Fortpflanzung und Sexualität von Cereus pedunculatus und Actinia equina (Anthozoa, Actiniaria)

Abstract

Sexuality and reproductive behaviour of Cereus pedunculatus (Pennant) and several forms (subspecies) of Actinia equina (L.) from populations collected along the French Atlantic Sea coast and in different habitats along the European Mediterranean coast were studied. At the stage of 96 septae C. pedunculatus and A. e. atlantica II exhibited mature oocytes which developed parthenogenetically into larvae. The latter appeared simultaneously in the gastrocoele. Adolescent A. e. atlantica II developed very few mature oocytes and larvae. Following a sterile period, oocytes and young individuals of different age groups were present almost throughout the whole year in adult anemones. A. e. mediterranea I was dioecious and oviparous in any habitat observed. Samples of the larviparous A. e. mediterranea II (collected near Banyuls, France) exhibited male gonads exclusively and contained larvae. Spontaneous longitudinal fission was occasionally observed in adult A. e. mediterranea I and adolescent A. e. atlantica II. © 1981 Biologische Anstalt Helgoland.