Effect of plant o-dihydroxyphenols and quinone on generation of reactive oxygen species within the grain aphid tissues

Effect of some dietary o-dihydroxyphenols and quinones on hydrogen peroxide (H2O2) concentration within tissues of the grain aphid Sitobion avenae (F.) (Homoptera, Aphididae) has been studied. Among the studied aphid morphs the highest level of H2O2 total was noted for winged adults (alatae) and the lowest for larvae. The aphids exposed to the dietary pro-oxidative o-dihydroxyphenols demonstrated significantly higher concentration of hydrogen peroxide than the control ones. Among the studied compounds, caffeic acid showed the strongest effect on the H2O2 level within the aphid tissues. The highest concentration (0.1%) of this phenolic acid caused above 2-fold increase in the content of this radical within the grain aphid tissues. The significance of these results for understanding the toxicity of phenols to cereal aphids is discussed.