Affiliation: | (1) Biologische Anstalt Helgoland, Alfred-Wegener-Institut für Polar- und Meeresforschung, Postfach 180, 27483 Helgoland, Germany;(2) Forschungsinstitut Senckenberg, Notkestrasse 31, 22607 Hamburg, Germany;(3) Present address: Institut für Zoologie, Allgemeine Ökologie und Limnologie, Universität zu Köln, Weyertal 119, 50923 Cologne, Germany |
Abstract: | This study details the investigations of the effect of temperature and the presence of predators on the vertical distribution of the ctenophore Pleurobrachia pileus. Previous studies had suggested that P. pileus moves to the sediment when exposed to colder temperatures as an energy saving strategy. Although we did observe an effect of temperature on the movement of the ciliate combs, the effect of temperature on the average depth of animals in the water column was not significant, but a significant interaction was found between temperature and exposure time. In the presence of benthic predators or of water previously inhabited by these predators P. pileus changed its vertical distribution significantly, and moved away from the sediment, thus reducing the risk of being predated. We conclude that P. pileus can sense the presence of its predators, and changes its behaviour accordingly.Communicated by O. Kinne, Oldendorf/Luhe |