Abstract: Plant secondary metabolites can deteriorate the feeding behavior, growth and reproduction of insects, and even exhibit toxicity to insects. During fighting against the influences and toxicity of plant secondary metabolites from host plants, insects gain adaptability to plant secondary metabolites by multiple measures such as avoiding feeding or detoxifying and metabolizing plant secondary metabolites. The insect metabolic enzymes including P450s and glutathione-S-transferase play key roles in the detoxification metabolism of plant secondary metabolites and the adaptability of insects to host plants. The metabolic enzymes of insects are involved in not only the metabolism of plant secondary metabolites, but also the metabolism of insecticides. Therefore, the adaptability of insects to host plants is closely related to the insecticide tolerance and resistance of insects. The activities of P450s and GSTs and the expression of these detoxification enzyme genes in insects could be affected by the exposure of plant secondary metabolites, and these not only result in the adaption of insects to the defense of host plants, but also affect the ability of detoxification metabolism to insecticides and the insecticide tolerance and resistance of insects. Understanding the metabolic adaptation mechanisms of insects to plant secondary metabolites and its roles in affecting the insecticide resistance of insects are of great importance to uncover the insecticide esistance mechanisms of insects. The influences of plant secondary metabolites on insects, the metabolic mechanism of insects to host plant secondary metabolites, and the effects of insect adaptability to plant secondary metabolites on insecticide tolerance and resistance of insects were reviewed in this article.

Key words: Insect, plant secondary metabolites, adaption mechanism, metabolic mechanism, insecticide resistance