American Dagger Moth Caterpillar

Deciduous forests, woodlands, parks, and suburban yards across eastern and central North America

Herbivorous, feeding on the leaves of various deciduous trees including oak, maple, birch, elm, willow, and alder

Active from mid-summer through autumn. The bright yellow to greenish-yellow setae (hairs) and distinct long black pencil hairs serve as a warning. When mature, caterpillars wander down trees to spin silk cocoons in bark crevices or leaf litter to overwinter.

The hairs contain urticating toxins that can cause skin irritation, itching, rashes, or burning sensations if handled directly with bare hands. As adults, the moths serve as prey for bats and birds, and the larvae contribute to natural forest herbivory.