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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