out of the release cage. Data followed by different letters differ significantly at P < 0.05 (GLM).