Where Do Cicadas Go When It Rains, and Does It Kill Them?

As cicadas emerge from the ground in parts of the eastern United States and Midwest, some people are wondering what the insects do when it rains and whether the wet weather harms them.

Periodical cicadas are seven species from the genus Magicicada that emerge every 13 or 17 years in North America. The cicadas that are emerging this year are known as "Brood X."

Gene Kritsky, a biology professor at Mount St. Joseph University in Cincinnati, Ohio, told Newsweek that the insects like to take shelter from the rain, although it doesn't kill them.

"When it rains, the cicadas simply hunker down and wait for it to pass. If they are in trees, they will have some protection from the rain. Their wings can shed rain, so it is not as detrimental as it might seem," he said.

Periodical cicadas spend most of their lives underground as nymphs. After spending 13 or 17 years below the soil—the time period differs between species—the insects crawl out of the earth and molt, transforming into their adult phase. During this part of their life cycle, the cicadas mate and lay eggs.

Trillions of Brood X cicadas are expected to emerge between mid-May and late June this year, in about a dozen U.S. states between Georgia and New York.

John Cooley, a researcher in the Department of Ecology and Evolutionary Biology at the University of Connecticut, told Newsweek that although rain is not fatal to cicadas, it does hamper their ability to fly.

"The adults never go back in the ground, and rain makes it difficult to fly. They may try to shelter under leaves," Cooley said.

In addition, he said, stormy weather could be a problem for the periodical cicadas because it can knock the insects to the ground and damage them.

Michael J. Raupp, a professor of entomology at the University of Maryland, shares the view that thunderstorms can pose a risk to the cicadas. "Gentle rains—no problem. Thunderstorms with accompanying winds—big problem because it blows them to the ground where they are vulnerable to ground-dwelling predators," he said.

Despite the risks from thunderstorms, Raupp said cicada wings deflected water, in the same way as other insects, and their bodies getting wet was not a big problem because they have a wax layer on the exterior.

"They really can't fly away in a rain but they might duck beneath a leaf," Raupp said.

Two periodical cicadas in Maryland
Two Brood X cicadas seen on May 25 in the city of Takoma Park, Maryland. Chip Somodevilla/Getty Images