Abstract: With the method of population accumulative culture, the effect of initial population density on the formation of resting eggs of freshwater rotifer(Brachionus calyciflorus), and on the rates of mictic female and fertilization was studied.During 11 days culture,the productivity and the formation efficiency of resting eggs,and the mean rate of mictic female were the biggest when the initial population density was 1.0～10.0 ind·ml^-1,second by the density of 20.0 ind·ml^-1,and the lowest by the density of 50.0 ind·ml^-1.There was no significant effect of initial population density on the fertilization rate.Statistical analysis on maximum formation efficiency of resting eggs,their emergence and productivity showed that when the production of resting eggs was large scaled proceeded,the feasible initial population density should be 10.0 ind·ml^-1,and the corresponding time should be 6 days to obtain a higher yield of resting eggs and a higher formation efficiency.

Key words: Brachionus calyciflorus, Initial population density, Resting eggs, Productivity, Formation efficiency