Story at a glance
- Periodic cicadas — insects with black bodies, orange wings, red eyes and a familiar loud buzz — lay eggs inside the twigs of trees and shrubs that later hatch and drop to the ground.
- Billions are expected to emerge this year between mid-May and late June to mate.
- Researchers believe cicadas have been carrying out their 17-year, underground cycle for millions of years as a way to avoid predators.
Billions of cicadas that have spent close to two decades underground are expected to remerge this spring and summer across large swaths of the eastern United States and Midwest.
Periodic cicadas — insects with black bodies, orange wings, red eyes and a familiar loud buzz — lay eggs inside the twigs of trees and shrubs that later hatch and drop to the ground. The tiny nymphs then burrow into the soil and suck fluid out of the roots of plants for the next 13 to 17 years as they develop.
After 17 years underground, the insects emerge from the ground as adults en masse to mate and lay eggs for about five to six weeks. The swarms of male cicadas fill the air with their distinct hum that can reach 100 decibels.
Researchers group the insects by the year they emerge as adults after spending years developing underground. Brood X is the name for the largest and most widespread colony of cicadas in the U.S.
Brood X last emerged in 2004, so the insects are expected to once again resurface this year between mid-May and late June once the ground hits about 64 degrees Fahrenheit. The insects are expected to emerge in 15 states: Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Washington, D.C., USA Today reports.
“Cicadas do not bite and are harmless to humans and property — other than being a nuisance. They may amass in millions in parks, woods, neighborhoods and can seemingly be everywhere. When they are this abundant, they fly, land and crawl everywhere, including occasionally landing humans,” Gary Parsons, an entomologist at Michigan State University, explained last year.
Researchers believe cicadas have been carrying out their 17-year underground cycle for millions of years as a way to avoid predators.
“By emerging in the millions all at once, they are too numerous for any predators that do eat them from ever wiping them out. There are so many of them that lots of them will always survive,” Parsons explained.
After mating and laying eggs, the brood will die off and the cicadas that hatch in 2021 will drop to the ground and burrow into the earth and develop for 17 years before emerging to breed in 2038.
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