Bt toxins safe to insect predators
US researchers have shown that genetically modified crops producing Bt toxins have no adverse effects on two beneficial insect predators or on an entomopathogenic nematode. The scientists took Bt-resistant cabbage looper (Trichoplusia ni) caterpillars and fall armyworms (Spodoptera frugiperda) and fed them Bt maize and cotton producing Cry1Ac, Cry2Ab and Cry1F toxins. They then fed the pests to insidious flower bugs (Orius insidiosus) and big-eyed bugs (Geocoris punctipes) for two generations and compared them with another group of predators that consumed insects fed on non-Bt plants. The researchers found that survival, development, adult mass, fecundity and fertility of the insect predators in both groups were similar. "This research demonstrates that current Bt proteins used in corn and cotton crops globally do not harm G punctipes or O insidious, two important insect predators that help suppress pest populations on corn, cotton and many other crops," says Dr Anthony Shelton, a professor of entomology at Cornell University and one of the co-authors of the study.