Stability in a population model without random deaths by the Verhulst factor

A large amount of population models use the concept of a carrying capacity. Simulated populations are bounded by invoking finite resources through a survival probability, commonly referred to as the Verhulst factor. The fact, however, that resources are not easily accounted for in actual biological systems makes the carrying capacity parameter ill-defined. Henceforth, we deem it essential to consider cases for which the parameter is unnecessary. This work demonstrates the possibility of Verhulst-free steady states using the Penna aging model, with one semelparous birth per adult. Stable populations are obtained by setting a mutation threshold that is higher than the reproduction age.

Research highlights► In many observed systems, the carrying capacity is commonly not well accounted for. ► Stable, Verhulst-free populations are found using the Penna model. ► Equilibrium is achieved by imposing one semelparous birth per adult.