Niewiarowski, P.H.*; Angilletta, Jr., M.J.; Leache, A.D.; Porter, W.P.: Phylogenetically-based Comparative Analysis of Life History Variation Among Populations of Sceloporus undulatus

The eastern fence lizard, Sceloporus undulatus, is one of the most widely distributed lizards in North America. Across its range, populations display two- to three-fold variation in many life history traits, including age at maturity, adult body size, clutch size, and longevity. Although this variation has been the subject of extensive empirical and theoretical study, comparative analyses of life history variation have been limited by the lack of a population level phylogeny. We used a phylogeny inferred from sequences of mitochondrial DNA to construct independent contrasts for comparative analyses of 13 widely-distributed populations. Our analyses explore patterns of covariation among life history traits predicted by life history theory (e.g., egg size vs.clutch size, reproductive output vs. survival), as well as covariation among life history traits and environmental parameters (e.g., precipitation, temperature, activity season length estimates derived from a biophysical model). Our study represents the first time that life history variation in this species has been interpreted within a rigorous phylogenetic framework. Intraspecific, phylogenetically-based comparative studies, like ours, provide insights for developing testable hypotheses about life history evolution and adaptation.