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. The eaten leaves pass through the caterpillar's body and emerge as little pellets which can break down easily, returning nutrients to the forest floor.
Pupae provide nutritious meals for small mammals, and moths are eaten by birds and bats.
Where trees are crowded or stressed, the defoliation could be a life and death matter. In a natural setting, surviving trees can prosper in the absence of competition. Healthy ornamental trees and shrubs should survive even serious defoliation. Natural Enemies Tent caterpillars have numerous enemies. One is a tachinid fly which parasitizes the larvae by depositing white eggs on the caterpillar's body.