Do not pick up any acorns that have strange, alien-looking growths all on them as summer draws to a close. Doing so might result in having larvae crawling all over your lap. Justine, who is located in London and works for NOTCOT, saw this. The gall wasp has laid eggs in these odd-looking acorns that have undergone some kind of mutation.
These growths are the result of a chemical reaction that takes place as a direct response to the wasp depositing its eggs. After completing their metamorphosis into adult females, the larvae spend the winter inside the Knopper galls, where they continue to develop until the following spring. Because the life cycle of the gall wasp is dependent on a kind of parasitic connection with two trees, namely the common oak and the Turkey oak, Knopper galls are often only found in areas where both of these types of oak trees are present.
You can probably guess that this kind of interaction is not exactly beneficial for the trees in any way. They impede the natural progression of the trees and their ability to reproduce. This species of wasp was brought to the British Isles in the 1960s, and it has since spread all the way up into Scotland. Visit NOTCOT to see a plethora of further in-depth photographs of a Knopper gall dissection.