Brood X Cicadas – Everything You Need to Know

Cicadas function like a very precise clockwork. They emerge at very precise times due to how their bodies function. Periodical cicadas are especially rigid about their emergence.

Brood X, the latest to see the light of day, got out of the ground in April and by the end of June, it was all over. The cicadas mated, and then they died. Now the eggs are left behind to repopulate the world with cicadas once again!

Once the eggs hatch, the larvae will go back into the ground and wait another 17 years before emerging. Ironically, there’s never an instance of an identical Brood X emerging very 17 years.

The emerging cicadas are different because adults can’t live past the mating season. Instead, their offspring are called Brood X because they come from the same genetic line that first appeared in 1715.

Why Are They Called Brood X?

Simply put, Cicada broods are named after Roman numerals in the order they were identified. And Brood X (Brood 10) is the largest of the known 17-year cicada broods. There are a total of 12 such broods in the world, with this one having the most members.

It first appeared on May 9th, 1715, and it was recorded by Reverend Andreas Sandel, a pastor of Philadelphia’s Swedish Lutheran Church, “Gloria Dei.”

What Month do Brood X Cicadas Emerge?

Brood X cicadas always emerge in May or April every 17 years. It’s like clockwork and they never miss this period. Studies deduce that their lifecycle naturally evolved as a way to confuse predators.

No predator will ever evolve to specifically wait 17 years for these cicadas to emerge. Their emergence is a complete surprise to everyone but humans. Fortunately, we aren’t set on hunting them.

The last time Brood X appeared was back in 2004 when Facebook was but an idea in the back of Zuckerberg’s mind. Cicada females placed their eggs in branches and twigs, and the nymphs eventually fell to the ground.

After burrowing into the earth, they’ve been waiting for 17 years, all the way until April 2021, to emerge. That moment was a truly magical one!

Where do Brood X Cicadas Emerge?

Brood X emerged in several states across the US, including northern Georgia, New York, the Mississippi River, and the Midwest. A large number of them emerged in Pennsylvania, in parts of New Jersey and Delaware, and a few places in New York. But they also emerged in Ohio, east Tennessee, Kentucky, Illinois, and across Georgia and North Carolina.

The mid-Atlantic and eastern Midwest regions of the United States were a focal point of Brood X populations. Their buzzing could be heard a mile away, and passers-by remained in awe of this natural phenomenon.

Entomologists from across the country were out there, studying this once-in-17-years event. The next time we’ll be seeing Brood X is in 2038, but we’ll be ready.

Cicada males emerged first, and as soon as they got their bearings, they started singing. But it wasn’t until a few days later that the females also emerged from the ground.

Mating quickly ensued, the females laid their eggs, and both males and females died shortly after. But those few days were sunken in the high-pitched noises of Cicada mating noises!

Are Brood X Cicadas Dangerous?

Not unless you’re surrounded by tens of millions of singing males, they’re not. Cicadas can’t even hurt a fly, let alone a human being. They can’t bite, scratch, sting, or harm you in any way.

In fact, the only thing they do when you grab them is making a distress call to warn other cicadas about the danger. The others will know to avoid that general area and stay away from you.

Cicadas aren’t harmful to the environment either. They do feed on tree juices but there’s no harm done. The trees will regain their sap quickly, even after the cicadas suck them dry.

The only way Cicadas can harm anyone is through their high-pitched noises that become deafening at times. I don’t recommend staying near a cicada population unless you enjoy having headaches and bleeding eardrums.

Cicada buzzing can go above 90 decibels and even reach 100 decibels. Sounds that are so loud can even harm your eardrums on prolonged exposure. Your lawnmower emits sounds at 90 decibels as a reference.

Now imagine having to listen to your lawnmower continuously for 1-3 hours. Though, I don’t know why you’d stay under a cicada tree for 1-3 hours. But, just imagine it for a few seconds. Yeah, not a pretty picture.

When Will Brood X Cicadas Go Away?

There are two answers to this question, depending on what you mean by Brood X. You see, it’s never the same Brood X that emerges every 17 years. The descendants of previous Brood X cicadas continue on the legacy and then die off.

Every 17 years, another Brood X population dies, and the nymphs take their place. So, Brood X cicadas go away every year, but they also never go away.

It’s an infinite life cycle that only ends if no Brood X eggs survive. That’s the literal end of Brood X. However, considering that cicada broods consist of tens of millions of individuals, it’s statistically impossible for something to kill all of them. Unless that something also killed the dinosaurs, in which case humans won’t survive either.

It’s safe to assume that as long as humans survive and thrive, Brood X will also continue to live in the future. If you’re lucky, you can even catch the following emergence of Brood X if you didn’t catch this one. There are plenty of videos showing the cicadas singing after their sweethearts, though!


Brood X was a natural wonder that only happens every 17 years. It’s something you don’t witness every day, that much is true. Their behavior, life cycle, mating process, and entire existence are extremely interesting for people everywhere. Insect lovers will rush to Pennsylvania and known emergence areas every 17 years to watch the new cicadas fly and buzz around!

Though, despite being very clumsy and occasionally hitting light poles or getting into your house unannounced, cicadas are good friends. Well, they don’t let you sleep either if you live near a cicada tree. They may also pee on you. Alright, they’re kind of rude but hey, at least they only come out every 17 years.

Cicadas   Updated: August 15, 2021
avatar Welcome to Insectic, a blog to learn about insects and bugs. I'm Richard, and I've created this website to share my experience, knowledge, and passion with others.

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