Association of temperature and cold season eggs mortality with the population dynamics of Aedes aegypti in Buenos Aires City

Several studies showed that Aedes aegypti has a heterogeneous distribution in the city of Buenos Aires. Favorable areas in the periphery and less favorable areas near the city center and the Rio de la Plata River were identified. The aim of this work was to study the effect of temperature and mortality of eggs as possible causal factors for the mentioned heterogeneity. Eggs mortality during the cold season was studied experimentally, the temperature variation during a year was measured, and population abundance through the oviposition activity during the warm season in two areas located in Mataderos (favorable) and Belgrano (unfavorable) was monitored. In addition, simulations were performed with a mathematical model of population dynamics of Aedes aegypti, using the temperature and mortality data obtained in the field studies. The experimental results showed that higher abundances were recorded in the favorable area and that the values of mortality were lower and the temperatures were higher than those registered in the unfavorable area. The results of model simulations showed that temperature differences had a greater influence on differences in population abundances, except at the beginning of the warm season when the effect of egg mortality predominated. The differences between the results of the field survey and the simulations allowed to infer that (among others) the rainfall is an important variable for the dynamics of the mosquito, and should be incorporated into future versions of the model. We conclude that among the evaluated factors the temperature is the most important in determining differences in the abundance of Aedes aegypti between the two study areas. In contrast, the mortality of the eggs would not have a significant impact in spite of the differences between zones found in experimental studies.