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Abstract
Mosquitoes and kissing bugs are blood feeding insects and principal contributors to the annual global public health burden. Vector management strategies that limit insect populations, have aided in the reduction of human and animal disease. Moreover, vector management strategies are informed by discovery and investigation of factors that promote the physiology, ecology, and behavior of pest insects. The bodies of work presented in this dissertation seek to explore the basic biology of mosquitoes and kissing bugs through examination of biochemical and microbial factors that contribute to insect reproduction, molting, development, and metabolism in hopes to inform future pest management strategies. Insect reproduction is made possible by the coordination of several hormones that are released from the brain or associated endocrine glands after a blood meal. The first two studies delve into: the role of the peptide hormone, CNMamide, its respective G protein-coupled receptors, and the role of two orphan G protein-coupled receptors, AAEL003647 and AAEL019988, in Aedes aegypti mosquito reproductive physiology. We found that Culicidae underwent a gene duplication event, resulting in two copies of the CNMa receptor, CNMaR_1a and CNMaR_1b. Only CNMa and CNMaR_1b were expressed in females, and CNMaR_1a was only expressed in male antennae. We found a reduction in fecundity in mated blood fed female mosquitoes, after injection of exogenous CNMa peptide. Next, I established that both AAEL003647 and AAEL019988 were highly expressed in the ovaries. Knockdown of both orphan receptors reduced egg laying in adult females. Altogether, these studies highlight the importance of hormones in reproductive physiology of female mosquitoes. In addition to hormones, gut bacteria also contribute reproductive and metabolic physiology in insects, primarily through nutrient supplementation. Thus, the final studies of this dissertation explore the role of the kissing bug microbiome in lipid metabolism and modulation of genes in the acetyl-CoA carboxylase de novo lipogenesis pathway. Results from this work in Rhodnius prolixus show that the microbiome differentially affects expression of acetyl-CoA carboxylase and downstream genes. Further, I demonstrate that the microbiome promotes blood meal digestion which may subsequently influence the synthesis of lipids involved in triglyceride energy stores, development, and desiccation resistance.