Gall Wasps - Dryocosmus favus

Moved

… Adam Kranz, 24 January, 2023 - 1:07pm

Did you ever get an ID back from Dr Liu? Based on the gall alone, I'd guess this is likely Eumayria enigma, or possibly Dryocosmus favus, on a red-group oak. It would be great to know one way or the other since we don't have color images of either species.

… Adam Kranz, 7 September, 2021 - 12:28pm

Moved

Dr. Zhiwei Liu says:

I am unable to identify the species more accurately, except that it was a cynipine, although the galls did remind remind of those of Callyrhitis seminator, except being without white hairs. Weld (1959) had a photo of similar galls from Indiana, but did not have a name for the wasp. In additon, the emergence time was in June, but this was in October!

Yes, I'd love to examine the adults he collected. If he would like to send me the specimens, please ask him to send multiple specimens, preferably 10 or more, which always helps, especially when dissections are required. Specimens can be mailed with the least damage if sent in alcohol (or the strongest vodka one can find!).

---
His address is:
Zhiwei Liu
Department of Biological Sciences
Eastern Illinois University
600 Lincoln Avenue Charleston, IL 61920

… Charley Eiseman, 29 November, 2012 - 3:31pm

Ok, and thanks!

I'm going to have to send them (12 adults, 1 larva, 3 unopened galls) in vodka (I he was actually being serious about that). Maybe the adults were just overwintering in the galls, but I opened them with tweezers, they didn't actually emerge. Also I found them the afternoon of the first frost of the year. After looking up Callirhytis seminator, I don't think that's them. These galls were literally like a growth on the base of the tree trunk, but slightly inside a hallow.

… Sean McVey, 30 November, 2012 - 2:34pm

Great!

Yes, vodka does work fine, or rubbing alcohol -- whatever you have that has the highest percent alcohol. I think you're right that the adults were just overwintering in the galls. Gall wasps have alternating generations, with a spring gall on one plant part and a fall gall on another -- so he may have meant what C. seminator does when it's not making those polka-dotted pom-poms, I'm not sure.

… Charley Eiseman, 30 November, 2012 - 2:50pm

But theres larva too...

so maybe it's alternating generations in the same cluster of galls?

… Sean McVey, 30 November, 2012 - 9:10pm

Good question...

There are often multiple types of wasps in a single set of galls, but in my experience the parasitoids and inquilines (some of which are cynipids) tend to emerge before the gallmakers, so maybe those larvae are the gallmakers... Sometimes cynipids from the same batch of galls will stagger their emergence over seven years or more; I guess the larvae are probably the stage that lies dormant for all that time. Not exactly alternating generations, but something like that.

… Charley Eiseman, 1 December, 2012 - 7:25am

Please hang onto the galls and the adult cynipids

I just contacted a cynipid specialist who may want to examine them. We will definitely want to get a species ID on the host plant sooner or later, but it must be some kind of oak. I've heard of galls like these but have never found them.

… Charley Eiseman, 29 November, 2012 - 3:04pm

Super!

Fantastic!
Now, it would be really nice to know what kind of tree.

… Beatriz Moisset, 28 November, 2012 - 5:58pm

I probably should have payed attention to that...

Not that I would have known... But I guess I could have at least taken a picture of a leaf. Either I'll have to try to get back there before all the leaves fall and decompose or wait till next summer. I'll remember which tree it was, it had a bunch of hollow holes at it's base.

… Sean McVey, 29 November, 2012 - 2:31pm

Host plant

Some are so host especific that sometimes this knowledge is needed for ID. Many common names refer to the host plant, oak, raspberry, etc. John Pearson, a botanist helps us with plant IDs. We post pictures of leaves, twigs, flowers or the whole plant, and they get frassed when no longer needed. I hope that you find it again.
Eventually we all learn to be more observant. It took me a while.

… Beatriz Moisset, 29 November, 2012 - 2:50pm