The Cost of Reproduction in the Rotifer <i>Brachionus calyciflorus</i> Pallas

Abstract

Abstract A study of lifespan, fecundity, and reproductive schedules was carried out with the rotifer Brachionus calyciflorus under different food concentrations. At high food densities (6.1 to 12.4 μg · ml −1 , dry mass) there was an increase in offspring number but the reproductive investment remained constantly. This was possible because Brachionus calyciflorus invested a smaller amount of energy one egg volume being able to increase offspring number. Although egg volume was reduced, this was compensated by the greater amount of energy available to the neonates. The length of the prereproductive period remained constant throughout this range of food concentrations. Within this range a reduction in lifespan was observed. This, however, was not due to a total higher reproductive investment, but to an increased offspring rate production resulting in a shortening of the reproductive period. The length of the post‐reproductive period was not different at all food concentrations.