Ratio between the survival and fecundity in the cohorts of Daphnia longispina (Cladocera) under different trophic conditions
The survival and fecundity of Daphnia longispina were studied in life-table experiments under different Chlorella sp. concentrations (0.08, 0.18 and 0.36 mg/L). The survivorship-weighted fecundity decreased at low concentration of food, but two or more maxima were found at higher concentrations. The “reproductive cost” hypothesis was tested using the data of life-table experiments. It was shown that this hypothesis is confirmed only for low food concentration.