Cornell University : Cornell Cooperative Extension

Monarchs Rule!
By, Sheri Mochamer

August 1 , 2001

If all good stories contain suspense, conflict and beauty, then the story of the Monarch butterfly's life cycle is truly a masterpiece! It also has the elements of travel and change. When talking about any cycle, it is difficult to know at which stage to begin, but the egg seems a perfectly good place to start. The female Monarch lays tiny eggs on the underside of milkweed plant leaves. After a few days, the eggs hatch into tiny caterpillars that have yellow, white and black stripes. The caterpillars remain on milkweed leaves, munching away to their hearts content. This diet of milkweed leaves is a major protector for the Monarch. Milkweed contains chemicals that are poisonous or at the least bad tasting to most birds that would like to feast on the fast growing, fat caterpillars. As the caterpillars eat milkweed leaves, the poison becomes part of their system and, luckily, they are not affected by it.

The caterpillars gain weight rapidly, and split their skins with a new, bigger skin beneath the old. When it is time for the caterpillar to move onto the next stage, something remarkable happens. Instead of making a cocoon as moths do, butterflies go into their pupal stage in a chrysalis. The caterpillar leaves the safety of the milkweed plant to find the perfect place to spend the next two weeks or so. A small bed of silky material is spun and attached to the place where the caterpillar will hook itself upside down and hang in what looks like the letter J. The caterpillar will squirm and puff itself until the skin splits, but instead of a new black, yellow and white skin, there is a beautiful pale green covering that is the chrysalis. Gold and black specks appear along the rim, making the chrysalis appear jeweled.

It appears as if nothing is happening inside the chrysalis, however about 10 days after the chrysalis was formed, there is a color change. The pale green begins to darken to a gray or black, and then becomes transparent.
You can actually see orange and black lines that are the wings all folded up inside this little case. A few more days pass and the chrysalis splits open. An adult Monarch butterfly is born into a world that is full of change. If you have actually witnessed the butterfly emerging from the chrysalis, you will know why I have chosen the word "born"!

The adult butterfly does not begin its new stage looking regal. After being crammed into the tiny chrysalis, its wings need to stretch out and dry. Its fat body becomes long and slender. This is a very critical time in the life of a butterfly. It is quite defenseless, and may come through the egg, larva and pupa stage only to be eaten by another insect or a bird! While most predators leave the Monarch alone, as stated earlier, some birds and insects can resist the toxins that are in the Monarch's body. While the adult Monarch will dine on nectar from a variety of flowers, the female will only lay eggs on milkweed plants. This is the purpose of the adults: to mate and lay eggs so the cycle can continue. By the way, male Monarchs are easily distinguished from females. They have scent glands that appear as dark spots on the lower wings. When you know what you are looking for, it is a cinch to pick out the males, and you don't even have to be too close!

So, you may ask, where is the suspense and travel? Unlike other butterflies, Monarchs migrate. Those that live their summers to the east of the Rocky Mountains winter in mountain forests near Mexico City, while those to the west of the Rockies winter in coastal California. Adults that begin the trek north in spring do not live all summer. After they reach land and lay eggs, they die. Their offspring travel further north to begin a new cycle. By the time they reach our area of the country, which is usually in mid July, they are the fourth generation from adults who left Mexico in spring. Now here's the mystery. This fourth generation of Monarch butterflies know when it is time to migrate south, and they also know where to go! They always winter in the same part of Mexico, but remember, it was their great-grandparents who ventured north way back last spring! How do they know when and where to go? It is one of life's great mysteries.

These late summer-early fall butterflies have a long distance to travel and spend winter flocked together on trees in the mountains of Mexico. It is important that they have a place to winter. However, people in the mountains of Mexico have been removing habitat for the butterflies. If the winter habitat of the Monarchs is destroyed, the whole life cycle will be affected! Luckily, people have voiced their concern for the regal Monarch and steps are being taken to preserve the forests where the butterflies overwinter.

Sometimes it is easy to blame the loss of habitat on "the other guy" or someone far away. It seems that some of this problem can be traced to our own backyards. Milkweed plants are the crucial plant for Monarch survival. Where fields of milkweed used to be, now there are homes and businesses. Considered a weed, milkweed is an easy target for destruction by herbicides when it is found in fields or along roadsides. Some people are concerned about the effects of pollen of genetically engineered corn when eaten by monarchs. More research is needed to fully understand this issue.

Respecting the habitat of other animals is a trait of a caring community. What can you do to insure the survival of Monarchs? Become aware of what is being done with pesticides and herbicides in your community. Learn about Integrated Pest Management (IPM). Keep milkweed available for the Monarch caterpillar and plant a variety of flowers as nectar food for butterflies. The story of the Monarch is, overall, one of mystery and beauty. Let's all help to keep it alive. For more information about your lawn and garden questions, call the Master Gardeners at Cornell Cooperative Extension 315-536-5123. Please leave your name, phone number, and a time to return your call along with your question.

Cornell Cooperative Extension Yates Association
Last updated: 7/31/01

top