Selective feeding of Acartia clausi and Centropages typicus on microzooplankton

Abstract

Selective feeding of 2 common copepods, Acartia clausi and Centropaqes typicus , on mixtures of ciliates and planktonic algae was investigated. Results show the ability of these copepods to recognize the quality of their particulate foods. An equiproportional mixture (in terms of biovolume) of the oligotrichous ciliate Strombidium sulcatum and either the dinoflagellate Prorocentrum micans or the diatom Thalassiosira weissflogii was offered to the copepods. The copepods ingested ciliates, at rates of 3.2 x 105 mu m3 copepod-1 h-1 for A. clausi and 4.3 x 10 105 mu m3 copepod-1 h-1 for C. typicus (67 and 80% of the total ingested ration respectively), when ciliate + dinoflagellate mixtures were offered. A. clausi preferred S. sulcatum to T. weissflogii , and ingested the ciliate at a rate of 3.7 x 105 mu m3 copepod-1 h-1 (75% of total ingested ration)