UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
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Item MOSQUITOES AND VEGETATION ACROSS SOCIOECONOMIC GRADIENTS(2024) Rothman, Sarah; Leisnham, Paul T; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The biomass and composition of local vegetation is a key resource for juvenile mosquitoes, affecting a suite of life history traits including survival, development rate, and body size. In cities across the United States, both plant and mosquito communities vary with socioeconomics. Vegetation is typically more abundant and biodiverse in high-income neighborhoods, whereas mosquitoes are often more numerous and more likely to vector diseases in low-income neighborhoods. While prior work has examined the effects of plant resources on mosquitoes, my dissertation evaluates how these communities interact across a socioeconomically diverse urban landscape. Chapter 1 is a scoping review of current knowledge of the individual relationships between mosquitoes, plants, and socioeconomics in cities. In Chapter 2, I describe fine-scale vegetation surveys on socioeconomically diverse residential properties in Baltimore, MD and Washington, D.C. that revealed less canopy cover, more vines, and more non-native plant species on lower-income blocks. In Chapter 3, I used leaves from the most frequently observed canopy species on low- and high-income blocks, and species common to both, as detrital resource bases in competition trials between two dominant urban mosquitoes, Aedes albopictus and Culex pipiens. Population performance for both species was greater when reared with characteristically low-income than characteristically high-income detritus, suggesting that socioeconomically diverse plant communities are an important factor in shaping urban mosquito communities. Overall, population performances were greatest when mosquitoes were reared in the regionally representative detritus, and I used this detritus base in Chapter 4 to evaluate the effects of varying temperatures. Aedes albopictus population performance was optimized at higher mean temperatures characteristic of low-income blocks, while C. pipiens performance was best at lower mean temperatures characteristic of high-income blocks. Population performance was often lower, however, when temperatures fluctuated around a high or low mean than when the temperature was stable, suggesting that laboratory studies may need to mimic field conditions to obtain applicable results. My research provides a deeper understanding of the mechanisms behind previously observed relationships, and may help guide management and policy strategies to address environmental injustices and public health threats.Item Studies on Host-Seeking Behavior and Differential Chemosensory Gene Expression in Above- and Below-ground Culex Pipiens(2020) Noreuil, Anna Nicole; Fritz, Megan; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Culex pipiens is the primary vector of WNV. It exists as two bioforms which can hybridize in nature. I characterized the behavioral and genetic variation across eight populations collected from above- and below-ground habitats. Three of the five above-ground populations had hybrid ancestry in our single locus assay, whereas the below-ground populations did not. In choice tests, four above-ground populations were avian-seeking, while the fifth showed no clear preference. All three belowground populations predominately sought the human host. Genetic ancestry was not correlated with host preference. Chemosensation drives host-seeking behaviors in female mosquitoes, which led me to quantify the expression of two chemosensory genes: odorant binding proteins (OBPs) 2 and 12. Both OBPs were more highly expressed in the heads of human-preferring females. While the patterns of OBP2 expression indicate that it may contribute to human host detection, OBP12 expression patterns are more consistent with odor-guided oviposition.Item Linking socioeconomic factors to mosquito control in residential Washington, D.C.(2011) Dowling, Zara; Leisnham, Paul T; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urban larval mosquito control strategies include elimination of aboveground water-holding containers by private residents (`source reduction') and larviciding of belowground storm drains and utility manholes. Effective source reduction is dependent on public education campaigns that identify key sources of mosquitoes, target at-risk neighborhoods, and create an informed and motivated citizenry. I conducted 242 yard surveys for mosquito larval habitats paired with Knowledge, Attitude, and Practice (KAP) questionnaires administered to residents in six socioeconomically-diverse neighborhoods in the greater Washington, D.C. metropolitan area, and sampled 201 belowground habitats adjacent to these households. In chapter 2, I analyze associations between resident socioeconomic status, knowledge, attitudes, practices and mosquito indices. In chapter 3, I examine variations in larval habitat quality, quantity and type across neighborhoods of differing socioeconomic status. In chapter 4, I compare larval populations in aboveground and belowground habitats. The implications for educational literature and mosquito management are discussed.