Most plants and animals live in variable environments and respond by adjusting their behavior and morphology in ways that improve their performance. There has been tremendous interest in understanding the evolution and ecology of such ?plasticity,? but biologists lack understanding of the process of evolution of plasticity at the among-species level. The PI proposes to examine the plasticity of behavioral, morphological, and life-history traits in 50 species of amphibians in response to predation. This project is a collaborative effort across the United States and represents one of the most extensive approaches to understanding the evolution of plasticity in any system to date.
The research will train seven graduate students and six undergraduate students including individuals from under-represented groups. Benefits to society include developing insights into how organisms evolve in response to environmental change. The results will be disseminated by the PI through teaching modules for regional middle and high school teachers.
Scientific merit The goal of this research project was to examine the phylogenetic patterns in the plasticity of amphibian phenotypes. Using amphibians as a model system, the goal of this work was to examine the life history plasticity of embryos exposed to predator cues and the behavioral and morphological plasticity of tadpoles exposed to different predator and competitor environments. In conducting these experiments, our objectives were to examine how phenotypically plastic traits evolve, how many independent evolutionary events have occurred, whether behavioral plasticity evolves before morphological plasticity, and the role of ecology in affecting the patterns of plasticity evolution. The research to date has been very successful. We have completed experiments on 25 species of embryos and tadpoles and this has produced a very large set of data. These experiments were being conducted through last month (August 2011), so the analyses have not yet been conducted. However, it is clear that there are large differences in phenotypes and the plasticity of phenotypes among the many species. In addition to achieving the major goals, we have also worked on a number of related side projects. For example, we have examined the effects of different species of leaf litter (which fall into natural wetlands) on the traits of tadpoles. This work has discovered that the species of leaf litter is incredibly important in determining how many species of tadpoles grow and develop. We have also examined how a variety of natural environments affect the traits of small crustaceans, known as amphipods. For example, we found that water bodies that have high fertility from fertilizer inputs, etc. cause male amphipods to develop much larger claws which they in turn makes them more attractive to female amphipods. We have also examined the phylogenetic patterns of sensitivity in amphibians to common pesticides. For the herbicide Roundup, all species have very similar levels of sensitivity. In contrast, species show very large differences in sensitivity to the insecticide endosulfan. Finally, we have been working on phylogenetic patterns of sensitivity to the amphibian pathogen known as the chytrid fungus. Species differ a great deal in their sensitivity and we are working to determine which species and genera have the highest susceptibility to this fungus. This is important because the fungus appears to be contributing to the decline or extinction of dozens of amphibian species around the world. Broader impacts During the years of this project, I have presented 43 invited talks and 25 conference talks. We have also trained a large number of post-docs, graduate students, undergraduate students, and high school teachers. For the past 4 years, we have conducted an annual High School Teachers Workshop, which brings in teachers for a week of training in how to do science and teach science.
