Meeting Abstract

73.3  Tuesday, Jan. 6  Up, up, and away! The jump of the amphipod Apohyale pugettensis EVANGELISTA, Dennis J.; Univ. of California, Berkeley

Kinematics of an intertidal amphipod (Apohyale pugettensis) jumping in air were obtained with high speed video and analyzed for jump distance, energy and power requirements. A. pugettensis launched itself with a muzzle velocity of 100 body lengths/s, tumbling at 2000 rpm. Takeoff accelerations reached 221 m/s2, approximately 23 Gs. Takeoff was accomplished with a rapid abdominal extension at extremely high specic power output (1100 W/kg), suggesting that an elastic storage mechanism is likely present. A mathematical model of the ground-contact phase of launch, applicable to other jumping organisms that use abdominal extension, is described. Anatomical studies suggest several possible storage mechanisms and triggers.