Predator discrimination of prey promotes the predator-mediated coexistence of prey species

The predator discrimination of prey can affect predation intensity and the prey density-dependence of predators, which has the potential to alter the coexistence of prey species. We used a predator–prey population dynamics model accounting for the predator’s adaptive diet choice and predator discrimination of prey to investigate how the latter influences prey coexistence. The model revealed that: (1) prey species that are perceived as belonging to the same species by a predator are attacked in the same manner, and it is more difficult for them to coexist than those that are recognised as different prey species; and (2) prey species that are not discriminated by a predator—and therefore cannot coexist—may coexist in the presence of an alternative predator that does discriminate between them. These results suggest that prey diversity, which favours the predator discrimination of prey, and the different capabilities of predators to identify prey species both enhance prey coexistence.

Methods
Numerical calculations were performed by python ver 3.8.9.

In the case that the time scale of adaptive foraging is the same as the population dynamics (G=1), numerical calculations were performed in odeint from SciPy ver 1.8.1.

In the case that the time scale of foraging is much faster than population dynamics (G>>1), numerical calculations were preformed by Runge-Kutta 4th Order Method. If the gain that predator species receives from the prey group utilized by the predator species, we assume that predator species allocate the same foraging effort for the prey group in numerical calculations.