BUTTERFLIES: SWALLOWTAILS AND PARNASSIANS

Western Tiger Swallowtail, Papilio rutulus

Family Papilionidae (Swallowtails and Parnassians)

Size: Wingspan 3–4"

Range: Throughout Colorado

Habitat: Gardens, parks, riversides, forest clearings

Among the largest of North American butterflies, the western tiger swallowtail is common throughout its range. It is diurnal and—typical of this family—has distinct projections or “tails” on its hind wings. When alighted and/or feeding, the wings may tremble. Both sexes are bright yellow above and show ragged black stripes, like those of a tiger, along the anterior forewings, and black marginal patterning on both fore- and hind wings. The first submarginal spot on the hind wing is orange. The underside is patterned similarly but is much paler yellow. Females show bright blue posterior markings. Like the wings, the body also has black and yellow stripes. The caterpillar is brown to greenish, smooth, and plump. The caterpillar eats the leaves of trees, including those from the rose, magnolia, poplar, and willow families. Adults feed on flower nectar and the salts and moisture from puddles.