A recent study published on March 18, 2025, sheds light on how elevated atmospheric carbon dioxide (CO2) levels and prolonged egg dormancy can significantly impact the life-history traits of the dengue vector, Aedes aegypti. As the global climate continues to change, understanding these effects is critical, considering the role of Aedes aegypti in transmitting diseases such as dengue, Zika, and chikungunya.
The research indicates that since the industrial revolution, atmospheric CO2 levels have doubled and are projected to reach 1000 ppm by 2100. This increase poses serious questions regarding the adaptability of disease-vectoring mosquitoes. Aedes aegypti has exhibited remarkable adaptation to urban environments, which are significantly affected by climatic changes.
The study, conducted at the Swedish University of Agricultural Sciences, utilized climate chambers set to varying CO2 concentrations—ambient (around 400 ppm), 600 ppm, and 1000 ppm—to analyze the mosquitoes' life-history traits under different conditions.
Results showed that for larvae emerging from eggs stored for two weeks, the developmental duration was significantly reduced at 1000 ppm CO2. In contrast, larvae from older eggs experienced increased developmental duration under elevated CO2 levels. This highlights how egg age interacts with atmospheric conditions to shape immature mosquito survival and development. The authors noted, "Extended egg quiescence duration, combined with elevated CO2 level, differentially affected developmental duration and larval survival, with carry-over effects on adult metabolic reserves, size and survival."
The findings also assessed adult female mosquitoes, uncovering that starvation tolerance was influenced by CO2 levels. Females from younger eggs demonstrated greater starvation tolerance at 600 ppm CO2, while those from older eggs showed reduced tolerance at 1000 ppm. These nuances in survival reflect how stressors interact across life stages and can reshape population dynamics.
Additionally, the research delved into the metabolic reserves of newly emerged female mosquitoes. The soluble carbohydrate content was significantly lower for females reared at 1000 ppm CO2, indicating potential energy shortages. Surprisingly, despite being nutrient-deprived, these females exhibited differential feeding behavior, implying a complexity in how these mosquitoes adapt to changing environmental stressors. "These stress factors also affect the teneral reserves of female mosquitoes, regulating their feeding behaviour, which could have important implications for vectorial capacity," stated the authors of the article.
As our climates evolve, understanding how such changes affect crucial species like Aedes aegypti is vital—not only for public health but also for predicting potential shifts in disease transmission landscapes. The outcomes of this study underscore the necessity for future models of mosquito dynamics, focusing on the interplay between climate change, life-history traits, and feeding patterns.
Long-term ecological studies and field experiments will be essential to further elucidate these findings and inform public health strategies aimed at mitigating the impacts of rising CO2 levels and enhancing preparedness against mosquito-borne diseases in the face of climate change.
