Little Black Spider Wasp

2014 August 30

On August 4, 2013, Sandy caught this little black wasp flying around the kitchen. It was a bit under half an inch long (about 10 mm).

It looks like one of the smaller species of “spider wasps”, in the family Pompilidae. I’m leaning towards the genus Auplopus, a group of small, dark wasps with varying degrees of redness in their legs.

I think that Auplopus carbonarius looks fairly likely. The coloration, size, and wing venation all match up. And, perhaps more importantly, A. carbonarius is evidently a European import that was first found in Michigan back in 1992. And if there’s one thing that we’ve noticed about the imported species, it’s that once they get established they tend to be way more common than any of the native species.

Anyway, these wasps build little barrel-shaped mud nests that they fill with paralyzed spiders, and then lay their eggs in. Even though they are quite small wasps, it looks like they are perfectly willing to tackle spiders as large or larger than they are (see, for example, the picture on this Wikipedia page about them).

Unlike the (much larger) mud-dauber wasps, which also hunt spiders, the spider wasps do not have very elongated waists.

The mandibles aren’t particularly large, because all they have to do is hold on to their prey. They aren’t going to eat the spiders themselves, they are saving them for their offspring. The adult wasps evidently subsist on liquid foods like nectar.

My thumb is in this next picture, to give some idea of the scale. Incidentally, this kind of indicates that they aren’t much of a stinging hazard to humans. If it was going to sting, it certainly would have stung me when I treated it like that.

While I can’t be sure it was the same species that made these little mud nests underneath one of our flowerpots in 2011, it was probably at least a close relative.

21 Responses
  1. Carole permalink
    August 30, 2014

    Fascinating, I’ll be on the lookout for those little nests.

  2. Frank E. Kurczewski permalink
    November 20, 2014

    Very nice photos and descriptions. Auplopus carbonarius is a possibility, but so is Auplopus mellipes variitarsatus–same size, same color, same nesting behavior, and, basically same host spider families with a preponderance of retreat-dwelling species in the families Clubionidae (Clubiona), Miturgidae (Cheiracanthium). The only way the two species can be told apart is by the relative amount “shine” on the pygidium (last dorsal abdominal segment). I could not derive a shot of the pygidium from any of your photos. Do you have others that show the tail end of the wasp in dorsal view? I am trying to use upper interocular width between the compound eyes/head width measurement. Thus far, based on European records, this measurement is pretty consistent–.48-.52 with an average of .496. Two measurements from your photos gave a .45 and .46, or slightly lower. I haven’t yet done the North American A. mellipes measurements. Should be interesting. Thanks for your excellent photos and write-up. Please get back to me if you have other photos such as tail end of the wasp or of prey transport with spider.

  3. November 21, 2014

    Unfortunately, I don’t have any dorsal shots of the abdomen tip. I just went through my photos, and in the few pictures that are from the right orientation, the wings are in the way.

    Thanks very much for the added information!

  4. Frank E. Kurczewski permalink
    April 30, 2015

    I re-measured several of your head-on or overhead photos of your wasp. I measured five such images of the head and got the following least interocular head width/total width percentages: .48, .48, .47, .49, .50–slightly different from what I measured before and more in-line with what I’ve measured for Auplopus carbonarius from Europe and Guelph, Ontario (museum specimen). If this measurement holds up, then I think you’ve got the recently introduced A. carbonarius.

  5. Catherine O'Neill permalink
    July 7, 2015

    This is great information! I find anywhere from one to five of these daily inside of my house. (I live in the north Georgia mountains.) I can’t figure out where they are coming from, but I did find a dirt “tube” on the ceiling of my patio filled with spiders….and was very confused by that. The ones I have are about 1/2″ – 3/4″ long and have definitely very red legs. Otherwise, they look alike. I have been researching ants trying to find them, makes sense it is a wasp instead. I would add a photo, but there is no option here to do that.

  6. July 28, 2015

    Thanks for the help with the ID. They do actually sting – as we found out when my 3 year old picked one up out of curiosity. We’ve suddenly got at least 3-4 in the house… I wonder where they’re coming from? And why they’re inside?

  7. James permalink
    June 16, 2016

    Ok…this in all a very interesting read. The funny thing, while scouring the intertube that I’ve discovered, EVERYONE HAS FAILED TO MENTION THESE LITTLE BUGGERS STING!! I CAN confirm this because I just had one surprise me in bed. So…if anyone would like to know that little tidbit, they are very aggressive and YES!!! they do pack a nasty sting

  8. Debi permalink
    August 22, 2016

    I’m not sure but I think my son and I were just stung by this little bugger! VERY aggressive and let me tell you the sting…WOW! Hours later, still having sharp pain in my leg. The longer it is attached to you the bigger the welt. The pain is lasting and nothing seems to ease it.

  9. August 23, 2016

    Debi: Where are you located? Our local black wasps are very mild-mannered, solitary wasps. Yours are behaving more the way I expect wasp colonies to behave – very defensive of their nests.

  10. Erin permalink
    September 7, 2016

    James and Debi are correct – they do sting! I live in South MS and just got popped 4 times – armpit, neck, back and toe – and it hurts terribly. I am allergic to most stings and bites so I came on here to identify what got me. Thank you for this thread. It was the first one I found that correctly id’d the perpetrator.

  11. September 8, 2016

    It is interesting that yours sting aggressively. I expect that they are not quite the same species as we have up here in the north, which I have never been stung by. It may be a climate thing, too: up here their main threat is that they have to get through the long, brutal winters (which also thin out the predator population). So they concentrate on the winter survival problem and there isn’t much pressure on them to defend their nests against predators. But down south where the climate is much less of a concern for them, the selective pressure is more on not getting eaten and so they adapt to be more eager to sting.

    This kind of holds across the board. We only have a few aggressive stinging insects up here, and most of the aggressive ones are invasives from warmer climates, not native species.

  12. Adele permalink
    July 26, 2017

    Just got a nasty sting by one of these yesterday. Today still very painful, and large hive at the site. Witch Hazel cools it momentarily. Bactine cools it momentarily. But still painful and swollen. We have these in southern Ontario, Canada.

  13. Adele permalink
    July 26, 2017

    Sorry, I meant Benedryl topical, not Bactine.

  14. madison permalink
    July 27, 2017

    So i live in central New Jersey and have never been stung by any type of insect before… until today when i found this exact bug under my foot.. and i even had sandals on! not sure what made him attack but the pain was awful. now it seems to be ok but still sharp pains here or there. since i am a hypochondriac i must know if it’s poisonous! can anyone help me with this question i’m scared slightly. especially the word spider in the name… scares me a bit..

  15. July 28, 2017

    Once the pain from an insect sting fades, the main effects are due to immune system reactions. You may have swelling and tenderness for up to a few days, depending on how your immune system reacts. It is pretty unusual to get one of the more serious allergic reactions, and usually these are devel0ped after a series of stings over a number of years. If you’ve really never been stung by a bee or wasp before, you should have no particular problem.

  16. Todd Painton permalink
    August 13, 2017

    Live in Wisconsin and finally decided to look these guys up. Get about 8-10 in the house every summer. Small, usually less than 1/2 inch, Like a big black ant. VERY AGGRESSIVE. If you swipe and miss, they will attack and typically come back for more. The stick is nothing compared to a Yellow-jacket or scorpion though. I would say a bad Fire Ant bite. Yes, I have been stung by all those critters. Scorpion seems to take the cake.. No spider bites yet.

  17. Todd Painton permalink
    August 13, 2017

    I should also add, they are very agile. Much more so than larger wasps. This might explain my many stings by the little buggers.

  18. August 14, 2017

    Todd: While I haven’t been stung by one, I think one got into my daughter’s room a few weeks ago and stung her on the arm, and her sting is along the lines of what you said: kind of painful, but not in the same league as some other stinging insects.

  19. Todd permalink
    October 3, 2017

    Was stung by what I believed to be one of these. Was pressure washing & reached into a bush.. I got hit hard on the back of the hand. 12 hours later it started to itch & swell.. 36 hours later & still swollen & a little itching. I was located on the Florida panhandle at the time.. painful

  20. Bruce permalink
    July 1, 2019

    I live in Minnesota. We have a lot of mud nest building wasps around my brick house. These images very closely resemble a wasp that attacked me in my basement workroom yesterday. Felt it land on my bare back. Shooed it away. Then felt it on my sandaled foot and it stung me there. The sting was not intense – probably didn’t get a good strike on me. Got a look at it and mistook it for a winged carpenter ant. Shooed it and could not find it on the floor. Moments later landed onto an anvil I was working on. I grabbed a swatter and stunned it. I inspected it with a magnifier. That’s when I realized this was no ant! Very agile, always moving and aggressive.

  21. Lindsey permalink
    September 3, 2020

    We live in MI and my 8yo daughter just got stung by one of these we think, on her upper back between shoulder and neck. She says it’s pretty painful, and she has a swollen red bump now. Otherwise seems okay. She rolled onto it in our house, then we killed it so can’t comment on it’s level of aggression. We were searching for what it is and came across this thread, but couldn’t find much else on the sting.

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