SPERM EVOLUTION · Towards an evolutionary ecology of spermatogenesis

The essentials of sperm function differ little from one species to another, and yet there is tremendous diversity among species in the type and number of sperm a male produces. My research programme aims to understand how these traits, which are fundamental to male fertility, evolve. Specifically, I aim to identify selective forces acting on sperm, spermatogenesis and the testis, and adopt a multidisciplinary approach to test the working hypothesis that post-copulatory sexual selection has been a major force during sperm and testis evolution. Such a research programme is needed, because evolutionary biologists have traditionally treated the testis as a “black box” (ignoring the details of its function) whereas more clinically-orientated research has usually not considered how evolutionary history shapes the complex machinery of spermatogenesis. The time is ripe for a more integrative programme.In this project, I will build on recent progress to develop Macrostomum flatworms as a model system for studying the evolutionary biology of sperm, spermatogenesis and the testis. By in-depth studies of two closely related flatworm species, and comparative studies incorporating additional species, I will focus on testing how two radically different fertilization mechanisms affect the evolution of male reproductive function. The project will provide crucial information on the genetic architecture of sperm traits