Environmental impacts of genetically modified crops are mandatorily assessed during their premarket phase. One of the areas of concern is the possible impact on nontar- get organisms. Crops expressing Cry toxins might...Environmental impacts of genetically modified crops are mandatorily assessed during their premarket phase. One of the areas of concern is the possible impact on nontar- get organisms. Crops expressing Cry toxins might affect Lepidoptera larvae living outside cultivated fields, through pollen deposition on wild plants, which constitute their food source. While pollen toxicity varies among different events, possible exposure ofnontarget species depends on the agro-environmental conditions. This study was conducted in two protected areas in Italy, characterized by different climatic conditions, where many Lepi- doptera species thrive in proximity to maize cultivations. To estimate the possible exposure in absence of the actual stressor （e.g., Cryl-expressing maize plants）, we conducted a two-year field survey of butterflies and weeds. Indicator species were selected--Aglais （Inachis） io in the Northern site and Vanessa cardui in the Southern site--and their phe- nology was investigated. Pollen dispersal from maize fields was measured by collection in Petri dishes. Duration and frequency of exposure was defined by the overlap between pollen emission and presence of larvae on host plants. Different risk scenarios are expected in the two regions： highest exposure is foreseen forA. io in the Northern site, while minimal exposure is estimated for V. cardui in the Southern site. In the latter case, locally grown maize cultivars flower in mid-summer in coincidence with an aestivation period for several butterfly species due to hot and dry conditions. Moreover, host plants of V. cardui are at the end of their life cycle thus limiting food availability.展开更多
Studies on the behavior of Helicoverpa armigera in relation to soybean cultivars expressing Bt proteins are fundamentally important for IPM. We determine the no-choice and feeding choice of H. armigera, the no-choice ...Studies on the behavior of Helicoverpa armigera in relation to soybean cultivars expressing Bt proteins are fundamentally important for IPM. We determine the no-choice and feeding choice of H. armigera, the no-choice and oviposition choice in different Bt and non-Bt soybeans cultivars. In the first step it was carried out the experiment to determine the no-choice and food choice in test for 12 Bt and non-Bt soybean cultivars. Simultaneously the consumption was determined. In a second step it was evaluated the no-choice and oviposition choice in different soybean cultivars. Helicoverpa armigera caterpillars showed neither attractiveness and preference for food nor attractiveness and oviposition preference for Bt and non-Bt soybean leaves when simultaneously contrasting the tested cultivars. This study showed that Bt toxin did not influence the oviposition preference, and H. armigera adults did not differentiate Bt and non-Bt soybean cultivars for oviposition indicating no behavioral preference. Third instar caterpillars showed no discrimination between Bt and non-Bt soybean leaves. Research in this area must focus on the possibility of widespread planting of genetically modified soybeans containing the Bt protein, which is associated with selection pressure and the behavior of pest species in relation to their hosts, as well as on the adequacy of management tactics that is able to prevent the loss of technology efficiency.展开更多
文摘Environmental impacts of genetically modified crops are mandatorily assessed during their premarket phase. One of the areas of concern is the possible impact on nontar- get organisms. Crops expressing Cry toxins might affect Lepidoptera larvae living outside cultivated fields, through pollen deposition on wild plants, which constitute their food source. While pollen toxicity varies among different events, possible exposure ofnontarget species depends on the agro-environmental conditions. This study was conducted in two protected areas in Italy, characterized by different climatic conditions, where many Lepi- doptera species thrive in proximity to maize cultivations. To estimate the possible exposure in absence of the actual stressor （e.g., Cryl-expressing maize plants）, we conducted a two-year field survey of butterflies and weeds. Indicator species were selected--Aglais （Inachis） io in the Northern site and Vanessa cardui in the Southern site--and their phe- nology was investigated. Pollen dispersal from maize fields was measured by collection in Petri dishes. Duration and frequency of exposure was defined by the overlap between pollen emission and presence of larvae on host plants. Different risk scenarios are expected in the two regions： highest exposure is foreseen forA. io in the Northern site, while minimal exposure is estimated for V. cardui in the Southern site. In the latter case, locally grown maize cultivars flower in mid-summer in coincidence with an aestivation period for several butterfly species due to hot and dry conditions. Moreover, host plants of V. cardui are at the end of their life cycle thus limiting food availability.
文摘Studies on the behavior of Helicoverpa armigera in relation to soybean cultivars expressing Bt proteins are fundamentally important for IPM. We determine the no-choice and feeding choice of H. armigera, the no-choice and oviposition choice in different Bt and non-Bt soybeans cultivars. In the first step it was carried out the experiment to determine the no-choice and food choice in test for 12 Bt and non-Bt soybean cultivars. Simultaneously the consumption was determined. In a second step it was evaluated the no-choice and oviposition choice in different soybean cultivars. Helicoverpa armigera caterpillars showed neither attractiveness and preference for food nor attractiveness and oviposition preference for Bt and non-Bt soybean leaves when simultaneously contrasting the tested cultivars. This study showed that Bt toxin did not influence the oviposition preference, and H. armigera adults did not differentiate Bt and non-Bt soybean cultivars for oviposition indicating no behavioral preference. Third instar caterpillars showed no discrimination between Bt and non-Bt soybean leaves. Research in this area must focus on the possibility of widespread planting of genetically modified soybeans containing the Bt protein, which is associated with selection pressure and the behavior of pest species in relation to their hosts, as well as on the adequacy of management tactics that is able to prevent the loss of technology efficiency.
