Cicadas

GENE KRITSKY: When swarms of periodical cicadas emerged around Plymouth Colony in 1634, the pilgrims—who had never seen or heard such a thing before—were quite bewildered.

PETER KUPER: Dr. Gene Kritsky is Dean of Behavioral and Natural Sciences at Mount St. Joseph University in Cincinnati, Ohio.

KRITSKY: Colonial governor William Bradford described in his journal “. . . such a quantity of a great sort of flies . . . which came out of holes in the ground . . . and ate the green things, and made such a constant yelling noise, as made all the woods ring of them, and ready to deaf the hearers.”

KUPER: This nearly 400-year-old account is considered the first written record of periodical cicadas. But their existence was known to humans much earlier.

KRITSKY: The Indigenous peoples of North America knew about them centuries before Europeans arrived on the continent. The Iroquois could tell when cicada emergences were approaching. They would dig up the nymphs—the early cicadas—and clean them and dry-roast them, as a food source.

KUPER: Predicting the emergences of periodical cicadas was no small feat because of their unique life cycle.

KRITSKY: Once every 17 years, in parts of the eastern United States, they emerge in incredible numbers to overwhelm their potential predators, giving them enough cicadas to eat until they get tired of eating cicadas, and there are still millions left to reproduce.

KUPER: It’s the drive to mate that motivates cicadas to create their high-decibel chorus.

KRITSKY: The males gather in trees to sing to attract a female. After mating, the females lay their eggs in the terminal ends of tree branches, and then both the males and the females die. Six to eight weeks later those eggs hatch. The nymphs drop to the ground, and they burrow down about a foot where they’ll be for the next 17 years.

KUPER: Cicadas can sense the changing of the seasons to track when one year goes by. But exactly why and how they emerge after 17 years remains unexplained.

KRITSKY: One of the real mysteries in biology is: how do they remember what year it is? I mean, that’s still a mystery.