posted on 2023-06-07, 19:37authored byGabriella Gibson, Ian Russell
Mosquitoes hear with their antennae, which in most species are sexually dimorphic. Johnston, who discovered the mosquito auditory organ at the base of the antenna 150 years ago, speculated that audition was involved with mating behaviour (1). Indeed, male mosquitoes are attracted to female flight-tones (2-4). The male auditory organ has been proposed to act as an acoustic filter for female flight-tones, but female auditory behaviour is unknown (5). We show, for the first time, interactive auditory behaviour between males and females that leads to sexual recognition. Individual males and females both respond to pure-tones by altering wing-beat frequency. Behavioural auditory tuning curves, based on minimum threshold sound levels that elicit a change in wing-beat frequency to pure tones, are sharper than the mechanical tuning of the antennae, with males being more sensitive than females. We flew opposite-sex pairs of tethered Toxorhynchites brevipalpis and found that each mosquito alters its wing-beat frequency in response to the flight-tone of the other, so that within seconds their flight-tone frequencies are closely matched, if not completely synchronised. The flight-tones of same-sex pairs may converge in frequency but eventually diverge dramatically.
We show, for the first time, interactive auditory behaviour between male and female mosquitoes that leads to sexual recognition. Opposite-sex pairs of tethered Toxorhynchites brevipalpis synchronize their wing beat frequency while the flight-tones of same-sex pairs diverge dramatically.