Reproductive Ecology of Diaseris distorta (Michelin) (Fungiidae) in the Galapagos Islands, Ecuador

The sexual reproduction of Diaseris distorta is described from a population at Devil's Crown, Floreana Island, Galapagos Islands, Ecuador. Gametogenesis is classified in four developmental stages for each gender. Individuals are gonochoric and most likely broadcast spawners. Gametogenesis was active during the warm, wet season from at least February to June, peaking at the end of April. Mature female gametes were abundant around full moon with lesser numberspresent around new moon. Synapticular spaces were replete with eggs or spermaries in all stages of development. It is likely that gametes develop continuously during the breeding season. Studies of fecundity of female individuals yielded estimates of 7894-13,000 mature eggs cm ^-2 live surface tissue per cycle. Total egg volume was approximately 4.90-8.06 mm ³ per cycle with 4-8 spawning cycles yr-1 (19.6-64.5 mm ³ eggs yr ^-1 ). The sex ratio of the study population was highly skewed toward males, approximately 5:1. Individuals as small as approximately 240 mm ² , or approximately 1.75 cm in diameter, were sexually active. Asexual fragmentation is important locally. The potential for sexual reproduction is high, but its effectiveness locally or in establishing new, more distantly located populations is unknown.