[cg] Monarch Butterfly Threat
Pollen From GM Corn Harms (Monarch) Butterfly Larvae - Study
Wednesday, May 19, 1999
(Try to find a news org that tells you the name of the company that makes
this genetically modified corn!)
(It's Novartis Inc. http://www.novartis.com/ see also
By Patricia Reaney
LONDON (Reuters) - In what could be a damaging indictment against
genetically modified organisms (GMOs), U.S. scientists said pollen from
corn engineered to reduce pests killed monarch caterpillars in laboratory
The hybrid crop, known as Bt-corn, is safe for human consumption and it
does not seem to harm honey bees or ladybirds but it produces a pollen,
dispersed by the wind, that can be harmful to monarch larvae.
``It's certainly a serious potential problem,'' John Losey, of Cornell
University, said in a telephone interview.
``If it's really having an impact on a large proportion of the
population (of monarch butterflies) I think it is a very serious problem.''
Bt-corn has genes from the bacterium Bacillus thuringiensis spliced
into the plant genes, making it resistant to a hard-to-control pest called
the European corn borer. Last year more than 7 million acres of the crop
were planted by U.S. farmers.
The genetically modified (GM) plants produce a pollen containing
crystalline exdotoxin from the bacterium genes. The pollen can be blown
more than 60 yards onto plants outside the cornfields, including the
milkweed that monarchs feed on.
Losey and his team fed monarchs milkweed dusted with the pollen from
Bt-corn. Their research, published in the science journal Nature, showed
the butterflies ate less than those fed on normal milkweed and nearly half
of the larvae died.
Although the research is limited to laboratory tests and there is no
evidence of what effect the transformed pollen has on monarch butterflies
in the field, the study highlights some of the worst fears about the
effects of GMOs on the environment.
``Monarchs are considered to be a flagship species for conservation. This
is a warning bell,'' said Linda Rayor, a co-author of the study.
``Monarch themselves are not an endangered species right now, but as
their habitat is disrupted or destroyed, their migratory phenomena is
becoming endangered,'' she added.
Losey emphasized the need for more data and the need to look at the big
Although he does not support a moratorium on the planting of GM crops, he
said the proven benefits in terms of increased yields and reduced rates of
pesticides needs to be weighed against any potential risks.
``If we are going to allow them to go forward what we need is a
commitment from the industries and the regulatory agencies and academia to
get the data to be able to tell the effects of GM crops on the
population,'' he said.
The British Medical Association Monday called for a moratorium on the
planting of GMOs until scientists know more about their impact on the
environment. Britain's Labor government said there is no evidence to
justify a ban.
Monarch butterflies and herbicide resistant crops
by Bob Hartzler:
January 26, 1999 - What's the connection between these two organisms you
ask? The monarch migrates each year from southern Canada and the eastern
half of the U.S. to a few small sites in the mountains of central Mexico.
Researchers in Saskatoon, Saskathewan conducted a study to determine the
range of monarchs during their summer stay in the US and Canada (Science, 8
Jan., 1999. 283:171). They found that approximately half of the monarchs
were from a relatively narrow-swath from Nebraska to Ohio.
The researchers were surprised that so much of the population was
concentrated in the heart of the cornbelt. They expressed concern about
the rapid changes in weed control practices occurring in this region.
Monarch larvae feed exclusively on milkweed plants, thus reductions in
milkweed populations could have a dramatic impact on monarch reproduction.
The use of herbicide resistant crops (Roundup Ready, Liberty Link, IMI
corn) could provide more effective control of milkweed than traditional
herbicides, thus the concern.
Several factors need to be considered when looking at the impact of HRC's
on monarch butterflies: 1) Will the rates and timing of herbicide
applications made to control annual weeds have a significant impact on
milkweed populations?, 2) What percentage of milkweed in the corn belt is
found in row crop acres vs in roadsides, pastures and other non-row crop
areas?, 3) Do monarchs have a site preference for egg laying (row crop vs
The researchers pointed out that their findings represent only a single
year's distribution of monarch butterflies and may not represent historical
patterns. However, it does illustrate the potential impact changes in
weed management strategies could have on the ecosystem.
Prepared by Bob Hartzler, extension weed management specialist, Department
of Agronomy, Iowa State University
For more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
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