Effects of migration on populations

Patrick Foley patfoley at csus.edu
Sun Dec 9 15:53:55 EST 2001

Paul and all,

My professional efforts in biological control consist of 1) Briefly
consulting with the USDA about the genetics of Biological control of
Yellow-star thistle (YST) in the late 1980's, 2) Writing up a couple of
grants to the USDA to undertake a DNA-level examination of Mediterranean
YST (Centaurea solstitialis) populations in order to introduce only those
insect control agents directly coevolved with YST. These were rejected by
USDA "scientists" on the grounds that protein electrophoresis was the wave,
not DNA, and 3) coauthoring a chapter with my late friend Charles Turner
(USDA) and others on biological control of weeds.

My conclusions from these experiences were that the US Federal government
was not serious about biological control (especially under Reagan and
Bush!), that it is a tricky and perhaps unwalkable line between introducing
lots of genetic variablity in your agents to guarantee success and avoiding
the evolution of host-switching  in the target region. I decided that in
most cases the dangers were great of uncontrollable biocontrol agent
evolution. And I changed the focus of my work accordingly.

I do not sell, nor am I knowledgeable about commercial releases of
biological control agents. I am sympathetic with the aims of these releases
(as I am with the aims of butterfly releasers). I suspect they have not
thought through what they are doing, and were I involved in that field I
would probably bug them as I do you. I doubt that many butterfly releasers
take the potential effects on their species seriously or they would be
supporting research on the problem.


Paul Cherubini wrote:

> 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."
> and
> "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:
> http://www.mindspring.com/~cherubini/ALB.JPG
> http://www.mindspring.com/~cherubini/PAO.JPG
> http://www.mindspring.com/~cherubini/EVA.JPG
> http://www.mindspring.com/~cherubini/SC.JPG
> 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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