palolo worm

Marine bristle-worm notable for transforming into a swarming, sexual individual in order to synchronize reproduction with other members of its species.

Palolo worms exhibit epitoky, a reproductive phenomenon that has evolved to ensure the optimum fertilization of eggs by sperm when they are released externally. The normal worm, at a certain time, converts into the sexual form, or epitoke, by transformation or budding. Gametes (sex cells) form and at specific periods in the lunar cycle these epitokes swarm on the surface, releasing eggs and sperm simultaneously.

In the Samoan palolo worm Eunice viridis, swarming occurs in October or November at the beginning of the last lunar quarter and the local people wait to catch them at this time, netting hundreds from the surface.

Classification The palolo worm is a member of class Polychaeta in phylum Annelida.