“It was too close to pass up,” said Ali Kane, a real estate agent who studied entomology in college, with her father Patrick in tow.

“We’re playing it by ear,” said Kane, who was wearing iridescent, dangly cicada earrings.

Mechanics of cicada songs

Insects, unlike humans and some birds, don’t have voice boxes. They use their body parts as instruments to produce sound.

Male cicadas have a membrane with ridges called a tymbal, which Katie Dana, an affiliate with the Illinois Natural History Survey, said will buckle and produce loud sounds. She said it works almost like a flexible straw — the expanding and contracting of the plastic makes the characteristic crackling noise.

The abdomens of male cicadas are also hollow, Dana said, which helps amplify the volume.

They can employ either their “song” or “alarm” call, she said. If they’re grabbed by a predator — say a fish or a raccoon — they’ll let out a sound Dana described as “screaming.” Their song to attract females is a bit different, and takes the form of a call and response, she said.

“It’s kind of a little dance where the males will sing, and the females will hear that and fly in closer to the males,” Dana said.

Female cicadas then flick their wings, which she said produces a song in response to the males. The more calls and responses, the closer the females get to the males until they mate.

When periodical cicadas emerge from their shells, Dana said they’re quite soft and squishy. It takes a few days for the males to fully harden and start singing. As more cicadas join the ranks, they get louder and louder, particularly in “chorus centers.”

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