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Energy Budgets, Growth Rates, And The Rmal Constraints: Toward An Integrative Approach To The Study Of Life-History Variation, Peter H. Niewiarowski
Energy Budgets, Growth Rates, And The Rmal Constraints: Toward An Integrative Approach To The Study Of Life-History Variation, Peter H. Niewiarowski
Dr. Peter H. Niewiarowski
Variation in thermal constraints on activity has been hypothesized to be an important ecological source of geographic variation in growth rates of juvenile eastern fence lizards Sceloporus undulatus. However, most of the evidence to support this hypothesis is either inferential or indirect. In this study, I quantitatively compared thermal constraints on activity and their relationship to growth rates of free-ranging juvenile fence lizards from two extremes of the range of variation in growth rate (Nebraska and New Jersey) used in a reciprocal transplant experiment. I also examined energy allocation made to growth and storage by yearling lizards. Reduced growth rates …
Life-History Variation In The Sagebrush Lizard (Sceloporus Graciosus): Phenotypic Plasticity Or Local Adaptation?, Michael W. Sears
Life-History Variation In The Sagebrush Lizard (Sceloporus Graciosus): Phenotypic Plasticity Or Local Adaptation?, Michael W. Sears
Michael W. Sears
We performed a laboratory common-environment study to determine the genetic and environmental sources of variation in growth rates of the sagebrush lizard (Sceloporus graciosus). Hatchling lizards were reared from gravid females collected from three study populations along an elevational gradient in southern Utah, USA. Hatchlings were fed ad libidum and were maintained on a 14:10 light:dark cycle, with temperatures at 33°C and 21°C during photophase and scotophase, respectively. Each hatchling was randomly assigned to either a water-supplementation treatment or a control group receiving no supplemental water. Once every five days, the water-supplemented lizards were administered orally a quantity of water …