Spanish Dancer




Side by side matingThe Hexabranchus sanguineus have a unique reproductive trait about them. Spanish dancers are hermaphrodite organisms. This means that they can carry both female and male sexual organs together in their body. They do not self-fertilize however, but reproduce sexually. The Spanish dancer nudibranch is sexually active throughout the whole year but their activity dies down during the cold months (Francis 1980).  Sex occurs when two nudibranchs align themselves up side by side, called copulation, where the male then exchanges sperm sacs. After sex, it may take moments or days before the Spanish dancer is ready to lay her eggs. When the female is ready she will lay her eggs on top of coral or on part of a rock, usually near her food source. She lays a ribbon-like structure with thousands of eggs forming what divers call a "sea rose". Spanish dancer eggs in the form of a ribbonShe does this so the eggs blend in with the coral, yet remain recognizable to her. Since the Spanish dancer eats toxic sponges, she can secrete her poison on to her eggs so that predators such as crabs, lobster and reef fish aren't able to eat them. This also means that she will not have to sit over the eggs to protect them. Along with this the Spanish dancer has an indirect life cycle. This means that after the Hexabranchus sanguineus eggs hatch, they grow up through larval stages. Since their life expectancy is only one year, they will mature very fast. They   grow into the one of the largest nudibranchs, with animals being recorded at over 40cm in length (Rudman 1999).



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