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Photo#276255
 oak leaf galls - Belonocnema treatae

oak leaf galls - Belonocnema treatae
Hondo, Medina County, Texas, USA
April 24, 2009
These galls were caused by cynipid wasps, which were then parasitized by eurytomid wasps.

Are the little brown spots on the leaf areas where the egg of a wasp failed to develop to produce the gall?

Wasps found nearby, perhaps parasitoids.

Moved
Moved from Gall Wasps.

Moved
Moved from Eurytomidae.

The galls are definitely cynipid galls, regardless of what emerged from them.

Moving to family page -
although with the caveat that the galls might be unrelated to the wasp...

 
Perhaps it would be best to j
Perhaps it would be best to just remove the galls, so there will be no confusion. I do not know how to remove just the single picture.

 
No, keep them
It may be possible for someone to identify the galls more specifically eventually, especially if you know what kind of oak this is. And even if not, this is important life history information--it's quite possible that this eurytomid only develops in this kind of gall. I just added some text below the photo to eliminate confusion. Feel free to edit it to your liking.

 
This leaf is from a Texas Liv
This leaf is from a Texas Live Oak, Quercus fusiformis.

  • Eurytomidae...
    There are several chalcid subfamilies whose larvae enjoy feeding on gall-making insects. Many eurytomids are primary, solitary ectoparasitoids of gall-forming fly, wasp, or beetle larvae. This seems to fit the description better than others including a hairy appearance, semi-quadrate head, dull black color, and punctate head and thorax. Nice find Virginia.

    See reference here:
    http://bugguide.net/node/view/57794

    Brown spots
    It's conceivable, but they may also be another type of gall. As for the wasp in your first photo, I'm not certain but it looks to me like it may be a chalcid parasitoid rather than a cynipid gall wasp. Did it emerge from one of the galls?

     
    Chalcid
    The insect did NOT emerge from one of the galls. However, I have noticed a high number of the them on the underside of the leaves of a live oak tree, usually one or two per leaf. The galls have been forming on the new leaves. Nearly every leaf on the tree has the galls and most appear in a single row midway between the outer edge and the mid-vein of the leaf. There is always some little brown spots where no galls form in this line. Very few leaves have escaped damage. I have tried to bring some galls inside to watch for emerging insects - no luck.

     
    gall wasp and oviposition scars
    Hi Virginia and everyone-
    The cynipid that formed this gall is the asexual generation of Belonocnema treatae. It actually forms a gall on the roots during its sexual generation through the winter and early spring.

    The brown spots you likely observed were one of two things associated with B. treatae: (1.) failed galls - the tree fights back against the gall former by killing galls before they can grow really big OR parasitoids kill the gall former during development; both scenarios result in a very small brown gall; (2.) the gall wasp also leaves oviposition scars that result in a very faint brown spot and a indentation into the leaf tissue.

    I hope this helps.

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