The mechanics and neural control of the prey capture strike in the mantid shrimps Squilla and Hemisquilla
- 221 Downloads
The prey capture strike of Squilla and Hemisquilla has been studied by high speed motion picture photography and by electromyography from the limb muscles of the unrestrained animal.
The strike consists of a rapid unfolding of the dactyl, propus and carpus about the merus of the raptorial, 2nd thoracic limb. The prey may be struck by the folded propus-dactyl joint, pierced by the extended dactyl or grasped between the open propus and dactyl.
Contact is made with the prey in 4–8 ms, when the animal is underwater, at which time the propus is moving about the merus at an angular velocity of 20,000°·s−1 or at a linear velocity of 10 m·s−1.
Acceleration is applied to the limb in less than 1.5 ms and an energy requirement of 1.25×105 ergs is necessary for the strike. This could not be produced by a single muscle twitch.
Electrophysiology and experiments in which the strike has been simulated have shown that the strike is produced by the co-contraction of flexor and extensor muscles in the merus operating a ‘click’ joint. The flexor muscles begin to contract first, often 1 s before the strike so pulling a sclerite over a stop on the ventral wall of the merus. This gives them a 900∶1 mechanical advantage over the extensor muscles and allows the extensor muscles to contract almost isometrically and time to reach tetanic tension. The flexor muscles relax just prior to the strike so that the sclerite then snaps over its stop on the merus allowing the stored energy of the extensor muscles to be delivered suddenly.
KeywordsPhotography Limb Muscle Extensor Muscle Open Propus Speed Motion
Unable to display preview. Download preview PDF.
- Atwood, H. L., and G. Hoyle: A further study of the paradox phenomenon of crustacean muscle. J. Physiol. (Lond.) 181, 225–234 (1965).Google Scholar
- Bennet-Clark, H. C., and E. C. A. Lucey: The jump of the flea: A study of the energetics and a model of the mechanism. J. exp. Biol. 47, 59–76 (1967).Google Scholar
- Brown, R. H. J.: Mechanism of locust jumping. Nature (Lond.) 214, 939 (1967).Google Scholar
- Hill, A. V.: The heat of activation and the heat of shortening in a muscle twitch. Proc. roy. Soc. B 136, 195–211 (1949).Google Scholar
- Hoyle, G.: Neuromuscular mechanisms of a locust skeletal muscle. Proc. roy. Soc. B 143, 343–367 (1955).Google Scholar
- MacGinitie, G. E., and N. MacGinitie: Natural history of marine animals. New York: McGraw-Hill 1968.Google Scholar
- Machin, K. E., and J. W. S. Pringle: The physiology of insect fibrillar muscle II. Mechanical properties of a beetle flight muscle. Proc. roy. Soc. B 151, 204–225 (1959).Google Scholar
- Maldonado, H., L. Levin, and J. C. Barros Pita: Hit distance and the predatory strike of the Praying Mantis. Z. vergl. Physiol. 56, 237–257 (1967).Google Scholar
- Mittelstaedt, H.: Prey capture in mantids. In: Recent Advances in Invertebrate Physiology (B. T. Scheer, ed.). University of Oregon Press 1957.Google Scholar
- Rilling, S., H. Mittelstaedt, and K. D. Roeder: Prey recognition in the Praying Mantis. Behaviour 14, 164–184 (1959).Google Scholar
- Sandeman, D. C.: A sensitive position measuring device for biological systems. Comp. Biochem. Physiol. 24, 635–638 (1968).Google Scholar
- Schaller, F.: Verhalten und sinnesphysiologische Beobachtungen an Squilla mantis. Z. Tierpsychol. 10, 1–12 (1953).Google Scholar
- Usherwood, P. N. R.: The nature of ‘slow’ and ‘fast’ contractions in the coxal muscles of the cockroach. J. Ins. Physiol. 8, 31–52 (1962).Google Scholar
- Vos, J. A., and R. A. Binkhorst: Velocity and force of some karate arm movements. Nature (Lond.) 211, 89–90 (1966).Google Scholar
- Weis-Fogh, T.: Tetanic force and shortening in locust flight muscle. J. exp. Biol. 33, 668–684 (1956).Google Scholar
- Wiersma, C. A. G., and S. H. Ripley: Innervation patterns of crustacean limbs. Physiol. comp. 2, 391–405 (1952).Google Scholar
- Wilson, D. M.: Proprioceptive leg reflexes in cockroaches. J. exp. Biol. 43, 397–409 (1965).Google Scholar