To a casual observer, it is obvious that individual organisms of the same species often differ from each other in many traits. When methods to quantify genetic variation emerged half a century ago, researchers discovered a remarkable degree of genetic differences among individuals as well. While many theories have been proposed to explain why there is so much genetic variation, the relative importance of different processes that could generate this pattern still remain controversial. This project tests the hypothesis that a large amount of genetic variation within populations is maintained when individuals are spread across environments that vary at a fine spatial scale, with different alleles (alternate forms of a gene) favored in different environmental conditions. Specifically, whole genome sequencing will be used to examine how levels of genetic variation differ in plant-feeding insects allowed to live and feed on a single species of plant (non-variable environment) versus multiple plant species (variable environment) in laboratory experiments. Additionally, genome sequencing of insects from natural populations will be conducted to infer if feeding on multiple plant species maintains genetic diversity within insect populations in nature. The goal of the project is to determine not only the extent to which environmental variation can maintain genetic variation within insect populations, but also which genes allow insects to adapt to diets consisting of different plants.
Genetic variation in natural insect populations enables rapid adaptation to novel diets or environments. These rapid adaptations, which can allow insects to acquire resistance to insecticides and feed on pest-resistant crop breeds, can have dramatic consequences for agriculture and public health, since insects are major crop pests and vectors of human disease. The goal of this project, understanding how genetic variation in insects is generated and maintained, is important for predicting when and how rapid adaptation occurs in insects. In addition, knowledge gained from this project will have broad relevance for understanding the outcomes of species interactions in natural ecosystems, as insects comprise half of all terrestrial animal species on Earth. Lastly, researchers will mentor undergraduate and high school students from underrepresented groups in science in the collection, interpretation, and public communication of data from this project.
