1Department of Entomology and Nematology, IACR-Rothamsted. Harpenden, AL5 2JQ, UK.
2Department of Biochemistry and Physiology, IACR-Rothamsted. Harpenden, AL5 2JQ, UK.
The GNA gene is a potential candidate for genetic engineering of plants resistant to sucking pests including aphids. GNA has been shown to decrease the growth and delay the reproduction peak of Myzus persicae, using artificial diets and clip-cages on whole potato plants. Although there is growing concern about environmental risk associated with transgenic plants, little is known about their effects on non-target insects such as parasitoids. This study deals with first-tier laboratory-scale experiments to assess the potential effect of GNA (product of gene) on an aphid parasitoid. Such bioassays form the basis of a tiered-risk assessment moving from laboratory studies assessing individuals, towards field-scale experiments assessing populations. Aphids (Macrosiphum euphorbiae) were fed on artificial diet, half of which containing or not GNA (0.1% W/V). The growth of aphids that had fed for 6 days on diet containing GNA significantly decreased.The effect of GNA on different several parasitoid fitness parameters (parasitism success, parasitoid development, emergence success, progeny survival and overall success) was evaluated. GNA was found in aphids, parasitoid pupae and adults. Preliminary results tend to show that there was no negative effect of GNA on parasitoid development. In addition, more mummies were formed in the GNA group. The reason for this higher rate of successful parasitism is being investigated. This study highlights the careful studies needed to assess the ecological impact of transgenic plants, and the importance to establish "cause and effect" when assessing the impact on non-target beneficial insects.