Animals with a Loud Voice (2): Cicada
Published on 7 October 2020 

When talking about animals with a loud voice, how could we miss cicadas? Every summer we can hear cicadas chirping in urban parks and countryside. Some species of cicadas can produce sound reaching 100 decibels (dB), as loud as an operating electric drill. How does a little cicada make such a loud sound? Firstly, only male cicadas can chirp, so as to attract females by the resounding calls. A male cicada has three specialised components in his abdomens: muscles, tymbals and a hollow abdominal cavity. In contrast, the abdominal structure of a female cicada is much simpler. You can see the differences in the pictures below.

Transverse section of first abdominal segment of cicada specimen

Location of tymbal on one side of a male cicada

Inside the abdomen of a male cicada, there is a pair of V-shaped muscles attaching to the tymbals on each side of the body. The tymbals resemble a piece of plastic sheet. When they are pulled by the muscles and deform, they produce sound. In the video below, you can see the demonstration on how the tymbal makes sound using a plastic water bottle. The clicking action of cicadas' tymbals is, of course, much faster - it can reach around 400 times per second. Moreover, the structure of the abdomen of a cicada is quite different from other insects, it has a hollow abdominal cavity. The sound produced by the tymbals resonates in the cavity and gets amplified. It works like the soundbox of a wooden guitar.

Scientists are eager to find out how do the cicadas produce a loud sound with less energy, and apply the working principles to our daily lives, such as improving the sonar detection technology. You can study the sound-producing principles of cicadas too, such as using the plastic water bottle to imitate cicadas' chirp as shown in the video or try to build your own soundbox to amplify sound.

Video demonstrates how sound is produced by the muscles in male cicada's abdomen pulling the tymbals