A rare double brood means the U.S. will get trillions of cicadas this spring

North Carolina can expect a lot of insect company at picnics and playgrounds in the coming months.

Why it matters: The U.S. will experience a rare phenomenon this spring: Two broods of cicadas are expected to emerge from the ground simultaneously. Our state will likely see one of these broods starting in April or May.

Zoom out: Cicadas are harmless and beneficial to local environments, so they're not considered pests. But they sure are noisy.

• That high-pitched buzz that's a classic sound of summer? That's the male cicada's mating call.

What they're saying: "There've been estimates that where they do emerge, there can be up to a million per acre," Eric Benson, an entomologist at Clemson University, tells Axios. "It's going to be a lot of cicadas."

Yes, but: The Carolinas won't see and hear all of the trillions of cicadas expected to emerge around the U.S. in this year's double brood.

• Brood XIX will emerge across several counties in North Carolina and across several other states, per the Wilmington Star News . They'll appear in Charlotte, plus western North Carolina and parts of the Triangle, too.
• Brood XIII is expected in states across the Midwest at the same time.

Fun fact: Broods XIX and XIII haven't specifically co-emerged since 1803, Axios' Jacob Knutson reports .

How it works: After cicadas mate, the female puts her eggs in a tree and the adults die off. The eggs hatch within a month or so, Benson says, and the young cicadas fall to the ground, burrow into the soil at the base of a tree and latch onto a root.

• They feed on the fluid of a tree for 13 years, slowly growing underground before the brood emerges en masse.

A few things to know about this year's big cicada event:

Snake buffet: "When cicadas come out in a month or so, it's going to be predator smorgasbord. An all-you-can-eat buffet," for cicada predators like snakes, skunks, possums and birds, Benson tells Axios.

• But the number of predators will not increase as a result of the influx of cicadas. "The ones that are here will be very well satisfied," he adds.

Different looks: There's a difference in appearance between periodic cicadas (in Brood XIX) and annual cicadas, or the ones that you hear buzzing in our trees every summer.

• Periodic cicadas are slightly smaller, with black bodies and wings with orange marks, plus red eyes, Benson says.
• Annual cicadas are bigger, with black or dark green bodies and black eyes.
• For anyone especially interested in cicadas, you can report sightings of periodic cicadas via the 2024 Periodical Cicada Brood Watch and iNaturalist .

Short-lived: This year's cicadas will only stick around for about a month, Kelly Oten, NC State Extension entomologist and specialist in the Department of Forestry and Environmental Resources, told the News & Observer recently .

• The last time this brood emerged in both the Triangle and the Charlotte area was in 2011, per Oten. They emerged in early May.

Environmentally beneficial: Cicadas can aerate lawns, improve water filtration into the ground and add nutrients to the soil they decompose, according to the U.S. Environmental Protection Agency .

• Some research shows that female cicadas can improve the health of a tree by laying her eggs in its roots, Benson says. But when a tree is cut down, it removes young cicadas' food source.
• "This has been going on since before recorded time. The thing that really knocks cicadas back is humans and development over time," he adds.

Editor's note: We've updated this story with details about cicada sightings.

Sign up for Axios Raleigh for free.