Cicadas wake up four years early

Should we worry about a cicada awakening this spring, which was not supposed to happen… before four years?

From North Carolina to New Jersey to Ohio, legions of cicadas are currently going through their awakening and breeding cycle: in the woods and forests, they emerge from the ground, the males emit their characteristic whistles and look for a partner. In a month, all these cicadas will be dead and the next generation, asleep under the ground, will not emerge for years.

There are different populations of cicadas known as “periodic” whose sleep cycle varies from 13 to 17 years, but the one that currently intrigues entomologists should not have woken up until 2021. The warmer temperature could be the cause, although this does not explain everything: in the time that these cicadas have been studied, it has never been clearly understood how the larva buried under the ground “calculates” the passage of the seasons, to the point of being able to come out exactly at the 17th spring.

Questioned by the magazine Scientific American, Indiana University biologist Keith Clay hypothesizes the insect’s growth rate: abnormally warm temperatures in recent years may have accelerated this growth, leading their “biological clock” to overestimate the number of past seasons. In fact, as early as 2000, entomologists had artificially accelerated the cycle of fruit trees around which nymphs are found, leading the insects to emerge from the ground a year earlier.

And this is not even the first time that some experts have sounded the alarm about the lineage called Brood X: 17 years ago, observations had reported an early awakening in several families of cicadas. But even if the emergence of this spring was that of the cicada offspring of 2000, this would not explain the acceleration observed in other lines. Biologist Joe Boggs of Ohio State University writes on his blog that “the most plausible explanation for such a widespread acceleration of development across several families of 17-year-old cicadas is climate change.

As for what will happen with this month’s “generation”, we’ll have to wait for its next cycle: a return to the normal 17-year-olds or a cycle now accelerated due to global warming? Or an unbalanced population because an insufficient number of individuals will have woken up and reproduced?

A citizen science project called Magicada allows amateurs to provide scientists with observations on this period that is as critical as it is brief for the future of the cicadas.