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

[Paul Cherubini]

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.