Location: Kickapoo State Park, Illinois
October 26, 2010 4:14 pm
I have a strange wasp I found at a local state park last week. Unlike most wasps, it did not have a tapering abdomen. I wondered if it was a queen of some sort, but I couldn’t find any matching images for a queen wasp. Any ideas?
We did not recognize this distinctive wasp, so first we tried Sawflies as a possibility. We quickly abandoned that venture and explored the Parasitic Hymenopterans on BugGuide where we found Leucospis affinis pictured. BugGuide indicates “One of the largest of the Chalcidoids in the U.S., and the only one exhibiting wing-folding as part of its mimetic morphology” and “Parasitic on Megachilid bees.” The family Leucospidae page on BugGuide states: “Usually black and yellow. They are stout insects, they fold wings longitudinally at rest and look a little like small yellowjackets. The ovipositor is long and curves forward and upward over the abdomen, ending over the posterior part of the thorax. Like the Chalcidids they have the hind femora greatly swollen and toothed on the ventral side.” It is difficult to be certain because of the camera angle, but your photo does appear to show the ovipositor curved over the abdomen.
When I zoom in on the full-size shot, I can definitely see the ovipositor as shown on BugGuide. Thanks!