Mosquito sex under lock and key

Female mosquitoes typically mate once in a lifetime^1–3, making this singular mating decision critically important for the female. Yet, mosquito mating has been historically viewed as male-guided, with the female exerting little control^4–6. To understand this contradiction, we investigated initiation of successful mating in mosquitoes. Here we show that females of two invasive mosquito species, the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus), actively gate mating through a previously undescribed behavior of female genital tip elongation. This female genital response is triggered by a rapidly-evolving secondary male genital structure that together act as a “lock-and-key” mechanism. We identified important differences in the genital interactions of the two species and show thatAedes albopictusmales, which have larger secondary male genital structures, can bypass the female genital response ofAedes aegyptifemales but not of females of their own species. Coupled with previous observations thatAedes aegyptifemales are effectively sterilized by such cross-species mating^7–9, the ability of maleAedes albopictusto “pick the lock” of heterospecific females provides a potential mechanism for the observed local extinction ofAedes aegyptiwhen they live in shared territory withAedes albopictus ^10,11. Our results redefine mosquito mating as a female-controlled process, with implications for the evolution of reproductive barriers and the population dynamics of these two globally invasive mosquito species.