Meeting Abstract

2-5  Monday, Jan. 4 09:00  Concerted optimization of propulsion, sensing and respiration during swimming AKANYETI, O*; THORNYCROFT, P/J/M; LAUDER, G/V; YANAGITSURU, Y; PETERSON, A/N; LIAO, J/C; University of Florida, Gainesville; Harvard University, Cambridge; Harvard University, Cambridge; University of Florida, Gainesville; University of California, Irvine; University of Florida, Gainesville otar@whitney.ufl.edu

Axial body undulation is the plesiomorphic motor pattern driving locomotion in vertebrates and predates the origin of paired fins and jaws. Previous work studied undulation as a means of propulsion without considering how it might affect other fundamental physiological processes such as sensing and respiration. Here we show that undulation in fishes optimizes propulsion, flow sensing and respiration concurrently without any apparent trade offs when head movements are coupled appropriately with body movements. We use a combination of theoretical, biological and physical experiments to reveal the hydrodynamic mechanisms underlying this concerted optimization. We reveal four key findings. First, we show that in freely-swimming rainbow trout (Oncorhynchus mykiss, body length = 18.5±2.1 cm), the phase difference between heave and yaw movements of the head increases with swimming speed (y = 9.24x + 38.20, R² = 0.6, p<0.01, n=7 fish). Second, experiments with a flexible 3D-printed fish model show that coupling head and body movements with the correct phase angle (which fell within the range displayed by live fish) minimizes power consumption by 50%. Third, trout move their heads in a way that automatically enhances lateral line sensing up to 50% by minimizing self-generated stimuli. Fourth, trout synchronize their respiratory movements with head movements, which likely minimize the energetic costs of pumping water. Based on our empirical results, we developed a control architecture that can be universally applied to all undulatory animals and machines.