BRC-BIO: An integrative approach to examine the impacts of evolutionary novelty on generalist species

Appalachian State University, Boone NC

Investigators

Abstract

Novel adaptations can significantly impact the behavior, evolution, and genetic diversity of organisms. One such novelty, toxin tolerance, is thought to be important in species richness and dietary breadth of plant-feeding insects. In general, tolerance of highly toxic compounds is predicted to limit the dietary range of insects. However, some species that feed on a wide range of plants/fungi are surprisingly able to detoxify noxious chemicals that only occur in a small number of their hosts. Furthermore, the impact of such novelties on generalist species is poorly understood. To address this knowledge gap, this project will examine tolerance to potent mushroom toxins in a fly species that uses a diverse set of fruit and mushrooms as hosts. By investigating how novelty affects generalist species and the conditions under which it is maintained, these studies will inform predictions about the evolution of novel adaptations. Fundamental to the research are activities designed to increase public engagement with science and technology. These activities will facilitate increased inclusion of students from historically excluded groups. In addition, the work will implement in-class, hands-on research opportunities, and generate a publicly available database containing trait information for the fly species. Flies in the genus Drosophila exhibit a spectrum of feeding behaviors. These range from specialists on a single toxic fruit to generalists that feed on a variety of mushrooms. Mushroom-feeders can tolerate high concentrations of deadly mushroom toxins that are lethal to many organisms. One mushroom feeder, Drosophila tripunctata, is unique in that it uses a combination of fruit and mushroom hosts. In populations of this species, the degree of toxin tolerance varies. In addition, females exhibit egg-laying preference for either fruit or mushrooms. Using a local population of Drosophila tripunctata, the planned research will test three hypotheses. The first is that toxin tolerance has the potential to drive sympatric speciation. The second is that maintaining this novel adaptation increases genetic diversity. Finally, the third is that the benefits of maintaining toxin tolerance outweigh the associated costs. The complementary evolutionary, behavioral, and ecological assessments of a novel adaptation in a generalist species will begin to uncover the impacts of these types of traits and characterize the selective pressures that maintain them. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.