SEXUAL VERSUS ASEXUAL REPRODUCTION IN AN OVIPAROUS ROPE-FORM SPONGE, APLYSINA-CAULIFORMIS (PORIFERA, VERONGIDA)

The order Verongida, considered to be exclusively oviparous and dioeci ous, exhibits great range in body form, including thin-bodied, rope- a nd stick-form members which have been postulated to be morphologically adapted to exploit fragmentation as an important asexual reproductive process. Here we report results of a one-year survey of sexual reprod uctive stages in a rope-form verongid, Aplysina cauliformis, which tes t the hypotheses of verongiid sexual pattern and reduced resource allo cation to sexual reproduction in rope-form sponges. Results confirm th e verongiid pattern of oviparity, dioeciousness and production of smal l oocytes. Data also support the hypothesis that rope-form sponges are characterized by reduced investment in gamete production relative to sponges of other body forms. The sexual reproductive pattern of the ma in macrosymbiont (parasite) polychaete, Haplosyllis spongicola, shows no correlation to that of its sponge host.