Meeting Abstract
Stomatopod crustaceans are well known for their predatory strike, which is one of the fastest recorded animal movements. In adult stomatopods, biomechanics of the rapid strike speeds of the raptorial appendages have been well studied. Larval strike behaviors, in comparison, have not been studied, although larval stomatopods also have raptorial appendage. We used high-speed video (1000 fps) to document the kinematics of larval strike speeds and swimming behaviors in squilloid and gonodactyloid larvae. In both types of larvae, antennal scales are used as rudders for stabilization during swimming. Differences between gonodactyloid and squilloid swimming behaviors include the resting position of the raptorial appendages; squilloid larvae hold the appendages out to the side while swimming, necessitating folding in the appendages before a strike is possible while gonodactyloids swim with the appendages already folded and ready to strike. The duration of larval stomatopod strikes (~3 ms ) are similar to those recorded in adults. Because larval stomatopods are pelagic (in comparison to benthic adults) and unconstrained in space, specific body movements precede each strike, including bending the cephalothorax back and, for squilloid larvae, folding in of the stalked eyes. We also document that the very earliest gonodactyloid larval stages have only rudimentary raptorial appendages, and do not appear to be able to perform strikes, although at what stage larvae become capable of strike behavior is unknown. Continuing studies will identify larval species using barcoding, quantify strike speeds, and calculate Reynolds numbers for the extremely fast stomatopod larval strike.
