Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

One of the main questions in evolutionary biology is how biological diversity between individuals and species is generated? Answering this question will help us understand fundamental biological processes, such the evolution of life on earth, and help us determine how best to conserve endangered species, especially when confronted with human-induced climate change.
Darwin was one of the first to differentiate between natural and sexual selection when attempting to explain how populations and species evolve. Natural selection is due to differences between individuals in survivorship and reproductive capacity, while sexual selection is driven by differences in the ability to get mates. We believe that sexual selection has led to some of the most exaggerated characters observed, such as large antlers, extreme courtship rituals, and bright coloration.
How has sexual selection led to this diversity? It is easy to understand the evolution of these extreme characters in males; presumably they have evolved because females prefer to mate with males having the most extreme form of these mating signals. It is more difficult to explain the evolution of the female preference for these extreme male characters in the first place, and this remains an unsolved question in evolutionary biology.
The guppy and closely related species is one of the best systems to study the evolution of female preference for “showy” male characters. My research takes advantage of several unique characteristics of guppies (multiple closely related species occurring in similar environments, differences in female preferences and male coloration patterns within species, easily bred in the lab for genetic experiments, etc.), in order to determine the genetic and environmental factors that determine female mate choice. My research program combines field studies in South America, lab genetic studies, and modern molecular approaches. In the proposed research, we will study the expression of opsins, the genes that control the tuning of the visual system in vertebrates, including humans. We will also examine expression of genes in the brain, to understand how differences in mate choice may be coded in these “higher order” processes. This will be one of the most complete studies of the genetics and environmental control of female mate choice, and will allow us to evaluate the role of sexual selection in the divergence of populations and ultimately in the production of biological diversity.