Ensign Wasp squashed out of fear

bugman

September 6th, 2009 at 6:35 am

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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

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.