Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
11/14/02
FOR IMMEDIATE RELEASE
Contacts:
Linda Naeve, Reiman Gardens, (515) 294-2710, lnaeve@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
For November 14, 2002
Monarch Butterflies Are a Favorite
By Linda Naeve
Extension Coordinator
Reiman Gardens
This week's Reiman's Pick is one of the most recognized butterflies in the Midwest and maybe the country - the monarch (Danaus plexippus). Even preschool children easily identify this orange-and-black butterfly. Traditionally, this time of year it would be appropriate to write about Christmas trees, poinsettias, and other holiday plants, but I am breaking tradition because monarchs and dozens of other butterfly species can now be seen year-round in the new Christina Reiman Butterfly Wing at Iowa State University's Reiman Gardens in Ames. This 2,500-square foot greenhouse is kept at a constant 80 degrees Fahrenheit and is filled with more than 800 fluttering butterflies.
The monarch has many unique characteristics that make it the perfect choice for the first butterfly to be "Reiman's Pick." It is native to Iowa and many other states, but approximately half of the monarch population originates right here in the Corn Belt.
The marvel of the monarch begins when adults arrive in late spring. The females instinctively begin looking for milkweed plants on which to lay eggs. Iowa is a great place for monarchs because milkweeds are common near farm fields and in other uncultivated areas. In four or five days, tiny yellow-, black-, and white-banded caterpillars emerge.
Although these caterpillars are picky eaters, feeding only on milkweed, they eat enormous quantities and grow quickly. In two weeks, they will have molted, or shed their skin, five times to allow for growth. When three weeks old, the caterpillars begin to pupate, or transform into adults, and eventually form the beautiful chrysalides characteristic of this species. The monarch chrysalis is one of nature's most beautiful creations. It is jade green and approximately three-quarters of an inch in length. Near the top of the chrysalis there is a band of small golden dots.
After approximately two weeks, the chrysalis becomes transparent and the dark butterfly inside can be seen. When the butterfly emerges, it inflates its wings with a pool of blood it has stored in its abdomen. The butterfly waits until its wings stiffen and dry before it flies away. Monarch butterflies live two to three weeks in the summer.
There are two interesting characteristics that make monarchs unique. First, the milkweed on which the larvae feed provides the monarch with much more than just food. Milkweed contains a milky sap that contains a toxin. When monarch larvae eat the milkweed they ingest the plant's toxins, called cardiac glycosides. These compounds make the larvae and adults toxic to many potential predators. Birds avoid monarchs because they learn that the larvae and adults taste bad and can make them sick.
Second, monarchs migrate in the fall. Unlike most other insects in temperate climates, monarch butterflies cannot survive the long, cold winter. Monarch butterfly adults in Iowa sense the seasonal change in the fall. Day length and temperature changes in late September signal that it's time for them to begin their annual migration. No other butterflies in the world migrate like the monarchs of North America. They travel up to 3,000 miles, much farther than tropical butterflies. They are the only butterflies to make such a long, two-way migration every year. Amazingly, monarch butterflies follow the same migration patterns every year. They fly en masse to the same winter roosts and often to the same trees. Tens of millions of monarchs spend the winter in a mountain forest in Central Mexico.
This generation of monarch butterflies lives approximately six months. In the spring, they begin the long journey back north and females lay eggs along the way. The butterflies that arrive in Iowa in late May are the children or grandchildren of those that left in the fall. The monarch's homing system is an unsolved mystery. It is amazing to think that these small creatures know their way back to the same forest in Mexico, even though they are the great-great-grandchildren of the butterflies that left the previous spring.
Watch a miracle happen as monarchs and other butterflies emerge from their chrysalides in the emergence case at Reiman Gardens, then enjoy the beauty of hundreds of exotic and native butterflies in the Christina Reiman Butterfly Wing.
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Editors: Two color photos, suitable for publication, are available at right. Click on each thumbnail photo to go to the fullsized photo. The top picture's fullsize photo is 268K and the bottom picture's fullsize photo is 260K. Caption: Monarch butterfly (Danaus plexippus). |
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