DISSERTATION RESEARCH: Testing Hypotheses of Morphological Differentiation in the Introduced Lizard, Anolis sagrei

Washington University, Saint Louis MO

Investigators

Abstract

The current rate of species introductions is unprecedented. Introductions of new species into communities with which they share no recent evolutionary history results in novel interactions between the introduced species and its new environment, and between introduced and native species. These unplanned experiments may be used to ask questions about fundamental ecological and evolutionary processes. Using introductions of the lizard, Anolis sagrei, we will test hypotheses about morphological differentiation predicted from habitat use for two traits with well-supported ecomorphological relationships among native populations. We will test the hypotheses that hindlimb length and toe-pad lamellae number differentiate in the direction predicted from the diameter and height of perches that lizards occupy. To identify the origin of introduced populations, we will reconstruct the history of the introduction by assigning mitochondrial DNA haplotypes from introduced populations to well-supported, geographically circumscribed haplotype clades in the native range. This allows identification of introduced-source population comparisons for hypothesis testing. Introductions present an excellent opportunity to test hypotheses of adaptive trait differentiation. At a broader level, studying patterns of differentiation and evolutionary processes in introduced populations leads to a better understanding of the causes, progression, and prediction of biological invasions, which pose a major threat to biodiversity.