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Oregon's State Insect: The Oregon Swallowtail

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Oregon's State Insect, the Oregon swallowtail butterfly

Oregon's State Insect, the Oregon swallowtail butterfly

The Oregon Swallowtail: Information for Teachers and Students

Oregon's state butterfly is the gorgeous Oregon swallowtail. It was designated in 1979 and is one of many swallowtail species that are distributed across the United States, and around the world. This article tells you what you need to know about this wonderful butterfly.

The Basics:

  • What is the scientific name? Papilio machaon oregonia
  • What does it eat? The larvae eat the leaves of tarragon sagebrush
  • Will it seriously damage plants or trees? No
  • Is it rare? This species is not common, but can be found at the right place and time of year.
  • Where does it occur? The Pacific Northwest
  • Can you raise it from caterpillar to adult? Yes, if you give it plenty of the food plant you found it on.

Make sure you take the Quiz at the end of this article before you leave!

Underside view of the Oregon swallowtail

Underside view of the Oregon swallowtail

The Oregon Swallowtail Butterfly's Scientific Name

Oregon's state insect belongs to a group of butterflies, the swallowtails, that are distributed around the world, from chilly northern regions to steamy tropical zones. Northern species are some of the most familiar butterflies you will see. They are big, beautiful, and often take nectar at flowers in the bright summer sun. Tropical swallowtail species are among the world's most breathtakingly beautiful insects, with some showing bright shimmering colors and iridescence. This group is known by scientists as the family Papilionidae. There are many kinds of butterflies in the group, and they all share some special characteristics.

The scientific name of the Oregon swallowtail butterfly is Papilio machaon oregonia. That means the genus name is Papilio, the species name is machaon, and the subspecies name is oregonia. Scientific names are always in italics.

As a middle school teacher myself, I wrote this guide to be useful for both students and teachers. It's a great place to start for research ideas and science fair projects!

Oregon swallowtail, Oregon's State Insect

Oregon swallowtail, Oregon's State Insect

Papilio Machaon and Its Several Subspecies

Oregon's state insect is actually part of a group of butterflies that are all closely related. The species, Papilio machaon, is a well-known part of the European fauna, where it is often simplycalled "the swallowtail." There are many subspecies, and they range around the world. The version of Papilio machaon that occurs in North America is the Oregon swallowtail. You can tell it's a subspecies because it has three names; the last one is the subspecies name, and indicates that it's found in Oregon (among other states in the Pacific Northwest).

Other Similar Species

In North America there are several species very similar to the Oregon swallowtail, especially the tiger swallowtail, Papilio glaucus. Like Papilio machaon, P. glaucus has several subspecies as well as several closely related full species, like the two-tailed swallowtail of the desert Southwest. All of these similar swallotails have a bright yellow-orange background and black "tiger stripes."

The Oregon swallowtail also resembles the closely related Anise swallowtail, a common feature of West Coast fauna.

Papilio machaon

Habits of the Oregon Swallowtial

Like all other swallowtails, the flight is strong and gliding, but they will often stop to nectar. At these times, you may see several visiting the same nectar source. Male swallowtails also sometimes participate in a behavior known as "puddling," which is when a group of butterflies congregates at wet sand or mud to draw nutrients.

Close-up of a swallowtail butterfly's "tails"

Close-up of a swallowtail butterfly's "tails"

Swallowtail Butterfly "Tails"

Swallowtail butterflies likely get their common name from the tails that grace their hindwings, which in some ways recall the forked tails of birds called swallows. Researchers who study insects ("entomologists") believe that these tails may attract the attention of predators, who are more likely to attack this part of the butterfly rather than the vital body or head. So if a hungry bird or lizard snaps at the tails, the butterfly will only lose a bit of wing and can live to fly, mate, and reproduce.

In many species the tails have a central spot, reminiscent of an eye. This may further the illusion that the expendable tails on the swallowtail's wings are where the action is for a predator to strike. The Oregon swallowtail is unusual in that it has a large, round spot just above the tails on the hindwing; this may serve as a false eye, and a kind of target for a hungry predator to strike.

Often you will see swallowtail butterflies with the tails missing; in some individuals, the missing part of the wing is in the shape of a bird's beak!

This Papilio caterpillar is very similar to that of the Oregon swallowtail.

This Papilio caterpillar is very similar to that of the Oregon swallowtail.

The Oregon Swallowtail Caterpillar

The caterpillars of the Oregon swallowtail, and in fact all swallowtails, have some fascinating habits and features. The most distinctive of these is the presence of an organ called an "osmeterium." This is a orange-red, forked gland that the caterpillar can pop out from behind its head when it's disturbed or threatened. The gland looks a lot like a small snake's tongue; it also smells bad. This remarkable evolutionary feature of swallowtail caterpillars is a reliable way to know if the caterpillar you have found is in fact a member of the family Papilionidae.

Oregon swallowtail caterpillars are a pretty combination of green, black, and yellow spots and stripes. This pattern is shared by several other North American swallowtail caterpillars, including the black swallowtail. They are remarkably well camouflaged on the food plant, and they can be nearly impossible to find, even if there are several not very far from your nose!

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Complete Metamorphosis

"Complete metamorphosis" is the term used to describe the life cycle of insects that go through a four-stage sequence of forms. For butterflies, this means egg-larva-cocoon/chrysalis-adult. It helps to take the butterfly as the example, although dragonflies, bees, wasps, flies, beetles, and many other insects also go through complete metamorphosis. Like butterflies, they all have larvae and all of the other developmental stages.

The Oregon swallowtail butterfly is typical of the insects that undergo complete metamorphosis. The egg is laid on a variety if leaves, and the caterpillar that hatches out eats the leaves of the plant. As it grows, it sheds its skin, also known as molting. The stages between molts are called instars, and after the last instar, the caterpillar sheds its skin one more time.


The last time the caterpillar sheds its skin, it enters the cocoon/chrysalis phase, known by scientists as "diapause." It's also called a "pupa." Inside the pupa, the insect's cells are rearranging. They actually break down into a kind of goop, and then reassemble to form the body and wings of the adult butterfly or moth.

The final "instar" occurs when the insect hatches out of the pupal skin. It is now ready to mate and continue the cycle. The adult feeds just enough to promote the goal of mating and laying eggs; other than that, it has no purpose on this planet.

Museum specimens of the Oregon swallowtail

Museum specimens of the Oregon swallowtail

Students – Can You Pass This Quiz?

For each question, choose the best answer. The answer key is below.

  1. What is the genus name of the Oregon Swallowtail?
    • Parnassius
    • Cremaster
    • Melissa
    • Papilio
  2. On what plant does the Oregon swallowtail cateprillar feed?
    • Milkweed
    • Tarragon sagebrush
    • Lemon alfalfa
    • None of these
  3. In what part of the country is this insect found?
    • The South
    • The East
    • The Northwest
  4. True or False: Oregon swallowtails are a serious pest species.
    • True
    • False
  5. The stages of complete metamorphosis, in correct order, are:
    • egg, pupa, larva, adult
    • pupa, larva, egg, adult
    • egg, larva, pupa, adult
    • adult, pupa, larva, egg

Answer Key

  1. Papilio
  2. Tarragon sagebrush
  3. The Northwest
  4. False
  5. egg, larva, pupa, adult

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The following sources were used for this guide:

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.