Monarch Butterflies, Amazing Travelersby Kool Cat KC on 01/10/13
Did you know that monarch butterflies migrate from as far north as the southern part of Canada to spend the winter in California and Mexico? Did you also know that Monarch butterflies only live two to six weeks? Impossible? It’s a difficult idea to understand; hang with me and we’ll learn all about it.
Monarch butterflies that live east of the Rocky Mountains overwinter in Mexico; monarchs that live west of the Rocky Mountains overwinter in California. My human, Terry, took the pictures you see in late November in Pismo Beach, California.
So how do they travel thousands of miles, spend the whole winter, and only live two to six weeks? Dr. Karen Oberhauser, who studies monarch butterflies says it’s actually different butterflies. Same species, but different individuals. Every year, several generations (groups of individuals born about the same time) of monarchs are born. Starting with the generation born in the spring, right after the parents overwinter in California and Mexico, monarchs only live two to six weeks. Most spend their lives flying north and a couple of generations spend their lives—as pupa, chrysalis and adult—in the most northern point of their range.
Then when the amount of nectar available for them to eat is decreasing, temperatures begin to cool and the days become shorter the last generation of butterflies is born. This is the tricky one, the different one. Because of the lack of nectar, and the other factors, the monarchs of this last generation do not mature to the point that they can mate and have babies. They fly south, searching for more plentiful nectar. Not mating and cool temperatures give these monarchs more energy and allow them to live longer. They live 8-9 months. They fatten up on the nectar they eat on their way south, and then they cluster together on trees on the California coast and in Mexico to spend the winter. When spring comes, last year’s last generation matures and has babies; those babies will be the monarchs that start the cycle again for the new year.
And how do butterflies know which way to go? Scientists at the University of Massachusetts proved they use their antennae to sense the position of the sun. In an experiment, the scientists removed or painted the monarchs’ antennae to block the sun. Can you figure out what happened? I bet you can; the Monarchs got lost.
Many other species of butterflies do not migrate. They can survive the cold where they live. Why do you think monarchs need to have this sort of migration pattern? Monarch butterfly larvae only eat milkweed, can you find out other animals that only eat one kind of food? Can you think of other animals that migrate? Monarchs fatten up on their journey south and then they don’t eat during the winter, there’s no nectar. Do you know any other animals that don’t eat all winter long? Maybe there are some animals that don’t eat during their migration! Can you think of some?
Get to know more about monarch butterflies and their life cycle; check out these websites: http://www.monarchbutterfly.org/faqs; http://www.cfans.umn.edu/About/NewsEvents/SpeakingofScience/KarenOberhauser/index.htm.
See other great pictures of monarchs here: http://www.monarch-butterfly.com.
My human, Terry, researched this information with Dr. Karen Oberhauser of the University of Minnesotta, information from the Pismo Beach Monarch Butterfly Grove, and Smithsonian Magazine, December, 2009.
If you want to grow your own butterflies in your classroom, have your teacher look into Dr. Oberhauser’s “Monarchs in the Clasroom” Program.