Which caterpillar is known to develop into the largest moth?

The carpenterworm is recognized for developing into the largest moth, specifically the regal moth or royal walnut moth (Ceratocampinae). This caterpillar can grow significantly in size, reaching lengths of several inches, and is known for its robust physical presence. Its larval stage occurs primarily in hardwood trees, where it feeds on the wood and foliage, contributing to its considerable growth before pupating and emerging as an impressive moth. The size and stature of the regal moth are indeed remarkable, making the carpenterworm caterpillar significant in terms of size compared to other moths.

In contrast, the fall cankerworm, variable oakleaf caterpillar, and walnut caterpillar, while they each have their unique characteristics and ecological roles, do not reach the same dimensions as the caterpillar of the carpenterworm. This important distinction highlights why the carpenterworm stands out as the caterpillar that develops into the largest moth.