The acoustic ecology of mosquitoes. (A) Mosquitoes copulate mid-flight, following a precopulatory pursuit (often taking place in large mating swarms) during which the male chases the female. (B) Males use the females’ flight tones to identify females within the swarm and to track them during the phonotactic chase. (C) (Top) The mosquitoes’ flight tones (bars) are nearly inaudible to both sexes, as they fall outside the mosquitoes’ hearing range (red highlighted area); (bottom) when male and female flight tones mix nonlinearly within the mosquitoes’ ears, however, they produce audible distortion tones (additional bars), which fall partly within the mosquito hearing range (green highlighted area). (D) Audibility thus arises from an interaction between (male and female) flight tones and the mosquito flagellar ear (see schematic drawing). Understanding the biophysical operation of the mosquito flagellar ear is key to understanding mosquito hearing and auditory behavior. (E) Within the Johnston's organ (JO), different populations of ciliated neurons (neurons red, cilia blue), and nonneuronal cell types, coalesce to mediate, and modulate, the process of mosquito hearing. The antennal nerve carries both afferent and efferent nerve fibers, which transmit, or modulate, sensory signals, respectively. (CB) Cell body, (C) cilia, (AN) antennal nerve, (M) muscle.