NYT article on : one type of "Biotech Corn" / swallowtail butterflies.
June 6, 2000
Type of Biotech Corn Found to Be Safe to a
Butterfly Species
By CAROL KAESUK YOON
A strain of genetically modified corn that
produces its own insecticide, known as
Bt, does not appear to harm black
swallowtail butterflies in the wild, according to
a report published today in The Proceedings of
the National Academy of Sciences.
In May 1999, scientists at Cornell reported in
the journal Nature that monarch butterfly
caterpillars died after eating Bt corn pollen in
laboratory experiments, raising concern that
these crops could be causing unintended harm
to monarchs and other insects.
The new research on the swallowtail butterfly is the first published field
study conducted since then to look for potential effects from genetically
modified corn.
The research team from the University of Illinois had studied the widespread
swallowtail butterfly for years. In this study, it found that both in the wild
and in the laboratory, swallowtail butterfly caterpillars did not appear to be
harmed by eating leaves dusted with pollen from a popular strain of Bt corn
known as Mon 810. The Bt toxin is aimed at killing European corn borers,
which can cause major damage to corn crops.
"The implication is that the impacts of Bt corn might not be as great as were
initially assumed," said Dr. May Berenbaum, ecologist at the University of
Illinois and an author of the study, which was paid for by the University of
Illinois Environmental Council.
But Dr. Berenbaum added, "I'm not saying Bt corn is just fine."
In fact, both those who were and were not involved with the new study
cautioned against overgeneralizing from these latest findings.
Dr. Berenbaum noted that her team also found that another strain of Bt corn,
known as 176, which has particularly high levels of toxin in its pollen, was
toxic to swallowtail butterflies in the laboratory.
The finding suggested that while Mon 810 may be safe, other strains of Bt
corn could pose a threat to swallowtails. Researchers will be studying the
effects of strain 176 on swallowtails and monarchs in the field this summer.
Researchers also agreed that the new study and the Cornell study could not
be directly compared since they involved different butterfly species and
different strains of Bt corn. The Cornell study used another popular strain
known as Bt 11.
"This study is important because it's one more species," said Dr. John Losey,
the lead author on the Cornell study.
But Dr. Losey echoed researchers on the new study, adding: "It would be
just as wrong to look at black swallowtails and say Bt corn is safe as it was
wrong when people looked at monarchs and our lab study and said there's
definitely a problem. I'm not ready yet to say either."
He said some 100 species of butterflies and moths could potentially be
affected by Bt corn pollen.
For those looking to mitigate the potential impact of genetically modified
corn, however, the new study suggests that there may be strains of Bt corn
that have little or no impact on nonpest species, said Dr. Arthur Zangerl,
another author of the new study.
Since the study on monarchs was published a year ago, critics of regulatory
agencies have cited its findings as a sign that environmental risks are not
being adequately monitored. The monarch itself has been brandished as a
symbol by critics of genetic engineering.
But biotechnology advocates have defended the new crop, saying that it has
decreased the use of pesticides and that the risks to monarchs, if they exist,
are likely to be minimal.
Copyright 2000 The New York Times Company |
