Abstract
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; on plasticity in sperm traits; and on how post-copulatory sexual selection shapes male reproductive phenotypes beyond gross testis size. The results of the project will begin to build a more complete “evolutionary ecology of spermatogenesis”, with wide implications for our understanding of the male gamete and its production by the testis; thus they will be applicable both to the immediate field of evolutionary biology, and to related areas of biomedical and clinical research.
Europe