[Leps-l] Monarch Armageddon revisited

[MexicoDoug]

Patrick, Paul,

Thank you for your contributions to this thread and mutual respect for 
each other in open discussion.  As both of you put the finishing 
touches on your points of view and concerns and take a mutually 
expressed need for a break ;-), let me suggest that anyone who either 
hasn't gotten enough or is wishing to learn more about the research 
methodology from one of the primary sources mentioned in the discussion 
has the option to attend a talk next Wednesday (27 Feb).

The topic is a prelude of Dr. Lincoln Brower's upcoming "Magnus Opus" 
on the Monarch Butterfly which I suspect will not disappoint in that it 
will be quite provocative, well composed, entertaining, and last but 
not least of all, action oriented.

http://sbc.edu/news/biology/expert-tells-butterflys-remarkable-story/

Best
Doug


-----Original Message-----
From: Foley, Patrick <patfoley at saclink.csus.edu>
To: Paul Cherubini <monarch at saber.net>; Leps List 
<Leps-l at mailman.yale.edu>
Sent: Wed, Feb 20, 2013 3:33 pm
Subject: [Leps-l] Monarch Armageddon revisited

Directly addressing Paul's 3 points below (paraphrased to put them in 
scientifically interesting form):

1) Can a small number of transported Monarchs lead to Eastern Monarch 
Migration Collapse through parasite transport? The risk of parasite 
spillover from one Monarch population to another through human 
transport depends on unique characteristics of the two populations 
concerned. For the most part with Monarchs the danger seems small, but 
it is not zero. This follows from our general knowledge of parasite 
host race formation, from our experience with introductions of Bombus 
and from Sonia Altizer's actual data showing that different Monarch 
populations have different levels of parasitism. As we have discussed 
often in the past, there are many kinds of parasites from transposons 
to viruses to protozoa to mites to parasitoid insects. We do not know 
all the present Monarch parasites, and more will evolve or spillover to 
Monarchs in the future.

2)  Do lower corridor milkweed populations threaten EMMC? The eastern 
Monarch migration does not simply depend on the persistence of 
wintering habitat and milkweed-rich migratory corridors. It depends on 
the overall fitness conferred by a migratory strategy versus a 
nonmigratory strategy. If, as is true for many Monarchs and almost all 
other butterflies, the migratory corridors do not confer superior 
fitness, the Monarchs will evolve away from a long-distance strategy. 
We do not have, as far as I know, satisfactory information or models to 
know how close the threshold (long migrate vs short migrate strategy) 
we are. We do have evidence that the corridors and the winter sites 
have degraded as Monarch habitat.

3) Does climate change in Monarch winter sites threaten EMMC? I am not 
a climate scientist. The papers I have seen suggest more precipitation 
and more variability in wintering site climate. Either of these could 
discourage Monarch migration. Again, the issue is not whether Monarchs 
can survive, it is whether long distance migration confers higher 
fitness.

My overall guess is that climate change is likely to be the biggest 
factor in changing Monarch's migratory behavior. The parasite risk 
seems small at the moment, but we have seen epidemics destroy entire 
species and populations in the past (for example the American Chestnut, 
the inhabitants of Tierra del Fuego, some Bombus species), so it would 
be well to be cautious about claims of invulnerability. Migratory 
corridors are under substantial remodeling in the US, but hopefully, 
local and national efforts can help to correct that. We should be 
grateful to those who help.

I have appreciated the chance to discuss this interesting topic ( I do 
research on epidemiology, extinction and parasitism, though not on 
Monarchs), and, now that Paul has summed up his main points and I have 
also, I'm happy to leave further discussion to others.

Patrick Foley
bees, fleas, flowers, disease
patfoley at csus.edu
________________________________________
 From: leps-l-bounces at mailman.yale.edu [leps-l-bounces at mailman.yale.edu] 
on behalf of Paul Cherubini [monarch at saber.net]
Sent: Wednesday, February 20, 2013 11:45 AM
To: Leps List
Subject: Re: [Leps-l] [leps-talk] Monarch Armageddon

On Feb 20, 2013, at 11:19 AM, Foley, Patrick wrote:

> Paul, I was not trying to reply to you, point for point, I was
> making some general points that undermine the view
> that Monarch releases are totally safe.

Pat, we're getting way off track from the three monarch
migration extinction questions at hand:

1) Is there credible scientific basis underlying the beliefs of
Dr. Brower, Oberhauser and Taylor that a few citizen scientists
like myself could inadvertently cause the collapse of the
whole eastern monarch migration-overwintering phenomenon
via shipping a few thousand wild field caught western
monarchs to the eastern USA?

2) Does professor Chip Taylor have a legitimate scientific
basis for telling the public and reporters that just because
there is less, but still alot, of milkweed growing on
midwestern farmland, the monarch migration could be
on the brink of collapse as he says or implies in these
videos?:

http://www.youtube.com/watch?v=qZXGRZMrsDU
http://www.features.ku.edu/monarchs/

3) Does any credible science exist to support the contention
that temperatures in the overwintering region of Mexico
could conceivably increase by a staggering and
unprecedented 3-4 degrees during the next 18 years
and (Chip Taylor's words} "eliminate most of the suitable
areas for overwintering because it would eliminate the
oyamel fir trees."?

So far, after several days of discussion, we see the answers
to all three questions are No.

So it appears it's time to end this discussion - although
bearing in mind that a new round of "monarch migration
could be threatened" type articles is very likely to appear
in the popular press within the next 1-3 weeks (i.e. articles
in the New York Times, Washington Post, Boston Globe,
Los Angeles Times, etc).

Paul Cherubini
El Dorado, Calif.
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