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Idaho State Insect Lesson: The Monarch Butterfly

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Idaho's State Insect

Idaho's State Insect

Idaho's State Insect: Information for Teachers and Students

The monarch butterfly (Danaus plexippus) was designated the official state insect of Idaho in 1992. This was the result of a campaign by the students in the 4th-grade classroom at Boise's Cole Elementary School. Seven states have adopted the beautiful monarch butterfly as their state's insect symbol, and for good reason—they are beautiful, widespread, and known for their spectacular migration.

The magnificent monarch may be the most well-known and best-loved of all our insects. There is something truly regal about its size, bright colors, and powerful, soaring flight, but its kingly name supposedly comes from the spotted margins of its wings, which resemble the sable-edged robes worn by royalty at the time of its discovery.

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!

The Magnificent Monarch: Idaho's State Insect

Nearly everyone has seen monarchs and is familiar with their mind-boggling migrations and million-butterfly roosting in the mountain forests of Mexico. But there are more reasons to be fascinated with this species. For one thing, it is thought that the poisonous sap in milkweed, the monarch's only food source, makes them distasteful to predators like birds. Milkweed plants are very common in Idaho.

The Basics

  • What is the scientific name? Danaus plexippus
  • What does it eat? Milkweeds
  • Will it seriously damage plants or trees? No
  • Is it rare? No, but this species is under threat from industrialized agriculture.

The Monarch's Scientific Name

Idaho's's state insect belongs to a very large butterfly family, Nymphalidae, that is distributed around the world from chilly northern regions to steamy tropical zones. Monarchs and their relatives are in the subfamily Danainae. In the U.S., there are only two common representatives of this group: the monarch and the queen. The queen is darker and less well-known than the bright-orange monarch.

The scientific name of the monarch butterfly is Danaus plexippus. Danaus is the genus and plexippus is the species name.

The Beautiful Monarch

The Beautiful Monarch

Why Are So Many Butterflies Orange Like the Monarch?

The state insect of Idaho has wings of brilliant orange and black, especially the male. There may be a very good reason why so many butterflies are orange—they are evolving to resemble monarchs so birds will think twice before eating them, even if they are perfectly edible. This is the idea behind mimicry, and if the theory is accurate, then the monarch is not only big and beautiful but highly influential as well.

The Intricate Wings of the Monarch Butterfly

The Intricate Wings of the Monarch Butterfly

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 an example, although dragonflies, bees, wasps, flies, beetles, and many other insects also go through complete metamorphosis.

The monarch butterfly is typical of insects that undergo complete metamorphosis. The egg is laid on the food plant, and the caterpillar that hatches out eats the leaves of the plant. As it grows, it sheds its skin, or "molts." 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 rearrange. They actually break down into a kind of goop and then reassemble to form the body and wings of the adult butterfly.

The final "instar" occurs when the insect hatches out of its pupal skin. It is now ready to mate and continue the cycle. The adult feeds just enough to maintain itself as it mates and laying eggs.

The Monarch Caterpillar

The Monarch Caterpillar

The Caterpillar Stage

The caterpillar of the monarch butterfly should be familiar to anyone who has looked for insects around milkweed plants. You will never find this species on anything other than some kind of milkweed (Asclepias species). Many insect species are tied to a particular plant, and Idaho's state insect is no exception.

If you have ever broken a leaf off of a milkweed plant, you will see where the plant gets its common name—white sap will quickly begin to ooze from the broken stem. Also known as latex, sap like this contains toxic alkaloids that protect the plant from most animals and insects that might eat the leaves. However, the monarch (and a few other insect species) have adapted to the poison. They eat the leaves, and it's thought that some of the poison works into their system and makes them toxic too. In this way, they may be protected from being eaten by a predator.

The Monarch Migration Diagram

The Monarch Migration Diagram

The Amazing Migration

Much has been written about the annual movement of millions of adult monarch butterflies from their overwintering areas of Mexico to nearly the entire temperate zone of North America. Between March and November, monarchs are on the move. This happens over the life cycles of several overlapping broods—laying eggs, developing into adults, and continuing to expand northward.

Monarchs you see in your garden in Idaho in the spring are on the move toward Canada; those floating in the air in the fall are on their way south as their range contracts.



Milkweed and Monarchs

Monarch caterpillars are one of few insects that feed on toxic milkweed sap. Source: By Hardyplants at English Wikipedia - Transferred from en.wikipedia to Commons using CommonsHelper.,Text

Milkweed can grow almost anywhere, although commercial pesticides and careless land use have made it less common than it once was—even very recently. For this reason, monarch numbers are dwindling at an alarming rate. The state insect of Idaho depends on milkweed.

Please help this magnificent animal by planting and nurturing milkweed plants in your garden or yard.

More Insect Articles From Owlcation

Resources and Further Reading

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.