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September, 2008
Source:
Proceedings of the National
Academy of Sciences (PNAS) - September 9, 2008
Long-distance pollen flow
assessment through evaluation of pollinator foraging range
suggests transgene escape distances
Rémy S. Pasquet, Alexis Peltier, Matthew B. Hufford,
Emeline Oudin, Jonathan Saulnier, Lénaic Paul, Jette T. Knudsen,
Hans R. Herren, and Paul Gepts
PNAS 105:13456-13461; published ahead of print ,
doi:10.1073/pnas.0806040105
Abstract
Foraging range, an
important component of bee ecology, is of considerable
interest for insect-pollinated plants because it determines
the potential for outcrossing among individuals. However,
long-distance pollen flow is difficult to assess, especially
when the plant also relies on self-pollination. Pollen
movement can be estimated indirectly through population
genetic data, but complementary data on pollinator flight
distances is necessary to validate such estimates. By using
radio-tracking of cowpea pollinator return flights, we found
that carpenter bees visiting cowpea flowers can forage up to
6 km from their nest. Foraging distances were found to be
shorter than the maximum flight range, especially under
adverse weather conditions or poor reward levels. From
complete flight records in which bees visited wild and
domesticated populations, we conclude that bees can mediate
gene flow and, in some instances, allow transgene
(genetically engineered material) escape over several
kilometers. However, most between-flower flights occur
within plant patches, while very few occur between plant
patches.
Source:
icipe - African Insect
Science for Food and Health
Bees can mediate the escape of
genetically engineered material over several kilometres’ says
icipe/IRD study
A study by scientists from the Nairobi-headquartered
international research centre
icipe, in collaboration with the French
Institut de Recherche pour le
Développement (IRD) has established that bees have the
potential to mediate the escape of transgenes (genetically
engineered material) from crops to their wild relatives over
several kilometres. The findings, which have been published in
the Proceedings of the National
Academy of Sciences (PNAS) of 9th September, bear
significant implications for the introduction of genetically
modified crops in Africa.
The research, which was partly funded by USAID and the
Rockefeller Foundation, was triggered by the planned release of
insect-resistant genetically engineered cowpea in Africa, where
cowpea’s wild relative, Vigna unguiculata var. spontanea, is
widely distributed. For the first time with insect pollinators,
the scientists used radio tracking to determine the movements of
the carpenter bee Xylocopa flavorufa and their implications for
long-distance pollen flow.
“Bees can visit flowers as far as six kilometres away from their
nest. From complete flight records in which bees visited wild
and domesticated plant populations, we concluded that bees can
mediate gene flow, and potentially allow transgenes to escape
over several kilometres,” explains icipe scientist Remy S.
Pasquet.
He adds that for genetically engineered cowpea in Africa, these
results indicate that although pollen movement beyond a few
hundred meters has a low probability, strict isolation by
distance may not be feasible. This research therefore confirms
the widely held hypothesis that deploying genetically engineered
cowpea in sub-Saharan Africa may mean that an escape of the
transgene to the wild cowpea relative is inevitable.
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