The adult moths emerge in approximately 7 to 10 days. The moths are stout-bodied and light brown. They often fly in clusters around street or porch lights on summer evenings. After the moths mate, the females lay 100 to 350 eggs in a froth-covered band around small twigs or branches of host trees. The eggs mature in 3 weeks but do not hatch until the following spring.
Tent caterpillars are primarily a nuisance.
They do not transmit diseases to humans, do not bite, and are not poisonous. During years when large numbers of these caterpillars hatch, they can cause slippery roads and walks when they leave the trees. Benefits of a caterpillar outbreak can be numerous in a natural setting. While caterpillars are distasteful to most birds, some birds feed on them. When alders and other trees are defoliated, the shrubs and trees below receive increased sunlight, giving some of them a boost in growth.