Parasites and Monarchs

[Ed Reinertsen]

Good Morning all

Paul I got a question,

You wrote "To the contrary, we know the monarch migration has been
robust for the past 125 years....."
Can you tell us more about this 125 years, is this the first recording of a 
Monarch migration?
Can you please tell us where you got the information?

My comment on #4
I would think this is a no-brainier.
Of course, Monarchs that are HEAVILY infected with O.e. are going to be 
unhealthy.
Also they will have higher mortality rates, are going to be smaller,and have 
deformities.

"4. The authors state "if this migration collapses we'd be left with
> remnant, nonmigratory populations that are heavily infected with
> parasites, which could have several negative effects, from higher
> mortality rates, smaller body sizes and deformities, to more virulent
> strains of the parasite,"  as if there was a solid body of evidence
> to support the notion that non-migratory monarch populations
> are uniformly small, unhealthy and riddled with deformities, etc.

Ed Reinertsen

----- Original Message ----- 
From: "Paul Cherubini" <monarch at saber.net>
To: <leps-l at lists.yale.edu>
Cc: <stan_gorodenski at asualumni.org>; <gatrelle at tils-ttr.org>
Sent: Friday, April 08, 2005 1:14 AM
Subject: Re: Parasites and Monarchs


> Stanley A. Gorodenski wrote:
>
>> I am in the process of reading this paper now. At this time
>> I do not see it as political propaganda in the least. What I
>> see is good science that draws upon results of research on
>> other taxa and puts the interpretation of their results in that
>> context.
>
> Stan, here is another write up of the same study
> http://news.emory.edu/Releases/monarch1109713157.html
>
> I would tend to agree with Ron Gatrelle this write up contains
> inappropriate alarmist type propaganda rather than just science.
>
> Using tethered monarchs in a lab, the authors measured the flight
> endurance of lab reared monarchs that were infected with variable
> levels of a protozoan parasite. They found highly infected
> monarchs flew somewhat slower, for shorter periods, etc. This
> is fairly interesting (though not real interesting since they
> apparently didn't flight test wild caught monarchs) and fairly good
> science as far as it went. But then the authors decided to launch
> into unjustified, alarmist monarch migration extinction propaganda
> with these statements:
>
> "monarch migration in eastern North America is threatened by
> several environment factors such as habitat loss at wintering sites,
> climate warming trends and an increase of tropical milkweed
> species in milder climates."
>
> "The results of our study add one more reason to protect monarch
> migration east of the Rockies. If this migration collapses due to
> climate warming, habitat loss, pesticide use or other reasons, we
> probably won't lose monarchs as a species, but we'd be left with
> remnant, nonmigratory populations that are heavily infected with
> parasites, which could have several negative effects, from higher
> mortality rates, smaller body sizes and deformities, to more virulent
> strains of the parasite," Altizer says."
>
> Why, in my opinion, is this propaganda? Several reasons:
>
> 1. As Ron Gatrelle pointed out "climate change is neutral,
> its functions work just as much against a disease  / parasite / plant /
> animal etc. as it can for it." Ditto in regards to the authors' claim
> of an "increase of tropical milkweed species in milder climates."
> An increase in the abundance of tropical milkweed could have
> neutral, positive or negative impacts on the abundance of migrant
> monarchs.  In fact, back in 1961, Dr. Lincoln Brower hypothesized
> winter monarchs in Florida bred on tropical milkweed then
> migrated north in the spring and repopulated the entire eastern USA
> with monarchs.
>
> 2. The authors state "habitat loss at wintering sites" as if the loss
> was an established fact when to the contrary we know every
> mountain in Mexico that contained overwintering sites
> 30 years ago still has them today and in similar quantities.
>
> 3. The authors state "If this migration collapses due to climate
> warming, habitat loss, pesticide use or other reasons" as if
> there was a solid body of evidence to support the notion that
> small, incremental changes in climate, habitat loss or pesticide
> use could cause a catastrophic collapse of the migration
> phenomenon.
>
> To the contrary, we know the monarch migration has been
> robust for the past 125 years despite massive human caused
> changes in the vegetation of the upper Midwest, Great Lakes
> States and New England (where monarchs breed in the summer)
> during that time period.
>
> 4. The authors state "if this migration collapses we'd be left with
> remnant, nonmigratory populations that are heavily infected with
> parasites, which could have several negative effects, from higher
> mortality rates, smaller body sizes and deformities, to more virulent
> strains of the parasite,"  as if there was a solid body of evidence
> to support the notion that non-migratory monarch populations
> are uniformly small, unhealthy and riddled with deformities, etc.
>
> To the contrary, there are dozens and dozens of  island populations
> of monarchs in the tropics that have survived since the mid-late
> 1800's with no reports of extinctions that I am aware of.
>
> Paul Cherubini
>
>
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