Sound and Size

Fruit flies mate quietly on an apple

During late summer in Indiana, the night is dominated by sounds of cicadas, crickets and katydids. Loud insect sounds are associated with large insects. Small insects are capable of only producing small sounds. H.C. Bennet-Clark* has calculated the potential sound production of small insects and has determined that small insects have limited range and volume.

The Drosophila (Fruit) Fly is one of the smallest insects known to communicate by sending sound through the air. Its sounds are soft and do not travel far. A cricket can generate 1000 times more muscle power than a Drosophila fly. In addition, Drosophila wings are too small to efficiently vibrate the air. Thus, the sound created by Drosophila wings is far below potential based on size; not much above a whisper within a few millimeters of the female. However, the flies use the sound at close range and a sound that is too loud might attract unwanted attention from predators.

Outdoors, cicadas make a deafening racket courting mates. Inside, above ripening fruits in the kitchen, the Drosophila flies are courting in relative silence.

Size and scale effects as constraints in insect sound communication. H. C. Bennet-Clark Phil. Trans. R. Soc. Lond. B 1998 353. 29 March 1998
doi: 10.1098/rstb.1998.0219