DISSERTATION RESEARCH: Asymmetric character displacement in evolutionary-novel Anolis lizards.

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This work will provide new understanding of how evolution can result in the coexistence of similar species that compete strongly for resources. When species compete for the same resource the weaker competitor can be eliminated from the community. Nonetheless, there are many communities that contain competing species. One hypothesis is that competing species diverge so as to reduce competition, a phenomenon known as character displacement. This work focuses on closely related lizard species that have been introduced to southern Florida. Their recent co-occurrence provides an opportunity to study how species respond to novel competition, and what traits in each species diverge as a result. Observed shifts in both ecology and morphology may ultimately contribute to their long-term coexistence. The result of this study will be a better understanding of the role of character displacement in the origin and maintenance of biodiversity. This project also creates a framework for teaching students and the public about the processes that enhance biodiversity. This framework will be implemented via an Ecology Club and an information webpage, as well as by engaging undergraduates in the research.Populations of two non-native Anolis lizards, that have had no prior evolutionary interactions, will be studied to quantify the progression of character displacement. These species, the Cuban brown anole (Anolis sagrei) and the Puerto Rican crested anole (A. cristatellus), are ecologically and morphologically similar. Throughout Miami FL, they exist in multiple spatially-independent communities that consist of either both species (sympatric populations) or only one species (allopatric populations). These communities are analogous to the early stages of adaptive radiation, whereby ecomorphologically similar species that have speciated in allopatry come into contact and adaptively diverge as a result of interspecific competition. The project will investigate the ecological relationship between these two species to test the following hypotheses: (H1) In the presence of each other, both species will experience a divergence in resource use to minimize interspecific interactions. This hypothesis will be tested through detailed analyses of the ecology and behavior of both species across multiple replicates of both allopatric and sympatric populations. (H2) Divergence in resource use leads to changes in the phenotype of both species ? this is the process of character displacement. This hypothesis will be tested by detailed phenotypic assessments of both species across the populations. (H3) Shifts in phenotypic traits are heritable. This hypothesis will be tested by measuring trait heritability with laboratory breeding experiments. Taken together this case study will provide a more detailed understanding of the role of competition in evolutionary divergence.