Acorn Gall Wasp

Over this winter I've come across a scientifically undescribed species of oak gall wasp quite a few times; at Camp Lake, Prairie Woods ELC, the Sheyenne Grasslands, and Armor Park in Fargo. This wasp creates very cryptic galls in the caps of bur oak acorns. And I mean VERY cryptic, they are essentially invisible, unless you know to look for them. Most of the time the swelling can be seen if you look inside the cap, but sometimes there is next to no indication that a cap is galled. Last year I saw this gall one time, how I first noticed it I have no idea. Now that I know to look for it, it was a lot easier to find them this year. Right now I have probably around 30 or so galled caps that I collected to try and rear adults from. I'll send these specimens to the Forbes Lab to be further studied.

Here is a gall where the gall is just barely noticeable, one of the first ones I saw this winter

The swelling on this one is a little more apparent, but still easy to miss

A cross section of the gall where you can see the larva

I was able to rear an adult from that single gall I collected last year; it was not the inducer, but rather, an inquiline in the genus Synergus. Hopefully with the number of galls I have this year I'll be able to get an adult of the inducer. So far 4 wasps have emerged, all the same inquiline as last year. All of these wasps have made their exit holes on the outside of the acorn cap. When I checked the rearing chamber today, I noticed a wasp starting to emerge, this time on the inside of the cap. Maybe that is an unimportant detail, but I'd guess that the inducer and inquilines would occupy slightly different areas of the gall, so maybe this is the inducer. Either way it should be out by tomorrow and I'll be able to see.

Exit hole from the Synergus sp. wasp on the outside of the cap

Wasp exiting on the inside of the cap, maybe the inducer?

Last week I collected a few bud galls on red oaks. I think I have two different species, both undescribed. I'll rear those ones out and also send in to be studied and then I'll know for sure. 

Likely an undescribed Amphibolips sp.

Maybe Callirhytis sp. or something else














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