Effects of Temperature on Life History Strategy of the Rotifer Euchlanis dilatata

The cosmopolitan littoral rotifer Euchlanis dilatata is a potential model species in eco-toxicological and ecological studies, owing to its unique characteristics, such as periphytic benthic living, sensitivity to toxicity, and laying eggs on substrates instead of carrying them on the mother's body. However, studies about the life history strategy of this species, in contrast to the intensely studied planktonic Brachionus species, are relatively scarce. Temperature is an important factor that affects the rotifer's life history traits, and is well known to induce phenotypic plasticity in planktonic rotifers. The present study measured life table parameters of the rotifer E. dilatata originating from one clonal population local to Beijing under three temperature treatments: 14°C, 20°C and 26°C (10 females/replicate × 4 replicates for each treatment). We also examined trade-offs between egg size and egg number, as well as current reproduction and future survival to evaluate the life history strategy of the rotifer. In contrast to cold conditions, in which mothers produced a few large eggs with similar egg sizes, in warm environments, mothers produced many smaller eggs and a few larger eggs, thus resulting in a clear variation in egg sizes. With increasing temperature, the pre-mature period, reproductive period, life span and generation time shortened, while the net reproductive rate and population growth rate increased. Temperature also affected the trade-off between current reproduction and future survival. This work provides basic data for the potential model species E. dilatata.