REPRODUCTIVE PATTERN OF BRACHIONUS-CALYCIFLORUS PALLAS AT DIFFERENT FOOD CONCENTRATIONS

Laboratory populations of Brachionus calyciflorus were grown at different food levels, to determine whether B. calyciflorus was capable of varying its reproductive pattern, according to the concentration of available food to maintain a high rate of population growth. The volume of eggs borne by females was measured, and the carbohydrate content of the animals was analysed. When food was abundant, egg volume and carbohydrate content were low. Since small neonates can easily become adults because of the good food conditions, B. calyciflorus utilized its energy to increase the number of offspring. At low food concentrations, there was an important increase in egg volume and carbohydrate content. As egg numbers decreased, then B. calyciflorus then appeared to use its energy to increase neonate size. This tendency was maintained down to a threshold concentration, below which egg volume and carbohydrate content diminished again due to insufficient food.