Abstract: 【Objective】 The objective of this study is to clarify the effect of heat stress on survival and reproduction of the female citrus red mites (Panonychus citri), and to explore the population dynamic law under high-temperature condition. 【Method】The P. citri were collected from Citrus Research Institute, Chinese Academy of Agricultural Science. Mites were reared on the citrus seedlings at least for 10 generations prior to the experiments in phytotron ((25±1) ℃, 75%-80% RH, 14 h﹕10 h (L﹕D) photoperiod). Some female adult mites were selected to detached citrus leaves remaining 12 h for oviposition. Then the females were moved, and the eggs were continuously cultured until the mite reached detonymph. Then every mite was reared on a fresh leaf disc. When the mites developed to adulthood, every female adult mite was shocked at 32, 35, 38 and 41℃ for some time in constant temperature incubator, respectively. After that the treated mites were returned to the above-mentioned phytotron, accompanied by a male adult mite for each female. Each treatment was repeated thirty times at least, 25℃ served as control. The survival and oviposition were observed every 24 h until the female died, to determine the effect of heat stress on the survival and fecundity of P. citri. Data were analyzed by one-way analysis of variance (ANOVA) and Duncan multiple range test (DMRT, P＜0.05) using SPSS 10.0 software.【Result】High temperature had a significant effect on life-span of female adult. The longevity became shorter with the temperature rising from 32 to 41℃ after exposed to the mentioned temperatures for 1 h, respectively (P＜0.001). The longevity became even shorter with the stress time elapsed. For example, when exposed to 38℃ for 3 h, the longevity was 9.6 d (P＜0.01), and it was 5.0 d when exposed to 41℃ for 3 h (P＜0.001). Furthermore, high temperature had an adverse effect on fecundity of female adult. The average oviposition distinctly decreased under exposure of high temperature for 1 h (P＜0.05), and the oviposition became fewer and fewer with the stress time elapsed, for instance, when exposed to 38℃ for 3 h, the average fecundity of a female distinctly decreased to 23.1 eggs (P＜0.001), the same case happened to 41℃ (P＜0.001). When the citrus red mite was exposed to 32, 35, 38 and 41℃ for 1 h, respectively, the age-specific survival rate (lx) curve all had “plateau duration”, but the “plateau duration” disappeared after the female exposed to 38 and 41℃ for 3 h, respectively, also, the gradient of lx curve became abrupt with the rise of treatment temperature and extension of treatment time. The age-specific fecundity (mx) curve showed that heat stress made the oviposition summit in advance and mx decline, especially when exposed to 38 and 41℃ 3 h, respectively, the mx of female adult mite obviously decreased. 【Conclusion】The longevity and oviposition dropped under short-time heat stress condition and the degree became even serious with the rise of treatment temperature and extension of treatment time. The exposure to heat stress had harmful effect on survival and fecundity of the female citrus red mite. This suggested that the population of P. citri could be distinctly inhibited by hot summer climate.

Key words: citrus red mite (Panonychus citri) , heat stress , survival , reproduction