We investigate the most probable phase portrait (MPPP) of a stochastic single-species model with the Alleeeffect using the non-local Fokker-Planck equation (FPE). This stochastic model is driven by non-Gaussianas well as Gaussian noise. It has three fixed points in the deterministic case. One of them is the unstablestate which lies between the two stable equilibria. We focus on the transition pathways from the extinctionstate to the upper fixed stable state for the transcription factor activator in a single-species model. This helpsus to study the biological behavior of species. The most probable path is obtained from the solution of thenon-local Fokker-Planck equation corresponding to the population system of the single-species model, andthe corresponding maximum possible stable equilibrium state is determined. We also acquire the Onsager-Machlup function for the stochastic model and solve the corresponding most probable paths. The numericalsimulation manifests that: (i) When non-Gaussian noise is presented in the system, the maximum of thestationary density function is located at the most probable stable equilibrium state; (ii) If the initial valueincreases from extinction state to the upper stable state, the most probable trajectory goes to the maximallikely equilibrium state, in our case it lies between 9 and 10; (iii) The most probable paths increase to stablestate quickly, then maintain a nearly constant level, and approach to the upper stable equilibrium state astime goes on. These numerical experiment findings accelerate growth for further experimental study, inorder to achieve good knowledge about dynamical systems in biology.
2020 MSC: 39A50, 45K05, 65N12