Papilio polyxenes

Fabricius, 1775

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

Papilio polyxenes, the black swallowtail, is a -sized to North America. are recognized by black with spots and 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. feed on plants in the carrot (Apiaceae) and possess a distinctive orange forked gland () that everts to release foul-smelling compounds when threatened.

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 spots on versus single row in tiger swallowtail, (2) presence of red spot with black bullseye on (absent in some relatives), (3) female dorsal of pipevine swallowtail with extensive 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).

Images

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 . First 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. 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
Ruta graveolens - larval rue
Zanthoxylum americanum - larval northern prickly ash
Magnolia virginiana - larval sweetbay magnolia

Life Cycle

Females lay single on new foliage or flowers. Egg stage 4–9 days. Larval stage 10–30 days, with five . Pupal stage 9–18 days in summer, or . Winter spent as , 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 behaviors include basking with spread, adjusting position relative to wings, changing perching height, and seeking . 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 . function as on Apiaceae, adapted to sequester and tolerate and other allelochemicals from plants. ' chemical defenses ( secretions) and provide examples of - evolutionary dynamics. host for some .

Human Relevance

State of New Jersey (2016) and Oklahoma. Occasionally considered a garden pest when 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 - , , and mating systems.

Similar Taxa

Papilio machaonOld World swallowtail with similar -spotted black pattern, but differs in distribution (Palearctic) and pattern details
Papilio joanaeExtremely similar appearance but restricted to Ozark Mountains; genetically related to P. machaon rather than P. polyxenes
Papilio zelicaonAnise swallowtail with similar use but western North distribution and different spot pattern
Battus philenorPipevine swallowtail, toxic model for female P. polyxenes ; distinguished by iridescent -green upper surface and single row of spots

More Details

Chemical Ecology

possess P450 adapted for detoxifying and other allelochemicals. Female 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 surface, reducing bird . surface 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 availability including agricultural and garden settings.