Temperature and competition: drivers in the ecological dynamics of <i> Aedes </i> mosquitoes and dengue spread

Abstract

Background Dengue is a mosquito-borne viral disease endemic to tropical regions, primarily transmitted by Aedes aegypti and Aedes albopictus. Climate-driven temperature changes are altering vector ecology and expanding the geographic range where both species coexist. However, the combined effects of temperature variability and interspecific interactions, particularly the highly competitive larval stage, on mosquito population dynamics and dengue transmission remain poorly understood. Methods We developed a deterministic model incorporating temperature-dependent parameters to analyze vector interactions across larval stage, coupled with a Susceptible-Exposed-Infected-Recovered (SEIR) framework for human infection dynamics. We evaluated species invasion capability, population dynamics, and transmission patterns through invasion and coexistence analyses, as well as infection peak assessment. The basic reproductive number ( $R_0$) was derived analytically using the next-generation matrix (NGM) method, while the effective reproductive number ( $R_t$) was computed from numerical simulations to capture dynamic effects of larval competition. Results The invasion analysis showed that larval competition was the central determinant of species outcomes. Under temperature-independent conditions, Aedes albopictus could invade only when the larval pressure exerted by Aedes aegypti ( $\omega _{ae}$) was relatively low, while intermediate values produced neutral dynamics, and higher values prevented invasion. Incorporating temperature dependence broadened the parameter space in which invasion was possible, indicating that thermal variation enhances the invasion potential of Aedes albopictus. Coexistence patterns reflected this shift; temperature-independent simulations favored Aedes aegypti dominance, whereas temperature-dependent scenarios led to nearly balanced coexistence between the species. Dengue transmission patterns qualitatively followed these ecological dynamics. Temperature-independent simulations produced smaller peaks in human dengue cases, while temperature-dependent scenarios yielded a larger number of cases.