Grant: Discovery Grants Program - Individual

At the most fundamental level, evolution can be thought of in terms of allele frequency changes over generations. As such, one of the main goals of evolutionary biology is to explain why some individuals pass on more of their genes than others. My research program falls neatly within this goal of evolutionary biology because it elucidates factors that affect sexual selection, which alters reproductive skews and thus is responsible for changes in allele frequencies from one generation to the next. Until recently, sexual selection theory assumed most taxa were monogamous and selection was thought to operate mainly via processes prior to copulation (i.e. pre-mating selection), namely mate choice (typically females choosing amongst males) and competition for mates (typically males vs. males for access to females). However, genetic and behavioural studies have revealed that sexual promiscuity is common among most taxa. Multiple mating by females creates the potential for sexual selection to continue after copulation through (i) the competition between sperm of different males for the fertilization of a set of ova (sperm competition) and (ii) the differential use of sperm from one male over another, with a presumed genetic benefit to offspring fitness (cryptic female choice). As a result, reproductive fitness is now understood to be determined by the complex interactions of traits (at both the phenotypic and genotypic level) selected in males and females during episodes of selection before and after mating. Thus, a central question emerging in sexual selection theory is whether post-mating selection reinforces or counteracts conventional pre-mating selection within mating systems. My long-term objective is to quantify the relative importance of pre- and post-mating selection on reproductive fitness in order to gain a better understanding of the evolutionary consequences of sexual selection. My short-term objectives (the next five years) are to build on my previous work and move into innovative new areas of research focusing on Chinook salmon (Oncorhynchus tshawytscha) and their unique mating system that includes male alternative reproductive tactics to examine: (1) investigate sources of genetic quality (good and compatible genes) among males and females, (2) explore pre- and post-mating paternity biasing mechanism, (3)  disentangle of the effects of pre- and post-mating on paternity biasing and ultimately reproductive success and (4) better understand broad patterns of selection arising from the interplay of both pre- and post-mating processes. These studies constitute new avenues of research and novel approaches for my research program that will advance our understanding of sexual selection. Overall, this research program promises to (i) produce high quality peer-reviewed publications, (ii) create innovative research tools for those who study sexual selection and (iii) train a diversity of highly qualified personnel.