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Nova Londrina, Brazil

Silva G.V.,Federal University of Parana | Pasini A.,State University Londrina | de Freitas Bueno A.,Laboratorio Of Parasitoides | Bortolotto O.C.,Federal University of Parana | And 2 more authors.
Revista Brasileira de Entomologia | Year: 2014

No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae). Biological traits of the stink bug Euschistus heros and its main biological control agent Telenomus podisi were evaluated under controlled environmental conditions (25 ± 2°C; 60 ± 10% RH; and 14/10 h photoperiod) by placing first instar nymphs into Petri dishes with pods originating from two soybean isolines (Bt-soybean MON 87701 × MON 89788, which expresses the Cry1Ac protein, and its near non-Bt isoline A5547) where they remained until the adult stage. Due to gregarious behavior exhibited by first instar nymphs, they were individualized only when at the second instar. Adults were separated by sex and weighed, and pronotum width of each individual was subsequently measured. They were placed into plastic boxes containing soybean grains of the same soybean isoline as food source. Egg viability and female fecundity were assessed in adult individuals. Adult females of T. podisi (up to 24h old) were placed with eggs of E. heros from mothers reared on both soybean isolines. Nymphal development time, insect weight, pronotum width, sex ratio, female fecundity, and egg viability (% emergence) of Euschistus heros did not differ between treatments. Eggto- adult development time, female longevity, sex ratio, and percentage of parasitized eggs were not impacted by the Bt-soybean (expressing Cry1Ac protein). Results indicate that the Bt-soybean, MON 87701 × MON 89788, has no direct significant impact on the two studied species. Source

Bortolotto O.C.,Federal University of Parana | Bortolotto O.C.,Laboratorio Of Parasitoides | Silva G.V.,Federal University of Parana | Silva G.V.,Laboratorio Of Parasitoides | And 7 more authors.
Bulletin of Entomological Research | Year: 2014

Genetically modified crops with insect resistance genes from Bacillus thuringiensis Berliner (Bt-plants) are increasingly being cultivated worldwide. Therefore, it is critical to improve our knowledge of their direct or indirect impact not only on target pests but also on non-target arthropods. Hence, this study evaluates comparative leaf consumption and performance of Spodoptera eridania (Cramer), a species that is tolerant of the Cry1Ac protein, fed with Bt soybean, MON 87701×MON 89788 or its non-Bt isoline. We also assessed the comparative performance of the egg parasitoid Telenomus remus Nixon on eggs of S. eridania produced from individuals that fed on these two soybean isolines as larvae. Results showed that Bt soybean reduced by 2 days larval development and increased by 3 days adult male longevity. Therefore, we conclude that the effect of Bt soybean MON 87701×MON 89788 on S. eridania development and reproduction is small, and favorable to pest development. These differences are less likely to directly result from the toxin presence but indirectly from unintended changes in plant characteristics caused by the insertion of the transgene. Our results should be viewed as an alert that S. eridania populations may increase in Bt soybeans, but on the other hand, no adverse effects of this technology were observed for the egg parasitoid T. remus which can help to prevent S. eridania outbreaks on these crops. © Cambridge University Press 2014. Source

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