Monarch Butterfly Migration Update: May 2, 2003
News From Along the Migration Trail
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? How Long Alive? Discussion of Challenge Question #21 Several people reported faded butterflies last week, one as far north as Ohio. It’s not clear whether these are monarchs from Mexico or their children. (The first children were first noted in Texas almost a month ago, so could be somewhat faded themselves already. After all, monarchs live only 2-6 weeks during the breeding season.) 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.” The Life Cycle Continues... Discussion of Challenge Question #22 So far we’ve followed the monarch life cycle from egg to larva. Next comes the chrysalis.
This picture was shown last week in preparation...Challenge
Question #22 asked, "What do you think is shown in this picture?"
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. Try This! Head Spinning With Questions About Silk? After seeing these photos, what questions do you have about silk? Generate a list of questions and then conduct your own research to find out about this fascinating fiber. Why Does the Chrysalis Twist and Turn as it Forms? With these photos in mind, watch the video clip of the chrysalis forming. Can you picture what’s happening to the hooks and silk when the chrysalis twists so vigorously?
Dr. Brower Describes the Magic
of Metamorphosis “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.
(To respond to this question, please follow the instructions below.) Mystery Monarch Habitat of the Week 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.
(To respond to this question, please follow the instructions below.) Last Week’s Mystery Monarch Habitat Discussion Challenge Question #23 Last week’s mystery monarch habitat was in... MINNEAPOLIS, MINNESOTA at Dave Kust's "Breck School." Dave spent last year at the monarch sanctuaries, 1836 miles (2955 km) from his home town. Milkweed Emerging Along the Migration Trail Please help monitor the spring emergence of the monarch's food plant across North America. You'll be amazed at the close connections the migration and this all-important plant. Please REPORT when your milkweed grows!
Noticia de la migracion de la mariposa monarca As the butterflies fly over your homes, schools and cities, we're sending the news back to the students in Mexico so they can track the migration too. Here is this week's report in Spanish, with an English translation:
How to Respond to Today's Challenge Questions:
1. Address an e-mail message to: jn-challenge-monarch@learner.org
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