Meeting Abstract

P2.128  Jan. 5  Spearing kinematics and behavior in mantis shrimp (Stomatopoda) DEVRIES, M.S.*; PATEK, P.N.; Univ. of California, Berkeley msdevries@berkeley.edu

Mantis shrimp are best known for the extreme forces with which they smash hard-shelled prey, yet most mantis shrimp species actually spear soft-bodied, elusive prey, such as small fish and other crustaceans. The goal of this study was to provide the first detailed kinematic, morphological and behavioral analysis of prey capture in spearing mantis shrimp. Through dissections of raptorial appendage musculature and high-speed image analysis, we examined the elongated, streamlined appendage of the spearing mantis shrimp Lysiosquillina maculata. We found that the strike proceeds in two distinct stages. First, the meral segment of the appendage extends upward while the dactyl segment opens with an average angular velocity of 37.17 rad s^-1 (range: 27.37-47.61 rad s^-1). The second stage begins when the dactyl rotates 90&deg and the propodal segment opens with an average angular velocity of 53.68 rad s^-1 (range: 20.61-115.49 rad s^-1). Therefore, although the sequence of events in a strike is predictable, strike velocities and durations are highly variable. In addition, behavioral analyses revealed that L. maculata have two modes of prey capture; they either spear prey with the tip of the dactyl segment (12% of strikes) or grab prey between the propodal and dactyl segments of the appendage (72% of strikes). During the grabbing behavior, movable spines and sharp teeth located between the propodal and dactyl segments are used to impale prey. The variation in the kinematic and behavioral results suggests that spearing stomatopods utilize a repertoire of behaviors to capture elusive prey. This study offers new insights into the functional diversity of raptorial appendage morphology and contributes to a deeper understanding of the evolution of strike mechanics and behavior in mantis shrimp.