A little over a week ago, I showed a photo of one of two eurytomid parasitoids that had emerged from some blueberry stem galls I collected in December. More little wasps have continued to trickle out of the two galls, and the count is now up to nine. The first two were males, but some of the later ones were females. As with the goldenrod torymids, the females were substantially larger and appeared at first glance to be a different kind of wasp.
A male eurytomid that emerged from a Hemadas nubilipennis gall. (2 mm)
A female eurytomid that emerged from a Hemadas nubilipennis gall. (2.4 mm)
The ninth one, on the other hand, was a different kind of wasp: Hemadas nubilipennis (Pteromalidae), the species responsible for the galls. Just when I was thinking about getting lazy and not looking closely at every single wasp in the bag. Each larva develops in a separate little chamber inside the gall, so presumably the mother eurytomid must insert her ovipositor into all of these chambers one at a time, laying one egg in each. Evidently she missed a spot.
Hemadas nubilipennis, the blueberry stem gall wasp (2 mm).
The wings of Hemadas nubilipennis have distinctive brown spots, which are easier to see in this image of a preserved specimen.
When I went through all my other bags of galls tonight, I found newly emerged insects in four of them. More on this later…
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