Cicada Invasion! East Coast Braces For Swarms

Colossal numbers of cicadas - quietly growing underground since 1996 - are about to emerge along much of the US East Coast to begin an orgy of passionate singing and mating.

Billions of so-called 17-year periodical cicadas, with their distinctive black bodies, buggy red eyes, and orange-veined wings will begin to settle along a roughly 900-mile stretch from northern Georgia to upstate New York.

The good news is they do not sting or bite, and are not harmful to crops.

But the eerie, cacophonous mating music they produce has simultaneously amazed and infuriated people for centuries.

Cicadas on a wall during a previous invasion in Virginia

In central Connecticut, particularly dense concentrations of so-called Brood II cicadas, named Magicicada septendecim, should arrive in late May or June this year as soon as the soil temperature exceeds 18C (64F).

Chris Maier, entomologist with the Connecticut Agricultural Experiment Station in New Haven, said the first scientific recording of Brood II specimens was in 1843.

The precisely-timed arrival of the 1.5-inch (38-mm) plant-sucking, flying adults takes place after a lengthy period of development underground as juveniles.

After maturing, males begin what cicadas may be best known for: their conspicuous acoustic signals, or "songs," to sexually attract females.

"When there's a lot of them together, it's like this hovering noise. It sounds exactly like flying saucers from a 1950s movie," said Chris Simon from Connecticut University.

When they suddenly emerge, the cicadas will be visible "on the sides of the trees, on the sides of the house, on the shrubbery - even on the car tires," said Mr Simon.

Magicicada population densities - from tens of thousands of cicadas per acre to 1.5 million per acre - are much higher than they are with other cicada species.

One theory behind their bizarre but sustainable life cycle is that their emergence produces such overwhelming numbers at once that predators, such as birds, spiders, snakes, and even dogs, cannot eat them all.

To create their unique choruses, male cicadas use ribbed tymbal membranes on their abdomens to produce sounds, while females click or snap their wings.

Fortunately for East Coast residents the clamour will be all over by July.

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