For nearly two decades, they’ve lain in wait underground. They’ve bided their time, digging through the soil beneath our feet and feeding on tree roots with their piercing, needle-like mouth parts. And now, they’re coming.
Pronounced “Brood Ten” and also called the “Great Eastern Brood,” Brood X is a group of billions of periodical cicadas that emerge from the ground every 17 years, explains Michigan State University entomologist Howard Russell. He says that periodical cicadas, which are unique to eastern North America, are different from the dog day cicadas that we see most summers because they surface synchronously, in one big swarm.
“It's not uncommon to see a million and a half adult cicadas emerge per acre,” said Russell. “They're really large, noisy, lusty insects.”
Don’t worry — these creatures might be noisy, but they don’t sting or bite. They’re also not like locusts, a different species of insect known for swarming and inflicting devastating damage to crops. Russell says that after cicadas first emerge, they crawl up into trees to mature. Then the singing starts.
“I've read where the noise may reach 100 decibels,” said Russell. “That's sort of close to a lawnmower or chainsaw, leaf blower, or something like that. That's pretty loud.”
The male cicada sings to attract female cicadas, Russell explains. The cicadas mate, then the female slices open a tree branch to create a place to lay her eggs. She dies after the laying is complete. Then, about five to six weeks later, the eggs hatch, and the young cicadas — called nymphs — fall to the ground, tunnel into the soil, and start munching on plant roots, as they start their 17-year-long wait underground.
“I mean, in terms of what we consider a full, enriching life, it doesn't seem like much,” Russell said. “But to a cicada, that's what they do.”
Wondering where and when you can see these bugs for yourself? Russell says the cicadas emerge from the ground en masse when the soil temperature reaches about 64 degrees Fahrenheit. Scientists guess that will be in late April or early to mid May.
Because periodical cicadas exist only in eastern North America, they won’t be surfacing all over Michigan. Russell says that over the past several Brood X cycles, scientists have recorded emergences in Washtenaw, Genesee, Livingston, Oakland, and Lenawee Counties. But generally, the Brood X bugs are most likely to emerge in southeastern Michigan, particularly the Ann Arbor area.
Russell adds that while Brood X usually emerges in the same areas across cycles, when humans cut down trees in a particular location — removing a source of cicada food as well as a place where they lay their eggs — the cicadas’ habitat can be destroyed.
“A lot can happen in 17 years,” Russell said. “That's probably why the Cherry Hill Nature Preserve outside of Ann Arbor continues to be a good spot to go and witness the spectacle, because it's undisturbed natural area, lots of mature trees. It's perfect for cicadas.”
So, how can you prepare for Brood X’s imminent arrival? Russell says it isn’t a good time to plant young trees, especially hardwoods, because female cicadas might damage them as they create spots to lay their eggs. For Michiganders with dogs, it’s recommended that you monitor your pet’s cicada consumption, as too many could lead to an upset stomach or an allergic reaction. And if the cicada song bugs you, you might want to consider some earplugs.
Insect enthusiasts — especially young bug fans who’ve never seen Brood X before — can check out a cicada map to ensure they get a chance to see (and hear) this special natural phenomenon.
“It'll be a spectacle this summer, for sure,” said Russell.
This post was written by Stateside production assistant Nell Ovitt.