Monarch
Butterfly Migration Update: April 14, 2006 |
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This
Week's Migration Map and Data |
Use
today's data to make your own map, or print and analyze our map:
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News
from the Migration Trail |
Thanks
to everyone for contributing! There are 55 new sightings on this
week's map.
The
migration's leading edge has now advanced to 39N, far beyond its
position at 36N just one week ago.
- How
many miles is that?
- How
many miles per day did the migration advance, on average? (Assume
69 miles for every degree latitude.)
- If
they continue at this rate, predict when the first monarchs will
reach you.
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Time
to Revisit Views About Monarch Migration? Scientists
Comment |
This is an unusual year! Monarchs overwintered as far north as Virginia
and began appearing inland in early spring. Is this significant?
Biologists Andy Davis and Dr. Sonia Altizer of the University of
Georgia shared their thoughts:
"We
are not aware of previous studies documenting this high number of
sightings, and these reports may stimulate scientists to revisit
common views of monarch migration and overwintering behavior,"
they began.
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Do
Only Females Migrate? Please Contribute Your
Observations |
Andy Davis made an interesting observation this spring. Of the
six monarchs he caught migrating from Mexico, all were females!
"That got us wondering," he said, "where are the
males in the spring? Could this have just been a fluke, or do
males really make the spring migration at all?"
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The
Life Cycle Continues...
Ms. Monarch’s Final Days and Her First Chrysalis
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"Well
the day finally arrived..." Dr. Edson wrote sadly at noon yesterday.
After laying a grand total of 758 eggs, Ms. Monarch's life finally
came to an end.
Special thanks to Jim Edson for sharing Ms. Monarch's story with
us! He faithfully counted her eggs every day at noon for over a
month, and gave us new insights about the monarch life cycle. Thank
you, Jim!
But the story is not over, he reminds us: "Now we wait for
the first butterfly," he said on Sunday, the day Ms. Monarch's
first child became a chrysalis. Soon her children will continue
the journey north. Get ready to watch for fresh-winged butterflies!
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Thank
you
Dr. Edson! |
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Over
750 Eggs! What Happens to Them All? |
Survival
is not easy. "Only about 10% of monarch eggs make it to the
5th instar," concludes Dr. Karen Oberhauser, based on data
collected by her volunteer network, the "Monarch Larva Monitoring
Project."
This means 90% die before they even become a chrysalis! Exactly
what do monarchs need to survive? What threats do they face? Begin
with an egg and keep a list. We've started with three needs, all
drawn from today’s update (Read on...)
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Monarch
Larva Monitoring Project: You Can
Help With Research! |
Volunteers
are invited to participate in Dr. Oberhauser's research this spring
and summer. Her project is gathering important information about
monarch biology.
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First
a Monarch Eats its Shell and Then...Discussion
of Challenge Question #10 |
Last
week Dr. Brower said, "Monarchs have to be careful not to lay
more than one egg per plant (or leaf) because, when they hatch,
the caterpillar will eat its own eggshell. The next thing it will
do is wander over and___."
"Eat the milkweed plant," said Amanda S. She is so right!
Monarchs eat a tremendous amount of milkweed. In fact, a monarch
increases in mass by 2,000 times while it's a caterpillar. This
amazing change takes place in only about 9-14 days. Imagine gaining
weight the way monarch larvae do!
Challenge
Question #11
"How much would you weigh if your weight increased 2,000 times?
With your answer, name something that weighs the same amount."
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Eating
its shell |
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Do
you see two monarchs?
One is 2,000 times larger! |
Speaking
of Eggs: A Conversation With Dr. Lincoln Brower |
There
is another reason female monarchs usually lay one egg per leaf or
plant. Listen to Dr. Brower. You are sure to be surprised. He watched
monarch eggs closely and here is what he discovered:
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For
Mexican Students: 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 month's report in Spanish, with
an English translation:
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Symbolic
Butterflies to Fly on Earth Day (April 22, 2006) |
Over 50,000 Symbolic Butterflies will begin the final leg of their
journey home this Saturday, Earth Day. How fitting that mailboxes
across North America will be filled with these symbols of conservation
and international cooperation. We have a new map this year that will
work like an online lost and found, so you may find where your own
butterflies landed! Stay tuned... |
Wanted: Your Monarch and Milkweed Sightings
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We
can't track migration without your help!
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The
Next Monarch Migration Update Will Be Posted on April 21, 2006 |