Monarch Butterfly Migration Update: May 2, 2003

Today's Report Includes:

• News From Along the Migration Trail
• How Long Alive? Discussion of Challenge Question #21
• What Does it Look Like? Discussion of Challenge Question #22
• Try This! Head Spinning With Questions About Silk?
• Why Does the Chrysalis Twist and Turn as it Forms? (Video Clip)
• Dr. Brower Describes the Magic of Metamorphosis (Sound Clip)
• Challenge Question #24
• Mystery Monarch Habitat of the Week: Challenge Question #25
• Last Week’s Mystery Monarch Habitat: Discussion CQ #23
• Milkweed Emerging Along the Migration Trail
• Noticia de la migracion de la mariposa monarca
• Year-end Evaluation: Please Share Your Thoughts

• Link to Data: Link to This Week's Data

Biodiversity increased in three states last week, when monarch butterflies arrived in Ohio, Maryland and Virginia. You can add those states to your list if you’re keeping track. When do you predict the first monarch will cross into Canada? Which Canadian Province do you think monarchs will reach first?

• Monarch Spring Migration Route Prediction Chart

In noting how long the over-wintering generation lives we asked, "Assume a butterfly emerged as an adult late last summer, on August 25th. As of today, April 25th, how long has the butterfly been alive?”

Mrs. Swentzel's class from Byram, NJ, have been studying calendars. “While looking at the problem, we figured out that our butterfly would have been alive for 8 months.”

Egg	Larva	Chrysalis

This picture was shown last week in preparation...Challenge Question #22 asked, "What do you think is shown in this picture?"

Courtesy of Dr. Lincoln Brower and Donna Williams, University of Florida

Mrs. Nunnally's second grade class at Peter Woodbury School in Bedford, NH thinks it might be part of the caterpillar's foot. “It might help it to hold on to things, especially when it has to hang upside down to form the chrysalis.”

WOW! What a terrific guess! The hooks you see are indeed for holding the monarch when it’s a chrysalis. BUT these hooks are not on the prolegs. They are on a special post-like structure called the “cremaster” which extends from the back-end of the caterpillar when it's ready to become a chrysalis. You can see it more fully in these pictures. (See web.)

The spaghetti-like material that the hooks are grabbing is silk. Immediately before hanging in the “J” formation the caterpillar spins a silk pad. The silk is produced by a special gland in the caterpillar’s head.

Courtesy of Dr. Lincoln Brower and Donna Williams, University of Florida

Video Clip Monarch Metamorphosis (.mpg file 192 Kb)

Audio Clip Hear Dr. Brower Explain (.wma file, 15 Mb) ( .wav file, 1.4 Mb)

Dr. Brower Describes the Magic of Metamorphosis
Listen to Dr. Lincoln Brower describe the process of metamorphosis. What’s the second reason Dr. Brower says the chrysalis twists while it forms?

“What is happening is a biological miracle going on inside that caterpillar,” he says. “Literally the entire internal contents of the caterpillar---the muscles, the entire digestive system, even the heart, even the nervous system--is totally rebuilt.” In the end, Dr. Brower says the caterpillar and adult monarch are as different as a mouse and a hummingbird.

Challenge Question #24
“In what ways is a field mouse is like a monarch caterpillar, and a hummingbird like an adult monarch?”

(To respond to this question, please follow the instructions below.)

This monarch habitat is located 688 miles (1108 km) from the overwintering sites in Mexico. At this site, the countryside looks like these pictures for thousands of square miles--covering an area the size of the state of Illinois! It is the most biologically diverse region on the North American continent.

Summers here swelter and seethe, they steam and they sizzle. Yesterday it was 95.5F, but that's still springtime. Summer is when it's 106F every day. We'll have almost 6 months of that. Asclepias oenotheroides (a milkweed) has to be quick and efficient, springing up after a rainshower and blooming quickly. This spring they were ready and waiting for northward-bound monarchs. Predators are fewer in this early season.

Monarchs don't breed here during summer months as they do at more northern latitudes. We see our last spring monarchs mid-April. They return in late August and early September, recolonizing into the region at the forefront of the actual migration, just as the mini-monsoons bring on a second crop of milkweed. This group of monarchs is still fertile and laying eggs, but now the struggle for survival in the milkweed patch is fierce and competitive, few if any caterpillars survive the fire ants and the other predators.

Challenge Question #25
"In what state or province do you think this monarch habitat is located? Send us your guess!

(To respond to this question, please follow the instructions below.)

MINNEAPOLIS, MINNESOTA at Dave Kust's "Breck School." Dave spent last year at the monarch sanctuaries, 1836 miles (2955 km) from his home town.

• Noticia de la migracion de la mariposa monarca

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of your message write: Challenge Question #24 (or #25)
3. In the body of EACH message, give your answer to ONE of the questions above.

The Next Monarch Butterfly Migration Update Will Be Posted on May 9, 2003

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