Department of Entomology

Title: Context matters: Genetic and environmental factors mediate the penetrance of symbiont phenotypes

Abstract: Wolbachia is a maternally transmitted, symbiotic bacterium that inhabits numerous arthropods and nematodes. Its ubiquity can be attributed to both fitness advantages for the host, and reproductive modifications of the host. Known reproductive modifications include cytoplasmic incompatibility, male-killing, feminization, and parthenogenesis-induction (PI), all of which increase the relative fitness of infected females. The strength of the reproductive manipulation and the level of maternal transmission are critical for determining whether or not Wolbachia successfully invades and persists in a population. We seek to identify the genetic and environmental factors that mediate these two parameters in Trichogramma wasps infected with PI-Wolbachia. We find that both genotype and reproductive rate interact to determine the final host-symbiont phenotype. Furthermore, reproductive rate can be mediated by environmental factors, such as access to oviposition sites. Findings from this research will allow us to better predict how Wolbachia infections behave in natural settings. Given the interest in using Wolbachia as a tool to control insect populations, it is especially critical that we understand the context dependent nature of Wolbachia phenotypes, and how this may result in different selective pressures for the host-symbiont relationship.