Humming in Tune: Sex and Species Recognition by Mosquitoes on the Wing

Abstract

Mosquitoes are more sensitive to sound than any other insect due to the remarkable properties of their antennae and Johnston's organ at the base of each antenna. Male mosquitoes detect and locate female mosquitoes by hearing the female's flight tone, but until recently we had no idea that females also respond to male flight tones. Our investigation of a novel mechanism of sex recognition in Toxorhynchites brevipalpis revealed that male and female mosquitoes actively respond to the flight tones of other flying mosquitoes by altering their own wing-beat frequencies. Male-female pairs converge on a shared harmonic of their respective fundamental flight tones, whereas same sex pairs diverge. Most frequency matching occurs at frequencies beyond the detection range of the Johnston's organ but within the range of mechanical responsiveness of the antennae. We have shown that this is possible because the Johnston's organ is tuned to, and able to detect difference tones in, the harmonics of antennal vibrations which are generated by the combined input of flight tones from both mosquitoes. Acoustic distortion in hearing organs exists usually as an interesting epiphenomenon. Mosquitoes, however, appear to use it as a sensory cue that enables malefemale pairs to communicate through a signal that depends on auditory interactions between them. Frequency matching may also provide a means of species recognition. Morphologically identical but reproductively isolated molecular forms of Anopheles gambiae fly in the same mating swarms, but rarely hybridize. Extended frequency matching occurs almost exclusively between males and females of the same molecular form, suggesting that this behavior is associated with observed assortative mating.

Use of acoustic signals in mating in an eavesdropping frog-biting midge

“…Our work provides a framework to understand the use of sound in multiple contexts in this eavesdropping midge and complements recent studies investigating the acoustic mating signals of mosquitoes (Cator et al, 2009;Gibson & Russell, 2005;Gibson et al, 2010;Pennetier et al, 2010;Warren et al, 2009). Harmonic convergence at higher frequencies suggests higher acoustic sensitivity in frog-biting midges than in the closely related family of mosquitoes.…”

Genome analysis of a major urban malaria vector mosquito, Anopheles stephensi

“…The male-biased genes are enriched for those whose products are involved in spermatogenesis and the auditory perception. Male mosquitoes detect potential mates using their Johnston's organ, which has twice the number of sensory neurons as that of the females [27,28]. The female-biased genes are enriched for those whose products are involved in proteolysis and other metabolic processes likely relevant to blood digestion.…”

Audio-based Relative Positioning System for Multiple Micro Air Vehicle Systems

“…However, existing examples in nature show the potential success of such a system for aerial robots. Flight calls of nocturnal migratory birds used for collision avoidance and coordinated migration during night [6], and phonotaxis behaviour among insect swarms for mating and predator avoidance [7] [16] are some of the many existing examples. Furthermore, in a recent work, an acoustic source localization system for MAVs was shown to be effective in locating the source of distress signals on the ground [2].…”