If you’re in the central United States right now, you might notice something strange: the sound of cicadas is everywhere. It’s an eerie, incredibly loud song that seems to drown out everything else.
“It’s beautiful chaos,” said Rebecca Schmidt, a researcher who studies insects for the U.S. government. “It’s like a symphony.”
Only the male cicadas make these sounds. It’s their way of trying to attract a mate. Each type of cicada has its own unique song, but two really stand out.
One is the song of the orange-striped “pharaoh” cicadas. “It’s a constant whirring hum, like a buzzing that doesn’t stop,” said Jennifer Rydzewski, another insect expert. Every so often, you might hear an individual cicada that sounds like it’s saying “eee-ooo.”
The other distinct song comes from the “cassini” cicadas. They’re a bit smaller and don’t have orange stripes. “Their song is more of a buzzy sound that goes up and down in waves,” Rydzewski explained. “When you hear it, you’ll often see groups of them flying out of the treetops to a new branch before they start calling again.”
So how do cicadas make these loud sounds? The males have a special white membrane on their midsection that vibrates, and the space underneath it works like an echo chamber to amplify the noise.
“It’s based on a lot of the same principles as a musical instrument,” Schmidt said.
“Think about how a relatively small drum can still be very loud if it’s designed the right way. Cicadas work in a similar fashion.”
The Associated Press contributed to this article.