[Leps-l] monarchs, reversal of orientation and overwintering temperatures

MexicoDoug mexicodoug at aol.com
Thu Feb 21 23:57:03 EST 2013


Paul, Chip;

Chip, thanks for clarifying some of my questions.  The pdf you so 
kindly sent didn't come though successfully for me so if you can just 
give us a link that might work better, or give it another shot (mine 
came in as a 2 MB+ web-attachment when it should have been I think a 
~950 KB pdf.

As Chip and I think all of us agree it will be helpful to go through 
the real data for which Monarchs are exposed that's already out there 
to see if it's reasonable to make sweeping statements or not.  I just 
hope Chip had any suspended-autumn Monarchs released in Texas tagged so 
he can tell us later where they really ended up.  Still the tethered 
flight set up is cool, Paul, you ought to get one of those to play with!

IMO, regarding the comment on the 'danger' statements, the Journal 
chosen for the publication (it wasn't an entomology journal) was more 
 from the perspective of a biochemical/neural signaling + pathway 
interest, which seems to be the research groups principal interest.  
Frequently authors are able to slip in these sorts of statements when 
the peer reviewers aren't concerned with such statements and just skip 
them unscathed - more worried about scientific verification (as in 
letting a real error get by on their watch) rather than appearing to be 
a nitpick at fluff that is common in many papers when authors 
contemplate the furthest reaching implications of their work from a 
purposefully biased viewpoint.

With Monarchs, I'm not even sure if there are enough independent 
researchers available in that even top tier journals would have 
difficulty putting together an unbiased, anyomous review panel 
sensitive to this.  Unless I'm missing something, all that is here is a 
statement that says the Monarchs need to experience a cold to warm 
switch in temperatures to change flight direction.  At the moment that 
doesn't sound to me like a novel idea since other non-migratory 
populations have already been discussed on the list show evidence of 
what happens when they lose their cold stimulus.

Best wishes
Doug



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-----Original Message-----
From: Paul Cherubini <monarch at saber.net>
To: Leps List <Leps-l at mailman.yale.edu>
Sent: Thu, Feb 21, 2013 9:14 pm
Subject: Re: [Leps-l] monarchs, reversal of orientation and 
overwintering  temperatures

Doug and Chip:

I havn't read the original paper yet, but from reading the
abstract, fall migrant monarchs exposed to 24 days of chilly
temperatures flew north when tethered in a flight simulator:
http://reppertlab.org/tools/flight-simulator/

So the study does not actually demonstrate the direction(s)
the cold treated butterflies would fly if they were released
into the wild. So I do not see how the authors can legitimately
make this claim: "Our discovery that coldness triggers the
northward flight direction in spring remigrants solves one of the
long-standing mysteries of the monarch migration."

Now on the basis of that crude experiment, look at what
the science news articles and the lead author of the study
are telling the public:

http://www.sciencedaily.com/releases/2013/02/130221141259.htm
Coldness Triggers Northward Flight in Monarch Butterflies:
Migration Cycle May Be Vulnerable to Global Climate Change

"The temperature of the microenvironment at the overwintering
sites is a critical component for the completion of the migration
cycle," said Steven M. Reppert, MD, professor of neurobiology
and senior author of the study. "Without this thermal
stimulus, the annual migration cycle would be broken,
and we could have lost one of the most intriguing
biological phenomena in the world."

and

"The more we learn, the clearer it becomes that the
monarch migration is a uniquely fragile biological
process," said Reppert. "Understanding how it
works means we'll be better able to protect this
iconic system from external threats such as global
warming."

Googling "monarch butterfly cold" will bring up
many more articles about this study.

Paul Cherubini
El Dorado, Calif.
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