Ash Street Housing Cooperative, in Park Forest, Illinois, is located directly across the street from the Sauk Trail Forest Preserve, offering our residents a daily look at nature's finest. This year, however, we'll be seeing possibly more nature than we bargained for, with two cicada broods emerging at the same time!
A Rare Occurrence
In the spring of 2024, Ash Street Cooperative, along with the woodlands and neighborhoods of Illinois, will reverberate with a symphony unlike any witnessed in over two centuries. A remarkable phenomenon is set to unfold as two distinct broods of periodical cicadas, creatures renowned for their prolonged subterranean existence and deafening mating calls, synchronize their emergence after 13 and 17 years respectively. This convergence, a rarity not seen since the early 1800s, promises to be a spectacle of nature's resilience and an extraordinary opportunity for scientific observation.
The Cicada Life Cycle: A Masterpiece of Patience
Periodical cicadas, scientifically classified under the genus Magicicada, are among the longest-lived insects on our planet. Their lifecycle spans 13 or 17 years, with the vast majority of this time spent underground, patiently feeding on the sap from tree roots.
This extended developmental period is a remarkable evolutionary strategy, believed to have originated during the ice ages when colder temperatures slowed their growth, inadvertently synchronizing their emergence cycles.
The Dual Emergence: A Confluence of Broods
In 2024, Illinois will bear witness to the simultaneous appearance of Brood XIII (13), also known as the Northern Illinois Brood, and Brood XIX (19), the Great Southern Brood. Brood XIII, comprising three species of 17-year periodical cicadas will grace the northern regions of the state. Simultaneously, the southern half will play host to Brood XIX, a formidable group consisting of four species of 13-year cicadas.
Park Forest just happens to be located within the overlap range where both broods are predicted to emerge in what has been jokingly dubbed the "cicadapocalypse".
The Awakening: Timing and Emergence Cues
The awakening of these ancient insects from their subterranean slumber is a meticulously orchestrated event, triggered by the warming of the soil to a precise temperature of 64°F (18°C) at a depth of 8 inches (20 cm). This climatic cue, expected to occur in mid-May, will prompt the nymphs to commence their journey towards the surface, where they will shed their exoskeletons and transform into their winged, adult forms.
The emergence itself will be a staggered process, unfolding over approximately six weeks, during which time the cicadas will engage in a frenetic symphony of mating calls and reproductive activities, culminating in the laying of eggs within the tender branches of woody plants.
The Broods: A Synchronized Symphony
The concept of a "brood" is central to understanding the periodical cicada phenomenon. A brood is a group of cicadas that emerge in a given year, regardless of species. The 12 broods with 17-year life cycles and three broods with 13-year cycles are each assigned a Roman numeral, representing their unique emergence patterns. For instance, Brood XIII emerges every 17 years (1973, 1990, 2007, 2024, 2041, etc.), while Brood XIX surfaces every 13 years (1985, 1998, 2011, 2024, 2037, etc.).
The Prime Number Theory: An Evolutionary Advantage
One of the most intriguing theories surrounding the periodical cicada's life cycle revolves around the prime numbers 13 and 17. Scientists hypothesize that these prime-numbered emergence intervals may have evolved as a defense mechanism against predators, making it challenging for other organisms to synchronize their life cycles with the cicadas', thus ensuring their survival and successful reproduction.
Predator Saturation: A Strategic Emergence
Another proposed rationale for the cicadas' mass emergence lies in their sheer numbers. Historical accounts from the Field Museum in Chicago estimate that as many as one million cicadas emerged per acre in a forested floodplain during the 1956 emergence, with over 130,000 emerging per acre in an upland site. This overwhelming abundance is believed to be a strategic adaptation, enabling the cicadas to overwhelm and satiate predators, ensuring that a significant portion of their population survives to reproduce.
Citizen Science and the Cicada Safari
The dual emergence of Broods XIII and XIX presents a unique opportunity for citizen scientists to contribute to the understanding of these remarkable creatures. By downloading the Cicada Safari app, available for free on the web, users can photograph any cicadas they encounter, with the images being sent directly to researchers. This crowdsourced data is invaluable for mapping the emergence patterns and studying the potential impacts of climate change on cicada populations, enabling scientists to make more accurate predictions for future emergences.
A Fleeting Spectacle: Embracing Nature's Rhythm
As the adult cicadas' brief aboveground sojourn draws to a close, their decaying bodies will nourish the soil, completing a cycle that has persisted for millennia. This ephemeral spectacle serves as a poignant reminder of the intricate rhythms that govern the natural world, rhythms that have endured through ice ages, societal transformations, and the relentless march of human progress.
Amid our fast-paced, technology-driven lives, the emergence of the periodical cicadas beckons us to pause, to marvel at the resilience of these ancient creatures, and to embrace the fleeting beauty of nature's grand symphony.
While we may not all feel like calling ourselves “fortunate enough” to witness this dual emergence, (think…seriously large bugs in massive quantities), on a historical level, we truly are.
Not yet a member of Ash Street Housing Cooperative? Take a look at our available units and stop by the office to learn more!
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