Papilio eurymedon

Lucas, 1852

Pale Swallowtail, Pallid Swallowtail

Papilio eurymedon, commonly known as the pale swallowtail or pallid swallowtail, is a native to western North America. It is distinguished from the western tiger swallowtail by its white-cream to very pale yellow coloration. The exhibits single-brooded development across most of its range, with multiple along the Pacific Coast. are active from April through October, with peak abundance in May and July.

Papilio eurymedon by the Smithsonian. Used under a CC0 license.

Papilio eurymedon (Pale Tiger Swallowtail) - Flickr - S. Rae by S. Rae from Scotland, UK. Used under a CC BY 2.0 license.

Papilio eurymedon, Mt. San Jacinto, California by Brian MacIntosh. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Papilio eurymedon: /pæˈpɪlioʊ juːˈrɪmɪˌdɒn/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from Papilio rutulus (western tiger swallowtail) by pale white-cream to very pale yellow coloration versus bright yellow, and by thicker tiger stripes and borders. Red-orange patches above the tail, when present, provide additional diagnostic characters. Similar overall pattern but markedly paler ground color separates it from other western swallowtails.

Images

Habitat

Open woodlands and forest clearings, especially near permanent water bodies such as ponds. Also occurs in urban parks and occasionally in suburban areas.

Distribution

Pacific coast from northern Baja California to southernmost British Columbia. Inland distribution extends to New Mexico and the Black Hills of South Dakota. Present from coast to western Montana, and from Wyoming to northern New Mexico. Absent from most of Nevada and western Utah.

Seasonality

fly from April to October, most abundant in May and July. Single throughout most of range; two or more broods along Pacific Coast.

Diet

sip water from damp soil at puddling parties to obtain nutrients for mating. Larvae feed on leaves of plants including Ceanothus (buckbrush, mountain balm, mountain lilac), red alder, ocean spray, bitter cherry, and serviceberry species.

Host Associations

Ceanothus - larval Includes buckbrush, mountain balm, and mountain lilac
Alnus rubra - larval Red alder
Holodiscus discolor - larval Ocean spray
Prunus emarginata - larval Bitter cherry
Amelanchier - larval Serviceberry

Life Cycle

laid singly on plant leaves. Caterpillars are plump green with single yellow band behind and two -shaped spots on upper thorax. Caterpillars turn brown just before fifth moult. Pupae are brown, bark-like in appearance, and overwinter. occurs with tip secured to branch by silk thread, hanging freely upright. emerge following winter .

Behavior

Males perch and patrol for receptive females. Females lay singly on plant leaves. Caterpillars rest on silken mats within shelters of curled leaves. Males participate in puddling parties where up to a dozen or more individuals may gather with other to sip water from damp soil. occasionally visit flowers for nectar.

Papilio rutulusWestern tiger swallowtail shares range and similar pattern, but distinguished by bright yellow ground color (versus pale white-cream), thinner tiger stripes and borders, and absence of red-orange patches

More Details

Puddling behavior

Males frequently observed in large at damp soil, less common than in western tiger swallowtail but notable when present

Brood variation

Multivoltine along Pacific Coast contrast with inland populations, representing geographic variation in