[Life history characteristics of different genotype clones of Brachionus calyciflorus (Rotifera) population in Jinghu Lake].

By means of life table demographic approach, the life-table demographic parameters and the percentage of mictic females in the offspring of thirteen genetically different Brachionus calyciflorus clones were studied at 15 degrees C, 20 degrees C, 25 degrees C and 30 degrees C. The results showed that the responses of the generation time, average lifespan, life expectancy at hatching, intrinsic rate of population increase, net reproductive rate, and percentage of mictic females in the offspring of B. calyciflorus to increasing temperature differed with rotifer clones. Temperature, clone, and their interaction influenced the life-table demographic parameters and the percentage of mictic females in the offspring of B. calyciflorus significantly. The temporal heterogeneity of water temperature could be one of the reasons for the high genetic diversity in B. calyciflorus population in Jinghu Lake. Natural selection occurred in coexisting clones, and its function might be too weak or too time-limited to make the clonal exclusion occur. Genetic drift might play an important role in genotype frequency variation. The coexistence of different genotype clones of B. calyciflorus population is of significance for the existence of the population in water environment.