It’s like clockwork. Seasons change. Fads come and go. And, once every 17 years, millions of cicadas emerge from the ground to scream. And scream. And scream.
This year, experts expect as many as 1.5 million cicadas per acre to emerge across parts of Virginia, North Carolina, and West Virginia after stewing underground for the better part of two decades. To put that into perspective, the last time these states heard that signature cacophony of alien-like wails, Friends still had new episodes, Arnold Schwarzenegger had just begun his stint as California’s governor, and Americans were calling french fries “freedom fries.”
Why do they cause such a ruckus? That’s just the male cicadas letting the female cicadas know that they are DTF.
Cicadas spend most of their life cycle as juvenile nymphs, quietly growing underground and feasting on sap from tree roots. When the nymphs finally burrow their way to the surface and moult into their adult form, they only live for two to four weeks. Just long enough to woo a mate with their loud, high-pitched buzzing and secure the next brood. Afterward, the females lay their eggs on trees, the next generation starts cooking, and the cycle begins anew.
Not all cicadas are on that 17-year life cycle grind, though. Other periodic cicadas come out every 13 years and a variety known as annual or dog-day cicadas makes an appearance every year. In Japan, such a large brood emerges every summer that the cicada’s iconic buzzing has grown synonymous with the season and become a fixture in anime.
While cicadas may look a bit ominous with their bulbous eyes and transparent wings, they’re harmless to pets and humans. They can be a serious headache for farmers, though. The way the species lays their eggs within a branch can cause it to split open and wither, stunting the growth of young saplings and threatening several tree species. Thankfully, their window for damaging crops is small thanks to their short above-ground life cycle. After a peak in mid-June, most cicadas should be gone by July.
Scientists theorise that the insects emerge from their underground nests en masse as a survival mechanism to ward off (and I presume deafen) nearby predators. Lately, though, some cicadas have been confounding experts by going rogue. Several broods have begun showing up topside ahead of their usual schedule, which could be yet another strange effect of climate change. Higher temperatures mean higher temperatures underground, after all, which experts think may be speeding up the cicadas’ growth.
That means Americans could start hearing the insects’ wail more often than they have in the past. Joy.