Papilio polyxenes

Fabricius, 1775

Black Swallowtail, Eastern Black Swallowtail, American Swallowtail, Parsnip Swallowtail, Parsleyworm (caterpillar)

Species Guides

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Papilio polyxenes, the black swallowtail, is a medium-sized native to North America. are recognized by black wings with yellow spots and blue scaling, with females exhibiting more extensive blue areas and effective of the toxic pipevine swallowtail. The employs a mating system where males defend hilltop territories and engage in aggressive aerial combat. Caterpillars feed on plants in the carrot (Apiaceae) and possess a distinctive orange forked gland (osmeterium) that everts to release foul-smelling compounds when threatened.

Papilio polyxenes var. curvifascia by the Smithsonian. Used under a CC0 license.Papilio polyxenes var. curvifascia by the Smithsonian. Used under a CC0 license.Papilio polyxenes var. curvifascia by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Papilio polyxenes: //pəˈpɪlioʊ pəˈlɪksəˌniːz//

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

Identification

Distinguished from similar swallowtails by: (1) two rows of yellow spots on forewing versus single row in tiger swallowtail, (2) presence of red spot with black bullseye on hindwing (absent in some relatives), (3) female dorsal mimicry of pipevine swallowtail with extensive blue scaling, (4) hindwing with orange spots and powdery blue areas. Separated from Ozark Papilio joanae by range and genetic affinity (joanae related to P. machaon, not P. polyxenes).

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Habitat

Open areas including fields, parks, marshes, and disturbed . Occupies tropical and temperate zones. Frequently found in agricultural and suburban settings where plants grow. Males establish territories on hilltops and elevated topographic features for mating.

Distribution

Southern Canada through the United States east of the Rocky Mountains, extending through Mexico to South America. More common east of the Rocky Mountains. Occurs in Arizona and southern California. polyxenes formerly in Cuba now likely extinct.

Seasonality

emerge in spring from pupae. First flies mid-May to late June, second brood early July to late August, occasional partial third brood later in season. Multiple annually in south (at least three), up to two generations in northern .

Diet

feed on nectar from diverse flowers. Larvae are on plants in Apiaceae (carrot family), including: Daucus carota ( Anne's lace), Pastinaca sativa (parsnip), Petroselinum crispum (parsley), Anethum graveolens (dill), Foeniculum vulgare (fennel), Conium maculatum (poison hemlock), and other umbellifers. Larvae also recorded on Rutaceae (Ruta graveolens, Zanthoxylum americanum) and Magnoliaceae (Magnolia acuminata, M. virginiana).

Host Associations

  • Daucus carota - larval Anne's lace, major wild
  • Pastinaca sativa - larval parsnip
  • Petroselinum crispum - larval parsley, common garden
  • Anethum graveolens - larval dill
  • Foeniculum vulgare - larval fennel
  • Conium maculatum - larval poison hemlock, toxic to humans but palatable to larvae
  • Ruta graveolens - larval rue
  • Zanthoxylum americanum - larval northern prickly ash
  • Magnolia virginiana - larval sweetbay magnolia

Life Cycle

Females lay single on plant new foliage or flowers. Egg stage 4–9 days. Larval stage 10–30 days, with five instars. Pupal stage 9–18 days in summer, or . Winter spent as chrysalis, emerging spring. Protandrous: males emerge 2–3 days before females. Survival varies by host plant, elevation, and timing.

Behavior

Males exhibit territoriality, defending elevated sites for mate location. Territorial defense involves aggressive aerial chases and audible collisions with rival males. Territories lack nectar sources or plants, serving solely for display. mating system: males aggregate at display sites, females choose mates based on territory quality. Thermoregulatory include basking with wings spread, adjusting position relative to wings, changing perching height, and seeking shade. Thoracic temperatures of 24°C required for ; optimal vigorous flight above 28°C. Males can mate twice daily; females mate multiple times to replace deteriorating sperm supply. Copulation lasts approximately 45 minutes.

Ecological Role

serve as . Larvae function as herbivores on Apiaceae, adapted to sequester and tolerate and other from plants. Caterpillars' chemical defenses (osmeterium secretions) and mimicry provide examples of -prey evolutionary dynamics. host for some .

Human Relevance

State of New Jersey (2016) and Oklahoma. Occasionally considered a garden pest when caterpillars defoliate parsley, dill, fennel, and carrot plantings. Easily attracted to gardens by planting herbs. Popular subject for butterfly photography and observation. Used in research on insect-plant chemical , , and mating systems.

Similar Taxa

More Details

Chemical Ecology

Caterpillars possess P450 adapted for detoxifying and other plant . Female oviposition guided by tarsal contact responding to specific phytochemicals including luteolin derivatives and chlorogenic acid.

Mimicry

Females exhibit effective of unpalatable pipevine swallowtail (Battus philenor) on wing surface, reducing bird . surface mimicry protects both sexes. Some males mimic female wing pattern for reduced predation, though typical males are more successful in territorial competition.

Conservation Status

Cuban P. p. polyxenes likely extinct. Mainland widespread and secure, benefiting from widespread plant availability including agricultural and garden settings.

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Sources and further reading