The taste of humans and nectar: gustation in the Asian tiger mosquito

The taste system controls many insect behaviors, but is greatly understudied in mosquitoes. Little is known about how tastants are encoded in mosquitoes or how they regulate critical behaviors. Here we examine how simple and complex taste stimuli are encoded by the Aedes albopictus mosquito, a highly invasive disease vector, and how these cues influence biting, feeding, and egg laying. We find that neurons of the labellum, the major taste organ of the head, differentially encode a wide variety of human and other cues. We identify three functional classes of taste sensilla with an expansive coding capacity. Unexpectedly, we discover strikingly prevalent inhibitory responses, in addition to excitatory responses. A subset of bitter compounds suppresses physiological and behavioral responses to sugar, suggesting their use as potent stop signals against appetitive cues. Complex cues, including human sweat, nectar, and egg-laying site water, elicit distinct response profiles from the neuronal repertoire. We identify key tastants in human skin and sweat that synergistically promote biting behaviors. Transcriptomic profiling identifies taste receptors that might be targeted to alter behaviors. Our study sheds light on key features of the taste system that suggest new ways of manipulating chemosensory function and controlling mosquito vectors.