School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia
School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556 Australia.
J Exp Biol. 2018 Apr 23;221(Pt 8):jeb172544. doi: 10.1242/jeb.172544.
Movement speed can underpin an animal's probability of success in ecological tasks. Prey often use agility to outmanoeuvre predators; however, faster speeds increase inertia and reduce agility. Agility is also constrained by grip, as the foot must have sufficient friction with the ground to apply the forces required for turning. Consequently, ground surface should affect optimum turning speed. We tested the speed-agility trade-off in buff-footed antechinus () on two different surfaces. Antechinus used slower turning speeds over smaller turning radii on both surfaces, as predicted by the speed-agility trade-off. Slipping was 64% more likely on the low-friction surface, and had a higher probability of occurring the faster the antechinus were running before the turn. However, antechinus compensated for differences in surface friction by using slower pre-turn speeds as their amount of experience on the low-friction surface increased, which consequently reduced their probability of slipping. Conversely, on the high-friction surface, antechinus used faster pre-turn speeds in later trials, which had no effect on their probability of slipping. Overall, antechinus used larger turning radii (0.733±0.062 versus 0.576±0.051 m) and slower pre-turn (1.595±0.058 versus 2.174±0.050 m s) and turning speeds (1.649±0.061 versus 2.01±0.054 m s) on the low-friction surface. Our results demonstrate the interactive effect of surface friction and the speed-agility trade-off on speed choice. To predict wild animals' movement speeds, future studies should examine the interactions between biomechanical trade-offs and terrain, and quantify the costs of motor mistakes in different ecological activities.
运动速度可以支撑动物在生态任务中的成功概率。猎物通常利用敏捷性来躲避捕食者；然而，更快的速度会增加惯性，降低敏捷性。敏捷性也受到抓地力的限制，因为脚必须与地面有足够的摩擦力，以施加转弯所需的力。因此，地面表面应该会影响最佳转弯速度。我们在两种不同的表面上测试了 Buff-footed Antechinus （）的速度-敏捷权衡。正如速度-敏捷权衡所预测的那样，Antechinus 在两种表面上的转弯半径越小，转弯速度越慢。在低摩擦表面上，滑倒的可能性高出 64%，而且在转弯前跑得越快，滑倒的可能性就越高。然而，随着 Antechinus 在低摩擦表面上的经验增加，它们通过使用较慢的转弯前速度来弥补表面摩擦的差异，从而降低了滑倒的可能性。相反，在高摩擦表面上，Antechinus 在后期试验中使用更快的转弯前速度，但这对它们滑倒的可能性没有影响。总体而言，Antechinus 在低摩擦表面上使用更大的转弯半径（0.733±0.062 与 0.576±0.051 m）和更慢的转弯前速度（1.595±0.058 与 2.174±0.050 m/s）和转弯速度（1.649±0.061 与 2.01±0.054 m/s）。我们的结果表明，表面摩擦和速度-敏捷权衡对速度选择的相互作用。为了预测野生动物的运动速度，未来的研究应该研究生物力学权衡与地形之间的相互作用，并量化不同生态活动中运动错误的成本。
