Every few years, Illinois becomes the center of attention for nature enthusiasts and curious onlookers when cicadas emerge in massive numbers. These insects, known for their loud, buzzing calls and unique life cycles, have fascinated scientists and residents alike for generations. The question Are cicadas in Illinois? often arises during spring and summer months, especially when large broods are expected to surface. The answer is a definite yes Illinois is one of the most active regions in the United States when it comes to cicada activity, particularly during the years when both annual and periodical broods overlap.
The Presence of Cicadas in Illinois
Cicadas are indeed present throughout Illinois, from the far northern counties near Chicago to the southern tip near Cairo. The state provides a perfect environment for these insects, offering plenty of trees for them to feed on and lay eggs. While annual cicadas appear every year in smaller numbers, periodical cicadas emerge in tremendous swarms once every 13 or 17 years, depending on the brood cycle.
Illinois is special because it hosts both 13-year and 17-year cicadas, which makes it one of the few places in the country where residents can experience these extraordinary events. The most famous broods, such as Brood XIII and Brood XIX, are well documented and attract attention from scientists and media outlets whenever they appear.
Types of Cicadas Found in Illinois
There are two main types of cicadas found in Illinois annual cicadas and periodical cicadas. Each has distinct characteristics and life cycles
- Annual CicadasThese cicadas appear every summer. They are often greenish or brown in color and have clear wings. Annual cicadas are also called dog-day cicadas because they emerge during the hottest part of summer, typically between July and September.
- Periodical CicadasThese cicadas are unique to North America and emerge either every 13 or 17 years. They spend most of their lives underground feeding on tree roots before surfacing as adults to mate and lay eggs. Their mass emergence can number in the billions, creating a loud and unforgettable event.
In Illinois, the most notable periodical broods include the 17-year Brood XIII and the 13-year Brood XIX. Occasionally, their emergence years overlap, creating an extraordinary phenomenon rarely seen elsewhere.
Life Cycle of Cicadas in Illinois
The cicada life cycle is one of nature’s most fascinating biological rhythms. After mating, female cicadas lay eggs in small twigs or branches. When the eggs hatch, the tiny nymphs drop to the ground and burrow into the soil, where they feed on tree sap from roots. This underground phase can last for years 13 or 17, depending on the species.
When the time comes, the nymphs tunnel to the surface, usually in late spring when soil temperatures reach around 64°F (18°C). They then shed their outer skins, transforming into winged adults. This process, known as molting, often leaves behind hundreds of brown exoskeletons clinging to tree trunks, fences, and buildings. Adult cicadas live for only a few weeks, during which they focus on reproduction before dying off, leaving their eggs to continue the cycle.
Why Cicadas Are Important to Illinois Ecosystems
While the sight and sound of billions of cicadas might seem overwhelming, these insects play a crucial role in maintaining healthy ecosystems. Cicadas provide food for many animals, including birds, raccoons, squirrels, and even fish. Their emergence serves as a natural feast that supports wildlife populations.
Additionally, when cicadas die, their bodies decompose and enrich the soil with nutrients, improving plant growth. Their burrowing also helps aerate the soil, allowing for better water absorption and root health. Despite being noisy and numerous, cicadas are an essential part of Illinois’s natural balance.
When and Where to See Cicadas in Illinois
The timing of cicada appearances depends on the type of brood. Annual cicadas appear every summer, typically from mid-July through early September. Periodical cicadas, however, follow a predictable cycle that can be traced using historical records.
Residents in Illinois can experience periodical cicadas in specific years when major broods emerge. For example, Brood XIII, a 17-year brood, is known to appear in northern Illinois, including areas around Chicago and Rockford. Meanwhile, Brood XIX, a 13-year brood, emerges in the southern and central parts of the state. During overlapping years, the state witnesses an incredible display of both broods emerging at once a rare natural spectacle.
The Famous Cicada Sounds
One of the most recognizable features of cicadas in Illinois is their distinctive buzzing sound. Male cicadas produce this sound to attract females by vibrating special membranes called tymbals located on their abdomens. Each species has a slightly different song, allowing females to identify males of their own kind.
During mass emergences, the sound can reach up to 100 decibels, roughly as loud as a motorcycle engine. While some people find the noise bothersome, others view it as a fascinating reminder of nature’s rhythm. The chorus of cicadas becomes a signature sound of Illinois summers.
Common Misconceptions About Cicadas
Despite their intimidating appearance and numbers, cicadas are harmless to humans and pets. They do not bite or sting, nor do they pose a direct threat to gardens or crops. Their main activity is mating and laying eggs, and while female cicadas may cause minor damage to young trees by cutting slits into twigs for egg-laying, established plants are rarely affected.
Another common misconception is that cicadas are locusts. While both can appear in large numbers, cicadas and locusts belong to entirely different insect groups. Locusts are a type of grasshopper that can destroy crops, whereas cicadas do not feed on leaves or grains and are not agricultural pests.
How Residents Can Prepare for Cicada Season
For Illinois residents living in areas where cicadas are expected to emerge, preparation can make the experience more manageable. Although they do not cause major harm, their presence can be overwhelming due to their sheer numbers and noise. Homeowners can take a few simple steps to get ready
- Cover small or newly planted trees with netting to protect them from egg-laying females.
- Keep windows and doors closed to prevent cicadas from flying indoors.
- Avoid using power tools or lawn equipment during peak hours of cicada activity to minimize noise interference.
- Teach children and pets that cicadas are harmless to avoid unnecessary fear or curiosity.
Most importantly, people should try to enjoy the phenomenon. Cicada emergences are temporary and rare, offering a unique chance to witness a natural event that connects generations.
The Next Big Cicada Event in Illinois
The state’s next major cicada event will depend on the brood cycles, but Illinois often experiences at least some cicada activity every summer due to its diverse population. When both 13-year and 17-year broods overlap, as happened in 2024, the event becomes even more spectacular, drawing media coverage and scientific observation from across the country.
For residents and visitors alike, witnessing billions of cicadas emerging at once can feel like stepping into another world a living example of nature’s timing and precision. Even though the event may seem chaotic, it represents one of the most organized and predictable biological phenomena on Earth.
So, are cicadas in Illinois? Absolutely. These remarkable insects are an integral part of the state’s ecosystem, appearing both annually and in massive periodical events that attract attention from scientists and nature lovers. Whether admired for their songs or marveled at for their synchronized life cycles, cicadas are a reminder of nature’s power and mystery. While their presence might test the patience of some residents, it’s worth remembering that their brief stay brings life, sound, and renewal to Illinois’s landscapes until they retreat underground once more to continue their timeless rhythm.