An invitation to the cicada party
By Eleanor Lutz
Some of our insect neighbors are already kicking off their once-in-a-cicada-lifetime party.
Before the festivities are over, billions of cicadas, part of a cohort called Brood X, will emerge from underground tunnels to sing, mate and die across the Eastern United States. Like any good party, the emergence will be loud. It will be crowded. And everyone’s invited.
Singing: The party will be announced by a cacophony of cicada song, as the males begin to gather in a treetop chorus to call for mates.
Mating: The Brood X females won’t sing in the chorus, but they have plenty of other activities to keep them occupied. After mating, a female cicada needs to choose a tree that will safely harbor her offspring for the next 17 years. Then she will use a sawlike appendage called an ovipositor to insert her eggs into a young branch.
Dying: The frenzy of singing, mating and egg laying will last just four to six weeks. Then the adult cicadas will die and fall to the ground, creating piles of brown carcasses underneath the trees.
The Brood X cohort actually consists of three different cicada species. The males of each species sing a distinctive song to attract others to their chorus. Males also have additional songs for courting nearby females, and they can make a rough, buzzing alarm if they are picked up or handled.
Male cicadas sing by using their muscles to flex ribbed structures called tymbals. A hollow air chamber inside the abdomen is thought to amplify their song. Females don’t have tymbals and can’t sing, but they respond to males by flicking their wings to make a faint clicking sound.
Thousands of Brood X cicadas will be eaten by hungry predators, ranging from birds to small mammals — likely even some household pets. These cicadas have few defenses. They don’t bite or sting, and they aren’t toxic or poisonous. Instead, their survival strategy seems to consist of emerging in such overwhelming numbers that the area’s predators can’t possibly eat them all. As for the cicadas themselves, they feed by drinking a watery fluid inside the xylem of trees and plants.
Brood X — or the Great Eastern Brood — is one of the largest periodical cicada broods in the United States. The insects are expected to emerge this year in at least 15 states, including in cities like Baltimore, Cincinnati, Indianapolis and Washington.
Periodical cicadas occur throughout the Eastern United States but are relatively rare across the world. Outside North America, there are eight-year periodical cicadas in Fiji and four-year cicadas in India.
Throughout history, periodical cicadas have been carefully tracked and mapped by agencies like the U.S. Department of Agriculture. Today, many scientists use community science projects like the Cicada Safari phone app to track the broods. Anyone using the app can take a photo of their neighborhood cicadas to contribute to the mapping effort.
As Brood X begins to emerge, you may see brown, cicada-shaped suits attached to trees or on the ground. These are leftover casings shed by the immature cicadas as they become adults.
During their 17 years in the ground, Brood X cicadas shed their skin four times as they move through their life cycle. The immature underground cicadas, called nymphs, also leave behind tunnels from their journey to the surface, which you may notice as tiny holes in the ground.
When they first crawl out of their nymphal skin, adult cicadas are the color of a slightly green toasted marshmallow. As they complete their transition into adults, their bodies will gradually harden and turn black. Brood X cicadas are known for their charismatic red eyes, though a rare few may have other colors, like blue or white.
The Brood X cicadas are due to appear aboveground from early May into June, depending on the weather. Although some go-getters can emerge early, the mass emergence usually begins after the soil temperature warms to 64 degrees Fahrenheit.
If you miss this party, the next one won’t be until 2024, when Broods XIII and XIX emerge throughout Illinois and other parts of the Midwest as well as the Southern United States.