The Cicada : a singer

Cicada chirps and emits stidulations.

Only male cicada sings to entice females.
The later ones take the first step. Our two cicada intertwine each other on their sides, mating lasts only a few minutes.

Cicada has the strongest insect voice in the world.

If you observe a cicada singing, you will see its belly moving up and down. How does everything work?

Part of the body works as the musical instrument called "cymbal". Under the chest, behind the posterior legs, two covers are used as dampers; two cavities are hidden under these two lids and they are known by the word "li capello" (the chapel) in the Provence region, all together they make "la gleiso" (the church). These cavities are restricted by a thin and soft membrane, by a thin and rainbow-coloured layer called "mirau" (mirror). All these organs (chapels, mirrors) are the resonance system, they do not produce the sound, but they modify it.

The real sound organ is elsewhere. An oval opening "the whistle", hidden by the lid, is located on the outer flanks of the chapels, at the junction between the belly and the back. These openings lead to a cavity: the sound chamber and its outer wall makes a flat black protuberance, right behind the connection site of the posterior wings. The inner wall of this sound chamber is made of a little white oval membrane called cymbal, diametrically covered by veins which gave it elasticity. This cymbal is similar to a rounded scale and is set in motion by a muscle which grows shorter and longer, compressing or lowering the cymbal. These deformations are followed by rattles, they are made very quickly (300 to 900 per second). The two cymbals vibrate that way. It can be compared to a can lid, pressed with the thumb, then relaxed curtly.

The lids are still. The abdomen makes the church open or close, when it gets up or down. Lowered belly: the lids close the chapels and whistles, the sound is reduced. Raised belly: the chapels stand ajar; the whistles let the air go in, the sound reaches a high power. The cymbal muscles are synchronized with the swings of the abdomen and determine the varying volume of the sound .

Sound changes according to the circumstances: the loving sound full of volume can become slow if the cicada is worried or perceive a hidden danger, distressed, hoarse and short when it is captured.

Some evenings their song stops between 7 p.m./20 hours to take again half an hour later for approximately new half an hour. This event is due to an atmospheric phenomenon. With laying down sun, the temperature falls and the moisture of the air increases, our insect is very sensitive to this moisture and stop its song. Then approximately thirty to forty minutes after this laying down sun, the temperature goes up, driving out moisture, then our cicada takes again its song until the new fall of temperature, final.
Take a cicada cautiously, turn it on its back, scratch its belly: you will be gratified with its song. If this is a female cicada, it will not sing. In the next page, we will teach you how to tell a male from a female cicada.

Sound organs


Working of a cymbal

A careless singer

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