Common spangle gall, Uden, Netherlands
A few weeks ago, Henriette and I did a short hike in a local forest and were shocked by what this year's summer had done to it. We've faced the hottest and most dry summer in 3 centuries. The forest was completely dried out, and we felt like aliens in our otherwise so cool, wet and moderate country. The whole place looked like a single spark of fire would destroy it entirely.
Not really finding anything to photograph for a while, my otherwise awful memory reminded me to check something. I had been inspired by Christine Young's work on describing gall wasps. Before that, I really didn't know they were a thing. I simply walked past them for years without any awareness of their existence, in full ignorance.
My rare moment of clarity triggered a lazy attempt (it really was hot) to check some leaves, so here you go, my first ever gall wasp observation. A new hidden layer of life discovered, thank you @Christine.
The common spangle gall on the underside of leaves and the currant gall on the male catkins or occasionally the leaves, develop as chemically induced distortions on pedunculate oak , or sessile oak trees, caused by the cynipid wasp ''Neuroterus quercusbaccarum'' which has both agamic and bisexual generations.
Previous names or synonyms for this species are ''Neuroterus baccarum'', ''N. lenticularis'', ''N. malpighii'', ''Cynips lenticularis'', ''C. quercus-baccarum'', ''Spathegaster baccarum,.. more