Locomotor performance of hatchling fence lizards (Sceloporus occidentalis): Quantitative genetics and morphometric correlates

We examined heritabilities and correlations among measures of locomotor performance (speed, stamina) and among possible morphometric determinants of performance (hindlimb span, tail length) in families of hatchling lizards (Sceloporus occidentalis). We were particularly interested in determining whether these traits were heritable and thus might potentially respond genetically to selection. Moreover, we wished to determine whether speed and stamina are negatively genetically correlated, as suggested by a priori physiological and empirical considerations. All four traits appeared to be significantly heritable. Broadsense heritabilities were 0.33-0.36 for speed, 0.35-0.36 for stamina, 0.45-0.51 for hindlimb span, and 0.46-0.47 for tail length. Contrary to expectations, speed and stamina were not negatively genetically correlated. Hindlimb span and tail length, however, were negatively genetically correlated (but not phenotypically correlated). Hindlimb span and stamina were positively phenotypically correlated. Thus, for example, selection for longer hindlimb span could potentially result in shorter tails, contrary to evolutionary predictions based only on phenotypic correlations.