Meeting Abstract
Predator-prey interactions put attributes of the predator (e.g. biting force) against those of the prey (e.g. body size). These attributes are constrained by both physical phenomena (e.g. lever mechanics) and physiological phenomena (e.g. force-length and force-velocity performance of skeletal muscle) in the predator. The force-velocity relationship is important for prey capture in centrarchid fishes, because these species often captures elusive prey. This family of fishes has a wide range of feeding behaviors, 2 examples of this are: largemouth bass swim quickly and then close the mouth over the prey, whereas bluegills suction feed. Both of these species need rapid mouth closure to preclude prey escape. These species also vary in skeletal anatomy; largemouth have long jaws, whereas bluegills have short jaws. Other members of this family fall along the continuum between largemouth and bluegills, and exhibit a range of jaw shapes and attack behaviors. Jaw-closing performance is governed by the interaction of skeletal anatomy and muscle physiology, and yet only skeletal anatomy and behavior have been deeply investigated to date in this group. We measured jaw-closing velocity across forces (i.e. the force-velocity relationship) in 5 species: Redear Sunfish,Lepomis microlophus; Black crappie,Pomoxis nigromaculatus; Largemouth bass, Micropterus salmoides; Bluegill, Lepomis macrochirus; and Green sunfish, Lepomis cyanellus. After accounting for the effects of skeletal leverage, we found that crappie and largemouth show similar patterns of force and velocity, whereas green sunfish, bluegill sunfish, and redear sunfish show similar patterns with each other. Interestingly, green sunfish skeletal anatomy is more similar to crappie and largemouth than it is to either other sunfish species. These results suggest that in this group, physiological performance of the jaw-closing muscle does not necessarily mirror lever mechanics in the skeleton.
