U.S. Navy Scientists Hope to Harness the Noise-making Abilities of a Cicada

Cicadas may be unpopular with the masses, but the U.S. Navy has spent the last several years studying the small bug and its ability to emit noises that far outweigh their small size.

In doing so scientists hoped, according to the 21st International Congress on Acoustics, to apply the bug’s secrets to developing a device that would mimic it for remote sensing underwater, ship-to-ship communications and rescue operations, among other things.

Derke Hughes is a researcher at the Naval Undersea Warfare Center who has long worked on the unfunded project to study the bug in his free time along with other volunteers.

Their resulting analysis shows that the insect manages to produce its massive sound due their unique anatomy that consists of a ribbed membrane on the torso that vibrates when they deform their bodies.

However, while this basic insight is clear, Hughes said the problem of reproducing the sound remains a daunting task. As of yet, the team has yet to work out an accurate physics-based model describing how the sound is made during the process.

“We’re still working on that,” he said in a press release.

However, the scientists are aware that it has to do with a buckling rib that’s arrested in the rapid motion by impact with the part of the cicada’s body called a tymbal, the corrugated exoskeleton, which acts like a hammer a gong being hit by a hammer.

To understand the process, Hughes explained, one must imagine all of his or her ribs being pulled to the point of collapse and then releasing them and repeating the cycle. A cicada is able to accomplish this task as many as 300 to 400 times a second using a thick set of muscles on either side of its torso that allows it to cave in its chest so far that the ribs are able to buckle inward.

By releasing the muscle, the ribs are then allowed to snap back into their regular shape. Pulling the muscle repeats the process again.

Replicating this behavior, however, is difficult because it’s nonlinear, meaning it is not a simple matter of one part moving and the sound emerging, according to Hughes. However it is because of this lack of uniformity that cicadas are able to vibrate out of phase with each other and somehow combine to “drown out even the noisiest summer barbecues.”