The monarch migration from Mexico won't begin for several weeks. However, over the next weeks, the days will continue to get longer and the temperatures will increase. This will cause the monarchs to become more active, particularly on sunny days. Within a month we expect to report that their migration has begun.
As the time for migration approaches, mating activity will begin. Right now, American scientist Dr. Karen Oberhauser is in Angangueo studying the monarchs' mating behavior. She has offered to tell you about her work when she returns.
Thanks to Steven Buchmann of the University of Arizona and the Arizona Sonora Desert Museum for this beautiful photograph. It was taken about this time last year.
Fat Math
Have you ever wondered how monarch butterflies survive for 5 months
without eating? The average fat content of monarchs on arrival at
the overwintering sites is 125 mg. By the time they leave their
average is down to 25 mg!
Can you answer Challenge Question # 18?
"How many calories does the average monarch butterfly burn during the winter? What favorite food do you eat that has the same amount of calories?"
How to Respond to This Challenge Question
1. Address an e-mail message to: jn-challenge@learner.org
2. In the Subject Line of your message write Challenge Question #18
3. In the body of your message, give your answer!(Also include your school name and state or province.)
Try This:
As a class, discuss how cold temperatures might affect the monarchs'
survival during the winter. If you would like to know more about
the rates at which monarchs burn fat at different temperatures see:
Masters, A.R., S.B. Malcolm, and L.P. Brower. 1988. Monarch
butterfly (Danaus plexippus) thermoregulatory behavior and
adaptations for overwintering in Mexico. Ecology 69: 458-467.
The Next Monarch Migration Update Will be Posted on March 5, 1996.
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