Flies buzz because the sound is a by-product of their rapid wing movements during flight. Their wings flap at very high speeds—often around 200 cycles per second or more—causing air displacement and vibrations that produce the high-pitched buzzing noise. The buzzing is essentially the sound of their wings knocking the air and sometimes each other as they flap so quickly. The buzzing also results from vibrations in the fly’s thorax, which is connected to the wing base, making the wings flutter in sync. Some species of flies may also use buzzing as a form of communication or warning signal, but primarily it is a mechanical consequence of their wingbeat frequency. Additionally, as flies buzz, they can gain a positive electric charge, which may influence their wing movements and the buzzing sound heard.
