FOOD RESOURCES, SURVIVORSHIP, AND REPRODUCTION OF THE OMNIVOROUS CALANOID COPEPOD EPISCHURA-LACUSTRIS

The alga Cryptomonas erosa and the rotifer Euchlanis dilatata both, when offered alone, serve as adequate foods to support survival and reproduction of Epischura, but survival and reproduction of individuals feeding on Cryptomonas vary temporally, even when resource availability is held constant. Extended survival and high egg production rates in the spring are followed by poor survival and minimal egg production rates later in the year. Survival and reproduction of individuals given the rotifer do not vary significantly across the seasons. Epischura lacustris reproduction may depend upon relatively large or evasive animal prey, eg the cladoceran Holopedium gibberum and the rotifer Polyarthra remata. -from Authors