Archive for Wednesday, August 29, 2007

Cicada chorus fills late summer air

August 29, 2007

Dear Mr. Cicada,

As your next-door neighbor, I think it's time that you turn down the volume a few decibels. Your acoustics are shrill and inescapable.

My cat is even afraid to go outside. But if you must sing, maybe you can take requests. I'd prefer to hear Mozart's Symphony No. 40 over that annoying C-flat screech any day.

Sincerely, Thad Allender

Cicadas, the world's loudest insect, have emerged from below where they have spent the last seven years underground as nymphs waiting for just the right time to climb out, shed their skin and sound their mating call.

Higher-than-average rainfall and ideal climate conditions have produced an abundance of cicadas that are joining in chorus across northeast Kansas.

"There are some that are basically as loud as a jet engine taking off," said Jeff Cole, a Ph.D. candidate at Kansas University's ecology and evolutionary biology department. "The loudest species can get up to 120 decibels, which is about the pain threshold of human ears."

This week, the cicadas have been singing nearly all day. "I've heard them singing until 1 a.m.," Cole said.

The cicada cacophony requires teamwork. Large numbers of males congregate in an area and sing to attract females, typically in the evening to avoid predation.

Male cicadas rely on their tymbal, an organ similar to a snap cap on a juice lid, to produce the sound. A strong muscle attached to the tymbal contracts, vibrating the tymbal membrane, and sends a pulsating sound through the cicada's mostly hollow abdomen.

Kathy Houchin doesn't know much about the insects other than that they are loud and one of summer's oddities.

"It sounds like an army of maracas," she said. "Thousands of them."

Houchin, who lives in south Lawrence off Lawrence Avenue, said she has empty shells of the cicadas littering her yard and clinging to her trees.

1. Female cicadas lay their eggs on bark.

2. Newborn nymphs drop to the ground, where they burrow in the ground.

3. Nymphs spend between two and 17 years underground feeding on root juice.

4. Nymphs emerge from the ground and shed their skin.

5. Adult males sing to attract females, a mating ritual.

6. Back to No. 1.

  • Other fact: The life span of an adult cicada is three weeks. (That means we'll have to put up with this racket for only about another week.)

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