Because cicadas come out every 17 years, their return often triggers a mixture of emotions in the human world, as their emergence signifies the passage of time. The familiar buzzing and clicking cacophony of these creatures is almost a reminder of events that occurred almost two decades ago. Once the nostalgia passes, though, most people will be wondering what the lifespans of these 17-year cicadas are. How long they are likely to stick around in 2021?
What is the lifespan of a 17-year cicada?
Oddly enough, Brood X cicadas live for around 17 years or so, as they're born and die above ground — just 17 years apart. According to USA Today, they usually come out in the spring, mate, lay eggs, feed, and die in late June or early July. It’s not a long “life,” so to speak, but it's a remarkable one.
This year’s cicadas, known as Brood X, will likely emerge when the ground temperatures reach around 65 degrees Fahrenheit. That’s when these amazing insects leave their long-standing nymph stage and begin the final, fast-paced stage of their life cycle, which ultimately ends in death.
How long do cicadas live above the ground?
According to Pets on Mom, cicada nymphs go through four molting stages while they are underground. Each molt changes them in different ways, but the fifth and final molt that occurs above ground grants cicadas their ability to fly. After digging themselves out of the ground, cicadas climb up nearby trees and shed their skin one last time. Once they emerge from hibernating underground, cicadas live from four to six weeks.
With their exoskeletons now fully hardened, these fully grown cicadas begin the arduous month-long process of mating. Over the next four weeks, cicadas engage in a buggy bacchanal, which involves singing, mating, and flying into people — often scaring the hell out of them.
You know that distinctive sound that cicadas make? According to National Geographic, that sound — known as “singing” — is only made by male cicadas. They sing to attract females and some species’ songs can register sounds louder than 1000 decibels.
How long do cicadas live after they mate?
Once their eggs have been fertilized, female cicadas seek out branches in which to lay them. Using their sharp ovipositor, the females cut slits into the branch, where they deposit all 500 of their eggs. As soon as that process is over, the female allows herself to fall off the tree branch. If the fall doesn’t kill her, the exertion of the past month, or a predator, certainly will. Males will usually live a few days longer, according to Pets on Mom, but they’re just as doomed in the long run.
Why do cicadas live so long just to die a month after emerging?
This is one of the biggest unanswered questions in the bug world, according to National Geographic. The 17-year cicada is a rarity, even among such a diverse group of animals. Some scientists believe that this long time in the ground allows cicadas to avoid predators during their sensitive nymph stage. More importantly, it makes it impossible for any predator to specialize in eating just cicadas.
Nevertheless, while the month-long mating season of 17-year cicadas is a nuisance for most humans, animals love the opportunity to feed on a plentiful and easily catchable food source. There is also a fungus that has evolved to specifically feed on dormant cicadas. So the theory isn’t totally sound. The only thing we can say for certain about the cicada’s life span is that they definitely make the most of their time above ground.