EFFECT OF TEMPERATURE ON THE EGG DEVELOPMENT,POPULATION GROWTH AND PRODUCTION OF BRACHIONUS CALYCIFLORUS PALLAS (ROTIFERA)

Egg develpoment time and population growth of Brachionus calyciflorus were observed at constant temperature, and the production rate of the species was estimated with three different methods.Development time decreases with increasing temperature from 5° to 30℃. The relationship between temperature (T) and development time (D) was found to be curvilinear and may be described by following equation:Ln D = 2.0539+0.1097LnT -0.3046(Ln T)2 The population growth curves of parthenogenetic females hatched from resting eggs are S-shaped or Logistic at 10, 15, 20, and 25℃. The time at which the maximum population density occurred was shortened with increasing temperature, but the carrying capacity would increase as the temperature increased.The mean daily production increases with increasing temperature. In general, similar results of production are obtained by using either linear or exponential method. However, a great percentage difference was found when the values were compared with those derived from the generation time method.From the data of the present study and those in the literature, a curvilinear logarithmic equation: Ln D=2.1869-0.1919 LnT-0.2218 (LnT)2 is derived to summarize the relation between developmental duration and temperature (0.6—35.2℃) in Brachionus calyciflorus.