Why the Navy wants to harness the piercing noise of cicadas
The small bug with the big sound could provide insight into new underwater technology
In addition to benefiting plants and serving as a debatably delectable source of nutrition, the Brood II cicada, with its signature, piercing noise, may hold the key to new naval technology.
At least that's what one U.S. Navy research team has theorized. They have been studying how cicadas make that annoying sound, and trying to determine whether a man-made device based on that natural mechanism could be used to develop better underwater tools of communication.
Scientists have for years been baffled by how a creature so tiny can produce such a loud noise. Some cicadas can screech at sounds up to 120 decibels at close range, or essentially the human ear's pain threshold, according to Animal Planet.
The keys to producing that noise are grooved membranes, called tymbals, inside the cicadas' bodies. By contracting and relaxing the membranes some 300 to 400 times per second, male cicadas emit their distinct mating call.
Still, exactly how that process results in such a boisterous racket has never been fully explained.
Enter the U.S. Naval Undersea Warfare Center in Newport, R.I., which will show in a presentation to the International Congress on Acoustics in Montreal this week how cicadas deftly manipulate their bodies to produce the loud noise. Using lasers, they've sought to precisely map the movements of cicadas' tymbals in hopes of better understanding the finer aspects of the process.
In a preliminary paper (Warning: Complex physics equations), the team outlined several mechanical designs that attempt to show how the cicada's biological system works. Real-world devices based on those designs, researcher Derke Hughes explained, could theoretically be used as noisy — yet super-efficient — underwater sound systems.
For at-sea and submerged vessels, producing a big noise with minimal effort from a small device represents a "triple-coupon," as the Los Angeles Times' Geoffrey Mohan put it. The Navy believes it can use the biology of a cicada to make improved versions of underwater sensing and inter-shop communications equipment.
However, the researchers say they're still far from actually devising a contraption to mimic the cicadas' noise. In the meantime, we'll have to settle for the sound of hundreds of millions of weird little bugs screaming out their annoying, confusing mating call — whenever they finally decide its warm enough to swarm the Earth, that is.