Document Type


Degree Name

Master of Science (MSc)



Program Name/Specialization

Integrative Biology


Faculty of Science

First Advisor

Dr. Tristan AF Long

Advisor Role

Supervisor/Principal Investigator


Female mate choice is a significant driving force of evolutionary change and can explain the evolution of exaggerated male traits and/or displays, and dimorphism between the sexes. Females are thought to choose mates based on the greatest provision of direct or indirect benefits. Despite this, we often still see substantial individual variation in female mate choice behaviours both within and across populations. Recent studies suggest that female mate choice is a complex decision-making process that involves many context-dependent factors. However, the precise sources of this variation, such as previous mating experience, are not completely understood. In Drosophila melanogaster, mating can be harmful and have costly effects on a female's lifetime fitness. As such, sexual conflict theory predicts that females may make trade-offs in their mate choice decisions to balance the direct costs and indirect benefits associated with mating. In this thesis, I set out to understand if the harmfulness of a previous mating experience influences a female's subsequent mate choice behaviours. In chapter two of this thesis, I assessed the effect of male exposure on female fitness by measuring the change in their fecundity (a meaningful metric of fitness) across a brief and prolonged period of exposure. In this experiment, we found that the degree that different males harm their mates across this time period largely depended on the male's genetic background. Using these results, I was able to quantify the harmfulness of 26 male hemiclone lines that each possess a unique genetic background. In chapter three of this thesis, I used these quantified males to examine if the direct costs of a previous mating experience has an effect on subsequent female mate choice behaviours and to quantify the degree of additive genetic variation associated with this effect. The results of my studies suggest that females alter their mate choice behaviours based on previous mating experiences, and that the degree to which these behaviours change has a genetic basis. I discuss how these results are significant for our understanding of the evolution of female mate choice, and the maintenance of variation in harmful male traits.

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