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Monarch Butterfly

Scientific name: Danaus plexippus

The monarch butterfly has captured the attention of many with its dramatic annual migration which can extend as far north as Canada during the summer breeding season. These seemingly fragile insects fly all the way to the highlands of Mexico for the winter months. Watch this Google earth video to learn more.

This is an easy butterfly to identify.  Its wings have a stained glass appearance as the dark black veins are filled with bright orange areas. The polka-dotted body and wing edges are very distinctive and give this butterfly a happy appearance.

© Missouri Dept. of Conservation


Up to 2 inches

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The caterpillar will only eat milkweed. The butterfly will drink nectar from many different flowers.


Meadows, woodland edges, gardens, parks, seashore. The monarch requires milkweed to reproduce and also depends upon the forests of the Mexican Highlands for its winter home. For a time, this was being destroyed, but now it is protected by the government and is a source of pride and revenue for the local community. Watch this to learn more.

Life Cycle

Adults migrate to Mexico in September to October. When they fly north in spring, they reproduce in the southern United States. Their offspring continue northward, returning “home” four generations later.

Eggs are laid throughout spring and summer on the leaves of milkweed. The newly hatched caterpillars can eat ONLY milkweed. This is considered its host plant. After about 2 weeks, the caterpillar transforms into a chrysalis. The mature butterfly emerges (ecloses)  shortly thereafter (in 7-12 days, depending on the weather). Please enjoy this video which shows the entire life cycle!


The migration from Mexico in the early spring to New York a few months later, is an amazing story. How does this insect know how and where to migrate north as its grandparents came to Mexico ?

There is an interesting website called Journey North which shows real time reports from spring through fall. You can be a citizen scientist and add your own sightings!


Ecosystem Connections

Monarchs are important pollinators. As each female pays up to 400 eggs in her lifetime and only a few survive, the eggs and caterpillars are also food sources for birds and other insects.

Human Connections

Monarchs are popular with gardeners and nature watchers. Educators commonly raise monarchs as a way of teaching about insect life cycles. Where they flock in great numbers, monarchs can contribute to the local tourism economy. The highlands of Mexico have several sanctuaries where the monarch spend the winter months.

Fun Facts

The monarch caterpillar, like all caterpillars undergoes a metamorphosis while it is in its chrysalis. It totally dissolves and reconstitutes itself into something entirely different.

Monarchs at Risk

There has been a severe decline in populations over the last several decades, placing this species in peril.

Its unique life cycle requires milkweed in order to reproduce. There are several factors at work. The use of Round-up on agriculture fields, which has suppressed the milkweed that had traditionally grown between rows of crops, has eradicated this butterfly. The overwintering areas in Mexico also had been disturbed, providing less habitat.

How You Can Help

Plant some milkweed in your own backyard. Local nurseries sell attractive milkweeds that do not take over, if you are limited on space. See below for photos.

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