Monday, June 16, 2014

Monarch Madness

The arrival of the Monarch butterfly is an exciting phenological event that is a sure sign of summer in Wisconsin. They can be found throughout the state beginning in early May when they migrate north from Mexico and Southern California, and until the last butterflies leave in October, migrating south again for the winter. Unfortunately, this beautiful migrating species, and the migratory phenomena that they rely on are in danger. 
Monarch butterfly, Aldo Leopold Nature Center

Monarch butterflies have an important migration process that spans four generations annually. The first generation migrates north in the spring and breeds there. This generation goes through the same life cycle as the following two summer generations, which lasts 6-8 weeks. This cycle consists of egg, caterpillar, chrysalis (also called cocoon or pupa), and adult butterfly. The adult butterfly then breeds and creates the new generation. As the summer comes to an end in late August, and the fourth generation becomes an adult butterfly, migration plays a key role. Unlike its parents and grandparents, this generation does not breed and die soon after it becomes an adult butterfly. They cannot adapt to the colder temperatures and lack of moisture of northern autumn, so instead of staying in the north and laying eggs, they put their energy into migrating south, up to 2,500 miles away. There, they live for six to eight months in Mexico or Southern California, where they enter a deep sleep called torpor, which is a very long, still sleeping state similar to hibernation. When spring arrives, they breed and create the new first generation. 
The Monarch Butterfly Annual Cycle from Journey North

This span of generations and annual life cycles could not exist without
migration. However, the number of migrating monarchs has been plummeting for the last few years. There are many reasons for this decline in monarch migration. One reason is that monarchs lay their eggs on milkweed plants. When the young caterpillars hatch, they rely on milkweed for food.  However, there has been a widespread loss of milkweed, due to deforestation, development, and farming. Global climate change has also had a significant effect on the migration patterns of monarchs, due to climate fluctuations such as extreme temperatures and precipitation events and changes in seasonal cycles.

In addition to being esthetically pleasing, monarchs are also important plant
pollinators. Therefore, they play extremely important roles in many ecosystems. They even pollinate some crops that humans rely on, such as corn. So what can you do to help stop the decline of migratory monarch butterflies and help this important and beautiful species?

As a child, I used to observe monarch butterflies undergo metamorphosis every summer. Being able to witness this natural phenomenon was a great learning experience for me, and it’s a wonderful way to teach your children about insect life cycles and the wonder of nature. It just wouldn’t be summer in Wisconsin without these beautiful butterflies!  Hopefully, with the collective efforts of citizens in Canada, the United States, and Mexico, these populations will be able to recover, so we can enjoy this unique and beautiful species for generations to come. 

Happy Summer!
Lauren, Communications Intern

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