Labellum of the mosquito proboscis contributes to host-seeking behavior. (A-C) A possible role for the mosquito labellum as a thermo-detector. Note that the ability of labellum-less mosquito to recognize pseudo-targets (A) and real hosts (B) is reduced (C) (***p < 0.001, t-test; mean ± SD, n = 4). (D-F) AsTRPA1 is expressed on the labellum. Scale bars: 5 μm.