Thursday, July 5, 2012

Wasp Wednesday: Stizoides renicinctus

NOTE: I failed to make it clear how many wasps, and even some flies, look nearly identical to this species if you are not an entomologist. There is the Blue-winged Wasp, Scolia dubia, spider wasps (Anoplius atrox and others), and even the enormous fly Mydas clavatus that are equal to or larger than Stizoides renicinctus. Stizoides renicinctus is also not nearly as common as these other wasps. So, those of you insisting you are seeing this species have likely mistaken it for something else. Thank you, and my apologies.

One of the cool “surprise bugs” from the ”wasp tree” was a kleptoparasitic wasp (I’ll explain that term below), Stizoides renicinctus. This insect is so obscure that it has no common name in English, but that doesn’t take anything away from its unique life history.

S. renicinctus is one of only two species in the genus occurring in North America. Globally, there are thirty species in the genus, most found in Africa, Mediterranean Europe, the Middle East, and India. The only other species in the U.S. is S. foxi, restricted to Arizona (and south into Mexico).

Field marks that help to identify S. renicinctus include an all black body with a red or orange band on the second dorsal abdominal segment (tergite), dark wings with translucent wingtips, and an overall elongate appearance. Both genders are nearly identical in appearance and size, at about 16-18 millimeters.

One usually encounters the males taking nectar from flowers. I was surprised at the fair number of them on the saltcedar tree during the latter half of June here in my Colorado Springs neighborhood. I have also seen this species in southern Arizona, coming to the blossoms of Seepwillow, Baccharis salicifolia in dry arroyos or along rivers.

Females are mostly busy seeking hosts for their offspring. The term “kleptoparasite” refers to an animal that essentially raids the refrigerator of its host organism. That means the parasite feeds on the material stored as food by its host. S. renicinctus is known to exploit the food caches of other solitary wasps in the genera Prionyx and Palmodes. Female Prionyx hunt grasshoppers (Acrididae), while Palmodes hunts katydids (Tettigoniidae). The wasps dig burrows and stock at least one prey item per cell that a single larva will consume to grow and mature into an adult wasp of the next generation. The female Stizoides renicinctus locates the closed burrow of a host, digs it open, destroys the host egg, and replaces it with one of her own. The larva that hatches will eat the food the host mother wasp took such care in providing.

It has been noted that S. renicinctus is not always solitary. Individuals will gather in “sleeping” clusters on vegetation at night. They apparently do this in the face of impending inclement weather, too. I found a loose aggregation forming in the saltcedar bush on the afternoon of June 16 as storm clouds began to gather. These wasps will sometimes be found amid sleeping clusters of other solitary wasps as well.

These wasps are quite efficient parasites, as documented by I. LaRivers in a 1945 paper in American Midland Naturalist. He found the species parasitizing Palmodes laeviventris in Elko County, Nevada. The Palmodes were doing local agriculture a service by slaying Mormon crickets (a type of wingless katydid), but the Stizoides wasps were also reaping the benefits. LaRivers estimated a parasitism rate of about 7.5 percent, which he extrapolated to roughly 10,000 destroyed Palmodes nests in about 350 square yards.

Ok, so Stizoides is an outlaw of the Old West (it actually ranges from Michigan and Wisconsin south to North Carolina and west to Alberta, British Columbia, California, Arizona, and Mexico). I would like to think that seeing a good number of specimens means that there is also a thriving population of host wasps. That in turn means abundant grasshopper prey, and thus a healthy habitat.

Be on the lookout for Stizoides where you live, and see if you can find one in the act of finding a host. You may discover a relationship previously unknown to science. You just never know.

Sources: Bohart, R.M. and A.S. Menke. 1976. Sphecid Wasps of the World: A Generic Revision. Berkeley: University of California Press. 695 pp.
Evans, Howard E. and Kevin M. O’Neill. 2007. The Sand Wasps: Natural History and Behavior. Cambridge, Massachusetts: Harvard University Press. 360 pp.

104 comments:

  1. they actually look friendly
    ...for wasps ;)

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  2. I think I have this bug in my yard. Many of them. Flying low to the grass all day. I also have one nestled into a near opening sunflower head (small 2.5ft one). But I live in Florida. Is it possible this is the same bug? I have some pics on my cell phone. I can email them if it will help. They aren't great.

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    1. What you are describing sounds like males of the Blue-winged Wasp, Scolia dubia. Good to have because they kill the "white grubs" that eat the roots of your lawn grasses.

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    2. Yes, they are in Central Florida ...my cat was playing with one today.

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    3. Again, any wasp in Florida is NOT going to be this wasp. Please look up "Scolia dubia" and I think you will have the answer.

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    4. Bug Eric - I also live in Central Florida, and I have seen many wasps in my yard that look much more like Stizoides renicinctus than Scolia dubia. Maybe it is a Scolia dubia that just has the same colors?

      I saw one of them digging a hole in the ground and I took a video of it pushing dirt out of the hole... here is a picture from my video: https://ibb.co/j20vef

      As you can see, the abdomen is completely jet black except for the bright orange spots. I've never seen a wasp like this before, and the Stizoides renicinctus is the first thing I've found on the internet that looks like it... a very interesting wasp!

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    5. Thank you for your observation, but....The link you provide does not correspond to a valid URL, and I recommend no one copy and paste it into their browser. I'm sorry.

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    6. Bug Eric - the URL does work, but you have copying and links disabled on your blog... if you manually type the URL(which was created using https://imgbb.com/) then it will work.

      However, I have provided a couple more ways for you to see my video/screenshot:
      1.) You may be more comfortable opening an imgur link since it's more widely known as an image hosting site... here you go: https://imgur.com/a/WMB3aW0
      2.) I went ahead and uploaded my video to YouTube. Here is the link: https://www.youtube.com/watch?v=HQYXkrFPq2k

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    7. Ok, let me try those....I have copying disabled because I have had this entire blog stolen and cloned before. I cannot afford for that kind of thing to happen repeatedly. Thank you for understanding.

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    8. Peter V: Ah-ha! I have the answer for you now. Your image is of a female spider wasp in the genus Anoplius, family Pompilidae, perhaps Anoplius semicinctus, though others have the red spots on the abdomen, too. Thank you for your persistence, your documentation, and your curiosity!

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    9. Sweet - thanks for looking into it! Those wasps sure make themselves hard to identify by using the same colors and all... I have gained a greater appreciation for your line of work! There certainly would be plenty of spiders for these wasps to hunt in our yard...

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    10. I have just killed a similar wasp. Do you have a place I could send you a photo for identification?

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    11. Dawnell: I do not receive images from people I do not know. I recommend posting images to Facebook groups devoted to insect identification. I don't do Instagram, rarely Twitter, but those would work, also.

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    12. I found one in my room today it was a big boy and scared me but I'm also in florida so maybe they are native here.

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    13. Please see the new note I added at the beginning of this post. You are most likely describing something completely different. I may try and update this post or make another one to show how many other insects look like Stizoides.

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    14. I live in central Florida and just killed one of these. Most definitely in Florida as well. Where can I post a picture?

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  3. I wonder if that parasitism rate of 7.5% is an EES? A higher rate might drive the parasitised species numbers down and make them harder to find? So by distributing her eggs amongst a number of different species she can maintain them all at a high rate.

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  4. Saw one today on a pile of logs for our wood burning stove that still need cutting. This wasp was not intimidated by me in the least. Are they as aggressive with humans, dogs, cats and birds as they are with the other bugs who's hives they take over? P.S.:I'm in the Northeast, didn'the see any states in this area noted as being home to this wasp.

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    1. Yes, these are western wasps, so I strongly suspect you are describing something different.

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    2. I live in a Syracuse, NY suburb and saw one of these today on one on my bushes. It looked to be 'mounted' by another flying insect that resembled what a mosquito larvae (ml) looks like. Another ml was attacking the first one to, I assume, mount the wasp. The wasp was black with a distinctive orange stripe.

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    3. Ed: This species does not occur in New York state. You were observing something else; and while I have suspicions about what you describe, without images, video, or my own firsthand observation, I am reluctant to speculate.

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    4. I’m in NC, and I saw something like this. After researching some more, I think what I have seen (and likely what many other folks from the eastern US have seen) is a known as a ‘peach borer’

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  5. Saw one today with a green cricket or grasshopper in its clutches. Just outside of Augusta Georgia.

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    1. You saw something else then, maybe a Tachytes sp. Please read the blog, this particular wasp is a kleptoparasite of other wasps. It does not hunt its own prey.

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    2. Live and learn! It was really cool whatever it was....

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    3. I live in Iowa & found one. I have a picture, but don't believe I can post here.

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  6. I have these in my yard and live in CT. Are they stingers? Should be sting allergic people be concerned?

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    1. This species is not found in Connecticut. Yes they can sting, but being solitary they are not defending a whole nest full of vulnerable larvae and pupae. I think you are probably seeing males of Scolia dubia, which are likewise solitary.

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  7. This wasp is found in CT. I found two in my school yard. It was the completely black with one single orange stripe on it

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  8. I saw one today in sc dragging a wolf spider I believe it was. Have picture of wasp, but couldn't get the picture of it carrying the spider.

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    1. Forgive me for asking, but have you read this post? This species does not prey on spiders, or any insect. It is a kleptoparasite of other wasps. You observed s spider wasp in the genus Anoplius, if it resembled the wasp that this post is about.

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  9. My mom just killed one in her kitchen. We live on Guam. It's the first kind of wasp we ever saw, so I had to look it up. It's weird to see one here I guess.

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    1. Hi, Samantha. You certainly saw some other kind of wasp, then. There is tremendous overlap in coloration and pattern across many different genera and families of wasps, not to mention their fly mimics.

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  10. This wasp flew into my home and tried to get out through a window beside my door, it had tiny gaps in between each glass slide. And the wasp tried crawling through it, it looked pretty intelligent doing it, it tried sticking its head through it first and then failed and then used its back. Eventually I opened the door and it took a while till it gave up and tried looking for another way out. I only took one picture as I was quite terrified of it. But I’m sure it is the correct one. Is it abnormal for this wasp to be in Malaysia? ( Asia )

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    1. This wasp does NOT occur in Malaysia. You do have hornets (Vespa spp.) over there that look somewhat similar to this species.

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  11. I just found one today, hanging out on top of the mulch where I was pulling a few weeds. I think I startled it. It took several hurried steps and stopped and just looked at me. I left it alone and went about my business, so I don't know what happened to it. I am in the northern Shenandoah valley of Virginia.

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    1. This is unlikely, but not impossible. There are spider wasps, mydas flies, and other species that strongly resemble this one. Stizoides renicinctus is mostly confined to states west of the Mississippi River.

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  12. I'm in East Texas and have seen these wasps for several weeks on my phlox and around my crepe myrtles. This is the first time we have ever had these.

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  13. Found this exact wasp swimming in my pool. First time ever seeing one in Royal Oak Michigan.

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    1. This species does NOT occur in your area, so I suspect it was some other kind of wasp.

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  14. One just stung my dog in the nose so I killed it and looked up it's species .we are in Louisiana.

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    1. Stizoides renicinctus is confined almost entirely to states west of the Mississippi. You may have seen a different wasp, or even a mydas fly, that greatly resembles the wasp under discussion here.

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  15. Just found one after seeing my dog's face and throat swelling up, it was in a tub of water for the dogs, my guess is that the pup tried messing with it and got stung.

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    1. I highly doubt it was this particular species that stung your dog. Scolia dubia is a much more likely possibility....I do wish your canine a swift and complete recovery.

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  16. Found one if these dead on my carpet didnt know it was there until picking up my shoes. I like in Texas. Should I be worried there are more lurking? It all black black eyes orange dots that connect towards the top half of the lower body. About the size of a dime.

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    1. That sounds like a paper wasp. Females will sometimes enter buildings for winter hibernation.

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  17. Do these occur in South TX? I think I saw one in Goliad. It was perusing the bee balm and chased off a red paper wasp. It was noticeably larger than the red wasp, was all black except for a bit of orange that resembled pollen pockets on a bee, and the abdomen was long which made the wings seem too short. In flight I could see that the orange went around the abdomen, under the wings. The abdomen curled under a bit, around the flower it was on.

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    1. This sounds like a large scollid wasp (family Scoliidae). The males, in particular, "sleep" in the posture you describe, curled round a flower or twig.

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  18. Hey this guy came flying at me in my workshop. Sorry but I killed him. Freaked me out. He has 2 touching orange spots on his back. The rest is all black. I live in Florida as well.

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  19. I have 2 of these that stay around my flower bed in my yard. Finally landed and I got a good look at the body which is huge..all black with a bright orange/red stripe on it's lower back. They fly so fast and they are freaking me out. Very large. Never seen these before til this yr.

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    1. In New York state, this would most likely be either a mydas fly, a scollid wasp, or a large spider wasp (Anoplius sp.). Stizoides renicinctus has not been recorded from your area.

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  20. I am in Ohio. I have one in my back yard right now! Amazing.

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    1. Unlikely, though not impossible. Please compare to Scolia dubia, Anoplius spp. spider wasps, and Mydas clavatus, a very large fly.

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  21. We live on acreage, and I saw one of these today in my fire pit while I was mowing. We live on the border of Iowa and Nebraska. While my grandpa was an exterminator and I've had all sorts of bug books growing up, I've always been on "team observe" not "team whack!".. I have to admit I was a bit shocked at its size.. very large for a "wasp" (what my initial thought of it was).. we do have apple trees, and a garden.. once they show up, do they stay? Or do they migrate on..?

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  22. NOTE: Most comments on this post likely reference some other species of wasp....but without seeing your insect *in person*, I cannot be conclusive. I have never seen Stizoides in the eastern U.S., but see Scolia dubia all the time, for example.

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  23. I as well saw one today for the first time... in New Jersey! I own a company called Howllelujah Pet Services and among other things we walk dogs. Today, on a walk I saw an unusual looking bug. It was too large to be a wasp (that I’m used to seeing) but all I could see was the head and wings. I got closer to inspect, it was a wasp! Longer, thicker, not like any I had seen. So, I had to research, it certainly wasn’t a Scolia dubia, though I can see why confusion comes in there. I’m weary of stinging insects as I’ve seen dogs have poor reactions, so I was curious. Had it been an hornet I probably would have avoided that spot in the future.

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  24. North Attleborough, Massachusetts.
    https://i.imgur.com/G1dDhuG.jpg
    It's a bit out of focus, but you can see part of the orange stripe.

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  25. I have these all over my yard in central Michigan it makes sense tho bc I also have at least 20 separate species of wasp living here, are these wasps aggressive towards humans?

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    1. No, the overwhelming majority of wasp species are solitary and do not bother people.

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  26. a whole bunch flying around my butterfly habitat bed. I'm in Northern Virginia.

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    1. Those are likely scoliid wasps like Scolia dubia. Stizoides renicinctus has never been recorded in Virginia.

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  27. Just saw one in our yard in Granville County, NC. It was lapping up water droplets after last night's rain. I took a few photos of it. Here's one: mtu.com/stizoides-renicinctus.jpg

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  28. Bug Epic...you are quite rude and arrogant I'm afraid. I live in Florida and I definitely saw one of these. Killed it actually and looked at it very closely. I looked up the scolia dubia and it did not look anything like this one. I believe all those in this post who have said they saw this one. Maybe your information is outdated.

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    1. I'm sorry that my being "insistent" is interpreted as being rude. I freely acknowledge that without seeing an actual specimen of what you are referring to, I cannot make a substantive identification. I would be interested to know the results if you can take a specimen to a local entomologist at a museum, university, state agriculture department, or maybe even public health department.

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    2. I have them in my yard in Toms River NJ. Are they agressive??

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    3. You should not have this species in New Jersey. There are other wasps that *look* similar. None of them are "aggressive."

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  29. Thank you for your blog. I am curious how to tell the difference between this wasp and a spider wasp? They seem so similar with the orange stripe. The one we had near our garden today (in DE) had wings that were the same length, if not a hair longer than the body.

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    1. Spider wasps are generally a bit more slender-bodied, with much longer legs.

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  30. Hi, it is July of 2020 and I live in Fairfax, VA. I thought we had one of these, but I think we identified it as a Midas Fly. It was as large as the cicada killers around here, and it reminded me of the tarantula hawks that we had when I lived in South Texas. How would we tell the difference?

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    1. If it was that large, then Mydas clavatus (a mydas fly) is your correct ID.

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  31. Hi there. I live in the Atlanta GA area and I am 99.5 % sure that I had one of these in my yard today. It was all black, very large and had an orange band about 2/3 of the way down the body. I was hoping there was a way to add a picture as I was able to take 2 decent pictures of the bug before it flew away. But I can not figure out how.

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  32. I observed a very similar wasp feeding on catnip blossom. Are they common to eastern West Virginia.

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    1. This species has never been recorded in Virginia. It is found almost exclusively west of the Mississippi River.

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  33. We found one in New York State 40 miles north of New York City. That seems unusual territory for them...

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    1. Please see the note I added last week at the top of this post. Thank you.

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  34. I just killed one this morning here in my yard in Des Moines, Iowa. I was concerned it may be aggressive towards my dogs or sting my pregnant wife. After reading some of these comments I feel bad for killing it as it seems I should be worried.

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  35. Hi ERIC, thank you sooo much for your awesome and informative blog!!

    Today we found a large fat black bellied wasp with an orange spot/band on its belly. It had black translucent wings. It was the size of a cicada, sipping on a swamp milkweed that often has two other types of wasps feeding on it. In the years we’ve been here we haven’t seen a wasp like this. I know all the other types of wasps here... most hv more segmented and slender bodies. We live in Rhode Island so I understand that they aren’t usually here but I don’t think it could be anything else!! I hv a bunch of photos of you are interested. Thx!!

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  36. I have a specimen of one captured in Montana. Exactly like description and pictures above. Definitely not a blue winged or spider wasp. Sadly, my wife accidentally hurt it while trying to catch it and it didn't make it. She said it was crawling on the ground under some bushes. No flowers blooming anymore this season so it wasn't doing whatever a wasp does on flowers. I suppose it could have been looking for a host. Too bad....

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  37. I’ve started seeing these more frequently than before in Guam. Saw two in the past week on base, at least I think it’s them. Here’s a pic: https://i.imgur.com/jZ8ClbV.jpg that sucker was massive!

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    1. Please see the note I made recently to the beginning of the post. You are most likely describing something completely different, ESPECIALLY if you are talking about a location halfway around the world from the U.S.

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  38. I saw one today here in New Jersey, I have never seen one before. I looked at all the other pictures and it is Exactly like the one I see here. It was actually hanging out on a tree.

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  39. I came across this post because I just saw one of these in my garden. It looked like it was digging around in the mulch and going in and out of holes that the pepper stakes make. Very strange. It looked like it was trying to find something it lost lol, moving little bits of dirt around. Thanks for this article.

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    1. I'm confident you are describing an entirely different kind of wasp, but perhaps it is "my bad" for posting about an obscure species that so closely resembles so many more common species. I'll see if I can remedy that in the next few weeks with another post.

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  40. Hi Eric,
    I believe that I came across one of these in my yard in Rhode Island today. It has an orange stripe on, I believe, the 7th section of its abdomen (counting from the back) and was otherwise pitch black and unusually large. I took some good pictures if you would like to see them. I am posting them to my Instagram account (@foodforestcardgame) today, if you would like to help me confirm the ID.
    Thank you!

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    1. I'm sorry, I do not have a smart phone, so no Instagram. I also cannot answer every ID question I receive. I respectfully suggest you post to Bugguide.net, iNaturalist.org, or on a Facebook group....Ideally, take your photos to a local entomologist at a university or museum. Good luck!

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  41. I have these in my garden in Wisconsin. They seem to enjoy the mint flowers.

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    1. Please read the note at the beginning of the post. You are almost certainly describing Scolia dubia, not Stizoides.

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    2. I have a dead one and it’s definitely a Stizoides

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    3. I posted photos on the bug identification and discussion group on Facebook if you want to see them.

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    4. I'll see if I can find the group on Facebook. I may not be *in* the group, though, and if not I will be unable to comment. Thank you for your persistence.

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  42. These are definitely in Florida. I just photographed one that died in my yard. I have excellent photos of it if you would like to see them.

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    1. There actually are records of this species in Florida.

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  43. I discovered one of these hovering over a large bush alongside some paper wasps outside our apartment in southeastern Washington State.

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  44. I have just caught one with a glass jar in northern Virginia. It visited to investigate my plate after lunch. I got lots of close looks. Matches this species in every respect. I got a picture, too.

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  45. I think I just stepped on this and it stung me through my sock...so painful...I have a picture of it.

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  46. https://ibb.co/939RGNb

    Hi Bug Eric! Attached above is a photo i took of a wasp that's been dead on my patio for the past day or so. This is in Tampa Florida. Any guess what it may be? I

    It's clear it's not this species due to a different banding of orange on it's tergum, but i think this photo can help clear up the past couple years of Floridian "sightings"

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  47. I think I found one of these guys floating in my pool, he is very hard not soft like a normal wasp would feel, I tried to get him out but to my surprise he was still very alive. I took a pic. I live in Texas and so I'm not sure what this is. Thank you.

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  48. my husband just had one on his hat and killed it not knowing what it was. Havre Montana

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  49. I just found one in Indiana

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    1. Unlikely, but not impossible. Stizoides renicinctus is an insect found almost exclusively west of the Mississippi River, and in deserts, prairies, and, rarely, glades.

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  50. Recently at a friend's home enjoying her pool. There were 3 of these wasps hanging on side of pool, then would either fall into the pool water or climb down into the water and then climb out. This was a salt water pool. Located in Eastern Panhandle of West Virginia. Is this a behavior known of the wasp pictured? Thank you!

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    1. Stizoides renicinctus has not been recorded in West Virginia, so I suspect it is another species of wasp....Many wasps need to drink, especially paper wasps, mud daubers, and mason wasps, which need to replenish their saliva which they mix with wood fibers (paper wasps) or soil (mason wasps) in order to form the building material for their nests.

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