Repeatability of Locomotor Performance in Natural Populations of the Lizard Sceloporus merriami

Huey, Raymond; Dunham, Arthur

The authors' investigated the repeatability of sprint speed in natural populations of Sceloporus merriami. Sprint speed is a performance trait that may influence fitness via its effects on feeding success, predator avoidance, and, possibly, social dominance. The feasibility of studying natural selection on speed is unclear, because the sprint speed of a lizard may not be a fixed trait in long-term studies: an individual's speed may vary with body size and age, body temperature, reproductive condition, and injury history, though perhaps not with season. The authors' addressed two specific questions. First, is the relative speed of an individual repeatable across temperatures? Second, is absolute speed of populations or individuals repeatable in time. They found that sprint speed is a repeatable trait in adult S. merriami. Lizards that were relatively fast at one body temperature were relatively fast at two other temperatures; intersexual and interpopulational differences in average speed were maintained between years; and individual lizards that were fast one year were still fast when recaptured a year later. However, whether fast hatchlings become fast adults remains to be determined,

Repeatability of Locomotor Performance in Natural Populations of the Lizard Sceloporus merriami

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