Eastern tent caterpillars live in the large groups in silk nests, or tents which they build in trees. They’re among the first insects to be active in early spring, when daily temperature alters from freezing to extremely hot. Over the course of day, they display striking differences in behaviour: Early in morning, they rest in tightly packed group on the tent’s east-facing surface. In mid-afternoon, they’re on its under surface, each caterpillar hanging by few legs. Recommend a hypothesis to describe this behaviour. How could you test it?