So they would probably be poorly represented on the fossil record. If only their wings were preserved we would probably have called them roaches. I suspect that they spread through the soil and mulch as much as possible by colony fission as wood roaches do today and, if so, this would have considerably decreased further their fossilization. This, if it obtained, would have decreased fossilization of wood roaches further, since most insect fossils are wings. It is highly probable that termites gained their most potent instinct attributes during the Cretaceous.
Termites are extremely varied.
Some eat wood. Others eat grass, cambium of trees, or animal dung. A very large number of species eat soil organic matter. The duration of the Jurassic would be by no means too long. Whether something resembling a soldier class appeared as far back as the early Triassic can not be determined from present fossils.