I spotted this on the leaves of an oak tree. It was vibrant & fuzzy against the leaf. I found the following scientific description…
Hedgehog gall wasps are dependent upon their host tree for survival so cause, at most, minor damage.
The hedgehog gall wasp has two different types of life cycles. One is the sexual generation, that will form galls on the leaf buds after mating, and the other is the asexual generation that includes only female wasps. These wasps form the “hedgehog” galls on the tree leaves.
When the larvae reach adulthood they will emerge from the gall as all female wasps. The females will then lay eggs on leaf buds of the host tree, creating a thin-walled blister on the inner face of the bud which will appear in the spring as the bud starts to open.
The newly hatched larvae will then develop into other galls and emerge weeks later as both male and female wasps. This generation will then mate and begin the cycle over again.
