WHEN THOSE NYMPHS EMERGE, THEY WILL FALL TO THE GROUND, DOWN TO THE TREE ROOTS. AND IN 17 YEARS, THEY’RE BACK. SO HOW DO THEY KNOW IT’S BEEN 17 YEARS? SO ONE OF THE THEORIES IS THE XYLEM THAT ...

Cicadas, which are called nymphs in their immature stage, don’t all emerge in one night, Kritsky said. “It takes about two full weeks for the great bulk of the cicadas to come out,” he said.

THOSE EGGS HATCH LATER IN THE SUMMER AS LITTLE TINY NYMPHS. PEOPLE DON’T REALLY SEE THE NYMPHS. THEY FALL TO THE GROUND AND THEN THEY LIVE, FEEDING ON THE ROOTS OF PLANTS FOR THE NEXT 17 YEARS ...

An adult spotted lanternfly found in Huntington, Ind., 2022. (Andy Lavalley/Post-Tribune/Tribune News Service via Getty Images) ...