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Badgering the Bug Guy: P. J. Liesch MS’10

Entomologist P. J. Liesch is Wisconsin’s Bug Guy — director of the university’s insect Diagnostic Lab. And with cicadapocalypse predicted for the summer of 2024, he’s preparing to see a lot of new chitinous companions.

Cicadapocalypse is coming.

In 2024, between the middle of May and the beginning of July, billions of periodical cicadas will emerge across the central and southern United States as the Brood XIII (which appears every 17 years in southern Wisconsin and most of Illinois) and Brood XIX (which appears every 13 years in Missouri, Illinois, and much of the South) emerge at the same time. It’s the first time the two broods have synced their appearance since 1803.

It's an exciting time to be a bug guy — or rather, the Bug Guy. P. J. Liesch MS’10 is director of the UW’s Insect Diagnostic Lab, and he has been in demand. In a typical year, Liesch receives about 2,500 requests to identify insects, most of which arrive as photos, but some come in envelopes or are brought by curious individuals. The Insect Diagnostic Lab’s job is to help people identify the creeping, crawling, and flying critters that they find in homes, gardens, fields, and forests.

But this year, Liesch is a media darling. He’s had about a dozen interview requests a week from journalists who want to know what to expect when the brood emerges. (“You’re actually interview number two of three for the day,” he says, “on the topic of cicadas.”)

This will be the first time periodical cicadas have emerged since Liesch took over the lab from its founder, P. J. Pellitteri ’75, MS’77, in 2014. “I’ve really been reading a lot about cicadas and have really become pretty fond of them,” Liesch says. We at Badger Insider went to him for the cicada scoop.

Don’t we see cicadas every year? What’s different?

The periodical cicada is a different type of cicada than the one that we see every year, later in the year, usually in July, August, and September. Those are annual or dog day cicadas because they’re out in the hot dog days of summer. The black-and-orange ones, only come out once every 17 years. There are actually three species of periodical cicadas in Brood XIII, but we only have specimens of one species here in Wisconsin. The dog day cicadas and periodical cicadas have different calls, and actually, the different species of periodical cicadas will have different calls as well. On my cicada website, I have some audio clips to tell them apart. There’s also a really cool website called, and they have a photo guide and audio clips.

What should we know about this year’s cicada brood?

The first thing I would highlight about this is that they come out every 17 years. If you’re lucky, you maybe have a handful of opportunities in your entire life to see these insects here in the Badger state. Another thing is that they’re generally harmless. They are going to come out in tremendous numbers in spots where they occur, but their overall distribution in Wisconsin is really pretty spotty. It’s really like pins on a map. You have them in these very particular spots, and in between those spots, they probably just don’t occur anymore. It’s also going to be very loud because the males produce sounds. They essentially sing to attract the females. If you’re up really close to that, it can be in the range of 90 to 100 decibels, which would be like being right next to a loud, busy highway

You say, “generally harmless.”

They are pretty clumsy, as far as insects go. And they’re also, for the most part, pretty defenseless. Animals are going to feast upon them. It’s going to be a free smorgasbord out there. Their damage isn’t through their feeding. It’s when the females go to lay eggs. They cut slits in branches and twigs.

And eyeballs?

Not quite. They won’t lay eggs on people or animals. It’s only on twigs in woody plants. If the female lays eggs on twigs or small branches, it might end up killing the outer six to 10 to 12 inches of those branches. The leaves there can turn brown, the twigs snap off. For large trees, this is going to be noticeable, but it’s essentially harmless. If you have a small tree and the canopy isn’t that large, the outer eight, 10, 12 inches might be damaged, which could be a pretty large percentage of the canopy. But in a case like that, you just cover the tree with some fine-mesh netting and tie that off. Cover the plant for the month or so when the adults are active, and once they’re gone, they’ll be gone for 17 years.

What do they do during those 17 years?

The eggs sit on the branch for about a month and a half to two months. At that point, the young juveniles, which we call nymphs, emerge and drop to the ground, where they burrow into the soil. They usually go down maybe about eight to 12 inches, and that’s where they're going to hang out for the next 17 years. They tunnel around and drink sap from tree roots. They spent well over 95 percent of their entire life below ground.

You say there will be a smorgasbord. Have you eaten a cicada?

I have not. But on my cicada website, I shared a link to a cicada cookbook. There are all sorts of recipes out there. Some of them actually sound pretty interesting. You fry them up, add some spices, you pair that with an IPA or something. That doesn’t sound all that bad.

What should cicada watchers do this year?

My website has a community science project, and I’d love to receive any cicada sightings, especially in spots where maybe we haven’t documented them before. I’m just trying to get a better idea of where they are, and document roughly how many might be present to gauge population size. And I encourage any photographs that [people] might take. You can just go on the website, answer a brief questionnaire, and upload a couple photographs, and that goes to a database. And then I’ll sift through all those and, hopefully, improve our Wisconsin cicada map a little bit.

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