Ecologists have historically adopted the simplifying assumption that interactions among species are sufficiently homogeneous that variation within species can be ignored. In other words, differences among individuals of the same species are largely assumed to be unimportant to understanding the interactions among species. At the same time, evolutionary biologists base their research on the fact that this assumption is false, i.e. that there are genetically based differences among individuals that have consequences for the fitness of that species. This project will examine this discrepancy, and contribute to the synthesis between ecology and evolutionary biology, by answering two fundamental questions: How do individuals within a species vary in their influence on the surrounding community based upon genetically based differences in an ecologically important trait? Does the amount of genetic variation in a population for an ecologically important trait have detectable consequences for the surrounding community? This project will address these questions by measuring the ecological consequences of population genetic variation in the aphid Aphis varians that engages in a mutualism with ants on the plant species fireweed (Epilobium angustifolium). Field experiments will test for aphid genetic variation in attractiveness to mutualist ants and measure the natural selection imposed by ants on specific aphid traits. This trait-based understanding of aphid-ant relations will be used to mechanistically characterize how aphid genetic variation influences both ants and the broader community in which this mutualism is embedded.
This project has the significant broader impact in that it will be conducted at, and support, the Rocky Mountain Biological Laboratory. This institution enhances intellectual exchange and collaboration among biologists from around the world. This project will provide research training for undergraduate and graduate students in evolutionary ecology. This project will also include an outreach effort to students and teachers in science classes in K-12 schools serving underrepresented minorities.
