Potential importance of algae in the diet of adult Cyclops vicinus

SUMMARY The potential importance of phytoplankton to the nutrition of adult Cyclops vicinus was studied. The flagellate Chlamydomonas reinhardii was ingested and digested at a higher rate than the coccale green alga Monoraphidium minutum . The predation rate on the rotifer Brachionus rubens decreased if C. reinhardii was also available as food. No significant reduction of predation was found when M. minutum was offered together with B. rubens . The species of available phytoplankton influenced egg production. Females which were allowed to feed on B. rubens and C. reinhardii produced more eggs than females which fed on rotifers only or a diet containing rotifers and M. minutum . Egg production was also possible when rotifers were absent from the diet. Production efficiency was higher when C. reinhardii was the only food resource than on a diet containing rotifers only.