Department of Biology

Research Overview

For the latest information about the Glor Lab, please visit our lab web page and blog.

Work in our lab is focused on two fundamental questions in the study of biological diversification:

1. What processes contribute to the formation of new species (i.e., speciation)?
2. What factors underlie macroevolutionary patterns of species diversity?

Our efforts to address these questions rely heavily on the adaptive radiation of Caribbean Anolis lizards (anoles) as a model system. Nearly 400 species occur across the neotropics, making Anolis the world’s most species-rich amniote genus. As many as 60 species may occur on a single Caribbean island, and specific communities may include as many as twelve sympatric congeners.

Speciation

Our work on species formation focuses on a number of longstanding controversies (e.g., the geographic context in which speciation occurs, the contribution of natural selection to this process). Our previous work on anoles establishes an important role for geographic differentiation, even within relatively small islands. We are now investigating the role of environmentally mediated dewlap divergence (a colorful throatfan used for signaling) in anole speciation. We are also developing new methods to assess the contribution of ecological barriers to speciation and the maintenance of species boundaries.

Map showing geographic structure and introgression of mtDNA haplotypes and rhodopsin sequences in the Cuban green anoles (Anolis allisoni and A. porcatus). Black bars indicate historically significant overwater barriers. The results of this sudy supported speciation via allopatric divergence prior to the formation of modern-day Cuba with some subsequent mitochondrial introgression.

Macroevolutionary Patterns of Species Richness

Macroevolutionary studies in the lab employ a comparative phylogenetic perspective to identify patterns of diversification and assess the causal mechanisms that underlie these patterns. Current work on this topic includes a test of whether distinct, predictable stages characterize the anole radiation and that of other adaptive radiations. As part of this work, we are also developing new multi-locus phylogenies for Anolis.

Phylogeny for Greater Antillean Anolis lizards showing reconstruction of microhabitat specialization via maximum likelihood. Microhabitat divergence occurred relatively early in the radiation. Subsequent speciation events have been associated with differentiation along other resource axes.

Selected Publications

• Ng, J. and R. E. Glor. Accepted Article. Patterns of gene flow among populations of Hispaniolan trunk anoles that differ in dewlap color and pattern. Molecular Ecology. [DOI link]
• Glor, R. E. and R. Laport. 2011. Are subspecies of an anolis lizards (A. distichus) that differ in dewlap color and pattern also genetically distinct?: a mitochondrial analysis. Molecular Phylogenetics and Evolution. [DOI link]
• Glor, R. E. and D. Warren. 2011. Testing ecological explanations for biogeographic boundaries. Evolution 68: 673-683 [DOI link]
• Rabosky, D. L and R. E. Glor. 2010. Equilibrium speciation dynamics in a model adaptive radiation of island lizards. Proceedings of the National Academy of Science USA. [DOI link]
• Glor, R. E. 2010. Phylogenetic insights on adaptive radiation. Annual Review of Ecology, Evolution, and Systematics 41: 251-270. [DOI link]
• Harmon, H & R. E. Glor. 2010. Poor performance of the Mantel test in phylogenetic comparative analyses. Evolution. [doi link]