[Leps-l] Monarch Armageddon revisited

Paul Cherubini monarch at saber.net
Wed Feb 20 16:10:58 EST 2013


On Feb 20, 2013, at 12:33 PM, Foley, Patrick wrote:

> We do not know all the present Monarch parasites,
> and more will evolve or spillover to Monarchs in the future.

We already know that no "unique characteristics" exist between 
eastern and western monarchs and that no seriously lethal
parasites are known to exist in either population and that 
western monarchs naturally mix their pathogens, parasites 
and genes with the eastern monarchs.  Thus there is no credible
scientific basis underlying the 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) 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.

We already know that at temperate zone latitudes worldwide 
the monarch migration-overwintering-clustering phenomenon
persists even when the size of the population is relatively
tiny; e.g. the sizes of the overwintering clusters in Spain,
Portugal, New Zealand and Australia usually involve mere 
dozens or hundreds of butterflies. Thus there is no credible
scientific basis underlying the the belief that a minimum 
migratory population size "threshold" exists in the first place.  

> 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.

We already know that the locations and altitudes at
which monarchs overwinter in both Mexico and
California did not change during the past 35 years
of global warming. We already know monarchs winter 
over rather broad expanses of geography and
where the winter climate varies substantially; i.e the
Santa Barbara and Ventura, Calif. region is substantially 
warmer and drier than the San Francisco and Monterey
Bay region.

Paul Cherubini
El Dorado, Calif.



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