Locomotor performance differs between foraging and predator escape but is not related to survival in hatchling lizards

Abstract

Abstract Behaviour is influenced by many factors, including morphology, performance capabilities and the surrounding environment. Behavioural adjustments in response to these factors have important fitness consequences, and therefore behaviour should be considered when evaluating relationships among morphology, performance and fitness. We used hatchling fence lizards (Sceloporus undulatus) to test if sprinting speed and movement behaviours (e.g. latency to approach prey, number of pauses when fleeing or foraging) differ between foraging and anti-predator contexts and if these behaviours are associated with body size, locomotor performance capacity and survival. We quantified maximal sprint performance of individuals and evaluated their running speed in laboratory trials of foraging (moving towards crickets) and predator escape (response to a swooping avian predator). We show that hatchlings run at ~17–36% of total capacity when foraging. Although the most common anti-predator behaviour was to remain still, those that fled from the predator ran at full burst speed. However, foraging and escape speed/behaviours were not associated with body size or locomotor capacity. Hatchlings were subsequently released at our field site for a recapture study to assess phenotypic relationships with survival. We found no evidence that survival was influenced by performance or behaviour, but body size was positively related to survival in the field. These results highlight how seemingly important fitness-relevant behavioural and performance traits may not mediate the relationship between body size and survival.