Effects of migration on populations

Paul Cherubini monarch at saber.net
Sun Dec 9 12:31:34 EST 2001

Pat wrote:

> If indeed, the mating in Mexico is panmictic for the Eastern 
> Monarchs, then humans shuffling genes within that region 
> will have no long term effect. There we are agreed.
> Are butterfly breeders careful not to ship across the 
> continent? Or are we only concerned here with shipments 
> from Maine to Minnesota. In which case we are wasting the time of
> everyone from other states and countries.

Yes we only concerned here (for the moment) with shipments 
from Maine to Minnesota or vice versa. Specifically, Dr. Karen 
Oberhauser wrote:

"If shipping monarchs from Minnesota to Maine has even the slightest
chance of disupting genetic structure, or of making it difficult to
study that structure, I don't think we should do it."  


"If releasing monarchs near endangered plants has even the slightest
chance of hurting those plants, we shouldn't do it."

Pat, I was just interested in knowing if you or anyone might be able to
provide us with a reasonable MATHEMATICAL model that might 
demonstrate the scientific validity of Dr. Karen Oberhauser's concerns.  

With regard to your question:

> Are butterfly breeders careful not to ship across the 
> continent?  

Many breeders don't feel there is a scientifically legitimate reason
to be careful about this. We already know from tagging studies that
monarchs released in the Rocky Mountain states cross the continental
divide in both directions and end up at overwintering sites1800 miles
apart regardless of natal origin or whether they were farm reared or
wild caught.  Here is what farm reared monarchs did after release:


I have a question for you since you have some background in
biological control:  Are the big biological insect control houses
that breed tens of millions of green lacewings, praying
mantids, etc, careful not to ship across the continent?   Because
of the lack of panmictic mating in these insects, isn't it
extremely likely there are genetic differences between California
lacewings and the lacewings that would naturally occur
in, say, a Texas pecan orchard? 

Best regards,

Paul Cherubini


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