Mathematical Biology Seminar

John Jaenike
University of Rochester
Wednesday Nov. 7, 2007
3:05pm in LCB 215
The dynamics of male-killing endosymbionts over evolutionary and ecological time scales

Abstract: Innumerable species of insects are infected with maternally transmitted endosymbiotic bacteria, many of which manipulate host reproduction in various ways that enhance endosymbiont fitness. Drosophila innubila, a mushroom-feeding fly common in the sky islands of Arizona, is infected with a male-killing strain of Wolbachia. I will briefly review the general biology of this association and then focus on two specific questions. First, is this an evolutionarily recent or more ancient infection within D. innubila? Patterns of variation in mitochondrial DNA, which is co-transmitted with Wolbachia, shed light on this question. Second, how does variation in the density of Wolbachia within hosts affect the dynamics of infection prevalence in host populations? Real-time quantitative PCR was used to quantify Wolbachia density, allowing examination of transmission fidelity and intensity of male-killing as functions of this density. Theoretical and empirical studies suggest that the dynamics of infection prevalence in host populations is coupled to the dynamics of endosymbiont populations within host individuals.