How Come?: Crickets and cicadas

Do crickets and cicadas make their sounds the same way? asks a reader.Crickets and cicadas have a lot in common (besides the "c"). Both insects begin making their music in summer. Both are loud. And among both insects, the noisemakers are mostly male.

But there the resemblance ends. If there were an insect orchestra, crickets would be in the string section and cicadas would be percussion. And while the crickets would happily play at night, cicadas would stick mostly to matinees.

Cicadas, whose racket rises during the daylight hours, are the loudest of the world's insects. In fact, a chorus of cicadas can be as deafening as a running vacuum cleaner. Yet the average North American cicada is less than two inches long.

Male cicadas make most of the noise, their music filling the few weeks the insects have to find mates. The males serenade the females using a pair of ridged membranes, called tymbals, in their lower abdomens. Strong abs are a must: A cicada contracts his ab muscles around the tymbals, causing them to cave in like a drum struck with sticks. Then, in the cicada's nearly empty abdominal cavity, the percussive sound resonates, like a musical note in a concert hall.

Next, the insect's angled-out wings act like a built-in megaphone, amplifying the sound as it exits his body into the air. The result: A noise that can reach 90 to 100 decibels, as loud as a nearby lawnmower or passing subway train.

When the cicadas have settled down for the night, the crickets take their place. Like the cicadas, it's the males that do the singing. But a cricket's chirping doesn't come from the gut. Instead, it's all in the wings.

Crickets have four wings, two front and two back. To begin the serenade, a cricket raises his front wings about 45 degrees. Then, like drawing a bow across the strings of a violin, he draws the thick, ribbed vein on one wing over a ridge of wrinkles on the other. The result is a kind of music. And as with the cicadas, the music's volume is turned up courtesy of the wings. Acting like a violin's sound board, the wings amplify the notes produced by the rubbing ridges.

Scientists think that male crickets, like male cicadas, sing mainly to attract females. Crickets also have threatening songs, warning off rival males. And crickets may chirp out alarms when predators, such as mice, frogs and lizards, are nearby.

So why don't the loud chirps and buzzes of male crickets and cicadas damage the insects' own hearing? Scientists say that a cricket's brain can temporarily turn down his hearing, muffling the sound of his own singing. Likewise, male cicadas also apparently disable their own hearing as they launch into their earsplitting routines.