In the coming weeks, as temperatures warm across a dozen states in the mid-Atlantic region, billions of Brood X cicadas will emerge from the soil and head for the trees to shed their exoskeletons, unfurl their wings, sing, mate, lay eggs and die.
Wonder about their purpose? Well, it’s not complicated, according to Gaye Williams, an entomologist with the Maryland Department of Agriculture.
“I mean, they’re not great writers or anything,” she said. “They exist to make more cicadas, the same as people.”
Certain types of the insect—known as annual, or “dog day” cicadas—are present every year, filling the humid air with distinctive buzzing each summer. But this year’s cicadas are different, part of a periodical “brood” that mature underground and then emerge in cycles of 13 or 17 years. This year’s group, Brood X (that’s 10, in Roman numerals), is also known as “the big brood,” Williams said, “because there are so many of them.”
Opinions differ on the brood’s distribution, though hot spots in the mid-Atlantic region are likely to include swaths of Pennsylvania, Maryland, Washington, D.C., West Virginia and Virginia, according to a map from cicadas.info, a tracking and information site.
Brood X consists of three species, Williams said—Magicicada septendecim (the most common and also the largest), Magicicada septendecula, and cicadas coming billions already
