Greenhouse and laboratory experiments reported have included DKc307 maize cultivar with Cry 1Ab gene (MON 810) as the GM reference crop and cv. Monumental, its isogenic line as representative of the first trophic level and a) Ephestia kuhniella Zell. and its parasitoid Venturia canescens, b) Rhopalosiphum padi L. and parasitic Aphidius colemani Viereck as the second and third level relations. No significant differences in larval survival of E. kuhniella on MON 810 flour in comparison to its non - GM isoline was observed, however, the average weight of larvae reared on MON 810 flour was significant lower. This effect did not affect the level of parasitation by V. canescens. The results clearly showed that grain and flour made of MON 810 during their storage should be less infected by the moth larvae and the role of parasitoid even stronger. It was confirmed that Cry 1Ab toxin did not showed a toxic effect on R. padi aphids feeding on MON 810. In addition they developed higher (but not significantly) populations on the transgenic plants, both in the winter and summer greenhouse tests. Higher aphids' parasitation level by A. colemani was observed on MON 810 in the summer tests and on cv. Monumental in the winter bio-assays, indicating an effect of season on the tri-trophic relations.
Maize and cotton genetically engineered for insect resistance have been commercially available in the United States for more than a decade. These crops have revolutionized pest control as broad-spectrum insecticides have been replaced with environmentally friendly protein toxins that are produced by the plants. These crops have been popular with most growers in the U.S. because they provide economic advantages and reduce the reliance on chemical insecticides. Prior to commercialization these crops underwent a comprehensive and rigorous evaluation by three U.S. government agencies to demonstrate their safety to the environment and human and animal health. This article focuses on non-target risk assessment of genetically-engineered cotton and maize. By outlining the principles of risk assessment, exploring ecosystem effects of Bt cotton, presenting a case study of risk assessment using the monarch butterfly and Bt-maize pollen, and considering possible environmental impacts of current GE crops.
The Authors’ critical review of laboratory and field experiments and observations on the effect of Bt maize pollen on butterflies (Lepidoptera) was provoked by two factors: (a) continuous uncritical reference by various groups of public in Europe and especially in Poland to the first report by losey et al. (1999) and ignoring following publications by other US researchers, and (b) recent discussions by members of the Polish Parliament (June 2006) and various advisory groups to the European Commission (May and June 2006). losey et al. (1999) in their correspondence to Nature reported that pollen from Bt maize could be hazardous to the larvae of the monarch butterfly, receiving much attention from the media. The following detailed studies by other scientists have proven that the experimental techniques and data extrapolation by the losey’s group did not reflect a real relation between maize pollen and monarch butterfly. The hazard is a function of exposure, e.g. larval development must coincide with maize anthesis (pollen shed), which takes place only in a few regions in the USA. Again, pollen movement and deposition decreased rapidly 2 to 3 m from the maize fields. The field observations on differences in butterfly fauna around Bt and non-Bt maize fields carried out in some European countries demonstrated that a special attention should be paid to a proper methodology (a number of replications and size of field margin under observation) and a caution should be taken in drawing conclusions. There is consensus between the EU experts that more research is needed on butterfly fauna in and around maize fields before the release of Bt maize for a wide cultivation in Europe is approved.
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