MULTIPLE-MODES OF ASEXUAL REPRODUCTION BY TROPICAL AND SUBTROPICAL SEA STAR LARVAE - AN UNUSUAL ADAPTATION FOR GENET DISPERSAL AND SURVIVAL

Sea star larvae (Echinodermata: Asteroidea), collected from the subtropical Northwest Atlantic Ocean, exhibited three distinct modes of asexual reproduction. A number of different bipinnariae and brachiolariae reproduced by paratomous cloning of the posterolateral arms. This morphogenesis was identical to that of larvae assignable to the genus Luidia. A second mode of asexual reproduction involves the autotomization of an anterior portion of the preoral lobe. Primary larvae with preoral lobes of varying sizes and free-swimming preoral lobes of various stages of morphological development were simultaneously collected. The free-swimming preoral lobes developed complete digestive systems and ultimately assumed the form of typical bipinnaria larvae. Asexual reproduction by larvae may also take the form of budding. The released individual is either a blastula- or gastrula-stage embryo. Subsequent development to a bipinnaria-stage secondary larva, with the possible exception of coelom formation, appears to occur through the events associated with normal larval development. These diverse methods of asexual propagation provide a common mechanism to increase the length of larval life and amplify the number of individuals. Thus asexual reproduction by larvae should increase the likelihood of genet representation in the next generation.