Wolbachia and Bag of Marbles (bam) Dynamics in Drosophila melanogaster

Wolbachia, a maternally inherited bacterial endosymbiont, is known to rescue the reduced fecundity phenotype of a bag of marbles (bam) Drosophila melanogaster partial loss of function mutant (hypomorph). We wish to understand the functional mechanisms behind the rescue of the bam phenotype in Drosophila. In D. melanogaster, genetically diverse substrains of Wolbachia have been identified and characterized. Wmel-like Wolbachia substrains are characterized by a longer life span and low Wolbachia titer while WmelCS-like Wolbachia substrains are characterized by a shorter life span and a high Wolbachia titer. We are testing whether different Wolbachia genotypes and different Wolbachia titer levels influence bam function (and resulting fecundity) in D. melanogaster. Our results show that virgin bam hypomorphs have have a constant Wolbachia titer over time compared to virgin WT flies that have an increase in titer over time. This suggests that there is tight regulation of Wolbachia titer in the bam hypomorphs in order to rescue the bam mutant phenotype. Additionally, mated bam hypomorphs have an increase in Wolbachia titer over time followed by a decrease in titer at day 12 compared to virgin hypomorphs. Wolbachia titer could be increasing over time in mated hypomorphs to ensure that a high titer (or any amount of Wolbachia) is passed onto progeny. However, the drop in titer at day 12 could be due sperm reduction in aged males over time as the initial experiments were done. Therefore, these experiments must be repeated with 3-5 day old males of a WT genotype mated with aged females.