I wrote a blog post about plate gall wasps on Sept. 11. I revisited the small oak tree by the path on the upper part of the first meadow south of the pavilion where they occurred. I observed that they had turned brown, and become thicker, and some had fallen to the ground. I was curious to see what was inside them because many of the galls remained on the leaf, and some looked shriveled. I was unsure if the ones on the ground were still viable. I picked one up and gently opened it to see if anything was inside. I found a small larva curled around the center. These little pastries provided protection and a food source for the insect larva to grow. I poked around through the fallen plant debris on the ground and found a few that looked like they had been opened. When I magnified them to take a photo I could see that the center had been removed and the larvae were gone. I imagine the larva chewed out of the gall to find a place to form a pupa and wait to hatch out in the spring. The circle in the middle seems even and well made as if the larva nibbled its way out. Also, a predator might have opened the gall to eat its juicy contents, but I only found these two. There were plenty of other ones lying around untouched.
In The Nature of Oaks, Doug Tallamy writes that it is necessary to leave the landscape underneath oak trees undisturbed. He even recommends letting some native plants grow around the tree to help create a habitat for insects to carry out their lifecycle. This creates a zone below the tree that keeps you from mowing it or walking on it which might harm them. The fallen leaves and other debris also help to create a layer of protection during the cold winter months.
