The guiding principle of this research is that adult mosquito production from container habitats is intimately linked to microbial transformations of organic matter and the production of microbial biomass. These relationships impose fundamental constraints on, and facilitate, larval mosquito growth by microbial communities in a variety of larval habitats. Rates of conversion of organic matter are postulated to be modulated by quality of substrates and governed by stimulation of microbial and larval growth. Our long-term goals are to delineate the constraints on mosquito production, to identify the efficiency of utilization of resources, and to elaborate a realistic model of larval growth. Although we have focused on the mosquito Aedes triseriatus and the invasive species Aedes japonicus into water-filled tree holes as a model ecosystem for study, we have now positioned our research to explore analogous relationships with the dengue virus vector Aedes aegypti. Several specific aims provide the research framework. We will stimulate polymer enzyme degradation with our Flavobacterium xylanase genetic constructs and measure differences in mosquito growth rates, and will employ metagenomics for nutrient-simulation/microbial community function relationships generally, and then use specific primers to utilize high throughput sequencing and qPCR methods. Nitrogen is identified as a key limiting nutrient promoting competitive advantage of invasive mosquito species. We will provision nitrogen in different forms and use isotope-labeled compounds to measure relative assimilation efficiency. Nitrogen will be varied in diets of larval Ae. aegypti to determine the influence of low nitrogen on dengue virus vector competence. A Flavobacterium construct strongly expressing larvicidal toxins of Bacillus origin will be evaluated for its stable integration and persistence into laboratory models of natural tree holes, tracked with qPCR and fluorescent reporters, and mortality rates of larvae quantified. Persistence of mosquito-pathogenic Phytopythium strains will similarly be studied. Lastly, we will analyze stable isotope enrichment signatures of emerged mosquitoes to source-track Aedes aegypti to diverse larval habitats and quantify larval resource utilization.
Mosquitoes are responsible for transmission of a large number of human pathogens, including those causing malaria, filariasis, and arboviral infections. Abundance and longevity of adult, female mosquitoes (the blood feeding and pathogen transmitting stage) are dependent upon the nutritional and other factors operating in the larval environment, the constraints of which are the focus of the research here.
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