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We used quantitative genetic analyses to test the hypothesis of a trade-of between locomotor speed and endurance in a population of the European lizard Lacerta vivipara, which is the subject of long-term demographic studies. We estimated the heritability of maximal sprint speed, treadmill endurance, and tail length, a morphometric trait that may afect locomotor performance, as well asphenotypic, genetic, and environmental correlations between these traits. Gravid females were captured in the field and held in the laboratory under standardized conditions until giving birth; traits were then measured on their ofspring. Prior to genetic analyses, we used multiple regressions to remove the efects of such covariates as body size (mass and snout-vent length), dam age, and length of time dams were held in captivity prior toparturition. When we examined the residual characters, heritability was low and statistically nonsignficant for speed but relatively high for both endurance (0.46) and tail length (0.51). None of the phenotypic, genetic, or environmental correlations between traits was statistically significant. Thus, we found no evidence for a trade-off between speed and endurance; these results are consistent with those reported in two previous studies of squamate reptiles (the garter snake Thamnophis sirtalis and the fence lizard Sceloporus occidentalis). The lack of a negative genetic correlation between speed and endurance suggests that these aspects of locomotor abilities are relatively free to evolve independently, such that natural selection could increase both speed and endurance. However, the species studied to date have low to moderate capacities for speed and endurance, as compared with other squamates. Physiologically based trade-offs-for example, those caused by the composition ofmuscle fiber types-should be more likely to exist in species that have high capacities for speed and/or endurance.
Sorci et al. (Sat,) studied this question.