Monarch Butterfly Migration Update: May 9, 2001
Today's Report Includes:
Highlights From Along the Migration Trail
First Monarchs Have Crossed into Canada!
05/01/01 Marlboro, NJ (40.31N, -74.25W)
Mapping the 1st Spring Generation
How far did the monarchs from Mexico go? And where are their offspring now being seen?
Right now, a transition is underway. The long lives of the overwintering generation are coming to an end. (See the story below from Arkansas!) As today's comments illustrate, a new generation of butterflies is beginning to appear.
Hereafter, as you plot migration data on your map, you may want to try to distinguish between the two generations--perhaps with a differently-shaped symbol. On our migration map, we've placed a dot in the center of those sightings we believe are "1st generation" sightings (where observers noted fresh, un-faded wings).
Roughly speaking, you can consider sightings AFTER the first week in May as the offspring of the monarchs from Mexico. (But this is subjective! Students who are interested in a precise answer to this question should conduct further research: Go to the Monarch database on the Journey North Web site. Read the comments from each observer. Make note of sightings of "FADED/OLD" butterflies and of "FRESH/NEW" monarchs. If the observer did not include this information, contact her by e-mail for these details.)
Please Watch the Wings--and Report Their Condition!
When you see your first monarch, pay close attention to the condition of its wings. When you report your sighting, be sure to tell us whether the wings were fresh--or faded, tattered and torn.
This is important information! You can help us determine how far the over-wintering population expanded this spring. This information also gives insight into the timing of reproduction for the 2001 season.
For those interested in learning how scientists rate wing wear and wing damage, see Dr. Karen Oberhauser's "Monarch Lab":
Still Alive After All These Days (and Eggs!)
Remember the first monarch reported in Arkansas by Jim Edson on April 3rd? He captured her that day, and she's been very busy laying eggs. Jim's observations illustrate the remarkable reproductive capacity of insects!
May 8 Monticello, AR
"My April 3rd female is still alive and continues to lay eggs, but not very many now. In the last 3 days she has only laid two. I would estimate that she has laid over 200 in the month I have had her.
"Her offspring began emerging last week. The first monarch emerged from its chrysalis on May 2nd, so it took 29 days from egg to adult (but it was raised indoors so the time it took might not be the same if it had been outside). I took 49 (adults) to a nearby elementary school and did a program with them about the life cycle and then we went out and released the monarchs. I had tagged them with last year's Monarch Watch tags. I plan to release another 50 or so today. I am giving my last final today so I thought I would let my college kids release them and make a wish for success on the test."
Take a look at the photos of this female laying eggs, and some of her many caterpillars and adult children. Remember: These butterflies all came from the same mother!
Insect Reproductive Strategy
Large Numbers, Raised by Mother Nature
Imagine a robin laying an egg in your yard and flying away. Not a chance! To increase the chances their young will survive, most birds and mammals invest a great deal of time in parental care. Even some social insects, like ants, termites and some bees, have complex societies that provide extended care for the young.
But most insects follow the opposite strategy: They produce great numbers of offspring and provide no parental care at all. To increase the odds of passing their genes to the next generation they rely on sheer numbers--and then depend on Mother Nature to raise them. That is, the young creatures' instincts--and the surrounding environment--must provide everything the offspring need. (So you can see how important good habitat is!)
A Day in the Life of a Butterfly Egg
Mother monarchs abandon their eggs the instant they're laid. (And the fathers are long gone, since a female can lay eggs her whole life after a single mating.) If you were a butterfly egg, your mother couldn't afford the time to raise you. You'd be just one of the several hundred siblings she'd try to produce in her short life. So she'd have to move on! To increase your chances of survival she would try to:
And although your parents wouldn't be there to protect you, your egg would have a hard shell and even a wax
coating to keep you from drying out. You'd be tiny and somewhat camouflaged but still, a nutritious meal for a
Try This! Insect Egg Hunt
Spring is a perfect time to look for insect eggs. Inspect the leaves of as many different plants as you can. See how many insect eggs your class can collect. Bring them to school and inspect their different colors, sizes and shapes.
The Next Monarch Migration Update Will Be Posted on May 16, 2001