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Papilio polyxenes

What do they look like?

Adult black swallowtails range in length from seven to nine cm, and can reach a wingspan of 11.5 cm. Older larva vary from green to yellow and most often each segment is crossed by a black band. Pupae of this species can vary from green and yellow, to brown and white, to a black form.

The upper surface of an adult is black with two rows of yellow spots. In females these yellow spots are narrow and lighter, or nonexistent. On the upper surface of the adults' hind wing, there are irridescent blue spots on males and an irridescent blue band on females. On the upperside of the hindwing there is a large red spot that has a black center towards the tail. Under the forewing there are yellow spots, and on the underside of the hindwing there are a row of orange-red spots, in front of blue caps, followed by black centered red spots towards the tail. (Douglas, 1986; Ehrlich, 1961; Neck, 1996; Scott, 1986)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range length
    7 to 9 cm
    2.76 to 3.54 in
  • Range wingspan
    11.5 (high) cm
    4.53 (high) in

Where do they live?

The range of black swallowtails (also known as American swallowtails) extends from Southern Canada, through North America, and down to South America. Included in the South American range are the West Indies. In North America, black swallowtails are not commonly found west of the Rocky Mountains. (Ehrlich, 1961; Neck, 1996)

What kind of habitat do they need?

Black swallowtails tend to be found in open areas such as meadows, fields, parks, gardens, lowlands, marshes, and deserts. (Jackman, 1998)

How do they reproduce?

To find a female black swallowtail, males alternately perch on the tops of hills and then patrol in flat areas. Males defend territories of about 70 square meters where they perch and patrol. Courtship lasts for about 45 seconds,and mating follows.

Females lay round, cream-colored eggs on the leaves of Umbelliferae plants. A female black swallowtail lays on average 200 - 440 eggs, 30 - 50 per day, starting at two days after emergence from the pupal stage. (Jackman, 1998; Scott, 1986)

  • Range eggs per season
    200 to 440

Once eggs are fertilized and laid, there is no longer any parental care.

  • Parental Investment
  • pre-fertilization
    • provisioning

How do they behave?

The nocturnal behavior of seeking a nightly sleeping perch occurs in several frenzied flights. Once the butterfly finds a good stalk or tip of an herbaceous plant, it will rest for a few minutes. When finally settled, it closes its wings and lowers its abdomen into the sleeping position where it will remain all night. In the morning the butterfly wakes up and positions itself again with its wings open, but this time it turns around to catch the morning light.

It has been discovered that black swallowtails mimic pipevine swallowtails, a distasteful species. By mimicking distasteful pipevine swallowtails, adult black swallowtails gain some protection where their ranges overlap. (Bordoni and Forestiero, 1998; Douglas, 1986; Scott, 1986)

  • Average territory size
    70 m^2

What do they eat?

The larvae of American swallowtails are attracted to the oils of plants such as dill, parsley, celery, carraway and carrots. These plants have adapted to insects herbivores by producing specific chemicals that repel the insects that try to eat them. American swallowtail larvae are resistant to these chemicals and make the caterpillar bad-tasting to bird predators. Some plants from the Umbelliferae family make psoralens that reduce growth rate and fertility in American swallowtails. The larva are most often found at small flowers. Adults feed on flower nectar and mud. (Douglas, 1986; Jackman, 1998; Neck, 1996; Scott, 1986)

  • Plant Foods
  • leaves
  • nectar
  • flowers

What roles do they have in the ecosystem?

These butterflies pollinate many plants. Their larvae eat many plant species. They also may provide food for many predator species.

  • Ecosystem Impact
  • pollinates

Do they cause problems?

The caterpillar of this species is occasionally a pest in gardens and farms. (Jackman, 1998)

How do they interact with us?

These butterflies have no positive economic effect on humans.

Are they endangered?

These butterflies are widespread and do not seem to be threatened.

Some more information...


Matthew Wund (editor), University of Michigan-Ann Arbor.

Katy Eby (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

  1. active during the day, 2. lasting for one day.

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


an animal that mainly eats leaves.


An animal that eats mainly plants or parts of plants.


animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.

internal fertilization

fertilization takes place within the female's body


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


marshes are wetland areas often dominated by grasses and reeds.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


an animal that mainly eats nectar from flowers


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland


Bordoni, S., Forestiero. 1998. Butterflies of the World. Ontario, Canada: Firefly Book.

Douglas, M. 1986. The Lives of Butterflies. Rexdale, Canada: The University of Michigan Press.

Ehrlich, P. 1961. How to Know Butterflies. Dubuque, Iowa: WM. C. Brown Company Publishers.

Jackman, 1998. A Field Guide to Common Texas Insects. Houston, Texas: Gulf Publishing.

Neck, R. 1996. Butterflies of Texas. Houston, Texas: Gulf Publishing Company.

New, T. 1991. Butterfly Conservation. New York, New York: Oxford University Press.

Scott, J. 1986. Butterflies of North America. Stanford, California: Stanford Press.

University of Michigan Museum of ZoologyNational Science Foundation

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Eby, K. 2001. "Papilio polyxenes" (On-line), Animal Diversity Web. Accessed April 24, 2014 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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