Specialized cells tag sexual and species identity in Drosophila melanogaster.

Many organisms use chemical signals to indicate species and sex. Cuticular hydrocarbon signals are used by insects, including Drosophila melanogaster, to distinguish conspecific individuals from others, and they also contribute to courtship and mating interactions. Direct evidence is now provided that a single compound is used to communicate female identity among D. melanogaster, and to define a reproductive isolation barrier between D. melanogaster and sibling species.