Cicada Map Shows States Where Trillions of Bugs Will Emerge

A map of where two periodical cicada broods have been observed across the eastern U.S. shows the areas in which they are likely to emerge in the next few weeks.

Experts are predicting that the two populations, which have been hibernating underground for over a decade, will appear at the same time, carpeting an area from southern Wisconsin to the Carolinas with as many as a hundred trillion bugs.

Periodical cicada broods develop over a number of years underground before burrowing up and out all at once. They are then active aboveground as adults for a matter of weeks before laying the next generation and dying off.

"It's like an entire alien species living underneath our feet and then some prime number years they come out to say hello," Saad Bhamla, a professor of biotechnology at the Georgia Institute of Technology, told Chicago TV station WFLD. "This year we're going to get two broods that are going to emerge at the same time."

Experts say that Brood XIX, which operates on a 13-year cycle, and Brood XIII, which arises every 17 years, are set to appear simultaneously—a coincidence that was last recorded occurring in 1803 and is not expected to occur again until 2076.

According to maps of where the two independent populations have been observed that were produced by the U.S. Forest Service and the University of Connecticut, Brood XIII occupies a smaller region, from southern Wisconsin to central Illinois, as well as parts of Iowa, Indiana and Michigan.

Meanwhile, Brood XIX—the largest in the U.S.—nests across a swath of the mid-South, from southern Iowa to the Carolinas, as well as parts of the Deep South. This brood is predominant in Missouri, southern Illinois and western Kentucky.

Based on where the different broods have been observed inhabiting, they may overlap in a portion of central Illinois, but it is not considered likely they will interbreed.

When they emerge, based on previous outings, the cicadas will cover fields and houses in their path with shed exoskeletons and produce a collective noise that rivals a jet engine in terms of volume.

Brood XIX has already been observed creating boreholes in the ground in Georgia, suggesting the swarm is about to come out of its hibernation, according to the Associated Press.

With the two broods emerging simultaneously, "you would have more than anywhere else any other time," Paula Shrewsbury, an entomologist at the University of Maryland, told WFLD.

The cicadas naturally emerge when the ground where they are nesting reaches 64 degrees Fahrenheit. While this usually occurs in the spring, entomologists say it is likely to happen earlier in the season because of the warming effects of climate change.