FARMINGTON, Mo. (NewsFirst) — Billions of cicadas with glowing red eyes and loud screams are expected to emerge in over a dozen states across the Southeast and Midwest this year.

The insects, which have the longest life cycle of any insect, spend 13 or 17 years underground before surfacing to mate and lay eggs. They are harmless to humans and plants, but can provide food for birds and other predators.

This year, two different groups of cicadas, known as broods, will come out of their long slumber. Brood XIX, which has a 13-year cycle, will appear in 14 states, while Brood XIII, which has a 17-year cycle, will show up in five states. The two broods are expected to overlap in Illinois and Indiana, according to Cicada Mania, a website dedicated to cicada information.

The cicadas will begin to emerge when the soil eight inches underground reaches 64 degrees, usually triggered by a warm rain. The emergence typically starts in mid-May and lasts through late June.

The last time Brood XIX emerged was in 2011, and the last time Brood XIII emerged was in 2007. The most recent brood of cicadas, Brood X, came out in the summer of 2021 across multiple Eastern, Southern and Midwestern states.