Community evolution in Greater Antillean Anolis lizards: phylogenetic patterns and experimental tests

Abstract

Phytogenies can be useful not only as a means of examining evolutionary hypotheses, but also as a source of hypotheses that can be tested using extant taxa. I illustrate this approach with examples from the study of community evolution in Caribbean Anolis lizards. Phylogenetic analyses indicate that not only are Anolis communities on Jamaica and Puerto Rico convergent in structure, but they have attained their similarity by evolving through a nearly identical sequence of ancestral communities. Examination of the pattern of community evolution suggests that interspecific competition is the driving force behind anole adaptive radiation. This hypothesis can be tested by investigating whether anoles shift their habitat use in the presence of competitors and, if so, whether such shifts lead to morphological adaptation to the new habitat. These hypotheses have been tested experimentally by introducing lizards onto small islands. Preliminary results indicate the existence of ecological interactions among sympatric anoles and that shifts in habitat use are accompanied by microevolutionary changes in morphology.