Tent caterpillars hatch from their eggs in the early spring at the time the leaves of their host trees are just unfolding.

The tent consists of discrete layers of silk separated by gaps and the temperature in these compartments varies markedly.

Later on in the spring, temperatures may become excessive at midday and the caterpillars may retreat to the shaded outside surface of the tent to cool down.

At the onset of a bout of foraging, caterpillars leave the tent en masse, moving to distant feeding sites.

Immediately after feeding the caterpillars return to the tent and aggregate in sunlight to facilitate the digestive process.

In contrast, the forest tent caterpillar is a nomadic forager that establishes a series of temporary resting sites during the course of its larval development.

Caterpillars move from the tent in search of food, laying down an exploratory pheromone trail as they pass over the branches of the host tree.

Leaves consist largely of nondigestible components, and it has been estimated that tent caterpillars void as frass (fecal pellets) nearly half of the energy they ingest.

Consequently, it is not uncommon for populations of forest tent caterpillars to go unnoticed until the last instar, when their feeding causes extensive defoliation of trees.

When fully grown, the caterpillars leave the natal tree and seek protected places on the ground or under the eaves of buildings to spin their cocoons.

During outbreaks, the caterpillars can become so abundant that they are capable of completely defoliating tens of thousands of acres of forest.

This has occurred when forest tent caterpillars defoliated sugar maples that were already stressed due to drought.