for IDing all of the galls. I, too, was surprised at the number of galls, and I find it curious that some of the oaks were covered with galls while others had virtually no galls. Most of the 80-100 oaks on our place are blue oaks, with just a couple of valley oaks.

The often very different distribution of galls on neighboring trees is an unsolved mystery. I've heard guesses about why this is but I don't think anyone really knows.

Yesterday I spent a lot of time looking at two exceptionally gall-loaded blue oaks in Del Puerto Canyon (yes, had to go back there again). The trees were in a field right next to each other, some of their branches intertwined. One tree had enormous numbers of Andricus crystallinus galls, the other had way fewer of them but had an exceptional load of Antron quercusechinus galls. I realized that in the places where the branches were intertwined I could tell which tree the leaves that I was looking at belonged to just by seeing which and how many galls were on them. The wasps know things that we don't yet know.