© University of BristolThis is a mosquito hearing organ.
A mathematical model has explained some of the remarkable features of mosquito hearing. In particular, the male can hear the faintest beats of the female's wings and yet is not deafened by loud noises.
The new research from the University of Bristol is published in the
Journal of the Royal Society: Interface.
Insects have evolved diverse and delicate morphological structures in order to hear the naturally low energy of a transmitting sound wave. In mosquitoes, the hearing of acoustic energy, and its conversion into neuronal signals, is assisted by multiple individual sensory units called scolopidia.
The researchers have developed a simple microscopic mechanistic model of the active amplification in the Tanzanian mosquito species
Toxorhynchites brevipalpis. The model is based on the description of the antenna as a forced-damped oscillator attached to a set of active threads (groups of scolopidia) that provide an impulsive force when they twitch. The twitching is controlled by channels that are opened and closed if the antennal oscillation reaches critical amplitude. The model matches both qualitatively and quantitatively with recent experiments: spontaneous oscillations, nonlinear amplification, hysteresis, 2:1 resonances, frequency response, gain loss due to hypoxia.