Brood IX: Why the 2020 cicada visit will be different than past arrivals
The 17-year cicadas are spreading across the Eastern United States.
Things are getting noisy in parts of North America.
After 17 years underground, it's time for millions of cicadas to emerge in southwestern Virginia, West Virginia, and North Carolina. They're known as Brood IX. They're red-eyed, loud-as-a-lawn-mower, and ready to have a single glorious month above ground before they die.
There are more than 190 species and subspecies of cicada in North America alone. While some of these curious creatures appear every year, others have a unique life cycle. Two types of cicada, 13- and 17-year cicadas, stay underground for their namesake time period before they emerge as nymphs — the name for immature cicadas.
Once above ground, the cicadas make the transition from nymphs to mature adults and try to lay as many eggs as possible. The hope is that their kids can survive and go on to live their own underground life. It's a real strength-in-numbers kind of move: Cicadas make a tasty treat for plenty of predators, including birds, rodents, fish, insects, arachnids.
What is Brood IX?
In North America, batches of cicadas on the same multi-year cycle are known as broods. They tend not to overlap geographically, so a given area will only see 17-year cicadas every 1.7 decades.
This year, Brood IX is finally having its moment. The last time they emerged was 2003.
Although they're the same brood, multiple species will be part of the big event. There are three species of 17-year cicadas in North America:
- Magicicada septendecim
- Magicicada cassini
- Magicicada septendecula
The cicadas are black and reddish-orange, and while you might not be able to tell them apart, they have distinct shapes, sizes, and sounds. This massive insect emergence tends to be extremely loud:
Brood IX is actually one of the smaller 17-year broods. Scientists are especially interested in it because it's nestled between several other 17-year broods, and possibly one 13-year brood, John Cooley, a professor of ecology and evolutionary biology at the University of Connecticut, tells Inverse.
Brood IX is also special because it is polyphyletic, meaning the cicadas come from two separate ancestries that scientists think diverged during the Pleistocene epoch.
"It is not the only polyphyletic brood, but the phenomenon is interesting nonetheless," Chris Simon, also a professor of ecology and evolutionary biology at UConn, tells Inverse.
Where and when will they climb out of the ground? — The process has already begun: Over the past week, cicada experts have reported sights of Brood IX.
These cicadas are coming up in southwestern Virginia, West Virginia, and North Carolina, and they'll continue to arise in the coming weeks, peaking in early June and declining by July, reports Virginia Tech.
The life of a cicada, though, is fleeting: Brood IX will only remain above ground for about four to six weeks before they begin to die off.
Perched on branches and trunks of trees, the cicadas will shed their nymph shells and spread their grown-up wings. Then it's time to start the cycle over again by laying eggs for the next cicada coming.
Those blessed with a glimpse of this year's brood can expect to see masses of cicadas seemingly spring to life and leave behind their old casings on trees. There could be as many as 1.5 million cicadas per acre, reports Virginia Tech.
Will the Covid-19 pandemic change anything for the cicadas? — Like most of 2020, this year looks different than most. Normally, researchers would flock to the area where the brood is emerging. But the global pandemic makes that impossible.
"For researchers, everything is different this year since many of us cannot travel," Cooley says. "So the data we cannot get is just another entry in a long list of things lost in the pandemic."
Some researchers are asking people to help gather cicada data by using an app called Cicada Safari, developed by researchers at Mount St. Joseph University. If you live in one of the areas where Brood IX is emerging, you can photograph the cicadas and submit them, contributing to a map of the emergence.
What do they want? — What cicadas want most of all, like all animals, is to survive.
It might seem weird that a single brood of cicadas waits long enough to become a teenager, then doesn't even get to enjoy a full summer above ground. But researchers think this life cycle is all about tricking cicada predators — making sure that they can't sync up their schedules with the next cicada emergence.
The cicadas generally follow an emergence schedule of either 13 or 17 years — both prime numbers. The schedule's indivisibility makes it more difficult for predators to predict the next emergence, research suggests.
What do they sound like? — One of the most noteworthy parts about a mass cicada emergence is the sound the swarms of cicadas emit. The screech of a cicada has been likened to an "alien-like wail" and "field of out-of-tune car radios."
The bizarre, robotic sound happens thanks to an organ called a tymbal, a membrane located in a male cicada's abdomen. With the help of fast-moving muscles, the tymbal vibrates, producing the cicada's song.
But not all cicada sounds are the same. Brood IX includes several species of cicada, and each has a distinct sound, Cooley says.
On the website Cicada Mania, you can play different cicada sounds to hear the difference between a call, a sign of distress, and full chorus of cicadas.
Is a cicada the same as a locust? — While both animals can swarm impressively, cicadas are not the same as locusts.
Locusts are a species of short-horned grasshopper — part of the order Orthoptera — while cicadas are in the order Hemiptera, also known as true bugs.
When is the next brood coming? — Look out for Brood X in 2021.
Known as the Great Eastern Brood, this batch of cicadas will emerge in parts across the eastern United States. The brood has been spotted before in Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington, D.C.
Some people might not have to wait until 2021 to see these guys — there are reports that a few have already begun to rise.