Brood X may sound like a ’50s sci-fi flick about swarming monsters but spring’s emerging of the 17-year periodical cicadas should only be a plague if you’re trying to enjoy a quiet night outdoors.

And not even in Alabama. Most of the trillions from May’s Brood X swarm will arise and fly and feed — and be fed on — in their monthlong above-ground life along the East Coast, from North Carolina to Indiana to New Jersey, possibly in parts of Georgia. Their pervasive song, an 85- to 90-decibal electric drone, comes from males attracting females, so they can create their own brood, which will drop in the ground for its own 17-year growth span, sucking sap from tree roots and biding time for emergence.

Alabama will get its turn in 2024 with the 13-year brood arising, leaving behind dime-sized holes, crooning from the treetops, then doing as teen-agers will, or want to, once mates have been wooed by song. Then like a ’50s teen-angel ballad, they die post-love, leaving in the trees eggs that hatch rice-grain-sized nymphs, which then rain down, burrow into the soil, and begin their own cycle.

But don’t confuse cicadas with locusts, they of the biblical plagues, the ones that actually can devastate crops. Except for some of the plant life they’ll feed on, and the potential noise pollution, slightly louder than a passing train, cicadas aren’t harmful at all, said John Abbott, director of museum research and collections at the Alabama Museum of Natural History, at the University of Alabama’s Smith Hall.