[CH] Re: Monarch thread

GarryMass@aol.com
Thu, 2 Mar 2000 10:48:56 EST

Thanks GMurray, Dave A. and others,
Peter gave me the U of Iowa site, abstract of study done there (Laura 
Hansen).  19% mortality for larvae force-fed milkweed collected from within 
Bt cornfields, 0% mortality with no Bt or any other pollen, 3% on open 
pollinated.  
Losey at Cornell got a 44% force-fed mortality on moistened and dusted 
milkweed leaves but he eyeballed the concentration of Bt corn pollen to "look 
like" the leaves in the field.

The Scientist June 7, 1999 

Could a diet rich in transgenic corn pollen doom the Monarch butterfly?
------------------------------------------------------------------------------
--
 
Bt or not Bt ...
Transgenic Corn vs. Monarch Butterflies
Author: Barry A. Palevitz
Date: June 7, 1999

'...Still, the Monarch flap may be a tempest in a corncob. Richard Meagher, a 
professor of genetics at the University of Georgia who genetically modifies 
plants for bioremediation, thinks Bt critics "have completely lost 
perspective." Bt crops involve a "couple of orders of magnitude less exposure 
to toxins" compared to wholesale spraying of fields with conventional 
insecticides or Bt preparations. Adds Meagher, "There are no perfect 
solutions, but this is so superior ecologically." Even ecologists and 
butterfly people admit that Bt is not the main threat to Monarchs. Says 
Parmesan, "What's causing most change in numbers is habitat loss," 
particularly in Mexico, where the butterflies migrate. An industry 
spokesperson was even more blunt: More Monarchs are killed by cars and trucks 
than by Bt corn. '

With respect to all, Gareth says, I'm willing to wait for the explosion of 
studies that will likely get many scientists published this (2000) growing 
season.  The strong feelings expressed on the list are, IMnotsohumbleO, 
decidedly premature whether pro or co(r)n.  I'm looking for field vs lab 
trials, better controls (milkweed collected from the field, rather than hand 
contaminated), no more guestimates or eyeballing.  Since corn pollination 
generally comes later in the season than Monarch larvae milkweed feeding, 
field trials would be much better empirical evidence.  In the interim, 
despite claims to the contrary, about 30% of all corn is Bt manipulated so if 
the news is bad, it will be big, bad news.  My fear, like Byron's, has more 
to do with any wildcard that might alter the environment for Chile growing.  
I've never ground up dried corn to shake on my food, never munched raw corn 
for the burn, never made a corn relleno.
I love Monarchs, but I'm willing to wait for the science rather than guessing 
that the sky is falling.  Drive carefully.
G