Phenotypic variation in populations of the mosquito vector, Aedes aegypti, and implications for predicting the effects of temperature and climate change on dengue transmission

There is concern that increases in temperature due to climate change could lead to shifts in the transmission dynamics and distribution of mosquito vectors. Many current models assume there are ‘average’ thermal performance curves for a given vector species’ life-history traits. However, this ‘one-size-fits-all’ assumption ignores the potential for standing phenotypic variation in life-history traits to create population-specific differences in thermal performance. In this study, we explored thermal performance of five independent field populations of Ae. aegypti from Mexico, together with a standard laboratory strain. We reared these six populations at temperatures between 13°C- 37°C to generate thermal performance curves for a suite of life-history traits. Composite models integrating these traits revealed the effects of temperature on population growth rates and dengue virus transmission potential. The results provide strong evidence for the potential for local adaptation in Ae. aegypti populations, challenging the applicability of ‘one-size-fits-all’ thermal performance models to assess climate impact on mosquito-borne diseases.Author summary: How climate affects the dynamics and distribution of mosquito-borne diseases is of considerable public health relevance, especially in a warming climate. Models often assume the relationship between temperature and transmission is fixed for mosquito species and can be extrapolated over time and space. We challenge this assumption with evidence for standing variation in populations of Aedes mosquitoes, the primary vectors of dengue, Zika, and chikungunya viruses. We show variation in thermal sensitivity of life-history traits for five field populations of mosquitoes and one laboratory-adapted population across 11 temperatures. We then use mechanistic models which integrate these life-history traits to understand the potential for differences in fitness and transmission for mosquito populations. Such effects will increase variation in the expected impact of climate and challenge the utility of ‘one-size-fits-all’ models to predict the effects of climate change on vector-borne disease transmission.