Expecting Monarchs in Arkansas
Monitoring the Development of the First Spring Generation
Spring, 2002

How Many Eggs Has She Laid So Far?

On March 27th, Jim Edson caught this worn-looking monarch in Monticello, Arkansas. Assuming she's flown from Mexico, she already has over 1,100 miles behind her. And she's probably laid many, many eggs on the milkweed she found along the way.

Jim took her into his lab to have her lay a few more eggs, and to watch the life cycle. He's offered to share her story with us each week. This information will help us to estimate when the next monarch generation will emerge across the southern tier of states. Remember, thousands and thousands of eggs have been laid there since the monarchs arrived three weeks ago.

Instructions: Print this blank life cycle chart, then make your predictions. We'll include news from Arkansas in each week's migration update, and record it on the chart below. Be sure to update your chart and revise your predictions as you learn more each week.

Jim Edson's Life Cycle Chart*

Estimated Development Time

Stage of Life Cycle


Development Time

3-5 days

Female from Mexico lays egg in captivity*

27 March

4 days

9-14 days

Egg hatches, 1st instart larvae emerges

31 March

14 days


1st instar molts into 2nd instar




2nd instar molts into 3rd instar

5 April



3rd instar molts into 4th instar

9 April



4th instar molts into 5th instar

11 April


8-13 days

5th instar becomes a chrysalis

13 April

9 days


Chrysalis ecloses (The adult butterfly emerges!)

22 April

20-32 days



27 days

?and Arkansas's first spring generation is on the wing!

Earth Day, April 22

* Note: The lab is maintained at a constant temperature of 21C (70F).

National Science Education Standards

Science as Inquiry
Use data to conduct a reasonable explanation. (K-4)

Scientists use different kinds of investigations depending on the questions they are trying to answer. Types of investigations include describing objects, events, and organisms; classifying them; and doing a fair test (experimenting). (K-4)

Life Science
Plants and animals have life cycles that include being born, developing into adults, reproducing, and eventually dying. The details of this life cycle are different for different organisms. (K-4)

National Math Standards

Numbers and Operations
Compute fluently and make reasonable estimates.

Problem Solving
Solve problems that arise in mathematics and in other contexts.

Data Analysis and Probability
Develop and evaluate inferences and predictions that are based on data.