Supersensitive Odorant Receptor Underscores Pleiotropic Roles of Indoles in Mosquito Ecology.

Mosquitoes exhibit highly diverse and fast evolving odorant receptors (ORs). The indole-sensitive OR gene clade, comprised of and is a notable exception on account of its conservation in both mosquito subfamilies. This group of paralogous genes exhibits a complex developmental expression pattern in : is expressed in both adults and larvae, is adult-specific and a third member named is larva-specific. OR2 and OR10 have been deorphanized and are selectively activated by indole and skatole, respectively. Using the two-electrode voltage clamp of oocytes expressing . ORs, we show that AaegOR9 is supersensitive and narrowly tuned to skatole. Our findings suggest that . has evolved two distinct molecular strategies to detect skatole in aquatic and terrestrial environments, highlighting the central ecological roles of indolic compounds in the evolutionary and life histories of these insects.