Abstract: The life history parameters (e.g. body length, time to maturation, survival rate, lifespan and the number of offspring) of Moina weismanni from Lake Nanhu in Wuhan (Hubei Province)and Moina micrura from Lake Taihu in Jiangsu Province were examined under 2×10⁵cells·mL^-1Scenedesmus obliquus at (25±1) ℃. The results showed that body length of bothMoina species showed an increasing trend with increasing instar number. Time to maturation （P=0.008) and the first reproduction time (P=0.022) of M.weismanni were significantly lower than those of M. micrura, whereas body length at maturity (P<0.001), lifespan (P=0.003) and the number of offsprings at first reproduction (P<0.001) of M.weismanni were significantly higher than those of M. micrura. Innate rate of increase was 0.73 ind·d^-1 forM. weismanni and 0.49 ind·d^-1 for M. micrura. Results from Pearson correlation analysis showed that there were significant relationships between the number of offspring at first reproduction and body length at maturity for both M.weismanni(r=0.659,P=0.008) and M. micrura (r=0.649, P=0.009). Our results suggested that M. micrura from Lake Taihu had a longer time to maturation, whereas M. weismanni from Lake Nanhu had a stronger reproductive ability, which might be related to differences in their genetic structure and adaptation to environmental factors in two lakes.

Key words: diversity index, Pteroceltis tatarinowii, similarity coefficient., isolation frequency