Exploring Mating Patterns: The Interplay of Genes, Environment, and Their Evolutionary Outcomes

There is great variation in the reproductive tactics exhibited both between and within different species, which is reflected in how individuals engage in mate assessment, mate choice and offspring production. It is therefore important to understand general mating patterns of populations, the factors that influence these mating patterns, and the consequences they carry, in order to get a more holistic understanding of mating systems. This doctoral research represents a multi-pronged investigation of the factors shaping mating patterns and their consequences, how environmental factors influence mating patterns, and how both genotypes and the environment interact to influence mate choice decisions and outcomes, in the model species Drosophila melanogaster. This thesis explores (1) mating patterns in D. melanogaster, revealing that they engage in patterns of non-random mating with others that are of similar quality to themselves, which enhances fitness at the individual and the population level; (2) the impact of the structural elements of physical environment on mating patterns, demonstrating how environmental complexity affects female fecundity, courtship behaviors and mating patterns; and (3) the interplay of genes and larval developmental environments in shaping the expression of components of mate choice, highlighting the role of both heritable and environmentally driven variation in female choosiness. Together, my research findings have led to a better understanding of sexual selection's role in population dynamics and its interactions with natural selection, and offer novel insights into how mating systems may evolve across different contexts.