Meeting Abstract
Animals move through their environments for a variety of reasons and at a variety of speeds, but what determines those speeds? Although locomotion is often viewed as a trait essential for survival and Darwinian fitness, we still know surprisingly little about how exactly locomotion is used to accomplish that goal. Not only can the stimulus to move in a given instance of locomotion vary, but so can the assessment of risk of that context, and the substrate over which locomotion happens. It is standard practice to assume that traits such as sprint speed measured in a laboratory reflect what animals do in nature, but the limited data available for locomotor capacity use in nature do not consistently show that animals use maximal abilities in every, or in some cases in any, context. Instead, slower ‘adequate’ or ‘preferred’ speeds are much more common and likely represent optimal speeds that have evolved via multiple selective pressures on the locomotor apparatus, in addition to sensory systems and neural processing. I discuss what we know about animal speeds in different ecological contexts, focusing on lizard locomotion, which has been well studied for decades. I suggest that investigators should be explicit about how their measures of performance are relevant to their study organism, and I discuss why some studies find strong discordance between laboratory and field studies of locomotion. Ultimately, the evolution of locomotion and what speeds animals use in nature depend on predation pressure, habitat complexity, prey performance and availability, tradeoffs with other aspects of performance, and the costs and benefits of using a particular speed in a specific context.
