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