Meeting Abstract

34-5  Thursday, Jan. 5 14:30 - 14:45  Strategic strikes: how mantis shrimp crack open different prey CRANE, RL*; KISARE, SA; PATEK, SN; Stanford Univ., Hopkins Marine Station; Duke Univ.; Duke Univ. rlcrane@stanford.edu

To fracture armored prey, crushing and peeling predators often strategically apply loads targeted to a prey’s particular morphology. However, unlike the slow, crushing forces of many such predators, some mantis shrimp (Stomatopoda) use small, lightweight appendages to deliver ultrafast, high-impact strikes with disproportionately large peak forces relative to their body size. Yet hard-shelled prey still present a challenge for mantis shrimp – taking from several to hundreds of strikes to crack. We tested how mantis shrimp (Neogonodactylus bredini) adjust their striking strategy to fracture different prey. Mantis shrimp were fed snails from their native habitat that had three shapes: high-spired (Cerithium atratum), medium-spired (Tectarius muricatus) and globular (Nerita peloronta or Nerita tessellata). We video-recorded 38 mantis shrimp striking snails of each genus until they started eating (96 trials). The location and timing of every strike was recorded (strikes/trial: mean=86, range=9–460). Mantis shrimp rarely (mean 5% strikes averaged across trials) struck the middle whorls of any of the snails. They focused their strikes on the aperture of the globular (mean 81%) and medium-spired snails (mean 74%), whereas they more frequently struck the apex of high-spired snails (mean 58%). Corresponding to strike locations, the majority of mantis shrimp fractured the shell enough to feed at the aperture of globular (76%) and medium-spired snails (68%) and at the apex of high-spired snails (70%). Therefore, mantis shrimp strike different locations depending on snail morphology. Their ultrafast hammers are potent weapons that enable mantis shrimp to crack open relatively large shells, yet their behaviors suggest that these strikes must also be strategically placed depending on a shell’s shape.