Tent Caterpillars Answer

We got an answer from the University about our caterpillar question. They said we were right, they are tent caterpillars. Yay, for our great bug identification techniques!! They explained they are called, fall tent caterpillars, and they breed twice a year, once in the spring and once in the fall. They said they are really quite harmless to the trees. The only explanation they could give for their "dance" behavior was that they were signaling each other of danger. Whenever we got closer, or they heard our voices (felt vibrations) they would signal each other. We are going to go out and experiment with that a little.