UC Santa Cruz

Globally, mosquito-borne diseases are a major source of mortality, with the burden focused primarily in the poorest nations. Central to reducing mosquito borne disease is an understanding of the biology of those species responsible for transmitting disease to humans. Accordingly, this work focuses on the ecology and evolutionary biology of two vectors of global importance: Aedes aegypti and Aedes albopictus. The first chapter examines the role of urbanization and species interactions in determining Aedes abundance across a 900km latitudinal range representing vast climatic gradients and the major ecotypes of Central Africa. Additionally, we performed pathogen screening on over 9,000 female mosquitoes for dengue, chikungunya, and Zika viruses. The second chapter focuses on the distribution and potential causes of insecticide resistance in Aedes across the same broad climatic and ecotype gradient in Cameroon. In this chapter we detected significant variation in insecticide resistance between cities, habitat types, species, and insecticide class. We applied land use data to show the significant effect that urbanization can have on determining insecticide efficacy across an area as small as a single city and further revealed the underlying genetic and metabolic mechanisms for insecticide resistance. The final chapter investigates viral fitness among the primary arboviruses transmitted by A. aegypti and A. albopictus: chikungunya, dengue (serotypes 1-4), yellow fever, and Zika. Our innovative approach to comparing relative viral fitness is multi-facted, combining field observations of human infection rates with laboratory studies of host and vector competence.