title: Suction power output and the inertial cost of rotating the neurocranium to generate suction in fish.
abstract: To expand the buccal cavity, many suction-feeding fishes rely on a considerable contribution from dorsal rotation of the dorsal part of the head including the brains, eyes, and several bones forming the braincase and skull roof (jointly referred to as the neurocranium). As the neurocranium takes up a large part of the total mass of the head, this rotation may incur a considerable inertial cost. If so, this would suggest a significant selective pressure on the kinematics and mass distribution of the neurocranium of suction feeders. Here, an inverse dynamic model is formulated to calculate the instantaneous power required to rotate the neurocranium, approximated by a quarter ellipsoid volume of homogeneous density, as well as to calculate the instantaneous suction power based on intra-oral pressure and head volume quantifications. We applied this model to largemouth bass (Micropterus salmoides) and found that the power required to rotate the neurocranium accounts for only about 4% of the power required to suck water into the mouth. Furthermore, recovery of kinetic energy from the rotating neurocranium converted into suction work may be possible during the phase of neurocranial deceleration. Thus, we suggest that only a negligible proportion of the power output of the feeding muscles is lost as inertial costs in the largemouth bass. Consequently, the feeding performance of piscivorous suction feeders with generalised morphology, comparable to our model species, is not limited by neurocranial motion during head expansion. This suggests that it is thus not likely to be a factor of importance in the evolution of cranial shape and size.
authors.affiliation: Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium; Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerpen, Belgium. Electronic address: sam.vanwassenbergh@ugent.be.
authors.forename: Sam
authors.initials: S
authors.lastname: Van Wassenbergh
authors.affiliation: Department of Mechanical Engineering, Rochester Institute of Technology, 76 Lomb Memorial Dr., Rochester, NY 14623, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Day
authors.affiliation: Department of Biological Sciences, Lisner Hall Rm 340, The George Washington University, 2023 G St NW, Washington, DC 20052, USA.
authors.forename: L Patricia
authors.initials: LP
authors.lastname: Hernández
authors.affiliation: Department of Biology, University of California, 900 University Avenue, Riverside, CA 92521, USA.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Higham
authors.affiliation: Department of Mathematics, University of Utah, 155 S 1400 E, Salt Lake City, USA; Department of Mathematics and Statistics, Cornell College, 600 First Street SW, Mount Vernon, IA, USA.
authors.forename: Tyler
authors.initials: T
authors.lastname: Skorczewski
mesh_terms: D000818:Animals; D001492:Bass; D001696:Biomechanical Phenomena; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D057446:Hydrodynamics; D008954:Models, Biological; D009055:Mouth / Q000502:physiology; D009068:Movement; D011235:Predatory Behavior / Q000502:physiology; D011312:Pressure; D012399:Rotation; D012886:Skull / Q000033:anatomy & histology* / Q000502:physiology*; D013396:Suction
keywords: Biomechanics; Cranium; Inverse dynamics; Prey capture