<i>Fruitless</i> mutant male mosquitoes gain attraction to human odor.

Abstract

The <i>Aedesaegypti</i> mosquito shows extreme sexual dimorphism in feeding. Only females are attracted to and obtain a blood-meal from humans, which they use to stimulate egg production. The <i>fruitless</i> gene is sex-specifically spliced and encodes a BTB zinc-finger transcription factor proposed to be a master regulator of male courtship and mating behavior across insects. We generated <i>fruitless</i> mutant mosquitoes and showed that males failed to mate, confirming the ancestral function of this gene in male sexual behavior. Remarkably<i>, fruitless</i> males also gain strong attraction to a live human host, a behavior that wild-type males never display, suggesting that male mosquitoes possess the central or peripheral neural circuits required to host-seek and that removing <i>fruitless</i> reveals this latent behavior in males. Our results highlight an unexpected repurposing of a master regulator of male-specific sexual behavior to control one module of female-specific blood-feeding behavior in a deadly vector of infectious diseases.