Ecological pressures affecting malaria transmission: sex, insecticides, and Wolbachia in Anopheles mosquitoes

Abstract

Anopheles mosquitoes are the only vectors of malaria, a disease that kills over 400,000 people each year. In malaria-endemic regions, interventions aimed at the mosquito vectors through the use of insecticides have been highly successful at reducing malaria cases and deaths over the last two decades, emphasizing the importance of effective vector control. As insecticide resistance rises sharply, threatening to circumvent current vector control efforts, it is imperative to address the need for novel vector control measures. Insecticide resistance management will shape the future of malaria control and studying how resistance traits affect mosquito fitness and vector competence is critical to this task. It is also important to address knowledge gaps that prevent the implementation of alternative control methods such as Sterile Insect Technique for suppression of Anopheles populations, or the use of Wolbachia bacteria to reduce malaria infections in mosquitoes in population replacement strategies. In Chapter 1, I will give an overview of the ecological and environmental factors that contribute to life history traits and affect parasite transmission by Anopheles mosquitoes, outlining aspects that are relevant for vector control. In Chapter 2, I will explore the mechanisms affecting mating iv behavior in Anopheles mosquitoes, focusing on the role of cuticular hydrocarbons in male mating success and their relationship with insecticide resistance. In Chapter 3, I will determine how selection for insecticide resistance may impact the ability of mosquitoes to transmit malaria parasites. In Chapter 4, I will evaluate the possibility of artificially recapitulating in Anopheles reproductive manipulations generally induced by Wolbachia endosymbionts in other insects. Chapter 5, will discuss these findings and provide an outlook of how these and other ecological factors interact to influence vectorial capacity and malaria vector control efforts.