No abstract

No abstract

1985. Behavioral interactions between the actinian Tealia piscivora (Anthozoa: Actiniaria) and the asteroid Dermasterias imbricata. Can. J . Zoo1 . 63: 192 1 -1929. Interactions between the sea anemone Tealia piscivora and the sea star Dermasterias imbricata have been studied in the laboratory and in subtidal habitats. Dermasterias causes the release of the pedal disk of smaller T. piscivora. The response is specific. Nineteen other sea stars did not cause release; four other species of Tealia did not respond to Dermasterias. The response is size dependent; unfailing and quick in small T. piscivora, less frequent and slow in those of intermediate size, it did not occur at all in large specimens. Unrestrained T. piscivora generally survived interactions with Dermasterias but when prevented from detaching, most of the small anemones were devoured. Tealia piscivora have been observed to detach and engulf small Dermasterias. Most small anemones were found at greater depths; most large anemones were found at lesser depths where Dermasterias were most abundant. It is suggested that by releasing the pedal disk, small T. piscivora eventually end up in deeper water where there are few Dermasterias and thus the anemones escape predation. ELLIOTT-, J., J. DALBY, JR., R. COHEN et D. M. Ross. 1985. Behavioral interactions between the actinian Tealia piscivora (Anthozoa: Actiniaria) and the asteroid Dermasterias imbricata. Can. J. Zoo1 . 63: 192 1 -1929.On a ktudik les interactions entre I'ankmone de mer Tealia piscivora et I'ktoile de mer Dermasterias imbricata au laboratoire et dans la zone des markes. Dermasterias provoque le dktachement du disque pkdieux chez T. piscivora de petite taille. Cette rkponse est spkcifique. Dix-neuf autres Ctoiles de mer n'ont pu provoquer ce dktachement; quatre autres espkces de Tealia n'ont pas rkagi a la prksence de Dermasterias. La rkponse dkpend de la taille: elle est rapide et infaillible chez les T. piscivora de petite taille, moins frkquentes et lente chez les sujets de taille intermkdiaire, et absente chez tous les individus de forte taille. Les sujets libres de s'kchapper ont gknkralement survkcu aux attaques de Dermasterias, mais non ceux que I'on emflchait de se dktacher: la plupart des sujets de petite taille furent alors dkvorks. On a observe des T. piscivora en train de dktacher et de consommer de petites Dermasterias. La plupart des ankmones de petite taille ont kt6 trouvkes en zones plus profondes, tandis que les sujets de forte taille ktaient concentrks plut6t en eau peu profonde oh les Dermasterias abondent. Nous croyons qu'en rellchant leur disque pkdieux, les T. piscivora de petite taille aboutissent kventuellement en eau plus profonde oh il y a peu de Dermasterias; elles kchappent ainsi ce prkdateur. IntroductionSeveral actinian species from the northeast Pacific release their pedal disks when brought into contact with certain sea stars. The behavioral physiology of these interactions has been studied in three species: in the "swimming anemones," Stomphia coccinea and S...

No abstract

No abstract