Comportement alimentaire de Centropages typicus (Copepoda, Calanoida) en milieux nutritifs a deux algues et en presence de nauplii d'Artemia sp.

Publisher Website
Google Scholar
Abstract
We have investigated Centropages typicus, a calanoid copepod which abounds in the Gulf of Marseilles. The experiments made with plant cell mixtures took place in confined medium in 500 ml erlenmeyer flasks containing 300 ml of nutritive medium (two algae + filtered sea water) and about 15 copepods. For the experiments with Artemia sp. nauplii, we generally used 150 or 200 ml flasks containing 100 or 50 ml of medium (numerous nauplii + filtered sea water). The plant cells used as food are diatoms (Skeletonema costatum, Phaeodactylum tricornutum, Lauderia borealis) and flagellates (Amphidinium klebsii, Prorocentrum micans, Isochrysis galbana) of different shapes and dimensions. All our results are based on the estimation of two parameters: the ingestion rate (I) (cells ingested/copepod/24 h) and the ration (R) (cells ingested/copepod/ml/24 h or nauplii ingested/copepod/50 ml/24 h). Two essential conclusions emerged from our experiments: a) The copepods tested do not show a high degree of selectivity for algae. Using the values of the relations % R/Ci, % Ci/ΣCi, % R/ΣR (R = ration; Ci = initial concentration of algae) and those of Ivlev's equation, we have established that C. typicus tends to prefer either the largest or the most abundant cells. This form of selection does not constitute a real choice by C. typicus because it seems principally linked to the distance between maxillae setules. b) If the ingestion of nauplii is not exceptional, and many authors consider C. typicus as an omnivorous copepod, their ability to vary the ration is a remarkable adaptation.

This publication has 0 references indexed in Scilit: