I’m starting to wrap up my research on the patches of translucent cuticle that are found in all Ceraphronoidea (for more information on the patches, check out my blog post from Istvan’s “Know Your insect” seminar).
One of the questions we had was whether similar patches are found on the abdomens of other Hymenoptera. Surprisingly, we found them in Orussidae!
![](https://c1.staticflickr.com/1/673/32862883796_ce562c32e9.jpg)
Just like ceraphronoids, orussids have two patches of translucent cuticle on the dorsal and ventral surfaces of the abdomen. The patches were dark in the specimen above, but translucent in the specimen Istvan dissected below.
![](https://c2.staticflickr.com/4/3682/32903320655_e7dd92efdc.jpg)
There are also two patches on the ventral surface of the abdomen, but these are normally hidden by the hind coxa, so you have to dissect them out to see them, like we did below.
![](https://c1.staticflickr.com/3/2153/32903320965_6035f0bd4e.jpg)
It is exciting to find these patches in Orussidae because they are the most derived of the sawflies, and represent an important step in the evolution of aprocritan wasps and the parasitoid lifestyle in Hymenoptera. It is unknown how Ceraphronoidea are related to other Hymenoptera, but it is possible that they may actually be the most basal apocritan wasp, which would put them close to Orussidae. The fact that both Orussidae and Ceraphronoidea have translucent patches of cuticle seems to suggest that they could be more closely related that previously thought.