Effect of algal diet and temperature on the embryonic development time of the rotifer Brachionus plicatilis in culture

The embryonic development times of two strains of Brachionus plicatilis (Bs and S-1) cultured on three different algal diets (Nannochloris oculata, N. maculata and Nannochloropsis gaditana), have been determined at 20°C, 25°C and 30°C. As expected, the embryonic development times decreased with increasing temperature in all cases. However, embryos from adults fed on N. gaditana tended to develop more slowly than those of individuals fed on the other algal species. Mean egg volume was also affected by diet, larger eggs being produced by females fed on N. gaditana. No obvious relationship between egg size and temperature was detected.Two principal factors seemed to affect the embryonic development time. The first was temperature which acts through its well known effect on metabolic rates. The second was maternal diet which probably affects development time through its effect on yolk content, as reflected in the size of the egg.