A Rare Synchronization: Central Illinois to Witness Dual Cicada Emergence

In a remarkable natural phenomenon not witnessed since 1803, Central Illinois is poised to experience a rare, synchronized emergence of two different cicada broods this spring. Brood XIII, a 17-year cycle cicada, and Brood XIX, a 13-year cycle species, will simultaneously break ground in an event that last occurred when Thomas Jefferson was president.

This year’s dual emergence is a once-in-a-lifetime event. The intersection of these two distinct life cycles, occurring only once every 221 years, is set to unfold across the Midwest and Southeast, beginning in late April. While individual 13-year and 17-year broods have occasionally overlapped, the specific pairing of Brood XIII and Brood XIX is notably unique, especially since these broods inhabit adjacent areas with a shared zone in central Illinois.

The spectacle is not just a marvel for entomologists but also a significant occurrence for the local communities. The emergence of billions of cicadas, known for their high-pitched mating songs reaching up to 100 decibels, is expected to create a symphony of sounds, drawing both fascination and mild annoyance. Despite their alarming numbers and loud mating calls, these insects pose no threat to humans.

Cicadas typically emerge when soil temperatures reach about 64 degrees Fahrenheit. Brood XIII, primarily found in the Midwest, has its population centered in Illinois, stretching into neighboring states like Wisconsin, Ohio, and Iowa. Meanwhile, Brood XIX boasts a broader geographical span, including Missouri, Illinois, Louisiana, North Carolina, Virginia, and Maryland.

The life cycle of these cicadas is intriguing. They spend the majority of their lives underground, feeding on tree roots. Upon emerging after 13 or 17 years, they engage in a frenetic month-long mating ritual before concluding their life cycle.

Gene Kritsky, an entomologist at Mount St. Joseph University and the author of “A Tale of Two Broods,” emphasizes the rarity of this event and the curiosity it has sparked. His 2019 app, Cicada Safari, encourages citizen scientists to document sightings, contributing to a broader understanding of these insects’ behavior and distribution.

While the main stage for this natural drama is set in central Illinois, the impact of this emergence will be felt across several states. From late April through June, areas across the Southeast and Midwest will witness the gradual appearance of these cicadas. After mating, the insects die off, leaving behind a brief but memorable natural phenomenon.

This year’s dual emergence provides an extraordinary opportunity for both scientific study and public engagement with nature. Researchers like Kritsky are particularly interested in tracking the cicadas’ range and studying potential cross-breeding between the two broods. Beyond its scientific significance, the event offers a unique chance for residents and visitors alike to witness a natural spectacle that won’t repeat for another 221 years.