The evolution of female mating systems: tracing the origins and tracking the consequences

Understanding how populations are structured with respect to sexual interactions (the mating system) has been a key focus in evolutionary biology. Mating systems have consequences for both genetic and demographic change, and polyandry (multiple-mating by females) is a particularly important factor therein. Recent scientific insights have revealed that polyandry, and not monandry (single-mating by females) as traditionally assumed, is the dominant female mating system across all taxa. Research on insects has contributed greatly to this paradigm-shift, with single-species studies revealing important factors that maintain female mating rates. Progress in understanding broader patterns has been relatively slow, however, as few studies have sought to elucidate evolutionary changes in female mating strategies in a phylogenetic framework. In this fellowship, I will combine a broad-scale phylogenetic approach and single-system experimental evolution to test novel theory about the evolutionary causes and consequences of female mating behaviour. My models are parasitoid wasps, important natural enemies that have been well-studied from an applied perspective. This work has revealed great diversity in female mating rates, life-history strategies and genetic systems in this group of insects. These features allow me to expand upon existing theory to generate novel predictions about when polyandry, monandry, or even asexuality are likely to evolve. The work that I propose will advance current mating systems research, by going beyond asking what maintains the female mating rate, to discover what drives its initial evolution.