The phenomenon is rare and spectacular. Every 17 years, these “periodic” cicadas come out en masse to the fresh air to mate, lay eggs … then die.
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They’ve been lurking underground for almost twenty years, waiting for the right moment to emerge. This is not a horror film or an ancient legend: billions of cicadas will soon invade part of the United States, including the capital Washington. The phenomenon is rare and spectacular. Every 17 years, these “periodic” cicadas come out en masse to the fresh air to mate, lay eggs … then die.
This year, cicadas are expected in May, or perhaps from April depending on the region, in parts of a vast territory stretching from Washington to the east of the state of Illinois, in passing through Georgia. “It’s really quite unique”, explains John Cooley, who teaches in the department of ecology and evolutionary biology at the University of Connecticut in Hartford. These cicadas, which are harmless, “simply have a life cycle of 17 years”.
And this is how their existence unfolds, both long when they are under our feet, and ephemeral when visible. “As soon as the ground reaches a certain temperature, around 62 degrees Fahrenheit (almost 17 degrees Celsius, editor’s note) on an evening that could be a little humid, but not too rainy, the nymphs will start to come out of the ground and then molt”, said John Cooley.
Then they will reproduce. “The noise you are going to hear is the male calling to attract a response from the female. Once the male and female are reunited, they mate, the female lays eggs.” and shortly after, “they die”. “The eggs will hatch six to eight weeks later, and the entire cycle will repeat itself”, he continues. The nymphs will therefore go and bury themselves and spend the next 17 years feeding on sap taken from the roots.