The evolution of semelparity: Therophyte, magicicada and salmon

Penna model is used to describe the characteristic of individual. In this paper, we discuss the evolution of semelparity based on Penna model. For the species, such as the therophyte and magicicada, which reproduce only once at a certain age, it is discovered that all the individuals will have a common ancestor after a long-term evolution and die soon after they breed. However, for those who reproduce only once in their lives but not at a certain age, it is also believed that all the individuals will be dead soon after their breeding, and they will not die periodically. This method can be used to explain the life cycle of salmons.