Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biology

Program Name/Specialization

Integrative Biology

Faculty/School

Faculty of Science

First Advisor

Tristan AF Long

Advisor Role

Thesis Supervisor

Abstract

Sexual dimorphism has been a long-studied phenomenon in the field of evolutionary biology. Usually, these differences in morphology, physiology and/or behaviour between the sexes are studied through the parsimonious lens of sexual selection. However, there are natural history cases where this lens does not seem applicable. Some species show sex specific morphological traits whose presence may not be due to a direct benefit to reproduction, but a difference in how each sex interacts with the environment and differing selective pressures from the environment on either sex. Darwin even brought up examples of this kind of dimorphism and pondered their existence, and since then, theory has dubbed these examples of sex-specific difference as “ecological sexual dimorphism”. Many studies have been conducted on certain examples of this phenomenon, and mathematic models have been used to predict the circumstances in which this type of sexual dimorphism may evolve. However, there are very few empirical studies that show exactly how, and why this phenomenon may evolve. My thesis research took inspiration from Stephen De Lisle in which I conducted a multi-generational experimental evolution project on Drosophila melanogaster to test how the sexes diverge when introduced into a heterogeneous food environment. In Chapter 1 of this thesis, I elaborate on natural history examples of ecological sexual dimorphism and the history of the theory, as well as provide the background and context to my research. Subsequently, in Chapter 2 I discuss the specifics of my experimental evolution procedure, the meaningful outcomes of my research as well as provide future avenues of study. Chapter 3 serves as an overall reflection and my own thoughts on my methodology and results, as well as potential aspects I may have changed with hindsight, and where future researchers may want to focus their attention. This research suggests that given the opportunity, a “generalist” species such as D. melanogaster can exhibit a divergence in sex-specific feeding behaviour.

Convocation Year

2027

Convocation Season

Spring

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