Scaling of in vivo muscle velocity during feeding in the largemouth bass, Micropterus salmoides (Centrarchidae).
Many vertebrates undergo large increases in body size over the course of a lifetime, and these increases are often accompanied by changes in morphological and physiological parameters. For instance, in most animals, increases in size with growth are accompanied by decreases in the maximum speed of shortening (V(max)) in locomotor muscles. Curiously, in muscles involved in suction feeding, V(max) shows no decreases with size in vitro, despite the fact that timing of kinematic events involved in suction feeding (e.g., time to peak gape) slow with increased size. The goal of this study was to examine whether muscular speed in vivo varies with size during suction feeding in the largemouth bass (Micropterus salmoides). The dorsal epaxial musculature of 10 individual bass (varying from 123 to 685 g and from 18.1 to 32.0 cm standard length [SL]) was implanted with sonometric crystals to measure muscle length during feeding on elusive prey (large goldfish). No relationship was found between the mean individual or maximum speed of shortening with mean individual log-transformed SL. However, mean magnitude of shortening and maximum shortening magnitude showed nonsignificant increases with SL ([Formula: see text] and 0.06, respectively). Average duration of shortening was found to increase with log-transformed SL. The size invariance of observed shortening velocity in the epaxial muscles during feeding may stem from size invariance of imposed loads during suction feeding. This is in contrast to what is normally seen in locomotor systems where loads on muscles often increase with body size.
Department of Anatomy and Physiology, Lincoln Memorial University, DeBusk College of Osteopathic Medicine, 6965 Cumberland Gap Parkway, Harrogate, Tennessee 37752, USA.
Andrew M
AM
Carroll
Peter C
PC
Wainwright
D000818:Animals; D001492:Bass / Q000502:physiology*; D049628:Body Size / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D004576:Electromyography; D009119:Muscle Contraction / Q000502:physiology*