Thursday, July 5, 2012

Wasp Wednesday: Stizoides renicinctus

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.

51 comments:

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

    ReplyDelete
  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.

    ReplyDelete
    Replies
    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.

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

      Delete
    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.

      Delete
    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!

      Delete
    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.

      Delete
    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

      Delete
    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.

      Delete
    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!

      Delete
    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...

      Delete
  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.

    ReplyDelete
  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.

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

      Delete
    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.

      Delete
    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.

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

    ReplyDelete
    Replies
    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.

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

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

    ReplyDelete
    Replies
    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.

      Delete
  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

    ReplyDelete
  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.

    ReplyDelete
    Replies
    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.

      Delete
  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.

    ReplyDelete
    Replies
    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.

      Delete
  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 )

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

      Delete
  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.

    ReplyDelete
  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.

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

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

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

    ReplyDelete
  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.

    ReplyDelete
    Replies
    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.

      Delete
  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.

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

      Delete
  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.

    ReplyDelete
  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.

    ReplyDelete
  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.

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

    ReplyDelete
  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..?

    ReplyDelete
  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.

    ReplyDelete
  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.

    ReplyDelete
  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.

    ReplyDelete
  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?

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

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

    ReplyDelete
  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

    ReplyDelete