The effect of resource limitation on the temperature-dependence of mosquito population fitness

Laboratory-derived temperature dependencies of life history traits are increasingly being used to make mechanistic predictions for how climatic warming will affect vector-borne disease dynamics, partially by affecting abundance dynamics of the vector population. These temperature-trait relationships are typically estimated from populations reared on optimal resource supply, even though natural populations of vectors are expected to experience variation in resource supply, including intermittent resource limitation. Using laboratory experiments on the mosquito Aedes aegypti, a principal arbovirus vector, combined with stage-structured population modelling, we show that low-resource supply significantly depresses the vectors maximal population growth rate across the entire temperature range (22-32{degrees}C) and causes it to peak at a lower temperature than at high-resource supply. This effect is primarily driven by an increase in juvenile mortality and development time, combined with an exaggerated decrease in adult size with temperature at low-resource supply. Our study suggests that projections of vector abundance and disease transmission based on laboratory studies are likely to substantially underestimate how resource supply can modulate the temperature-dependency of population-level fitness through its influence on juvenile survival and development time. Our results provide compelling evidence for future studies to consider resource supply when predicting the effects of climate and habitat change on disease vectors and transmission.