[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?
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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