How
Many Eggs Can a Single Monarch Butterfly Lay?
Observations by Dr.
Jim Edson, University of Arkansas
Spring 2007
Ms. Monarch
We have a volunteer who will help us learn about the monarch's life cycle. Her name is “Ms. Monarch.” Dr. Jim Edson of Monticello, Arkansas, caught and named this lovely female butterfly on April 2, 2007.
If we assume she flew up from Mexico, this worn-looking monarch has over 1,100 miles behind her--and certainly many, many eggs!
Dr. Jim Edson
Once egg-laying has begun monarchs do not live long. Ms. Monarch is spending the last of her days in the safety of Dr. Jim Edson's lab, laying eggs for the next generation. Dr. Edson is counting her eggs every day at noon. Take a look:
- Ms. Monarch's Egg-laying Calendar (complete with Dr. Edson's field notes)
Why
is This Important?
The monarch migration is unique because it takes two generations to
complete. Ms. Monarch's life story gives us clues about how long the
monarchs that overwintered in Mexico will live, and when and where the
next generation will appear.
Ms. Monarch's Daily Egg Laying Calendar
- How many eggs do you think Ms. Monarch will lay?
- How long do you suppose Ms. Monarch will live? (On what date do you think she will die?)
- How do you think Ms. Monarch's egg-laying behavior will change over time?
Try This!
- What is the average number of eggs Ms. Monarch laid per day? Graph your results and describe what you see. (Teachers: see 2005 and 2006 examples.)
- Look at the migration map. Imagine that eggs have been laid wherever monarchs have been seen. Use Ms. Monarch's calendar to predict when and where the first new butterflies will appear. (These butterflies are the children of the monarchs that overwintered in Mexico.)
