TRANSGENIC PLANTS AND INSECTS Using Resistant Prey Demonstrates That Bt Plants Producing Cry1Ac, Cry2Ab, and Cry1F Have No Negative Effects on Geocoris punctipes and Orius insidiosus

Geocoris punctipes (Say) and Orius insidiosus (Say) are generalist predators found in awide range of crops, including cotton (GossypiumhirsutumL.) andmaize (ZeamaysL.), where they provide important biological control services by feeding on an array of pests, including eggs and small larvae of caterpillars. A high percentage of cotton and maize in the United States and several other countries are transgenic cultivars that produce one ormore of the insecticidal Cry proteins ofBacillus thuringiensis Berliner (Bt). Here we quantify effects of three Cry proteins on the life history of these predators over two generations when they are exposed to these Cry proteins indirectly through their prey. To eliminate the confounding prey quality effects that can be introduced byBt-susceptible prey, we used Cry1Ac/Cry2Ab-resistant Trichoplusia ni (Hübner) and Cry1 F-resistant Spodoptera frugiperda (J.E. Smith) in a series of tri-trophic studies. Survival, development, adultmass, fecundity, and fertility were similar when predators consumed larvae feeding on Cry1Ac/Cry2Ab cotton or Cry1 F maize compared with prey feeding on isogenic or near-isogenic cotton or maize. Repeated exposure of the same initial cohort over a second generation also resulted in no differences in life-history traits when feeding on non-Btor Bt-fed prey. Enzyme-linked immunosorbent assay showed that predators were exposed to Bt Cry proteins from their prey and that these proteins became increasingly diluted as theymoved up the food chain. Results show a clear lack of effect of three common andwidespread Cry proteins on these two important predator species. The use of resistant insects to eliminate prey quality effects provides a robust and meaningful assessment of exposure and hazard.