What's That Bug? does not endorse extermination

Black wasp with blue eyes
September 5, 2009
I found this black wasp in our chihuahua’s bed after it had apparently bitten or stung her. It was inside the house and seemed to prefer to crawl rather than fly as I had to chase it out of the bed to catch it. My initial instinct was to grab a paper towel and squish it since I did not want to be stung. My second reaction was to grab the camera. Luckily, it seems to be quite tough and only the abdomen was injured. From tip to tail, it is a little less than one half inch long. It has very tiny wings, about 3/16th of an inch long. I can not tell if it does or doesn’t have a stinger. It has striking deep blue eyes.
Tyson
Baton Rouge, Louisiana, USA

Ensign Wasp:  Unnecessary Carnage

Ensign Wasp: Unnecessary Carnage

Dear Tyson,
This is an Ensign Wasp, probably Evania appendigaster.  There is a photo on BugGuide that shows the same blue eyes.  Since Ensign Wasps parasitize the egg capsules of cockroaches, they are quite effective in the control of what many people would agree is one of the more undesirable household intruders.  We are nearly certain that Ensign Wasps are incapable of stinging.  If one does a bit of math, the single Ensign Wasp that you killed might have prevented hundreds of cockroaches from infesting your house by destroying eggs.  This single Ensign Wasp might then have prevented hundreds times hundreds (or tens of thousands) of Cockroaches in the second generation had the first generation all lived.  Would you like us to do the math for the third generation of Cockroaches that would have been prevented from existing?  Because of fear, all too often people have the inclination to kill and ask questions later, be that regarding the Unnecessary Carnage of arthropods or the irrational invasion of foreign countries.  We hope the next time an Ensign Wasp finds its way into your home, which it most likely did because of the available food source for its progeny, you will allow it to search for prey without intervention.

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What's That Bug? does not endorse extermination

33 Responses to Ensign Wasp squashed out of fear

  1. I saw one of these today.,. Snapped some pics and looked it up… What an amazing creature! I mean, how do they find those eggs?! I hope I see it, or more, so I can show my kids, they will love it! Natures Raid lol

    • bugman says:

      We suspect a female uses the senses that are controlled by her antennae as well as sight to locate Cockroach ootheca.

  2. David Lopez says:

    Wow! These insects are incredible, they are now my favorite insects having in mind that they get rid of those roaches,I believe this information should be posted on the local news so we the people can cooperate with this insect.

  3. Merav says:

    There is one of these in my kitchen!
    I know it is harmless but I have a crazy phobia of insects (stupid, I know)

    Will it sting a human if annoyed??

    I don’t intend on killing it but if it comes near me I might swat it away from me out of fear!

    • bugman says:

      We have never heard a report of a person being stung by an Ensign Wasp.

      • Jeremy says:

        I got one by the leg the other day with a tissue. As I held it, it kept jabbing its tail end at me like it was trying to sting me. It would seem that its instinct is to sting. I did not see a stinger though, so perhaps it cannot sting.

        • bugman says:

          We have never heard of a person being stung by an ensign wasp. Perhaps you just threw off its equilibrium by grasping a leg.

      • Susan says:

        You have one now! I was awakened from a deep sleep last night by something “biting” my neck. It was an ensign wasp. Maybe it was technically stinging, but it felt like a bite, and it hurt.

        • bugman says:

          Thanks for your first hand knowledge that Ensign Wasps are capable of stinging, though we believe the sting was more accidental than intentional. Solitary Wasps are not malicious towards humans.

  4. Was indeed stung.... says:

    I was just stung by one of these 10 minutes ago. Some how it got into the bathroom and was hanging out inside my towel. Was unaware of it until it stung me on the side of the stomach. It was indeed a sting. I have a slower acting allergy to Yellow Jackets, but don’t seem too phased by other wasps. Hope a trip to the ER isn’t in order this evening!

  5. gill says:

    Yes they can sting. I was just stung on the hand by one.

  6. Cyndi says:

    I was stung this weekend. It’s doesn’t hurt as bad as a bee sting.

  7. Jason says:

    I see these at the Baton Rouge zoo sometimes. At first I always think it is an injured wasp with no tail till I get a closer look. They are really incredible. Thanks for the info.

  8. Savannahs Mom says:

    My 11 month old daughter got stung tonight on her little thumb. I think she may have tried to pick it up and it stung her. There is a little spot with blood underneath maybe it was a bite? An way she howled and her thumb is swollen! Hoping a trip to the ER wont be necessary, the bugs life ended.

  9. Bonnie says:

    Ensign wasps DO sting. I have been stung on several occasions. Didn’t know what was stinging me until I found the bug. Assumed they were spider bites . I am allergic to insect bites & stings, and am especially sensitive to spider bites. I was stung 4 days ago and ended up in the ER this time. Apparently the wasp was caught on a seam inside my tank top and couldn’t get loose.. What appeared to be 1 huge bite turned out to be 8 separate stings. It is still swollen and sore.

  10. fin says:

    I have been stung twice by Ensign wasps when i was doing research on them.

  11. wagun says:

    Not biting is a very big lie, I was bitten by this insect before and its painful.

  12. Wajeeha says:

    I was bitten too. It’s become red like a pimple. First it stung me below my wrist, when I flapped it off, it got me above my knee. It keeps inflating n deflating since the bite. It seems every time I eat or drink something it reacts n inflates, itches n deflates again. Except water.
    Wajeeha from Karachi, Pakistan

  13. Aaron says:

    I often see these flying around indoors and one has never come near me or paid me any attention. If they do sting id say the chance of that happening is pretty small.

  14. Mario German says:

    Can it also eat bed bug eggs?

  15. Tarantulagal says:

    I’ve got several of these guys in the yard and house. I let them land on me and crawl. They seem curious and intelligent. They’ve not stung me, and as long as they don’t mess with my pet spiders and tarantulas, they’re welcome to stay. I adamantly refuse to use insecticides or chemicals in or around my house. It’s better for everyone that way.

  16. XXX says:

    I’ve gotten stung/bitten by one 3 times on my left arm. It seemed to swell up to a large size, and by placing an EXTREMELY hot wet towel on it for a period of time on it seemed to help with the itching. After a day or so it went away. I know that it was definitley not any other bug. I spent a long time looking it up to find out that it was indeed a Ensign Wasp. But it said that “they don’t sting” and that they are “harmless” and that “they kill roaches” which is in my opinion mistakenly false. I believe that they kill roaches, but they do sting. There are reports^^ of people being stung.

  17. Sean says:

    I believe they do go after cockroaches. I live in a run down apartment building and have to deal with a bad roach infestation every year. After being stung by an ensign wasp last year, I started killing every one I saw. May have been a mistake since the roach problem is ungodly this year.

  18. Christina says:

    He got my niece on her toe. Clean the sting with peroxide and have her taking a Benadryl to be safe…

  19. Nicole says:

    Yes, it’s proven to sting! My 2 year was stung and I was sure that was it., I have seen it lately in the main bathroom floor or bath mirror, even on top in my master bedroom ceilings. My child’s ear swell up and it obviously was a sting. Next morning found a dead one in the very bed.

  20. Kyriakos says:

    in my house there were 2 big Ensign Wasp and they made a huge nest on our lamp when we wanted to go upstairs and down stair they were attacking jumping off their huge nest and running to attack us. Luckily no one of us got stinged but these creatures were waking us up in the morning because they were making a loud noise when they were flying close to us. Then one day we destroyed their nest when they were gone and now one year later they are back. Pls i need advise for how to get rid of them.

    • James Sorensen says:

      I was stung about 16 times one nite looked like pimple I scratched some of them and they got worse took a mounth to finally go away left little round scare

  21. James Sorensen says:

    I got stung 14 times one nite left a pimple like sore that when scratch it got worse like a spider bite took a mounth and a half to heal still little scare found it my bed next day hard to kill never thought they could sting wrong they hurt

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