A model of gender modification in gynodioecious plants.

The conditions under which hermaphrodites in gynodioecious populations might evolve increased allocation to male function are important for understanding the evolution of plant mating systems. A model is presented here that investigates these conditions under the assumptions that sex determination is nucleo-cytoplasmic and polymorphism is maintained by population subdivision. It is found that modifiers affecting the sex allocation in gynodioecious populations can invade under restrictive conditions, and that under these conditions hermaphroditism no longer is an evolutionary stable strategy. The reasons for the differences between this and related models are discussed.