Analysis of climatic and seasonal effects on the oviposition activity of Aedes spp. females in municipalities of Paraná, Brazil

Abstract

Climate and environmental changes driven by global economic activities directly affect the physiology of insect vectors, such as Aedes spp., accelerating their development, increasing the number of generations per season and increasing the risk of transmission of aetiological agents. This study aimed to analyse how local climatic variables and seasonal variation influence the oviposition dynamics of Aedes spp. in urban environments. Between 2020 and 2023, 68 monthly sampling sessions were conducted across five municipalities in the state of Paraná, Brazil, utilising 8080 oviposition traps. Monthly oviposition density index (EDI) values were calculated per locality. Two hypotheses were tested: (1) Climatic variables significantly modulate the EDI of Aedes spp., and (2) seasonality and minimum temperature act synergistically on EDI dynamics. A total of 174 979 Aedes spp. eggs were collected across the five municipalities. Results indicated that the minimum temperature was the strongest climatic predictor of oviposition. Specifically, each 1°C increase in minimum temperature was associated with a 7% rise in the EDI. Seasonal analysis revealed that the EDI exhibited significant seasonal variation, being higher in summer and autumn compared to winter (p < 0.05). These patterns suggest that sustained thermal warming could maintain continuous vector activity, facilitating Aedes population persistence and arbovirus transmission even during winter periods, particularly in urban areas. This underscores the urgency of developing vector control strategies synchronised with emerging climatic patterns and implementing public health interventions targeted at urban communities facing epidemiological and climatic vulnerability.