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The cicadas are coming! Or are they?

  • Mike Baltz photos

By Mike Baltz
updated: 6/1/2021 3:24 PM

Unless you've been living under a rock, you've heard about Brood X, also known as the Great Eastern Brood, and its emergence this summer in parts of 15 states.

But news flash: Only parts of Illinois are expected to be impacted by Brood X, specifically a few eastern counties along the Illinois-Indiana border. So, it doesn't look like southern Illinois will be getting any periodic cicadas this year.

Cicadas, sometimes called locusts because of the enormous numbers that periodically emerge, are not a kind of grasshopper (as the common name "locust" would suggest), but are technically "true bugs" most closely related to planthoppers, aphids and, interestingly, bed bugs.

There is the dog-day group of cidadas that emerge in small numbers from July to September across much of the eastern United States and the periodical cicadas that have 13- or 17-year life cycles. The emergence of periodical cicadas is pretty much a Midwestern and mid-Atlantic phenomenon, and there are broods emerging somewhere in those states every year. Last year, for example, Brood IX of the 17-year cicadas emerged in parts of West Virginia and Virginia.

Entomologist C. L. Marlatt began assigned Roman numerals to the different broods of periodic cidadas in 1898. He assigned brood numbers I through XVII to the 17 distinct broods of the 17-year cicada and numbers XVIII through XXX to the 13 distinct broods of the 13-year cicada. Interestingly, only 15 of those 30 broods are known to survive today.

In southern Illinois, we only get 13-year cicadas, and you may remember the last emergence, back in 2015 (Brood XVIII). Unfortunately, I had also planted a couple of apple trees that spring. I say unfortunately, because my poor little apple trees didn't stand a chance against the cicadas. First, female cicadas slit the bark of tree limbs and lay their eggs in the grooves. The groove provides shelter to the egg, and once the cicada hatches from the egg it begins feeding on the tree fluids. Then, when the young cicadas are ready, they crawl out of the groove, fall to the ground and dig until they find the host tree roots, on which they feed until they emerge again!

For the record, 2024 promises to be a big cicada year all across Illinois. There will be an emergence of 17-year cicadas (Brood XII) in the northern half of the state and an emergence of 13-year cicadas (Brood XXIV) in the southern half of the state.

So, mark your calendar and definitely avoid planting any trees in the spring of 2024!

• Mike Baltz has a PhD in biology from the University of Missouri and writes about changing the world from his home in Carbondale.