Swimming muscles power suction feeding in largemouth bass

Abstract

Most aquatic vertebrates use suction to capture food, relying on rapid expansion of the mouth cavity to accelerate water and food into the mouth. In ray-finned fishes, mouth expansion is both fast and forceful, and therefore requires considerable power. However, the cranial muscles of these fishes are relatively small and may not be able to produce enough power for suction expansion. The axial swimming muscles of these fishes also attach to the feeding apparatus and have the potential to generate mouth expansion. Because of their large size, these axial muscles could contribute substantial power to suction feeding. To determine whether suction feeding is powered primarily by axial muscles, we measured the power required for suction expansion in largemouth bass and compared it to the power capacities of the axial and cranial muscles. Using X-ray reconstruction of moving morphology (XROMM), we generated 3D animations of the mouth skeleton and created a dynamic digital endocast to measure the rate of mouth volume expansion. This time-resolved expansion rate was combined with intraoral pressure recordings to calculate the instantaneous power required for suction feeding. Peak expansion powers for all but the weakest strikes far exceeded the maximum power capacity of the cranial muscles. The axial muscles did not merely contribute but were the primary source of suction expansion power and generated up to 95% of peak expansion power. The recruitment of axial muscle power may have been crucial for the evolution of high-power suction feeding in ray-finned fishes.epaxial | hypaxial | XROMM | muscle power | volume

Neural precursor cells form integrated brain-like tissue when implanted into rat cerebrospinal fluid

“…These 3-dimensional (3D) organoids have provided a tool for understanding central nervous system (CNS) development and disease mechanisms 3,4 . While much work has been done to integrate new cell grafts into the brain, there have been fewer efforts to form complex neural tissue in vivo, which may be necessary for the repair of brain injury and treatment of neurological diseases 5 .…”

A biorobotic model of the suction feeding system in largemouth bass: the roles of motor program speed and hyoid kinematics

“…The lateral expression of the suspensoria from hyoid movement is an established component in suction-feeding fishes (Aerts, 1991;De Visser and Barel, 1996). In addition, the axial muscle-tendon unit was the largest input of force in our robotic system, a characteristic of the system that mirrors recent studies highlighting the great importance of the axial musculature in driving kinematic behavior in suction feeding (Camp and Brainerd, 2014;Camp et al, 2015). The effective transmission of lateral forces to the suspensoria resulting from retraction of linkages posterior to the hyoid also corroborates the hypothesis of other authors (e.g.…”

“…S1). This represents approximately one-third the volume increase of a live bass (Camp et al, 2015). Second, the kinematic velocities of BassBot were slower than those of live bass.…”

“…In addition, BassBot was only able to achieve very modest upperjaw protrusion ( Figs 6A,B and 7B). This difference in peak excursion resulted in a reduced volume change of 77%, much less than a live bass (Camp et al, 2015). We suspect that this difference in the pattern of relative excursions is likely due to the limited mimetic properties of our skin analog.…”

“…In addition, this species has been the subject of previous analyses, including the classic paper by Nyberg (1971) and a number of studies that evaluated the functional role of musculoskeletal units in feeding (e.g. Camp and Brainerd, 2014;Camp et al, 2015;Lauder, 1983;Richard and Wainwright, 1995;Wainwright and Richard, 1995) and several that explored the relationship between musculoskeletal morphology, kinematics and suction generation (e.g. Carroll et al, 2004;Grubich and Wainwright, 1997;Higham et al, 2006a,b).…”