| Biology of natural enemies is a prerequisite for carrying out biological control pests. In order to explore safe and effective control methods, based on the screening of natural enemies, we studied the basic biological characteristics and predation at 25±1°C, 100% RH , L:D = 0:24 with two different preys. The results of this study were summarized as follows:1. H. chianensis had two reproductive modes, gamogenesis and parthenogenisis. Two reproductive modes had some influence on reproduction of offpring. The oviposition period of unfertilized females of H. chianensis was 57.70 days, which was significantly (p<0.05) longer than that of the fertilized ones. The total fecundity was no significant difference between the two reproductive modes. The eggs hatching rate and survival of larva, nymphs were 91%, which had no significant difference between the two reproductive modes. The female and male sexual ratio of H. chianensis was 1.04 at gamogenesis and the offspring were all male mites at parthenogenesis.2. Though the development and reproduction were normal, the developmental duration and numbers of laying eggs of H. chianensis were significantly different fed on different preys. The developmental duration of H. chianensis fed on C. lactis were significantly (p<0.05) longer than those fed on T. putrescentiae. The oviposition period of adult females of H. chianensis fed on C. lactis was 40.31 days, which was not significantly (p﹥0.05) longer than those fed on T. putrescentiae. The life time of adult females of H. chianensis fed on C. lactis was significantly (p<0.05) longer than those fed on T. putrescentiae. The numbers of laying egg of adult females of H. chianensis fed on T. putrescentiae were 35.93 grains pre female, which was significantly (p<0.05) more than those fed on C. lactis. The eggs hatching rate of H. chianensis fed on T. putrescentiae was 91%, which was significantly (p<0.05) higher than those fed on C. lactis.3. H. chianensis was very sensitive to relative humidity. It was suitable to its development and propagation at 25°C, 100%RH. The development time of generation was significantly longer at 96%RH than that at 100%RH. Death of groups occurred and the larva, nymphs could not develop to stage at 92% RH. 4. Temperature, humidity, density and hunger affected the fecundity of adult females. At the 15~35°C temperature range, the fecundity of adult females first increased and then decreased as the temperature changed and were maximum at 30°C.The numbers of laying eggs of adult females of H. chianensis were maximum at 100%RH. Predatory mite density affected fecundity in the individual keeping small room and reached maximum at 2 per room. Hunger did not impact on the fecundity.5. Intraspecific cannibalism of H. chianensis was not obvious. Happened only when there were 8 per room of protonymph or deutonymph. Adult females did not kill each other at that density. The development duration of experiment group compared with the control group which was significantly (p<0.05) longer, adult females did not lay eggs, also a significant (p<0.05) difference with the control group.6. The functional response pattern of adult females of H. chianensis was fit for Holling II. The parameters of functional response were affected by temperature and preys, but the types of equations were not changed.7. With the adult females increasing density, the total prey increasing, but the predation rate would decline. The relationship between predation ratio (E) and natural enemy density (P) was described by equation of E=0.1798P-0.6216, disturbing coefficient (m) was 0.6216.The results showed that H. chianensis had a big appetite and active movement. So it was worth to exploring and using H. chianensis as a natural enemy of T. erputrescentiae. The technology of breeding H. chianensis use C. lactis need to be further study.
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