How long will they stay there and when will they leave?

This year, billions of periodical cicadas from two broods are emerging from their underground habitats in more than a dozen states, filling the air and creating lots of noise.

There are two broods affecting a total of 17 states this year: Brood XIX of 13 years located primarily in the Southeast, and Brood XIII of 17 years in the Midwest. The two broods, which have not emerged together since 1803, are found in both Illinois and Iowa.

You may have already seen some of these cicadas emerge, but how long will they be there this year and how long will they stay underground between emergence years?

Here’s what you need to know about the life of a cicada, below and above ground.

Cicada map 2024:Find out where Brood XIX and XIII cicadas emerge in the United States

When do cicadas emerge?

According to Cicada Mania, cicadas begin to emerge from their underground habitats when the ground 8 inches underground reaches 64 degrees and are often triggered by warm rain.

Thanks to warm temperatures, cicadas have already been seen above ground in the Southeast and Midwest states.

Can you eat cicadas?Try these tasty recipes with Brood XIX, Brood XIII this summer

How long will cicadas stay on the surface?

The lifespan of cicadas depends on their brood and whether they are an annual or periodic species.

The two periodic broods this summer are brood XIX, which has a life cycle of 13 years, and brood XIII, which has a life cycle of 17 years.

Once male and female periodical cicadas have mated and the latter has laid eggs, the insects will die after spending only a few weeks above ground – between three and six weeks after they first emerge.

That means many of this year’s periodical cicadas are expected to die in June, although some could die in late May or July, depending on when they appeared.

Annual cicada nymphs stay underground for two to five years, according to the Missouri Department of Conservation. These cicadas are called “annuals” because some members of the species emerge each year as adults.

What is the life cycle of a cicada?

The life cycle of a cicada begins with mating. The female then lays her eggs in holes dug in the branches of trees and shrubs, reports National Geographic. The eggs hatch in six to ten weeks and the cicada nymphs burrow into the soil and attach to the roots of the tree.

Cicadas will stay underground for a “dormant period” of two to 17 years, depending on the species. Then they emerge in adult form, according to National Geographic.

2024 emergence map: discover where broods XIX, XIII emerge

Both broods of cicadas are expected to emerge in 17 combined states in the South and Midwest. They emerge once the ground eight inches underground reaches 64 degrees, which is expected to begin in many states in May and last until the end of June.

The two generations last emerged together in 1803, when Thomas Jefferson was president.

Contributor: Olivia Munson, USA TODAY.