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Abstract
Mosquito-vectored pathogens are globally significant sources of disease across equatorial areas and have expanded into temperate regions of the world. This dissertation examines heterogeneity in vector-borne disease (VBD) transmission across scales by investigating the invasive disease vector Aedes albopictus across an urban gradient in Atlanta, Georgia, USA. To begin with a broader perspective, I developed a synthetic review to critically evaluate different methods of modelling vector-borne disease systems across spatial scales. I offer perspectives regarding the importance of choosing the appropriate spatial scale to model transmission in response to environmental or biological processes. I also address both the relative strengths and limitations of statistical versus mechanistic representations of VBD systems and advances that can be made by integrating the two approaches. My empirical work focuses on larval and adult mosquito populations across a range of impervious surfaces to investigate the effects of human activity on Ae. albopictus populations. I identify and describe microclimatic and land use practices that impact vector abundance. This study shows a significant negative effect of minimum relative humidity and a positive effect of impervious surface coverage and daily temperature range on adult Ae. albopictus abundance. Canopy cover strongly predicted greater larval habitat density. As these microclimate and landscape factors change in response to urbanization, findings here underscore the significance of human activity in determining fine-scale variation in vector populations. In other work, I measure the genetic population structure of Ae. albopictus populations across Atlanta using a SNP microarray for 95 mosquitoes collected across 12 locations. Analysis showed a mosquito population with small but significant genetic sub-structuring, suggesting a population shaped by a combination of human-mediation dispersal, natural dispersal, and landscape barriers. Reconstructions of the admixture history of these Ae. albopictus populations predict a single invasion event during the initial invasion of this species and population movement across the study area. This research highlights how anthropogenic landscapes produce fine-scale heterogeneities that drive variation in vector abundance while facilitating vector dispersal. This work also advises that integrated statistical and mechanistic models can advance understanding of how heterogeneities in biotic and abiotic factors drive pathogen transmission across spatial scales.