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The first known report of a large brood of cicadas emerging from the ground was recorded by William Bradford, the governor of the Plymouth Colony in modern-day Massachusetts, in 1633. Bradford described the brood as making a “constant yelling noise” and that they were “ready to deafen the hearers.” The citizens of the Plymouth Colony thought the red-eyed insects might be the swarm of locusts foretold in the Old Testament, but they were wrong. This was just the first-ever recorded emergence of a periodical brood of cicadas in North America.
If you’ve ever lived through a periodical cicada emergence, you know pretty much what to expect. There’s going to be a persistent buzzing noise that will get extremely loud at times, particularly before a storm. Yes, cicadas do sing louder before storms. You’ll be driving around and hear the constant thwack of rogue cicadas hitting your windshield. Bushes and trees will be teeming with life as the cicadas hustle and bustle around to try and find a mate.
This year, in 2021, 15 states in the eastern United States are due for a full-on cicada invasion. The invading force? Brood X. While that name may be extremely menacing and, in fact, their numbers are in the trillions, this cicada emergence is part of a routine life cycle and may have wide-ranging positive impacts on local ecosystems. So, while you may have to brush quite a few dead cicadas off your front stoop, and you’ll probably even get hit in the face by one if you live in one of those 15 states, at least we can thank these crazy creatures for helping maintain the health of our ecosystems.
Here’s what you should know about the 2021 Brood X cicada invasion:
What Are Periodical Cicadas?
There are two broad types of cicadas: annual cicadas and periodical cicadas. All cicadas do most of their development underground and then emerge to mate when they reach maturity. Annual cicadas appear far more often than periodical cicadas; however, their broods still only emerge every 2 to 5 years, so “annual” is a bit of a misnomer. Annual cicadas can be seen every summer in eastern North America because they are not developmentally synchronized. So, while some annual cicadas will be ready to emerge in 2021, others will wait until 2022, and others will wait until 2023.
Periodical cicadas, on the other hand, are developmentally synchronized, meaning they all reach maturity and emerge from the ground in the same years, in intervals of either 13 or 17 years. That’s why periodical cicadas emerge in such massive broods, because their emergences are not staggered, but rather all in the same year.
Periodical cicadas live underground for a period of either 13 or 17 years as nymphs, surviving off of tree root sap and growing towards maturity. Then, once they’ve all matured, each brood emerges from the ground synchronously for a brief stage of adulthood and mating. After the mating rituals have been completed, the female cicadas will lay their eggs in the roots of woody plants, and all the adult cicadas will die. This is what we are about to see in 2021 with Brood X.
What Is Brood X?
The North American cicada broods are grouped by Roman numerals from I to XXIII depending on their geographic location and the time of their emergence. This year, Brood X, or the Great Eastern Brood, is set to emerge. This brood of cicadas emerges every 17 years, which means the last time that Brood X emerged was from mid-May to the end of June of 2004. In those months, Terry Nichols was convicted on murder charges for the Oklahoma City bombings, Massachusetts legalized same-sex marriage, and Ronald Reagan died. It was a long time ago.
Brood X actually consists of three different cicada species: Magicicada septendecim, Magicicada cassinii, and Magicicada septendecula. These different species will gather on different types of trees and the males will sing different-sounding songs. Brood X is expected to emerge in 15 different U.S. states (as well as Washington, D.C.) this year, including Delaware, Illinois, Georgia, Indiana, New York, Kentucky, Maryland, North Carolina, New Jersey, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Michigan.
While the lion share of the cicadas is going to emerge from mid-May to the end of June of this year, there were some individual cicadas sighted around Washington, D.C. about four years ago, so it’s possible that some emerged early.
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The song Day of the Locusts by Bob Dylan was written about a swarm of Brood X cicadas that were present in Princeton, New Jersey when he went to get his honorary degree from Princeton University in 1970. Ogden Nash published a poem called Locust Lovers, Attention! about Brood X cicadas that he saw while living in Baltimore in 1936.
What Can We Expect?
Trillions of cicadas and a whole lot of noise. For a little over two months, you’re going to be up to your eyes in cicadas if you live in Washington, D.C. or one of those 15 states. All you can really do is keep your windows and doors shut and try not to be too squeamish while they’re buzzing all around your head as you walk down the street.
Don’t worry too much, though, cicadas are not harmful to humans whatsoever. They don’t bite, sting, or carry diseases. They can harm your plants, though, if they choose your garden as a suitable place to eat some leaves and lay their eggs. Young fruit trees are especially at risk, as these are cicadas’ favorite sites for laying eggs.
You might also want to consider getting some earplugs if you’re particularly sensitive to sound. Brood X is a very large brood of cicadas, and they can make up to 120 decibels of sound when they’re all singing in unison. That’s as loud as a clap of thunder or a chainsaw.
In terms of their behaviors, you’ll probably see some cicadas climbing up trees (probably the one whose roots they emerged from) and looking for the right place to shed their exoskeleton. Once they shed their exoskeleton, they will spread their wings and wait around for a few days. This gives their shells time to harden and their wings time to grow strong enough to fly. Once they’re ready, that’s when the singing begins. The cicadas will start flying around, frantically looking to find a mate.
If you’re deathly afraid of cicadas, this isn’t going to be a good few weeks for you. However, don’t bother calling the pest control professionals; insecticides should not be used on cicadas, and wouldn’t work anyway. Cicadas are incredibly resilient and will not die from pesticides, and besides, they play a crucial role in our ecosystems, so we shouldn’t try to kill them.
Why Cicadas Are Good For Our World
Cicadas generally have a very positive impact on the ecosystems in which they emerge. First of all, they serve as a source of food for predators. Squirrels, birds, amphibians, fish, reptiles, mantises, spiders, and many other animals will feed on cicadas both dead and alive. And if you haven’t been grossed out by this article enough yet, some humans even eat cicadas as well.
They can also be extremely beneficial for moving nutrients around the ecosystem. The little holes that they make in the ground when they emerge play a powerful role in aerating the soil and allowing free movement of nutrients and aiding plant growth.
The presence of cicadas can also help relieve a great deal of predatory pressure on other insect populations. That means that after the cicadas are all gone, other insect populations will be stronger, which means a larger food supply for animals higher in the food chain, which makes the ecosystem stronger overall.
So, regardless of how disgusted or terrified you are by cicadas, just remember: they aren’t biblical harbingers of death or angry parasites here to sting you. They just want to get freaky and make babies, and they actually do great things for the world while they’re at it.
