A 14-d continuous dietary exposure bioassay using nymphs of the insidious ßower bug,
Orius insidiosus (Say) (Heteroptera: Anthocoridae), was conducted to assess nontarget impacts of
genetically modiÞed corn event MON 863 expressing the Cry3Bb1 protein for management of corn
rootworms, Diabrotica spp. (Coleoptera: Chrysomelidae). Nymphs of O. insidiosus were continuously
fed a bee pollen diet inoculated with a maximum hazard exposure dose (930
g/g of diet) of the
Cry3Bb1 protein for 14 d. The Cry3Bb1 protein at a concentration of 930
g/g of diet had no adverse
effect on the survival and development (to adults) of O. insidiosus nymphs. In contrast, when O.
insidiosus nymphs were fed bee pollen diet treated with a hazard dose of the protease inhibitor E64
(53
g/g of diet) or the stomach poison potassium arsenate (8.9
g/g of diet), all nymphs died before
developing to adults. Furthermore, statistical power analysis indicated that at levels of 80% power and
a 5% type I error rate, the study design would have been able to detect a minimum 30% reduction in
survival of test nymphs and a 20% reduction in nymphal development to the adults relative to the buffer
control groups. Based on the maximum level (93
g/g) of the Cry3Bb1 protein expressed inMON863
corn tissues including leaves, roots, and pollen, Þndings from this study indicate that corn hybrids
containing theMON863 event have a minimum 10 times safety factor for nymphs of O. insidiosus and
thus pose minimal risk to this beneÞcial insect.