[Objective] Mononychellus tanajoa is a mite speices recently invaded into China in 2008. Temperature is one of the most important ecological factors affecting the growth and reproduction of M. tanajoa. The objective of the current study was to reveal the effects of high temperature incubation on the activities of some protective enzymes in M. tanajoa at different growth stages. The results would contribute to the understanding of the adaptable distribution of M. tanajoa after its invasion into China, the mechanisms in its invasion, diffusion and ecological adaptation, and the monitor- ing, early warning and effective prevention of its damage. [Method] Six protective enzymes, Le. polyphenol oxidase （PPO）, peroxidase （POD）, ascorbate oxidase （AsA- POD）, catalase （CAT）, superoxide dismutase （SOD） and esterase （EST）, were cho- sen to study their activities after the mites at different growth stages were incubated at a extremely high temperature of 42 ~C for a certain period of time up to 24 h. The activities were measured by spectrophotometric endpoint assay method. [Results] Enzyme activities in M. tanajoa were affected by the high temperature incubation. However, differences in enzyme activity changes were found among different protec- tive enzymes and among different growth stages of M. tanajoa. Activities of PPO, POD, AsA-POD and CAT were significantly increased in the larval mites and female adult mites of M. tanajoa. CAT activity was significantly decreased in protonymph and deutonymph of M. tanajoa. Activities of PPO, POD and AsA-POD in protonymph and deutonymph showed no obvious difference from the control. [Conclusion] The activity changes of some protective enzymes in M. tanajoa following high-temperature treatment are part of its anti-stress reaction mechanism. In mite protonymph and deutonymph, activities of PPO, POD and AsA-POD are similar to the untreated con- trol which may be associated with the thermostability of M. tanajoa. It is concluded that, the long-time stress of extrem
