Meeting Abstract
Octopus and cuttlefish use muscular suckers to capture the preys; while octopus are known to generate suction force by muscle contraction, the functioning mechanism of cuttlefish suckers remains unexplored. Here we examined the suction performance and detachment process of tentacular suckers of cuttlefish Sepia pharaonis. Suction without muscle contraction implies a passive mechanism; pressure difference might be created by pulling the stalk. To examine the role of sucker ring, we compared suction performance with ring intact, removed, and replaced. Results suggest that the ring is critical presumably in distributing the pulling stress for better contact. However, insertion of a stiffer ring could not enhance its performance. Although intermittent leakages were observed, pressure difference still generated, implying self-sealing even with imperfect contact. On substrates of varying roughness, suction performance remains similar. Synchronous recordings of suction force, sucker deformation, and internal bubble formation during attachment-detachment process reveal that bubbles could change the force-deformation curve; because gas deforms more easily than the liquid, bubble expansion could retard pressure increase hence to prolong attachment duration. This study demonstrates the functioning mechanisms of tentacular suckers of cuttlefish. The identified mechanical features fit their predation strategy for capturing fast-moving preys. Unlike artificial suckers, cuttlefish suckers perform well on rough, curved, or even soft surfaces, which provide insights for future bio-inspired design of underwater attachment devices.
