I've been hearing about the ensuing dual emergence of cicada broods this summer in the Midwest. I've even gotten a few queries about it, asking if I know anyone who can share expertise or be quoted, but I'm not an entomologist or a tree expert.
Today I finally saw this in one of my local papers, adapted from the New York Times:
Seeing this map made me realize the people who've written about the emergence have a very strange idea of what "the Midwest" means. They've been freaking out people in at least a dozen states, when what they really meant was two states, plus parts of a few others, and a bunch of the South, which I hadn't seen mentioned before.
The green dots are the Northern Illinois Brood and the red dots are the Great Southern Brood, according to this Illinois Extension flyer.
The only state that will get to experience the actual "dual" broods is Illinois, though whether that will be any worse than what happens in Missouri where it's just one kind of cicada is debatable. Southern Wisconsin looks no fun either.
In case you haven't heard, the last time these two broods coincided was more than 200 years ago. The fact that their territories are adjacent has naturalists very excited.
Here's my favorite new fun fact about the Northern Illinois Brood — it's known to be very populous:
In 1956, entomologists reported as many as 311 "emergence holes" per square yard in a forested floodplain near Chicago.
More than 300 holes in a square yard — for insects that are at least an inch long... that doesn't leave a lot of undisturbed ground behind.
The good news is, the cicadas die off fairly rapidly after mating and become food for the trees. (The buzz is the sound of the males hoping to attract females.) The die-off can be very messy and smelly.
2 comments:
East-central Illinois, as only people who live here call it, looks like it will again be nightmare alley for these critters. I remember the Great Confluence of 1998 — I would put my hands over my ears when walking home from teaching. One detail I’ll add — the cicadas become food for dogs too, who gorge and then vomit, like Roman emperors. It’ll be a fun summer!
What an image! Another fact I never knew.
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