The effects of autotomy and regeneration on the locomotion and behavior or brittle stars (Echinodermata: Ophiuroidea) of Moorea, French Polynesia

Abstract

Autotomy and regeneration of body parts is a defense mechanism that a multitude of taxa have evolved in order to escape predation. While both autotomy and regeneration are very commonly observed traits in brittle stars, little has been studied about them in relation to many aspects of their ecology, including its effects on their locomotion and behavior. This study compared the tendency to autotomize across brittle star taxa by way of a field survey and quantified the effects of autotomy on the locomotion and behavioral ecology of genus Ophiocoma. This was done by taking and analyzing videos the movements of eighteen individuals over the course of four weeks, comparing locomotive and behavioral changes over the course of the autotomization and regenerative process. Of the three genera of large epibenthic brittle star found, there was no one genus that seemed more likely to autotomize than another. When examining the effects of autotomy on Ophiocoma, there were very few differences among any of the sampling periods or treatments. Any changes occurred immediately after autotomy, but did not persist for more than that one sampling period, and yielded results comparable to those of pre-autotomy one week into regeneration. This may imply that Ophiocoma—and brittle stars as a whole—are extremely well adapted to autotomy as a defense strategy, more so than many other taxa who also employ autotomy as a defense mechanism.