A red-eyed cicada insect sits on a long green leaf.
Periodical Cicada Two cicada broods are simultaneously emerging for the first time in two centuries in Illinois. © David Gumbart/TNC

Stories in Illinois

Illinois' Summer Cicada Symphony: 200 Years in the Making

Everything you need to know about the double-brood periodical cicadas emerging in the Prairie State.

Picture this: you're taking a walk on a warm day in June, admiring the sun's rays shining through trees swaying in the breeze. One collective sound rises above the rest of nature's symphony: the inescapable hum of hidden cicadas.

This iconic cicada cacophony can be heard most summers in Illinois, but 2024 is a particularly special year for these critters. Two broods, or groups of periodical cicadas, are emerging simultaneously for the first time in 200+ years (since 1803), and Illinois is one of two states (the other being Iowa) where both broods will be making an appearance.

Keep reading to find out who will be a part of this year's cicada chorus, what they contribute to nature's band, where you can go to hear their songs in Illinois and more.

Billions of Cicadas Emerge After 17 Years (2:25) TNC's Conservation Ecologist, Deborah Landau explains this amazing natural phenomenon happening every 17 years.
Cicadas emerging out of their shells.
Periodical Cicadas Cicadas are at their most vulnerable right after shedding their shells. It takes a newly emerged cicada around 30 minutes for its new carapace to harden. © David Gumbart/TNC

Cicada Broods to Expect in This Year's Emergence

This spring, two broods are sprouting at the same time in the Prairie State for the first time since 1803—Brood XIII and Brood XIX—and they won't cross paths like this again until 2245.

Periodical cicadas spend most of their lives underground, emerging after 13 or 17 years (depending on the species) to transform, reproduce and eventually die over the course of just a few days. Characterized by their big red eyes and orange-veined wings, they leave quite the impression in the short time they are above ground.

A cicada on a flower.
Brood XIII Cicada Northern brood cicadas have emerged at TNC's Nachusa Grasslands preserve. © Charles Larry

Cicada Brood XIII Fast Facts

Nickname: Northern Illinois brood
Species included: Magicicada cassiniMagicicada septendecimMagicicada septendecula
Life-cycle length: 17 years
Emergence range: Illinois, Iowa, Indiana, Michigan and Wisconsin

Source: University of Connecticut Biodiversity Research Collection
× A cicada on a flower.
A cicada with bulging red eyes emerges from its shell. The empty brown husk is attached to a tall stem of grass.
Coming Out of Your Shell Cicadas will burst out of their exoskeleton just a few hours after emerging out of the ground. © Douglas Croft/TNC Photo Contest 2021

Cicada Brood XIX Fast Facts

Nickname: Great Southern brood
Species included: Magicicada neotredecim, Magicicada tredecim, Magicicada tredecassini, Magicicada tredecula
Life-cycle length: 13 years
Emergence range: Illinois, Iowa, Louisiana, Maryland, Missouri, North Carolina and Virginia

Source: University of Connecticut Biodiversity Research Collection

× A cicada with bulging red eyes emerges from its shell. The empty brown husk is attached to a tall stem of grass.

"These cicadas spend 16 years underground drinking the sap from tree roots, so you only find them near trees and forest habitat," explains Dr. Elizabeth Bach, the research scientist at TNC's Nachusa Grasslands Preserve (one of TNC's preserves that will witness a brood XIII emergence this year).

Once they begin to emerge, the symphony will begin. Illinois residents can expect to see, or more likely hear, trillions of cicadas this spring. This happens as a result of an evolutionary survival strategy called predator satiation. When a population of organisms shows up in mass, predators get their fill, but can’t possibly eat all the creatures. This ensures that plenty of cicadas will live on and reproduce. For cicadas, there is certainly safety in numbers.


Quote: Dr. Elizabeth Bach

After 17 years, they emerge from the ground as semi-adults. They harden into their exoskeletons and become full-fledged adults, and then they spend a couple of weeks calling for mates.

Dr. Elizabeth Bach Nachusa Grasslands Restoration Scientist
Five adult cicadas perch on the tall blades of a green plant.
Cicadas Emerge Cicadas in Killingworth, Connecticut. © David Gumbart/TNC

Brood XIII Cicadas Calling for Mates

At Nachusa Grasslands, mating season for Northern Illinois Brood XIII cicadas is in full swing.

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Cicadas calling for mates.

After the cicadas mate, the females will lay their eggs in the branches of trees. Once the eggs hatch, the nymphs will crawl back into the ground near the tree's roots where they will spend years growing before emerging another 17 years from now. And just like that, the cycle repeats. Not much is known about what happens while they're underground since we can't see it, but they are likely not moving around or communicating with each other down there.

The exact emergence timing varies by location and other factors, the largest being soil temperatures. Soil must reach 64 degrees Fahrenheit before cicadas begin to come out. For example, soil is warmer near pavement, so areas in or near cities like Chicago are expected to see a faster emergence than other locations. Some cicadas have already begun to emerge at preserves like TNC's Indian Boundary Prairies Preserve and will continue to do so through mid-June.

Illinois Emergence Map

Since periodical cicadas are dependent on trees for sustenance, they are most likely to be found in forested habitat with plenty of trees. The Nature Conservancy has preserves that lie in both the Northern Illinois brood (XIII) region and the Great Southern brood (XIX) region.

Explore the map to see what preserves are near you and which brood you'll be able to hear by visiting.

Find a preserve with a brood near you RETURN

The Cicada's Contributions to Ecosystems

Despite their noisiness, periodical cicadas are a natural wonder that can provide a number of environmental benefits for the ecosystems they live in.

  • A bird on a tree branch.

    Cicadas are a huge food source for wildlife.

    Billions of cicadas will be emerging in Illinois this year. Many of them will serve as a valuable food source for birds and other natural predators, bolstering wildlife across the state.

  • Soil.

    The holes dug during the emergence helps aerate soil and filter water.

    While it may muddy up your lawn in the short term, the holes dug up by cicadas when they emerge will help in the long term by aerating the ground, allowing more water and oxygen to reach the soil that bolsters healthy plant and tree growth.

  • Flowers growing.

    Their bodies provide key nutrients needed for healthy soil.

    Like any carbon-based life-form, cicadas will eventually die and decompose in soil, releasing rich nutrients like nitrogen and carbon that help plants grow.

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Effects of Climate Change on Cicadas

The biggest surprise of this year's cicada emergence is how early they are coming out, appearing several weeks earlier than researchers expected.

A consequence of rising temperatures is lengthened growing seasons for the plants cicadas feed on. Longer growth seasons speed up and intensify cicadas’ development while still underground, which can cause some stragglers to emerge early. If enough of them fall into this early emergence pattern, the entire population could potentially shift timing permanently.

Similar to many other insects, cicada habitat ranges have also been shifting northward in recent years. As the climate warms, the normal range of plants and trees has gradually moved further up north, forcing cicadas to relocate to be near their preferred food sources.

Cicada on a leaf after shedding their exoskeleton.
Shedding the Exoskeleton Cicadas shed their exoskeletons in just a couple of hours. © Charles Larry
A cicada on a leaf.
Cicada Season Gardeners can breathe easy knowing cicadas will not destroy their hard work in the yard. © Charles Larry
Shedding the Exoskeleton Cicadas shed their exoskeletons in just a couple of hours. © Charles Larry
Cicada Season Gardeners can breathe easy knowing cicadas will not destroy their hard work in the yard. © Charles Larry

How You Can Help Cicadas

With cicadas popping up all over the state, you may be wondering how they will affect your pets, plants or yard. Good news: cicadas are harmless on all counts.

While they may emit a piercing screech to attract a mate, they do not bite or sting and are not poisonous to humans, dogs or cats. They also do not eat plants and will not kill mature trees and shrubs they may lay their eggs on. If you are worried about potential damage, the best thing to do is to cover your trees with netting. Spraying the tree with chemicals won’t stop the cicadas and may poison the animals that eventually eat them, so avoid pesticides.

Despite the blaring mating calls yet to come, Illinois residents have many reasons to be excited for this rare combination of cicada broods showing up in huge numbers this year. Enjoy the concert!

Three children stand together looking at a phone that one of them holds.
Inspiring a Love of Nature Children engaging in a nature learning game. © wavebreak media

Stay Connected to Cicadas

Help track this exciting natural phenomenon using phone apps like Cicada Safari and iNaturalist to record observations that can help to determine if or how a brood's range may have shifted since they last emerged.

Post your best cicada shots on social media too! Share your favorite photos and tag us on Instagram at @nature_illinois to keep the cicada conversations going.

× Three children stand together looking at a phone that one of them holds.