Octopus bimaculoides visually-evoked prey capture

<p>Octopus limb hyper-redundancy complicates traditional motor control system theory by its extensive sensory inputs, subsequent decision making and arm coordination. Octopus are thought to reduce flexibility control complexity by relying on highly stereotypical motor primitives (e.g. reaching and crawling) and multi-level processes to coordinate movement utilizing extensive peripheral nervous system (PNS) processing. Division of labor along the anterior-posterior axis and limb- specialization of the four anterior arms in T-maze food retrieval further simplify control. Yet, specific arm recruitment and coordination during visually guided reaching behavior remains poorly understood. Here, we investigated visually triggered <em>Octopus bimaculoides</em> hunting capabilities by eliciting and examining prey-specific arm recruitment. When striking crabs, octopus preferred synchronous arm recruitment while sequential arm recruitment with a characteristic swaying movement is employed for shrimp. Such behavioral selection aligns with specific prey escape strategies and the octopus' flexible arm biomechanical constraints. Although side bias existed, we found significant bilateral symmetry, with one side being functionally a mirror of the other rather than anterior arm use being functionally equal and differing to posterior arm use. Among arms, the second limb is unequivocally dominant for goal-directed monocularly driven prey capture. While the eight arms share gross anatomy and are considered equipotential, such arm specialization for specific actions could reflect different degrees of specialization in organismal structures. Finally, we quantitatively show, corroborating earlier observations, that octopus employ a dimension reduction strategy by actively deciding to recruit adjacent arms over other available arms during either sequential or synchronous visually triggered prey attack.</p>