Have you ever heard a buzzing sound in the summertime? It might be a male cicada trying to impress a mate. But depending on where you live and what year it is, you might not hear just a few buzzing bugs hanging out in the trees—things might get so loud you won’t hear anything else but the buzzing!
A Bug's Life
Cicadas start their lives as eggs. Females lay 200 to 400 eggs in tiny holes that they make in the branches of trees and shrubs. After six to 10 weeks, cicada young called nymphs hatch from the eggs and immediately fall to the ground. They burrow underground and attach to tree roots. The nymphs stay buried to suck tree sap from two to 17 years, depending on the species. When this underground life—called the dormant period—ends, the cicadas emerge aboveground at sunset, climb the trunk of a nearby tree, and shed their skin. Now they’re adult cicadas.
Next, male cicadas fill the air with shrill buzzing sounds created by rapidly vibrating drum-like plates on their abdomens. The females make clicking sounds with their wings if they like the song. They mate, lay their eggs, and then both male and female cicadas die after just about five weeks aboveground.
Scientists divide the over 3,000 cicada species into two groups: annual and periodical. Annual cicadas emerge from the ground at different times each summer. They’re usually dark with greenish markings. These insects avoid predators by camouflaging themselves in the trees and flying from hungry birds and moles.
Only seven species of cicadas are in the other group, called periodical cicadas. These bugs all emerge from the ground at the same time. Called broods, these groups appear after a dormant period of either 13 or 17 years. That’s a long nap!
Periodical cicadas live only in the central and eastern part of the United States. They have black backs, orange bellies, and red eyes. Millions—or even billions!—of cicadas might come out all at once, so these bugs aren’t trying to hide. They survive by having such a large population that predators couldn’t possibly eat them all at once.
A different periodical brood emerges almost every year in different parts of the country. Some broods are small, like Brood VII (the Roman numeral for seven), which is found only in upstate New York. But others are huge: In the summer of 2021, hundreds of billions of cicadas in Brood X (the Roman numeral for 10), will buzz through parts of Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington, D.C.
Although the emergence might sound scary, these bugs aren’t harmful: They don’t attack people, they don’t bite or sting, and they don’t destroy crops. So just enjoy the sights and sounds!