Cicada Killer Giant Wasps

Cicada Killer Giant Wasps

Part of Ep. 2004 Whiffs, Wasps and Wonders

Entomologist Phil Pellitteri introduces us to a giant wasp new to Wisconsin.  Luckily it's not interested in humans--but cicadas beware!

Premiere date: May 12, 2012

TRANSCRIPT+
Wisc Gardener Transcript: 

SEGMENT #3: CICADA KILLER GIANT WASPS

 

Shelley:

If I saw these anywhere near me, I would run for the hills. These are the scariest looking wasp-like thing I've even seen. We are at Allen Centennial Gardens on the UW-Madison campus and I'm with UW-Extension entomologist Phil Pellitteri to hopefully give us good news about these monsters.

 

Phil Pellitteri:

This is kind of a special treat if you really want to think about it that way.

 

Shelley:

Oh, really?

 

Phil Pellitteri:

The critters are called cicada killers, and they are a type of solitary wasp. They remind you of the biggest yellow jacket you've even seen.

 

Shelley:

Oh, yeah.

 

Phil Pellitteri:

But the name really describes much more what they are about.

 

Shelley:

Cicada killers.

 

Phil Pellitteri:

And these things go around and attack cicadas, which are the creatures that start buzzing in the trees in the middle of July through August.

 

Shelley:

That kind of raspy noise especially late in the afternoon.

 

Phil Pellitteri:

Right. And what they need to do is dig a burrow into the ground. They will dig a burrow as deep as 5-7 inches.

 

Shelley:

Wow.

 

Phil Pellitteri:

Then they will go, the female will paralyze the cicada. She has to fly with it or drag it, whichever she can do, bury it in the ground, lay her egg. One of the fascinating things about their biology is if she puts one cicada in the hole, she will lay an egg that's not fertilized that will transform into a male.

 

Shelley:

Okay.

 

Phil Pellitteri:

If she puts two cicadas in the hole, she then will lay an egg that is fertilized and will transform into a female.

 

Shelley:

So the females get special treatment.

 

Phil Pellitteri:

Right.

 

Shelley:

Makes sense to me.

Phil Pellitteri:

Now, the way the life cycle works, this is what we would call a solitary wasp. This is not a nest. Once she provisions it and lays her eggs, she has nothing to do with it. And why this is important, is solitary wasps are not aggressive because there's no nest to defend.

 

Shelley:

So she doesn't stick around to raise these or to protect these eggs.

 

Phil Pellitteri:

No. Now here's what the complication is. It's big. It's scary looking. If you're in an area where these are found, the males are very territorial, and they literally patrol back and forth to keep other males out. They're looking for a female that's emerging and they're going to mate with her as quick as they can. That's part of their biology.

 

Shelley:

So the territory is more just to hang out. They're looking for the female. Again there's nothing they're protecting.

 

Phil Pellitteri:

Now they use landmarks to figure out where the territory is and like the mistake is if you walk into the area, you're a new landmark and they're very curious. And so people misread this as being an aggressive behavior. And so, you know, people go screaming and yelling they have giant wasps that are nesting in their house and it'll kill the kids. This is not the way this thing works at all. Now first of all, the males can't sting.

 

Shelley:

They can't?

 

Phil Pellitteri:

This is typical with bees. You know, males have no reason to have stingers. Stingers are basically modified egg laying devices. And if you're a male, you don't lay eggs.

Shelley:

That's true. So the females.

 

Phil Pellitteri:

Even with the females, you would have to tackle one of these to get stung and it's not going to happen because you'll notice they fly very well, and they'll fly away from you. You know they're not going to.

 

Shelley:

They're just not interested in us basically.

 

Phil Pellitteri:

Right.

 

Shelley:

Okay.

 

Phil Pellitteri:

Now, fun to talk about the cicada life cycle.

 

Shelley:

Well, let's bring them in, because they're also I happen to think they’re very, very beautiful, very primitive looking.

 

Phil Pellitteri:

This one is what we would call the Dog-day cicada. And it really fits with the July and August. They're out in the late summer. They are often associated, I think, of when it's time for the kids to go back to school, because that's about the time it overlaps.

 

Shelley:

So, it's a good news bug.

 

Phil Pellitteri:

This is a prey, honestly this one was stung by a cicada killer.

 

Shelley:

Really?

 

Phil Pellitteri:

And this is what she'd have to drag and put into the burrow. Now, this has a three year life cycle. But there are Dog-day cicadas that come out all, every year, so we always have some. What people confuse this with is the 17-year cicadas which we have in the southeastern part of the state, and they only come out once every 17 years.

 

Shelley:

That's kind of a big emergence.

 

Phil Pellitteri:

Right. So cicada killers don't attack 17-year cicadas because it takes 17 years before your next meal comes by. That doesn't work.

 

Shelley:

Yeah.

 

Phil Pellitteri:

But it works very well for these. Now the fascinating thing to me is as a young entomologist we did not have cicada killers in the state.

 

Shelley:

Really?

 

Phil Pellitteri:

I would tell people we would have to go to Indianapolis to find them. But with the mild winters that we've been having lately, they have moved northward, and so we have cicada killers in the southern part of the state from basically Wisconsin Dells south. But, you need light soils to find it, so sandy kind of areas are more likely. You don't find it in heavy clays and the like, so they can be very much localized. But if you have them in the right areas, I mean you can see 15 or20 flying at once between the males, the females, and the like, and that's what people misread.

 

Shelley:

So, these guys are digging their burrows un light soils, not heavy clay.

 

Phil Pellitteri:

Right.

 

Shelley:

Can I find them in my garden then?

 

Phil Pellitteri:

If it's bare soil. You don't find them in mulched areas. You don't find them in heavy vegetation.

 

Shelley:

Okay.

 

Phil Pellitteri:

That's one of the things that people can do to keep them away. We sometimes get them in flower beds or in planters. There, what somebody could do if they don't want to put the mulch on it, is put a piece of landscape fabric. These won't be able to dig through it, and they'll move on to somewhere else, but yet you'll get the water through. So that's another adjustment.

 

Shelley:

So as good gardeners we of course are all mulching so we shouldn't have a problem.

 

Phil Pellitteri:

Right, and we don't normally suggest to treat these. If somebody absolutely insisted I want to get rid of them, the appropriate way is to dust the burrows.

 

Shelley:

Use a dust in the burrows.

 

Phil Pellitteri:

But as I said, if you look at their biology, you can easily make the argument why do you have to kill them.

 

Shelley:

Right, they're not harming anything else.

 

Phil Pellitteri:

No, other than cicadas and there'll always be cicadas around. They’ll never get all of them. So it's not a problem, don't run. Just don't worry about them.

 

Phil Pellitteri:

Right.

 

Shelley:

Thanks, Phil.

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