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Up to 60 billion cicadas are about to emerge in St. Louis. Here’s what you need to know

A Brood X periodical cicada collected in Cincinnati, Ohio, in 2021.
Emily Woodbury
Periodical cicadas are between three-quarters of an inch to an inch and a half long.

This spring marks the first time since Thomas Jefferson was president that periodical cicada Broods XIII and XIX will emerge in the U.S. at the same time. There are 15 periodical cicada broods throughout the country, most of which emerge once every 17 years.

Brood XIX, known as “the Great Southern Brood,” is about to surface in St. Louis.

“That could be as many as 60 billion cicadas for St. Louis city alone,” said Nicole Pruess, invertebrate keeper at the Sophia M. Sachs Butterfly House.

Nicole Pruess with a periodical cicada landed between her eyes
Nicole Pruess
Nicole Pruess traveled to Cincinnati, Ohio, in 2021 to observe the Brood X cicadas, which emerge in areas of the eastern U.S. once every 17 years.

Unlike the annual green-and-black cicadas the region sees — and hears — every year in mid- to late summer, Brood XIX periodical cicadas emerge from the ground in spring every 13 years. They are smaller than the annual cicadas, with large red eyes and orange wings and legs. The cicadas spend all but the last few weeks of their 13-year life cycle underground.

While she hasn’t seen signs of them yet, Pruess expects them to emerge from the ground in St. Louis any day now.

“It needs to be 64 degrees Fahrenheit eight inches below the soil surface to trigger their emergence,” she said. On Tuesday, the soil temperature was 54.1 degrees.

“Once they start emerging, we’re going to be seeing dime-size holes in the ground where they’re coming out of the soil. We’ll be seeing the cast skins that you may be familiar with on tree trunks,” Pruess said. “And then of course, [we’ll see] the adult cicadas.”

Pruess visited Cincinnati in 2021 to witness a similar periodical cicada emergence. She said it was striking to see them flying, as annual cicadas aren’t seen flying around often.

“Also, the sound was really quite striking,” she said.

Periodical cicadas emerge en masse as a way to overwhelm predators and make sure that enough of them survive to mate and lay eggs. This year’s cicadas are expected to be a nutritional boon to the region’s wildlife.

“If you love nature, be excited because birds, mammals, reptiles, amphibians and even other invertebrates are going to have this huge feast,” Pruess said.

Cicadas are high in protein, fiber and minerals, and they are safe for humans to consume as well — though people with shellfish allergies are advised to avoid eating them, as they are related to crustaceans.

“Anything you can make with shrimp you can make with cicadas,” said Pruess, who said it’s best to collect them just after they emerge and have molted, so their exoskeleton is still soft. “I’m very excited to try it.”

For those who are feeling less than excited — perhaps even anxious — about the number of cicadas about to emerge from the ground, Pruess shared this advice: “Try to find some wonder in it.”

“If you’re just staying in Missouri, you’re only going to see this every 13 years,” she added, “so try to soak it in and enjoy it — and know that they are completely harmless.”

Learn more about periodical cicadas by listening to St. Louis on the Air on Apple Podcast, Spotify or by clicking the play button below.

St. Louis is about to see up to 60 billion cicadas emerge

St. Louis on the Air” brings you the stories of St. Louis and the people who live, work and create in our region. The show is produced by Ulaa Kuziez, Miya Norfleet, Emily Woodbury, Danny Wicentowski, Elaine Cha and Alex Heuer. Roshae Hemmings is our production assistant. The audio engineer is Aaron Doerr.

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Emily is the senior producer for "St. Louis on the Air" at St. Louis Public Radio.