Zur Nahrungsaufnahme von Tetrastemma melanocephalum (Nemertini)

Abstract

The proboscis of hoplonemerteans is armed with a stylet apparatus, which is used for capturing prey. Tetrastemma melanocephalum (Johnston) is a common hoplonemertean in the littoral of the Baltic Sea and the North Sea. It lives in the phytal and on sand- and mudflats and occurs in large numbers in the Corophium belts in the waddenseas. T. melanocephalum feeds on arthropods, mainly on copepods and amphipods. The prey is caught with the proboscis, penetrated by the stylet and grows weak (reduction of movements) within a few seconds; it is then sucked out. During the summer, a 15-35 mm long nemertean captures about 3 specimens of Corophium volutator of 3.5-6 mm length per day. In the Corophium belt at Sahlenburg, German Bight, North Sea, 29 nemerteans/0.25m2 were found; they feed mainly on C. volutator, so that on average more than 10 000 specimens of C. volutator/m2/month are sucked out by these nemerteans. Hence, T. melanocephalum is an important consumer of Corophium. © 1973 Biologischen Anstalt Helgoland.