The mosquito, sworn enemy of exposed ankles and elbows, locates each bloody meal using a finely tuned sense of smell. Yet, not all insects can sniff out vulnerable flesh. Butterflies, for example, feed not on necks but on nectar, and accordingly excel at smelling flowers. Each insect olfactory system is, in fact, tailored to a species’ particular habitat and needs. And a new study from a group of Rockefeller scientists suggests that this versatility is facilitated by the unique structure of odorant-gated ion channels.