Ecological impact of transgenic potato expressing the anti-aphid snowdrop lectin on predatory ladybirds | [Impact écologique des pommes de terre transgéniques exprimant la lectine du perce-neige anti-puceron sur les coccinelles prédatrices]
1999
Birch, A.N.E ((Scottish Crop Research Institute, Dundee (Royaume Uni)) | Majerus, M.E.N. | Geoghegan, I.E. | McNicol , J.W. | Hackett, C. | Gatehouse, A.M.R. | Gatehouse, J.A.
An experimental potato line was genetically engineered to express the anti-aphid lectin from snowdrop (GNA), field-grown in mesh tunnels and assessed for possible tri-trophic interactions involving the insect resistance transgene (GNA lectin), target aphid pest (peach-potato aphid, Myzus persicae) and aphidophagous predator (adult 2-spot ladybird, Adalia bipunctata). A full-sib reciprocal cross design was used to mate ladybirds subjected to 3 different aphids diets, thus partitioning out effects of ladybird interfamily genetic variance, aphid diet and ladybird sex. In no-choice feeding trials under laboratory conditions, ladybirds fed to excess on aphids from the transgenic GNA-expressing potatoes for an initial period of 12 days, then switched to optimal aphid diet (pea aphids, Acyrthosiphon pisum from normal Vicia faba) until natural death, showed adverse effects on ladybird egg production, egg fertility and egg hatch. Adult longevity of female ladybirds was reduced by 51/ after 12 days' feeding on M. persicae from GNA-expressing potatoes. The adverse effects on ladybirds' reproductive biology were reversed after switching to the optimal aphid diet for 2-3 weeks following feeding on aphids from GNA-expressing potatoes. The possible implications for risk assessment and field management of insect-resistant transgenic crops, to minimise adverse effects on natural enemies are discussed
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