Research Insights

When natural selection is strong, evolutionary changes in populations may operate on the same time scale as ecological changes, leading to the entanglement of ecological and evolutionary dynamics. These eco-evo dynamics connect two central questions in ecology and evolutionary biology: What allows species to persist and maintain biodiversity, and what preserves the genetic diversity of populations? Both questions relate to stability, the first to ecological stability and the second to evolutionary stability. Here, we use “stability” to broadly encompass both the persistence of species/genes and the dampening of fluctuations in population abundance and genotype frequency. Spatial heterogeneity and the movement of individuals/genotypes throughout a landscape promote the stability of population dynamics and generate balancing selection. The factors facilitating both ecological and evolutionary stability are the same: if some species/genotypes are favored in some but not all areas, and if there is enough dispersal to link populations across the landscape, then the diversity of species/genotypes can be maintained. In ecology, much of the research on stability focuses on predator-prey (or consumer-resource) interactions, as understanding their stability is challenging both theoretically and empirically. Similarly, predator-prey coevolution has been extensively studied because predators can exert strong pressures that result in selection for prey resistance. Thus, ecological and evolutionary stability is central to understanding predator-prey systems. We will investigate the stability of eco-evo dynamics in a host-parasitoid system.

Our study will test the hypothesis that spatiotemporal variation in population abundances and selection pressures stabilize the eco-evo dynamics of pea aphids and a parasitoid, A. ervi, combining laboratory and field experiments with theoretical models to understand eco-evo stability. Eco-evo models fitted to the experimental data will quantify the strength of spatiotemporal variation in maintaining diversity. Finally, theoretical models will extend our qualitative findings to other systems that involve genetic recombination, predator-prey trait matching, and coevolution of prey resistance and predator counter measures.

We will focus on broader impacts in education and outreach. For education, we will expand current lab initiatives to foster diversity within the pipeline of the next generation of biologists, focusing on high school (through the federal Upward Bound program and UGA’s Young Scholars Program) and freshmen/sophomore undergraduates with no prior research experience. We aim to provide students with STEM experiences that broaden their understanding of science and inspire them to pursue scientific careers. In our graduate students, we will instill an ethos for engaging a broad audience in science through participation in educational programs at high school and college levels, and in outreach events to our local communities. We will also engage farmers: while evolution in agriculture is familiar from selective breeding and the evolution of resistance of insect pests and weeds to pesticides, the role of evolution and natural selection in shaping the impacts of pests on crops is likely unfamiliar. In fact, this is a topic that we personally want to understand better.

Funder: NSF

Amount: $509,821

PI: Kerry Oliver, College of Agricultural and Environmental Sciences, Department of Entomology