Using a female-specific isoform of doublesex to explore male-specific hearing in mosquitoes

Animal reproduction relies on elaborate divisions of labor, and multiple dimorphisms, between the sexes. Primary dimorphisms affect core reproductive elements; secondary dimorphisms affect indirect traits, including complex behaviors. Male disease-transmitting mosquitoes locate female mating partners acoustically before copulation (phonotaxis). Male ears-and hearing performance-have thus evolved to become substantially more complex, partly due to sex-specific expression of the gene doublesex (dsx). dsx links primary and secondary dimorphisms: spermatogenesis and ear morphogenesis share considerable molecular overlap; both depend on dsx expression patterns. Here, we combine functional-anatomical analyses of mosquito ears with transcriptomic profiling to dissect dsx-dependent hearing in the malaria mosquito Anopheles gambiae. Female dsx mutant ears are anatomically and functionally intersex, although they still completely lack some male-specific characteristics. By cross-linking our auditory findings to the genetic bases of spermatogenesis we advance the molecular understanding of sex-specific hearing mechanisms in insects, highlighting the special roles of ciliary factors.