The mosquito Aedes aegypti can survive winter in temperate regions in the form of eggs. In South America, the annual 15°C isotherm has been considered a reliable criterion to delimit the mosquito’s survival range. Recent studies suggest that Ae. aegypti has established itself in colder areas in Buenos Aires Province, Argentina, in southern locations, below the 14.5°C isotherm. The reasons for the mosquito’s southward colonization remain unknown. Two hypotheses have been proposed: climate change and adaptive development. The last decade has been warmer and drier than previous ones. While the increase in temperature favors the mosquito's expansion, the decrease in rainfall could potentially disfavors it.

In 2019, Ae. aegypti collected in Buenos Aires Province was found to possess a diapause mechanism: females lay eggs prepared for a prolonged period of inactivity when daily sunlight hours are fewer than 12. It appears that a strategy for surviving winter in temperate regions is to inhibit egg hatching during the winter.

In this work, we explore the questions: Can these biological factors explain the expansion of Ae. aegypti? How far south can it reach? We address this problem using the latest version of a detailed population model (stochastic and spatial) for Ae. aegypti that incorporates climate and food production dynamics. We incorporate the diapause mechanism and performed simulations for various cities in Buenos Aires Province.