Abstract: 【Aim】 Insect feeding can induce the defense responses of host plants. Different species feeding on the same host plant may have different physiological adaptation. This study aims to investigate the effects of plant damaged by one pest on the enzyme activities in the other subsequent herbivore. 【Methods】 Biochemistry analysis method was used to study the changes in activities of protective enzymes ［peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD)］ and detoxification enzymes ［mixed-function oxidase (MFO), carboxylesterase (CarE), glutathione S-transferase (GSTs) and acetylcholin esterase (AchE)］ in deutonymphs and female adults of Tetranychus urticae at different time points after feeding on kidney bean plants damaged by the 2nd instar nymphs of Frankliniella occidentalis and in the 2nd instar nymphs and female adults of F. occidentalis at different time points after feeding on bean plants damaged by female adults of T. urticae. 【Results】 The activities of POD, CAT and SOD in female adults of T. urticae at 5 h after feeding on bean plants damaged by F. occidentalis (BPDF) were significantly higher than those after feeding on healthy bean plants (HBP) (P<0.01), whereas the POD activity in female adults at 18 h after feeding on BPDF was lower than that after feeding on HBP (P<0.01). The CAT activity in deutonymphs of T. urticae at 5 h after feeding on BPDF was significantly higher than that after feeding on HBP (P<0.01). At 5 h after feeding on BPDF, the activities of MFO and CarE in female adults of T. urticae were suppressed (P<0.01), while the GSTs and AchE activities were higher than those after feeding on HBP (P<0.01). At 18 h after feeding on BPDF, only MFO activity was different from that at 5 h. Only MFO activities in deutonymphs of T. urticae at 5 h or 18 h after feeding on BPDF were higher than those after feeding on HBP (P<0.01). The activities of POD, CAT, and SOD in female adults of F. occidentalis at 5 h or 18 h after feeding on bean plants damaged by T. urticae (BPDT) significantly increased (P<0.01), whereas only the CAT activity in 2nd instar nymphs significantly rose as compared with the control (P<0.01). At 5 h after feeding on BPDT, the changes in detoxification enzymes activities in female adults of F. occidentalis were the same as those in female adults of T. urticae, while at 18 h after feeding, their GSTs activities were different from those at 5 h after feeding. Changes in the activities of detoxification enzymes except GSTs in the 2nd instar nymphs of F. occidentalis were just the opposite at 5 h and at 18 h after feeding. 【Conclusion】 Bean plants damaged by F. occidentalis or T. urticae could cause a series of stress responses in the other subsequent herbivore between T. urticae and F. occidentalis. Changes in activities of protective and detoxification enzymes in adults of the two pests at 5 h after feeding were the same, while they were different at other time after feeding and in other developmental stages. The results suggest that the activities of protective and detoxification enzymes in the two pests have somewhat similar change patterns and their changes also are related with pest species, developmental stages and feeding time. The two pests might have various mechanisms of physiological adaptation to plants damaged by insect herbivores.

Key words: Key words: Tetranychus urticae, Frankliniella occidentalis, kidney bean, protective enzymes, detoxification enzymes, enzyme activity, physiological adaptation