Cicadas are relatively harmless compared to some insects. They don't bite, and they typically stay away from the plants in your garden. But if you're sensitive to sound, the bugs can be a major nuisance. Their choruses can reach up to 100 decibels—which is equivalent to a car stereo playing at max volume. For an idea of what cicadas sound like, listen to the videos below.
As their name suggests, 17-year-cicadas emerge once every 17 summers after spending the majority of their lives as nymphs underground. In 2021, Brood X—the most widespread cicada brood in the U.S.—will crawl out of the ground, molt into their mature forms, and spend a few weeks copulating before ending their brief adult lives. Male cicadas attract mates by letting out chirps, rattles, and high-pitched screams from the tops of trees. Females can hear the songs from up to a mile away—as can anyone else with functioning ears.
The key to a cicada's deafening call is a pair of percussive organs called tymbals on either side of the males' abdomen. Cicadas buckle these organs by contracting the muscles attached to them. The compression creates a loud clicking sound, which travels to a large air sac in their abdomen and is amplified by their eardrums. When cicadas produce a series of clicks in rapid succession, it creates a buzz, and numerous males buzzing together creates an ear-splitting roar.
The 100-decibel screams of cicadas rival traffic, lawn mowers, and low-flying planes. They exceed public noise ordinances in some parts of the country, and can disrupt everything from sports games to mid-afternoon naps. If you live in an area of the east coast where Brood X will appear this summer, noise-canceling headphones may be a good investment. Of course, you can always sit outside and bask in the cacophony; you won't get to hear this particular brood of cicadas again for another 17 years.