ZANI, P.A.; Univ. of Colorado: Linking morphology, locomotor performance, and fitness in lizards

While the link between morphology and performance has been well studied, evidence that functional morphology affects organismal fitness is scarce. I examined the links between morphology, performance, and fitness by measuring the body and limb morphology of 64 hatchling side-blotched lizards, Uta stansburiana. Within the first week of life I measured sprint performance on a 1m raceway and subsequently released lizards into a semi-natural field enclosure. Hatchlings had to acquire resources (insects) and avoid predators (spiders, scorpions, birds, snakes, and other lizards) for 2-3 summer months in an enclosed patch of natural habitat (600 sq. m.). Hatchling lizards had an average (�1 S.D.) snout-vent length of 22.5 � 0.80 mm, mass of 0.4 � 0.06 g, and hind- and fore-limb lengths of 17.5 � 0.74 and 10.1 � 0.53 mm, respectively. Despite variation, body size (SVL, mass) did not correlate with hatchling speed. However, both hind- and fore-limb lengths correlated with maximum sprint speed (1.27 � 0.196 m/s) such that lizards with intermediate length limbs (both in absolute terms and relative to body size) had the greatest speeds. I detected significant among-clutch variation between incubation period and both morphological (body size and limb lengths) and performance traits. By assaying the population just prior to the onset of winter, I was able to determine the relationship between both morphological and performance traits and summer survival in these lizards. Only by determining the selective fate of known organismal phenotypes can one link morphology, performance, and fitness in an evolutionary sense.