Barbehenn 9603621 Oxidative stress is caused by reactive oxygen species (ROS), such as free radicals. The consequences of ROS in herbivorous insects range from no effect, in well-protected species, to reduced growth or death, in species that are less well protected. The ingestion of prooxidant chemicals in plants can greatly exacerbate the production of ROS. Research on the ways insects are protected from ROS has focused on the role of antioxidative enzymes in the gut tissues, rather than on mechanisms that may exist in the lumen of the gut. This work is designed to determine the effectiveness of defenses that may exist in the gut lumen, where ROS are first formed. The investigators will test a general hypothesis that the detrimental effects of prooxidants on susceptible insects are the results of ineffective defenses against ROS generated in the gut lumens, whereas well-protected insects have effective defenses against ROS in their gut lumens. The importance of this work lies, in part, in developing a better understanding of the different antioxidative strategies of herbivorous insects that enable them to feed on "toxic" plants.
