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State Insect of Montana Lesson: The Mourning Cloak Butterfly

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Montana's state insect is the mourning cloak butterfly. It was designated in 2001. It is a butterfly that you may overlook, thanks to its gray-brown appearance in flight. However once it lands and you get a bit closer, you can see that it is in fact a spectacularly beautiful creature. This article tells you what you need to know about this wonderful butterfly.

The Mourning Cloak Butterfly's Scientific Name

Montana's state insect belongs to a group of butterflies that are distributed around the world, primarily in nearctic zones, meaning temperate regions well north of the equator. Known generally as angle-wings, they often have "ragged" wing-margins and plain, camouflages undersides. They belong to the family Nymphalidae. Within that huge group, the mourning cloak belongs to the genus Nymphalis. This is something like your last name -- it shows you belong to a closely related group, but within that group are individual species. The mourning cloak's species name is antiopa. Therefore the insect's scientific name is Nymphalis antopa.

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!

My Encounters With the State Insect of Montana

I am always amazed when I get a chance to see a mourning cloak up close. When they're on the wing they appear to be little more than a medium-sized dark gray butterfly, but once an individual lands on a sunny patch of moist earth, the true glory of its markings can be seen. The ground color is a deep, almost iridescent purplish-brown, bordered by a band of royal blue-black with bright lavender spots; the entire margin of the wings is a pale yellow. Underneath, it's a different story. The wings are mottled gray and black, which gives rise to its common name -- the colors are so somber that early entomologists compared it to the dark cloaks worn by mourners at a funeral.

This butterfly has a nearly world-wide distribution, but it is exceedingly rare in the UK, where it is known as "the Camberwell Beauty." A much better name, I think, for one of the most beautiful of all butterflies.

Mourning Cloak Showing Underside of Wings


Mourning Cloak Butterfly Early Stages and Caterpillar

After mating, the mourning cloak female lays her fertilized eggs on leaves of elm plants. The tiny immature caterpillars crawl out to the edge of the leaf and begin to feed.

Over the course of a few weeks, the tiny mourning cloak caterpillars eat and grow. Since they have an exoskeleton, a cuticle-like body covering, they have to shed their skin in order to get larger.

With each shedding of the skin, called "instars," the caterpillar gets larger. Finally the mature caterpillar sheds its skin and becomes a pupa; the adult butterfly hatches out in the spring and the process repeats.

Take Part in a Poll!

Mourning Cloak Caterpillar -- AKA the Spiny Elm Caterpillar


The Mourning Cloak -- Early Stages

The mourning cloak's caterpillar eats elm, and is sometimes known as "the spiny elm caterpillar." It's black, spiny, and has red spots running along its back. The chrysalis is angular and looks very much like a dried leaf.

The mourning cloak often hibernates over the winter in a sheltered place, or inside a garage or shed. It is typically one of the first butterflies on the wing once the weather warms up.


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 mourning cloak 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 tine 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 following sources were used for this guide:


David Stillwell from Sacramento, California on January 01, 2013:

I always think it a lucky day when I find a Morning Cloak Butterfly. We don't see them very often anymore, but they are rich like velvet when settled in the sun. Nice article... am glad Montana chose this one.

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