POTENTIAL IMPORTANCE OF ALGAE IN THE DIET OF ADULT CYCLOPS-VICINUS

1. The potential importance of phytoplankton to the nutrition of adult Cyclops vicinus was studied. 2. The flagellate Chlamydomonas reinhard ii was ingested and digested at a higher rate than the coccale green a lga Monoraphidium minutum. 3. The predation rate on the rotifer Brachi onus rubens decreased if C. reinhardii was also available as food. No significant reduction of predation was found when M. minutum was offer ed together with B. rubens. 4. The species of available phytoplankton influenced egg production. Females which were allowed to feed on B. ru bens and C. reinhardii produced more eggs than females which fed on ro tifers only or a diet containing rotifers and M. minutum. Egg producti on was also possible when rotifers were absent from the diet. 5. Produ ction efficiency was higher when C. reinhardii was the only food resou rce than on a diet containing rotifers only.