Joseph Baafi, Amy Hurford
Mosquitoes are important vectors of infectious diseases affecting humans and animals. In North America, Culex mosquitoes transmit West Nile virus and other arboviruses, while their persistence in temperate regions depends strongly on seasonal processes such as diapause. Temperature, rainfall, and photoperiod jointly regulate mosquito development, survival, reproduction, and seasonal activity, yet many climate-driven models do not explicitly represent diapause or interacting environmental drivers. We develop a mechanistic, stage-structured model for temperate Culex populations that includes eggs, larvae, pupae, active adult females, and diapausing adult females. The model integrates temperature-dependent oviposition and mortality, temperature- and rainfall-dependent maturation, and photoperiod-driven diapause induction and termination. Mathematical analysis establishes positivity and boundedness of solutions and derives a mosquito population replacement threshold that links climate-dependent life-history rates to population persistence. Using historical climate data, stochastic rainfall sampling, and prescribed warming and rainfall scenarios, we examine how climate variability shapes abundance and active season length. Simulations reveal strong nonlinear responses to warming, with active adult female abundance increasing substantially under higher temperature shifts and the active season expanding into early spring and late fall. Rainfall modulates population responses, with dry conditions suppressing abundance, wet conditions producing the largest increases, and erratic rainfall yielding intermediate outcomes. These results show that temperature, rainfall, and photoperiod jointly shape temperate mosquito dynamics and highlight the potential for climate warming to increase vector abundance and extend seasonal windows of activity. The framework provides a basis for evaluating climate-sensitive vector dynamics and informing adaptive mosquito control strategies under environmental change.