Reproductive biology of Sabellaria wilsoni (Sabellariidae: Polychaeta), an important ecosystem engineer on the Amazon coast

The sabellariid worms are important ecosystem engineers in coastal zones, due to their ability to construct sand reefs, modify environments and structure biological communities. This article describes the reproductive biology of Sabellaria wilsoni on a beach of the Amazon coast. Each month between May 2008 and April 2009, specimens were collected for morphometric and histological analyses for sexing and determination of gonadal maturity. In females, the number and diameter of the oocytes at different stages of vitellogenesis were also recorded. The results showed that the species is dioecious, with sexual reproduction, females larger than males, and a female-biased sex ratio (overall, 1.6♀: 1♂). Four distinct stages of gonadal maturation were identified in the males and females – (i) initial development, (ii) maturing, (iii) mature and (iv) spawning. Sexual maturity is attained rapidly, and reproduction is continuous, with two breeding peaks, one in the dry season, related to the increased intensity of hydrodynamic conditions and reef erosion; and the other in the rainy season, when the availability of space and nutrients increases. The reproductive strategy of the species reinforces the classification of the sabellariids as r-strategists, adapted to colonize habitats with unstable environmental conditions.