Male reproductive proteins (Acps) transferred to female at mating are required for full fertility and have profound effects on female physiology, affecting fecundity, female remating rate and mediating the sperm competition (SC) outcome. Acps are the primary target of postcopulatory sexual selection (PSS) on males, a potent force that may drive rapid evolution of Acps and female reproductive proteins (Frps) with important consequences for speciation. Despite the vital role of PSS in speciation has been documented, its role in Acps divergence is poorly understood. Acps were identified and their function elucidated in few cases and, at present, our understanding of the selective forces responsible for their rapid evolution is incomplete and remains to be determined.
Compare changes in Acps between species with divergent mating system is ideal to study the effect of PSS on Acps diversification. Interlineage variation in the degree of polyandry and so, in sperm competition intensity, might cause male reproductive gland (Ag) proteome divergence. Using phylogenetic comparative analysis this project will study the evolution of Ag-proteome on closely related species of beetles with different mating system. It will explore the interlineage changes in the Ag-proteome and the potential for correlated evolution between Ag-proteome and female remating rate. The project will also investigate direct effects and causality of varying levels of SC on Ag-proteome using experimental evolution approach in seed beetles. This part of the project will examine the Ag-proteome variation in relation with different levels of SC and identify the Acps and Frps that have evolved under of SC. This proposal is unique and innovative in combining quantitative comparative proteomics, phylogenetic comparative analysis and experimental evolution to provide us with an exceptional understanding and more comprehensive overview of the evolutionary processes affecting the divergence of Acps and Frps and its role as a driving force in speciation.