FIGURE 9.

Optimal progeny number theory. The schematic of hypothetical progeny production curves display how progeny number can be controlled: (1) timing of onset of reproduction, (2) quantity of progeny, and (3) timing of cessation of reproduction or reproductive aging. Thus, reproductive aging is one of the critical inputs that controls progeny number. According to the theory, there is an optimal progeny number that stabilizes population dynamics and support long-term survival of populations. Therefore, reproductive aging can be an advantageous trait that might be sculpted by evolution. Adapted from Hughes et al. (2007).