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South Carolina's state butterfly is the eastern tiger swallowtail. It was designated in 1994 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 Tiger Swallowtail Butterfly's Scientific Name
South Carolina's state insect belongs to a group of butterflies 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. All swallowtail butterflies belong to the family Papilionidae. There are many butterflies in the group, and they all share some special characteristics.
The scientific name of the tiger swallowtail butterfly is Papilio glaucus. That means the genus name is Papilio and the species name is glaucus. 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!
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.
Often you will se swallowtail butterflies with the tails missing; in some individuals, the missing part of the wing is in the shape of a bird's beak!
Bright Stripes: How the Tiger Swallowtail Got Its Name
There are very few butterflies in North America that you can confuse with South Carolina's state butterfly. The bright yellow and black tiger stripes are visible from far away, especially in full sunshine. The undersides are very similar, with bright blue spots around the margin of the hindwing.
Why Are Some Female Tiger Swallowtails Almost Black?
Interestingly, some females of this species are not tiger striped, but are instead a dark smoky-black color. These dark females are generally more common in the southern part of the tiger swallowtail's range. This kind of difference between males and females is known as "sexual dimorphism." One theory for this phenomenon is that this color pattern mimics another swallowtail species called the pipevine swallowtail, which is common in the South, including South Carolina. The pipevine swallowtail is thought to be protected by the toxic sap of the plant that the caterpillar eats, so looking the same as this species might be an evolutionary outcome that protects the tiger swallowtail.
Features of Swallowtail Caterpillars
The caterpillars of the tiger swallowtail, and 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 looked a lot like a small snake's tongue; it also smells bad. This remarkable evolutionary feature of swallowtail caterpillars is a reiable way to know if the caterpillar you have found is in fact a member of the family Papilionidae.
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These caterpillars also tend to make a shelter by drawing the edges of a leaf together with silk, where it rests when it's not feeding.
Is It Poop or a Swallowtail Caterpillar?
"Baby" swallowtail caterpillars almost all look something alike no matter what species they are, or where they occur. They are small and dark, with a distinctive white "saddle" mark on the back, which makes the immature larva look exactly like a little bird poop. Needless to say, very few predators are on the lookout for a bit of bird poop on which to feed.
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"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 tiger 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.
The Tiger Swallowtail's Range
South Carolina's state butterfly occurs throughout the eastern United States, including, of course, South Carolina. There are several subspecies and related species that fly across all of North America, from Canada to Mexico. This species is not just the state butterfly of South Carolina; it is also the state butterfly of several other states across America.
You will see this magnificent yellow and black butterfly in the early summer, gliding around the tops of cherry, willow, and ash trees, looking for mates or a place to lay eggs.
Check Out These Other State Insect Articles on Owlcation!
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- The State Insect of Alabama: The Monarch Butterfly
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- The State Insect of California: The California Dogface Butterfly
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- The State Insect of Nevada: The Vivid Dancer Damselfly
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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.