The lifecycle of a cicada is a journey like no other species experiences. Reproduction requires 17 years underground, the perfect temperature and a whole lot of noise. If you live in the eastern part of the United States, you’ve likely been exposed to the swarms of cicadas at some point. That’s because there are annual cicadas, then there are broods that show up every 13 or 17 years. Between March and May of 2021, a 17-year invasion will occur, and it’s called Brood X.
This flood of flying insects will appear across portions of the Midwest, mid-Atlantic and southern parts of the country. In all, 14 states will see some activity from the 17-year cicadas.
The emergence signals ends and beginnings of the lifecycle of these insects, and it’s an interesting one. That’s because in order to mate, these cicadas wait 17 years underground, feeding on plant and tree roots. As it turns out, that’s literally a lifetime. When the ground warms to 64 degrees and the calendar indicates the 17-year mark, the insects dig their way to the surface, where the real party begins.
There are actually three species that will emerge in Brood X. Although humans will unavoidably hear the males ‘singing’ their mating song, we won’t necessarily be able to distinguish one species from another by the noise alone. Female cicadas, however, will only respond to the male’s song that indicates he is from her same species. Once they mate, the male dies. The female then lays eggs on tree branches. Once she performs her motherly duty, the female also dies, leaving the future of the species to the eggs left sitting on a branch. When mature, the nymphs drop to the ground and burrow underneath the soil to await their return in another 17 years.
While the process is easily summarized now, it has taken scientists millennia to understand what was referred to as “the plague of locusts” by early European entomologists. What used to seem random with the emergence of large broods is now better understood, but there is still some hypothesis involved. For billions of years, cicadas only visited annually, but scientists believe the 17-year broods began around a half-million years ago. At some point, scientists believe the three broods that now emerge every 13 years got the wrong message, likely due to climate conditions or a natural event. After the initial misfire, however, they continued to return every 13 years.
As a relatively rare event, scientists aren’t the only ones looking forward to the emergence. Birds and other animals such as squirrels, chipmunks, skunks, ants, raccoons, snakes, frogs and possums feast on the insects. It’s a once-in-a-lifetime gorge, when animals in the area will stuff themselves into a food slumber while taking advantage of the buffet. But being hunted makes it harder for the cicadas to perform the task at hand, reproduction. There are 12 broods that are on the 17-year schedule, making for quite a clatter when they’re in town. It’s believed each brood comes in such large numbers to give it the best chance of survival. The philosophy is basically along the lines of “safety in numbers.” By showing up in masses, many will be sacrificed in the name of distraction while the rest of the team gets the job done.
The event only lasts from a few days to a few weeks, so while it might seem like an intrusion, the scientific community is excited to witness an event that won’t return for nearly two decades and doesn’t happen anywhere else.
Mike Raupp, an entomologist with the University of Maryland who travels and gives informational presentations about cicadas, explained, “We are at the epicenter of an event that happens nowhere else on the planet except here in the Eastern United States … It’s going to be pretty remarkable, come the latter half of May. The densities of these things is going [to] be phenomenal, about 1.5 million per acre. It blows your mind.”
If you’re wondering just how loud the mating call is, the male cicadas can chirp out around 100 decibels. Raupp said, “That’s the sound equal to a chain-saw, a lawn mower, [or] a jet overhead.”
Contrary to what people may perceive as an invasion of locusts, cicadas do not devastate crops or pose a risk to humans. Cicadas do not sting or bite. They will, however, take over any space they can find to mate, so those who live in the area will want to keep the windows closed and the insect screens up. There’s also clean-up after the event is over, with piles of cicada carcasses littered about. With sheets of red eyed, black carcasses left behind, property owners might wonder what to do with the debris. Compost them! The crispy husks the nymphs leave behind can also go in the compost pile. For a rare experience, look up a recipe and eat cicadas. Coat with seasoned flour and cook, roast them like nuts, or toss them into a stir fry. Whether you classify them as a delicacy or not, it’s an opportunity you won’t have for another 17 years.