(WBBM NEWSRADIO) – – It hasn’t happened since the Louisiana Purchase in 1803, but two broods of cicadas are expected to emerge at the same time this spring, bringing 1 trillion of the insects to Illinois and the Midwest.
Unlike dog-day cicadas that serenade us annually, periodical cicadas have been growing underground for 13 years or 17 years.
University of Illinois entomologist Kacie Athey said the Northern Illinois Brood and Great Southern Brood should are expected to emerge in mid-May or June when the ground warms to 64 degrees.
As the name indicates, the Northern Illinois Brood is what we’ll see in the Chicago area, while the Great Southern Brood should show up south of Joliet.
Athey said parts of far southern Illinois could potentially see a third brood, as well: the Mississippi Valley Brood that has been known to show up four years early.
The insects should only stay for about four weeks before they die off.
Athey and other researchers will be busy mapping the overlapping emergence to see if any of the broods have gone extinct.