Saturday, January 26, 2013

An Interesting Winter Wasp Acquisition

A couple of weeks ago I went for a winter walk with my son-in-law. While we were checking under tree bark for hibernating insects he found what appeared to be a spider egg sac. Upon returning home we examined our discovery a little more closely with a magnifying class, and the "eggs" inside the sac proved to be papery brown cocoons containing tiny white grubs about 3 mm long.

The egg sac was placed in a container and kept it indoors at room temperature, and yesterday this small wasp – between three and four millimeters in length – emerged.

My best guess is Tribe Phygadeuontini. I've submitted some of the photos to BugGuide.Net, where hopefully this image of the wing venation will help narrow down the ID.

Two more eclosions produced what I believe, based on the distinctly visible ovipositor, are wingless females.

One more winged specimen and three more wingless forms emerged overnight and early the following morning. It's safe to say these wasps are all the same species and that the winged ones are males, as I observed it mating with the others on three occasions.

Wow, that was fast! The folks at BugGuide.Net have responded already (less than two hours since my posting ID request) and it appears that our mystery Hymenopteran belongs to the genus Gelis.