A mammoth Black Oak - or about any other big tree - harbors FAR more life than the average observer would suspect. There is a reason that birds such as nuthatches, creepers, and Black-and-white Warblers have evolved an up close and intimate relationship with tree bark. These birds and others forage by creeping along tree trunks, carefully inspecting nooks and crannies for goodies.
Anyway, we were naturally quite interested to learn of her moving lichens, a clump of which can be seen in the photo above. I happened to know what was going on, having seen this phenomenon before. She had discovered larval lacewings,a type of insect that in its immature state, camouflages its body with bits of lichens.
When nabbed and flipped upside down, we can see the larva's lattened, ribbed body, and a few of its legs protruding. This species, which I believe is Leucochrysa pavida, slowly collects small lichen bits until it builds up an impressive shelter. This "blind" serves at least two purposes. One, it allows the tiny predator to evade detection by bigger predators such as birds. A foraging nuthatch would likely blow right by. Two, this lichen shelter eventually becomes the insect's pupal case, in which it will transform into an adult.
Lacewings are largely predatory as adults, and totally predatory as larvae. The one above slowly moves about the bark, grabbing , piercing, and sucking the life from tiny aphids and probably any other small animals that it is capable of overpowering.