[Leps-l] [leps-talk] Monarch Armageddon

[Foley, Patrick]

Paul,

You keep giving evidence that Monarchs are not endangered. But that is not controversial. Every entomologist knows they are not endangered. What is poorly known is why _some_ Monarchs regularly migrate, and whether natural selection in the future will continue to encourage this migratory behavior. 

Most butterfly species do not make regular migrations. Many Monarch populations do not migrate readily. Why is it so obvious that the appropriate natural selection conditions will continue to apply, when this migratory strategy is rare and not fully understood?

There certainly has been serious loss of Mexican overwintering habitat. And again, the issue is not whether there is no habitat left. The issue is whether a Monarchs overall fitness is best served by migrating to an uncertain winter site through a patchy and uncertain milkweed landscape. For some Monarchs it makes sense to stay in one predictable habitat. This already happens in warm areas such as Australia, the Caribbean etc. With a little global warming and a lot of habitat destruction, the Monarch migratory strategy may be the wrong one. This is the issue, not whether somebody was once wrong on the internet.

I am not a Monarch fanatic. You are. Doesn't it bother you a little that we do not yet understand why so few butterflies migrate regularly? Doesn't this give you a little pause?

Patrick

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: Thursday, February 14, 2013 9:46 PM
To: Leps List
Subject: Re: [Leps-l] [leps-talk] Monarch Armageddon

On Feb 14, 2013, at 8:08 PM, Roger Kuhlman wrote:

> Remember the Passenger Pigeon.  Once there were
> billions of them.

And remember in 1991 Dr's Lincoln Brower and Steven
Malcolm wrote this about the monarch in a peer
reviewed scientific journal*:  "its eastern North American
migratory phenomenon is now threatened with extinction
and will probably be destroyed within 10-20 years."
http://saber.net/monarch/extinction2.jpg

Unlike passenger pigeons, monarchs are not stressed
by a shortage of food, disease and are not being mass
hunted and shot.

And despite the widespread adoption of Roundup Ready
corn and soybean plants by Midwestern farmers and the
resulting reduction in the abundance of milkweed on farmland,
there are still billions of milkweed plants growing along the
edges of those same farm fields and will be for the forseeable
future. So to this day monarchs can still be routinely seen
laying eggs on those crop margin and farm roadside milkweed
plants like this:
http://www.youtube.com/watch?v=0MqrvAxTl0I
http://www.youtube.com/watch?v=rKmDId55pfc

And to this day migratory monarchs continue to be
spectacularly abundant in the late summer in midwestern
farm towns that are surrounded by the Roundup Ready
crops.  Like this:

http://www.youtube.com/watch?v=j4e3S2sm13g
http://www.youtube.com/watch?v=WJCnU7PB9to

So one wonders: 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.youtube.com/watch?v=W_Y9CKP1DuQ

Paul Cherubini
El Dorado, Calif.

*Brower, L. and S. B. Malcolm. 1991. "Animal migrations:
Endangered phenomena." Amer. Zool. 31: 265-267.
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