Evolution of reproductive systems in flowering plants : from hermaphroditism to separate sexes

Dioecy (the co-occurrence of female and male individuals within the same species) has evolved multiple times in flow- ering plants, although it remains a quite rare reproductive system. Because a transition from hermaphroditism to com- pletely separate sexes involve more than one step, other reproductive systems that exist in nature, such as the co- occurrence of only one type of unisexual with hermaphrodites, are considered as possible evolutionary steps toward dioecy. In this seminar, I will present a synthesis of our research on the topic, by focusing on several steps along the evolutionary pathway from hermaphroditism toward dioecy and beyond. In particular, I will present our theoretical and empirical projects that attempted to answer some of the following questions:

About the possible evolutionary pathways from hermaphroditism to dioecy: How females can be maintained in com- petition with hermaphrodites? Why is the co-occurrence of males and hermaphrodites so rare? And when it happens, how does this work?
Once dioecy has evolved: Why sexual dimorphism often evolves in dioecious plant species? What are the consequences of such sexual dimorphism on pollinator behavior and pollination efficiency?