Viceroy
Limenitis archippus
Orange-and-black brushfoot butterfly whose larvae feed on trees in the willow family (Salicaceae) — willows (Salix) plus poplars, aspens, and cottonwoods (Populus). Caterpillars sequester salicylic-acid compounds from these hosts, which makes the adults distasteful to birds; the viceroy and the monarch are now understood as Müllerian co-mimics, two unpalatable species that share a warning pattern and reinforce each other's protection rather than the long-taught one-way Batesian story. Larvae overwinter as third-instar caterpillars inside a rolled-leaf hibernaculum anchored to a host twig, so leaving willow and poplar leaf litter and standing stems undisturbed through winter directly protects the next generation.
Conservation
Common and widespread across its range with no IUCN, Xerces Red List, or USFWS listing; one regional subspecies (L. a. obsoleta) is noted as of conservation concern due to habitat loss. Do not treat the species as imperiled.