Life history traits, dengue virus infection and dissemination, and immune gene expression of Aedes aegypti are modulated by larval and adult nutrition

The yellow fever mosquito, Aedes aegypti, is the primary vector of a number of arboviruses, spreading several tropical diseases including dengue fever. Given their medical importance, it is pivotal to understand the mechanisms underlying their vectorial capacity.  Life history traits, susceptibility to infection and dissemination and immunity of the mosquito are important components/factors of vectorial capacity. However, few studies have focused on the effects of nutrition on mosquito energetic reserves and how this may affect these components/factors. Here we experimentally tested the effects of larval and adult nutrition on mosquito size, fecundity, survival, susceptibility to dengue infection and dissemination, and immune gene expression against dengue infection. We found that larval and adult nutrition influenced mosquito size and survival, respectively, while both larval and adult nutrition affected fecundity, without interactions. Poor adult nutrition and mosquito size was positively and negatively associated with the positive infection status, respectively. For dissemination status, only the interaction between poor adult nutrition and survival had a significant effect. Both the infection titers in mosquito bodies and legs were negatively affected by poor adult nutrition but positively affected by the interaction between poor adult nutrition and survival.  Finally, we found that larval nutrition significantly affected the expression of 8 out of 10 immune genes, while adult nutrition and dengue infection status significantly affected the expression of one gene in Toll pathway and two genes in JAK–STAT pathway, respectively. Our results may have important implications for the understanding of dengue virus transmission by Ae. aegypti.