Regeneration rate after fission in the fissiparous sea star Allostichaster capensis (Asteroidea)

RUBILAR, TAMARA; MERETTA, PABLO EZEQUIEL; CLEDÓN, MAXIMILIANO

REVISTA DE BIOLOGíA TROPICAL

REVISTA DE BIOLOGIA TROPICAL

Lugar: Turrialba; Año: 2015 vol. 63 p. 321 - 328

0034-7744

Many studies have focused on the regeneration rate of arms in Asteroidea but no studies have focusedon the regeneration rate after fission. Allostichaster capensis is a fissiparous sea star with a wide range of distribution.In Golfo Nuevo (42°46?49?? S - 64°59? 26?? W) sea stars undergo fission every spring and summerand regenerate the rest of the year. To analyze the regeneration rate, we conducted an experiment with sea starscollected just before fission. After sea stars underwent fission, the length of the three non-regenerating and thethree regenerating arms were measured weekly. The arm length (regenerating and non-regenerating) was usedin non-Linear Mixed Effect models in order to account for within-individual correlation in different models.The regenerating arms regenerate according to a Quadratic model, while the non-regenerating arms regenerateaccording to a linear model. In the regenerating arms, the regeneration rate was estimated to be 0.1 mm.week-1and in the non-regenerating arms, the growth rate was 0.004 mm.week -1. Sea stars regenerate ca. 20 % of thearm in one month, and it takes about 5 months to be completely regenerated. At the beginning, the regenerationrate is fast generating the growth of the arms, once the pyloric caeca and gonads are present inside the arms theregeneration rate slows down probably due to allocation to gametes and pyloric caeca and arms. The factorsthat regulate the regeneration rate are unknown. However, food availability and energy storage seem to play animportant role.