Here's a nuisance we haven't had to deal with for a while: Brood X cicadas. They've been burrowed in the earth since 2004 and are almost ready to come topside. Tens of billions of them will be around for four to six weeks, the New York Times reports, then leave us alone until 2038. Even experts think the concept is odd. "It's really strange that a group of insects spends 17 years underground, and then they decide to come up," said Matt Kasson, who teaches forest pathology and mycology at West Virginia University. Other cicadas are on a 13-year cycle, but Brood X is a slower developer, as well as one of the biggest groups. They could well show up in other places but surface mostly in the eastern US. Brood X is expected in an area bounded by Michigan to the north, Illinois to the west, and Georgia to the south.
At the moment, Brood X is letting the soil reach the right temperature—around 64 degrees—before emerging in the next few weeks. Once they arrive, cicadas will climb trees after losing their exoskeletons, then make a racket looking for mates, per Live Science. The noise makes them hard to miss: They're as loud as a motorcycle. If enough are assembled in a tree, the noise can drown out a lawnmower. The cicadas reproduce once, at best, then die. The nymphs then go underground, and the long cycle starts over. While they're above ground, cicadas are no threat to people. But they can damage small trees while feeding off the sap. The Brood X population doesn't all show up at once; some have come up four years early or four years late, per the Washington Post. Scientists don't know why. (Read more cicadas stories.)