Figure 4. Bioallethrin-induced EAG and repellency are impaired in orco^−/− mosquitoes.

(A) and (B) EAG responses of Orlando (wild-type) and orco^−/− mutant strains, respectively, to purified bioallethrin (volume of 1.0 μL of undiluted compound into the odorant cartridge). The blank represents the control (0 μL). Representative traces are shown above the plot. Two-tailed Paired Student’s t-test, Orlando: t = −6.837, df = 6, P < 0.001, orco^−/−: t = 1.233, df = 6, P = 0.264; ns = not significant, **P < 0.01. n = 7 insect antennae for each strain. Boxes represent the 25^th, 50^th and 75^th, whiskers the 10^th and 90^th, and open circles the 5^th and 95^th percentiles of the data (C) Repellency by purified bioallethrin in Orlando (wild-type), orco^−/− mutant, and Rockefeller (wild-type) mosquitoes. Two-tailed Student’s t-test, control (0): t = 0.046, df = 18, P = 0.963, 10⁻⁵ dilution: t = 4.92, df = 13, P = 0.0002; ns = not significant, ***P < 0.001; n = 10 cages for both mosquito strains in control (0), n = 7 cages for Orlando, 8 cages for orco^−/−, and 8 cages for Rockefeller in 10⁻⁵ dilution. The 10⁻⁵ dilution corresponds to 114 ng cm⁻². The control represents the baseline activity in response to the solvent. Data are presented as mean ± SEM. The dots over bars represent individual replicate values.