Field
Notes from Mexico
from Dr. Bill Calvert
March 17, 2006
Transcript
Departure
Gone were the swirling rivers of butterflies that descended and climbed
the mountains with us each day that we had previous visited Pelon and
Rosario. Gone were the lower colonies at each of these locations. These
colonies had presumably formed again higher up the slopes in the direction
of their breeding grounds to the north. Only a few scattered flying butterflies
remained in the former locations to attest to the masses that had occupied
those positions only a week earlier. And gone was the entire Chincua colony,
said to have emptied completely last Friday and Saturday. The monarchs
have started home en masse.
Research
Wednesday afternoon, (3/15/06) an intrepid research team from St. Hubert’s
Middle School in Chanhassen, Minnesota, began to scan the forest floor
on the high altitude slopes of Cerro Pelon for mating butterflies. They
were participants in a research project being conducted by Dr. Lincoln
Brower to determine the amount of nutrients transferred from the male
to female during the mating process. The results are not yet analyzed,
but it’s believed that the amounts of lipids transferred may be
significant.
Now
we have some reports of students who have participated in the research
program down here:
Imagine
trucking through foreign trees and flowers that are incapable of growing
in your homeland. Next imagine these plants suddenly becoming alive
fluttering with innumerable butterfly wings. Listening to the of millions
fluttering of wings reminded us of traffic from distant freeways. As
middle school students from St Hubert’s School in Chanhassen,
Minnesota, we witnessed this reality in the monarch overwintering sites
as we hiked through El Rosario and rode on horseback through El Pelon.
Together these colonies hold approximately 10-15 million monarchs. In
these breathtaking sanctuaries we were exposed to many different behaviors,
for example, mating and cascading.
After months
of reproductive diapause, mating finally occurred because their reproductive
organs matured. As the male takes charge he grabs and pins the struggling
female to the ground in an attempt to transfer his genes to the next
generation after a long flight. If the male is successful the female
will begin the next generation of monarchs.
As these
days warmed to approximately 85 F the monarchs begin to break away from
their clusters. Several times we saw them exploding from the boughs
of the oyamel fir trees in a cascading behavior. The sky was thick with
monarchs fluttering in all directions. We have been so fortunate to
witness this spectacle and it has inspired us to learn more abut the
mysteries the monarchs still hold. Thank you, the monarch research team,
Chanhassen, Minnesota, Grades 7 and 8.
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