What is this? My boys and I saw it hanging from an oak tree in Camassia yesterday.
Maybe it’s a gall?
Remember a couple of weeks ago when I posted about an oak gall wasp that affected leaves? The link is here. We saw a lot of these leaf galls laying on the ground while we hiked. But, this one is different.
It is likely a California Oak Gall Wasp and it affects twigs. The gall wasp lays its eggs inside of the bark. Then, according to National Audubon Society Field Guide to Insects & Spiders, the larvae bore further into the wood. This causes the tree to grow these large galls around the wound. The larvae then feed on the inside of the gall until they mature. Once they become adults, they leave the gall and the females will eventually lay their eggs on another oak. Interestingly, like some other insects, the adults do not eat. These galls start off green but become brown and red as they age.
Here’s two more. They were all over the place inside the reserve. They can get as large as 4 inches across. That is huge!