title: Energetic cost determines voluntary movement speed only in familiar environments.
abstract: Locomotor performance is closely related to fitness. However, in many ecological contexts, animals do not move at their maximal locomotor capacity, but adopt a voluntary speed that is lower than maximal. It is important to understand the mechanisms that underlie voluntary speed, because these determine movement patterns of animals across natural environments. We show that voluntary speed is a stable trait in zebrafish (Danio rerio), but there were pronounced differences between individuals in maximal sustained speed, voluntary speed and metabolic cost of locomotion. We accept the hypothesis that voluntary speed scales positively with maximal sustained swimming performance (Ucrit), but only in unfamiliar environments (1st minute in an open-field arena versus 10th minute) at high temperature (30°C). There was no significant effect of metabolic scope on Ucrit Contrary to expectation, we rejected the hypothesis that voluntary speed decreases with increasing metabolic cost of movement, except in familiar spatial (after 10 min of exploration) and thermal (24°C but not 18 or 30°C) environments. The implications of these data are that the energetic costs of exploration and dispersal in novel environments are higher than those for movement within familiar home ranges.
authors.affiliation: School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia frank.seebacher@sydney.edu.au.
authors.forename: Frank
authors.identifier: 0000-0002-2281-9311
authors.initials: F
authors.lastname: Seebacher
authors.affiliation: School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Borg
authors.affiliation: School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Schlotfeldt
authors.affiliation: School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Zhongning
authors.initials: Z
authors.lastname: Yan
mesh_terms: D000332:Aerobiosis; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D004777:Environment; D008954:Models, Biological; D009068:Movement; D013550:Swimming / Q000502:physiology; D015027:Zebrafish / Q000502:physiology*
keywords: Calcium cycling; Cost of transport; Locomotor performance; Metabolic scope; Muscle