Tuesday, July 26, 2011

Giant Hornets of Death: Cicada Killer Wasps

For some reason in my Entomology class, my professor really liked to talk about giant ground hornets and how territorial and mad they were.  He told us they would be a trophy to add to our insect collections, but that they were dangerous to catch because their sting was so painful.   Unfortunately, I was afraid of them for years until the owner of the farm on which I work told me that the insect I knew as a giant ground hornet was the same as the cicada killer wasp, which her 9-year-old son loves to follow because of their unique behaviors.

Cicada Killer Wasp, picture source


Well, I had to do some research, and she is absolutely right - they are the same, and cicada killer wasps are generally docile and always awesome.  I actually got to know cicada killer wasps a few years ago because there were dozens of them living in an ivy patch outside the school where I used to work.  We science teachers had to research them to see if they were a danger to the students, and we decided that they were so easy-going that we'd just keep kids from walking through the ivy and that the third graders would study them as part of their Biology unit.  They loved it and no one got stung.  I wish I had connected the dots at that time between cicada killers and giant ground hornets, because I had a close encounter with a giant ground hornet on the farm last week and had a very unnecessary scare.  It would be less confusing if we all just used the scientific name, Sphecius speciosus.

Cicada killer wasps/giant ground hornets are gigantic, up to two inches long.  They are yellow/orangeish and black and variously patterned with usually black abdomens.  They are charismatic animals, and they live large on the landscape.  When they are present, you will see them, but don't be afraid.  The females are technically capable of stinging, but they won't unless they are actually handled.  I'm assuming the ones in the picture below are deceased, either that or they are in the process of stinging.

They're gigantic!  Source


Cicada killer wasps emerge from the ground in early summer.  They feed on flower nectar and search for mates.  After they mate, the females dig a burrow 1-4 feet into the ground, piling up dirt at the entrance to the ground.  The burrows are quite visible in lawns, and many lawn-farmers usually don't appreciate the mini-mole-hills.  They wasps actually prefer bare soil, since it's easier to dig through.  Males cruise around the entrance to the burrow, protecting the burrow from enemies and other males.  Their buzz is definitely bigger than their bite because males can't sting.  Still, they can and do fight fiercely in mid-air, careening around in wrestling-holds with their competitors.

After digging a burrow, the females go on the hunt.  They search for cicadas - but not to eat.  When a female finds a cicada, she stings her prey, paralyzing it but not killing it.  Then the female begins the gargantuan task of hauling the cicada, which can be three times her weight, back into her burrow where she will lay an egg on it and seal it into a chamber.  The egg hatches into a larva which then slowly eats the cicada until the cicada is a shrunken shell and the larva is huge.  Females will make several chambers in each burrow - each of her children gets its own room.  The kiddies overwinter as larvae to emerge next year.

The Wasp Finds a Victim, Source


It seems the female can tell the sex of the eggs she lays.  Her female offspring get two or three cicadas to eat, and her male offspring get just one.  Females grow much larger than males, so they need more food.

Cicada killer wasps have their own parasites that lay their eggs on the cicada killer larvae.  Velvet ants, which are wingless wasps, are parasites on parasites.  If you must fear an insect, you could choose velvet ants (also know as cow-killer ants, though they don't actually kill cows).  Velvet ants have a MAJOR sting, which I can attest to from personal experience.  If you see one, don't bother it!
Velvet Ant Source

31 comments:

  1. HI,What states are the most common in,I live in Illinois, are the here to?

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    1. I live in Illinois too and I saw one yesterday as well. It gave me quite a good scare! Glad to know that they aren't as harmful as I thought it should be.

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    2. I'm not sure where they are most common, but they are common in Illinois! Here is a link to more information about them, including a range: http://www.masterbeekeeper.org/stinging/cicadakiller.htm

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    3. I live in Texas, and we have some living under our deck. I was rather freaked out when I saw one carrying a cicada between the deck boards.

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    4. Wish I had been there to see the wasp lugging the cicada along!

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    5. Yes they are in Illinois! I have them in my yard every year. Hate these things.

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    6. I just saw one this morning a little north of Tampa Bay Fl. I have lived in Florida all my life and never saw one before. Scary big, but very cool to watch. It must have been a female as it took a Cicada off the deck behind the house and flew off with it.

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  2. I'm not sure where they are most common, but they are common in Illinois! Here is a link to more information about them, including a range: http://www.masterbeekeeper.org/stinging/cicadakiller.htm

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  3. They are very common here in Iowa also. I've watched em since I was maybe six or seven and I'm 50 yrs now. The cicada killer carrying a cicada reminds me kinda of a chinook helicopter and they kind of hover as they begin to head near their tunnel, most the time, the don't bother you....but you know kids. We got the wise idea to poke a stick in the hole and stir things up and we ran from front of yard to back to go in house because they cut us off before we got to front door. The secoond or third time they figured us out and flew over the house and met us at the back door. None of us ever got stunt they just flew around our faces and hair and scared the bejesus out of us.....they are really cool to watch though....they'll even look at you while you watch them, you can see them blink...kinda like looking in a fish bowl and talkin to goldfish

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  4. Oh yes, I forgot to add that the mailman refused to deliver mail to our house because of the bees even though never stung him, we had to drive three miles every day if we wanted mail, wouldn't leave at neighbors either....said he was allergic to bees and a health hazard, postmaster said no mail til they are gone. Parents tore down rock wall and put in railroad ties....got mail again....dang it....this was in Nebraska that this happened, our Iowa mailman walked around em and said most the time so busy walking and sorting he didn't even see them.

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    1. Hilarious! Finally something that stops a mailman! Great story about the cicadas confronting you at the door to your house. I like to watch the males fight and wrestle in mid-air. If someone could film that up close and slowed down, it would make a great fight scene in a nature movie. Thanks for posting.

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  5. We are in Ohio almost in Michigan and we have a bunch!!!!

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  6. I'm on the Space Coast of FL & found this article while watching a male & female mate. My husband & I were doing yard work when he saw them together on the ground. The flew across the yard still attached and landed on a tree branch. If the female is the larger one, then she was dominate in this pairing as well. The smaller sometimes hung upside down freely as she held onto the branch. While mating, several other females landed on her but the pair stayed connected & the other female flew away. By the time we initially saw them in the yard to the time they separated (when another male flew over to them), they mated about 20 minutes. Once the male flew off, the female stayed and appeared to be cleaning herself before flying away about 5 minutes later. Who new yard work could be so educational!

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    1. Fascinating. Unfortunately our usual patch of cicada killers is gone this year. I'd love to watch and see if I could observe this behavior. I'll try again next year. Thanks for posting!

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  7. I found one this morning while walking my dogs in Hewitt TX, thought it looked like one of those Japanese wasps - thanks for the info on them, glad I don't have to worry!

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  8. been building rock beds for 2 weeks, and just yesterday, i noticed a female one of these beasts buzzing around the yard. Not sure why but we have these all red hornets that the insect guy killed off 3 days ago, and this female cicada killer keeps picking them up and dragging them off. guessing she has a grudge against em since they are all dead lol. Anyways, I am EXTREMLY afraid of wasp. This afternoon i was working in a rock bed and herd a tremendous buzz right by my ear. Just from the sound i know who it was. I thought she had flown off but when i glanced to my right the sucker was on my shoulder staring me down not 2 inches from my face... Thanks to this article i now know she was just asking if she could build a home in my paving sand... hopefully she got the message when i ran into the house screaming and slammed the door. I'v been inside all day, too paranoid to go back out and continue working. But again, thanks to this article i now know there is nothing to fear. Thanks ^_^

    Oh And I'm in DFW Texas, yet even with all the landscaping and fishing I've done over the years this is the first time I've seen them here.

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    1. Hello, I'm sorry to tell you, but the females do sting! The males usually buzz over their nest areas, and they can't sting. The males are usually the ones you notice. The females are the ones that mostly stay in the nest and drag prey back into the nest to feed the offspring. It's a little difficult to get the females to sting you - you've got to specifically bother them. I've heard the sting does hurt a lot. If you watch where you put your hands and don't get too close, you should be fine, but only you know your level of risk tolerance. Good luck! Interesting comment - thanks.

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    2. Yea I had one fly into the garage today here in Arlington. It buzzed around and since it didn't find food it left I guess. I hate stings as well and back off quite quick, but by the time I looked to see if it was still there it was gone. I wasn't sure what I was looking at so glad to know they won't mess with me unless I mess with them.

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  9. been building rock beds for 2 weeks, and just yesterday, i noticed a female one of these beasts buzzing around the yard. Not sure why but we have these all red hornets that the insect guy killed off 3 days ago, and this female cicada killer keeps picking them up and dragging them off. guessing she has a grudge against em since they are all dead lol. Anyways, I am EXTREMLY afraid of wasp. This afternoon i was working in a rock bed and herd a tremendous buzz right by my ear. Just from the sound i know who it was. I thought she had flown off but when i glanced to my right the sucker was on my shoulder staring me down not 2 inches from my face... Thanks to this article i now know she was just asking if she could build a home in my paving sand... hopefully she got the message when i ran into the house screaming and slammed the door. I'v been inside all day, too paranoid to go back out and continue working. But again, thanks to this article i now know there is nothing to fear. Thanks ^_^

    Oh And I'm in DFW Texas, yet even with all the landscaping and fishing I've done over the years this is the first time I've seen them here.

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  10. Do these eat bees too? Or gather bees for their young?

    Are they declining or inceasing?

    Lisa around Ft.Worth

    Have seen in ground nest making by front door...had to get rid of for property owners...and dead ones after pest spraying in greenhouses. Just curious if they are going like the bees? Or bumblebees?

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    1. Hi Lisa,

      My searches of information from Entomology websites say they are specific predators of cicadas. I have never personally observed them eating other food sources. The larvae eat only cicadas, and the adults eat flower nectar, (but I'm not an expert, just an enthusiast). I'm sure they are somewhat declining due to humans not tolerating them and our overall pesticide usage (as you have seen), but they are not reported to be experiencing the colony collapse disorder like honeybees. Still, they play a role in pollination, as the adults move from flower to flower.

      Thanks for your comment,

      Lorna

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  11. Do these eat bees too? Or gather bees for their young?

    Are they declining or inceasing?

    Lisa around Ft.Worth

    Have seen in ground nest making by front door...had to get rid of for property owners...and dead ones after pest spraying in greenhouses. Just curious if they are going like the bees? Or bumblebees?

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  12. Kentucky Ohio Indiana Illinois are most common

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  13. I live in Royal Oak, MI - just outside of Detroit. Our soil is VERY sandy, and these wasps love it.

    Last year, I destroyed two burrows and killed 3 wasps before I knew what they were (also thought they were Japanese hornets or what-have-you). Now, they are just an annoyance, as I get buzz-bombed every time I put the garbage out. I have still been flooding out the burrows as I am trying to keep our lawn in decent shape for selling the house next spring. Still, for a Cicada year 17, things have been awfully quiet!

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  14. Didnt know .what it was or why I see them every summer about this time. Caught one in a pickle jar. Wish I knew some one doing a bug collection. Living in Carthage, Texas

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  15. I have the "mounds" in my backyard and didn't know what they were until I saw them in my neighbors yard while we were out talking. This HUGE WASP/HORNET-looking thing was flying around and he told me they lived in those holes/mounds. He'd looked them up and told me all about them. He said they only live in August and September and don't really bother humans unless you aggravate or bother them. I STILL don't want to be around them though. I kind of worry about my dog getting stung too. We live in Dayton Ohio.

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  16. I have the "mounds" in my backyard and didn't know what they were until I saw them in my neighbors yard while we were out talking. This HUGE WASP/HORNET-looking thing was flying around and he told me they lived in those holes/mounds. He'd looked them up and told me all about them. He said they only live in August and September and don't really bother humans unless you aggravate or bother them. I STILL don't want to be around them though. I kind of worry about my dog getting stung too. We live in Dayton Ohio.

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  17. I've killed a couple of them this summer in southeastern MA

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  18. i found a dead giant cicada killer wasp if you want it for your school thegoodrobot 888888atyahoo.com888888 ignore the 8's

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  19. Oh yea forgot to mention I have seen them carry off the cicada. Hurst TX

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  20. I see them every he and until now have killed them. Think I'll watch this year. Hurst TX

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