Extinction and persistence of Peregrinus maidis: Stochastic modeling under thermal, density-dependent, and maize...

We developed a stochastic dynamic model to simulate the development of Peregrinus maidis, capturing key ecological interactions and stage-structured population dynamics of this maize-specialist insect. The model incorporates a density-dependent regulation mechanism that acts during the nymphal stage, with population size constrained by a fixed pseudo-carrying capacity. Development rates are temperature-dependent, allowing the model to capture the insect's sensitivity to environmental conditions. Simulation results reveal two distinct population regimes: extinction and persistence. Persistence is characterized by stable equilibrium distributions across life stages, with peak abundances occurring near 25 ^∘C. In contrast, low temperatures (below 20 ^∘C) and limited resource availability significantly increase extinction probability. The analysis also highlights the buffering role of high pseudo-carrying capacities against demographic collapse. Importantly, our simulations of "quasi-extinction" times indicate that local populations often collapse within 1.5-4 months, a range comparable to or shorter than the harvest-to-sowing interval in many maize-based cropping systems, thereby highlighting the potential role of migration or alternative hosts in sustaining persistence. In this framework, population regulation is governed by density-dependent effects through a constant pseudo-carrying capacity, while temperature modulates development rates. These findings provide a mechanistic basis for understanding how stochasticity, nonlinearity, and environmental drivers shape insect population dynamics, with potential applications for anticipating pest behavior under variable climatic and agronomic conditions.