KSEF R&D Excellence: A Quantitative Evaluation of the Bioaccumulation of Bt-toxins Within Predators in Kentucky Using Diagnostic Immunological Techniques

Throughout Kentucky and the United States, the planting of transgenic crops has increased rapidly since the mid-1990's. This proliferation in use of genetically modified crops could lead to an accumulation of toxins within invertebrate food chains and the build-up of Bacillus thuringiensis (Bt) toxins within predators could reduce their fecundity. This reduced reproductive output would ultimately deplete population densities and the importance of the natural enemy complex in biological control would decline. It could also have a profound impact upon vertebrate predators since they may feed on contaminated invertebrates within agricultural systems and. the long-term consequences of such actions are unknown. We are proposing to develop a quantitative system using monoclonal antibodies (which have been developed against Bt-Cry 1Ab protein toxins) to measure the quantities of these toxins present within predator communities. Laboratory trials using pollen and anthers from Bt-com will determine levels of target proteins within predators following feeding on contaminated prey. In com fields, we propose to collect a range of arthropod predators and their prey to determine whether these toxins accumulate within populations in the agroecosystem, where exposure to Bt-com would occur at natural levels. The development of this assay system will enhance our understanding of the potential for Bttoxin flow through the food chain (and its presence within non-target herbivores and predators). Laboratory feeding experiments will also determine the fecundity of generalist predators following consumption of prey contaminated with the Bt-toxin. This unique and highly innovative study will develop an assay system to detect Bt-CrylAb proteins within invertebrates, provide a key advance to our understanding of the potential non-target effects of genetically modified crops and form the basis for a future competitive federal grant application. To our knowledge, no previous studies have examined the potential for Bt-toxins to accumulate in invertebrate food chains inThroughout Kentucky and the United States, the planting of transgenic crops has increased rapidly since the mid-1990's. This proliferation in use of genetically modified crops could lead to an accumulation of toxins within invertebrate food chains and the build-up of Bacillus thuringiensis (Bt) toxins within predators could reduce their fecundity. This reduced reproductive output would ultimately deplete population densities and the importance of the natural enemy complex in biological control would decline. It could also have a profound impact upon vertebrate predators since they may feed on contaminated invertebrates within agricultural systems and. the long-term consequences of such actions are unknown. We are proposing to develop a quantitative system using monoclonal antibodies (which have been developed against Bt-Cry 1Ab protein toxins) to measure the quantities of these toxins present within predator communities. Laboratory trials using pollen and anthers from Bt-com will determine levels of target proteins within predators following feeding on contaminated prey. In com fields, we propose to collect a range of arthropod predators and their prey to determine whether these toxins accumulate within populations in the agroecosystem, where exposure to Bt-com would occur at natural levels. The development of this assay system will enhance our understanding of the potential for Bttoxin flow through the food chain (and its presence within non-target herbivores and predators). Laboratory feeding experiments will also determine the fecundity of generalist predators following consumption of prey contaminated with the Bt-toxin. This unique and highly innovative study will develop an assay system to detect Bt-CrylAb proteins within invertebrates, provide a key advance to our understanding of the potential non-target effects of genetically modified crops and form the basis for a future competitive federal grant application. To our knowledge, no previous studies have examined the potential for Bt-toxins to accumulate in invertebrate food chains in agroecosystems.