Published online by Cambridge University Press: 10 February 2010
Certain starfish have a restricted autotomy region at the base of each arm, at which the whole arm is detached if damaged or trapped. These species are common prey items of gulls, which have been observed to break-up starfish by gripping one arm and shaking the whole animal. This raises the possibility that shaking invokes the autotomy response, thereby accelerating consumption of prey and reducing the opportunity for prey to be stolen. To evaluate the role of autotomy in this interaction, specimens of Asterias rubens were shaken manually and the timing and pattern of breakage recorded. It was found that arm detachment was usually mediated by autotomy, although this depended on the way in which animals were shaken, and that autotomy did not effect detachment more rapidly than breakage outwith the autotomy region.