Meeting Abstract
The mechanics of grasping soft, and irregular material is challenging for both biological and designed systems. Many animals have evolved to meet this challenge. In particular, the feeding system of the marine mollusk Aplysia californica, an herbivore generalist, allows it to grasp and eat seaweeds of different textures, toughness and shapes. The surface of the grasper is known of as the radula, a cartilaginous sheet with fine teeth. Previous in vitro studies suggested that the I7 muscles, deep in the grasper, were responsible for the opening of the radula. Lesions to these muscles do not prevent animals from grasping and ingesting food. New in vivo studies demonstrate that a previously uncharacterized set of fine muscular fibers – the sub-radular fibers (SRFs) – mediate openings even in the absence of the I7 muscles. Both in vivo and in vitro studies show very large deficits in opening when the SRFs are lesioned. A theoretical biomechanical analysis of the actions of the SRFs suggest that they reverse the folding of an anatomical crease to create an arched shape that can conform to irregular structures.
