We are finding these all over the place underneath Oak trees. I chatted to Google about them, but he just shrugged and asked me why I didn’t buy some oak furniture, like everyone else.
The Good Folk over at Wild About Britain were much more helpful – “It’s a Knopper Gall” they said. So off I went to Google armed with the updated information. “Oh, yes. Why didn’t you say so.” he said, offering me ‘About 587,000 results (in 0.26 seconds)’.
Let me go through a few of them with you. First, I better deal with the Knopper part of the story. In the seventeenth century – that’s sixteen hundred and odd – in Germany, people wore a felt cap called a knoppe. I will say nothing here. Except, look at the picture and look at my title.
Secondly, I can now tell you, it is produced by a tiny little wasp who has an, as almost unbelievable, lifestyle. It’s a circular sort of thing so we’ll start with how we arrived at where we’re up to now. That tiny wasp laid an egg in the bud of the acorn. It made the acorn grow into the thing in our picture. If the egg/bug doesn’t get eaten by all the things that eat little scratchy things, the egg/bug will live in there until Spring when she (they are all She) will escape through the hole in the top and fly off, find a specific type of Oak Tree only, and lay eggs in the flowers. These eggs will hatch into the more usual male and female who will mate. The females will then toddle off to find an ordinary Oak tree, like ours, to lay eggs in an acorn bud.
We’re keeping an eye on things, but so far, no Oak trees have been harmed by all of this.