UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
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Item UNDERSTANDING THE RELATIONSHIP BETWEEN THE BROWN MARMORATED STINK BUG, HALYOMORPHA HALYS (STÅL), AND ITS SYMBIONT, PANTOEA CARBEKII, WITH IMPLICATIONS FOR STINK BUG MANAGEMENT(2016) Taylor, Christopher Michael; Mitter, Charles; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Symbiotic relationships between insects and beneficial microbes are very common in nature, especially within the Hemiptera. The brown marmorated stink bug, Halyomorpha halys Stål, harbors a symbiont, Pantoea carbekii, within the fourth region of the midgut in specialized crypts. In this dissertation, I explored this insect- microbe relationship. I determined that the brown marmorated stink bug is heavily reliant on its symbiont, and that experimental removal of the symbiont from the egg mass surface prior to nymphal acquisition led to lower survival, longer development, lower fecundity, and aberrant nymphal behavior. Additionally, I determined that even when the symbiont is acquired and housed in the midgut crypts, it is susceptible to stressors. Stink bugs reared at a higher temperature showed lower survival, longer development, and a cease in egg mass production, and when bugs were screened for their symbiont, fewer had successfully retained it while under heat stress. Finally, with the knowledge that the stink bug suffers decreases in fitness when its symbiont is missing or stressed, I wanted to determine if targeting the symbiont was a possible management technique for the stink bug. I tested the efficacy of a number of different insecticidal and antimicrobial products to determine whether prevention of symbiont acquisition from the egg mass was possible, and results indicated that transmission of the symbiont from the egg mass to the newly hatched nymph was negatively impacted when certain products were applied (namely surfactants or products containing surfactants). Additionally, direct effects on hatch rate and survival were reported for certain products, namely the insect growth regulator azadirachtin, which suggests that nymphs can pick up residues from the egg mass surface while probing for the symbiont. I conclude that P. carbekii plays a critically important role in the survival of its host, the brown marmorated stink bug, and its presence on the egg mass surface before nymphal hatch makes it targetable as a potential management technique.Item TRAINING THE BODY FOR HEALTHISM: REIFYING VITALITY IN AND THROUGH THE CLINICAL GAZE OF THE NEOLIBERAL FITNESS CLUB(2013) Wiest, Amber Lynn; Andrews, David L; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Against the backdrop of changing understandings of (public) `health' and `fitness' in the contemporary United States, and through a nuanced critique of healthism (Crawford, 1980; Kirk & Colquhoun, 1989; Skrabanek, 1994), the aim of this project is to investigate how mediated renditions of `healthiness' are constructed and maneuvered in the for-profit fitness industry--and interrogate the non-necessary interrelationship between health, fitness, and (bio)citizenship in the historical present (Grossberg, 2006). This is examined through a critical explication of Amber's experiences and observations drawn from her period of (ethnographic) employment in the fitness industry. Focusing specifically on personal training as a biotechnological and pedagogical tool, we explicate how personal training becomes complicit in the communication of particular "healthist" understandings, which unerringly benefit private enterprise (as well as corroborate a pervasive political individualism) through the normalization of the individual's moral responsibility to embody, practice, and ultimately consume healthist practices and ideologies.Item Relationships Between Health Behaviors, Perceived Health Status, and Cardiovascular Disease Risk Factors in Adolescent Girls(2008) Goldsholl, Stacy Danielle; Young, Deborah R; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Poor physical fitness and diet contribute to increases in cardiovascular disease (CVD) risk factors including BMI, waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP), and HDL-C levels. These behaviors are also associated with positive perceptions of health status. It was hypothesized that the associations between positive health behaviors and CVD risk factors would be mediated by perceived health status in adolescent girls. Regression models were used to test for independent effects and mediation. 185 girls were analyzed, 83% were African American and 50% were overweight. Perceived health status predicted WC, BMI, and SBP. Fat consumption predicted WC and SBP. There were no associations between health behaviors and perceived health status. Adolescent girls are able to accurately assess their overall health status regardless of fitness or dietary behaviors. Interventions should encourage girls to consider these healthy behaviors when assessing health status to increase participation in these behaviors.Item Post-bottleneck inbreeding accumulation reduces fitness in laboratory populations of Tribolium castaneum under environmental stress(2008) Choiniere, Ashley Danielle; Siewerdt, Frank; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Populations are often driven to extinction due to low genetic diversity. One major cause for loss of genetic diversity in a population is a demographic bottleneck. A demographic bottleneck was imposed on twenty-one populations of Tribolium castaneum using multiple strategies. After recovering to original census numbers, the populations were subjected to stressful environments, and fitness was quantified. There was a significant decrease in additive genetic variance in all populations as a result of the bottleneck event (P<0.05). As estimated inbreeding accumulation increased, there was a decrease in the mean of fitness related traits, such as adult weight, total progeny, fecundity and survivorship. This relationship was best explained using quadratic models and became even more significant when the populations were under stress. This suggests that both dominance and epistatic gene effects are playing a role in phenotypic expression of traits and that expression may be flexible, supporting survival and fitness.Item Global Capitalism Meets Local Postcommunism: Tensions in Transition as Manifested through Physical Culture and the Female Body in Romania(2008-11-21) Chin, Jessica; Andrews, David L.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Nearly two decades after communism officially ended in Romania, the nation continues to struggle in its transition from state socialism to liberal democracy. The increased presence and influence of Western images, democratic ideals, and social ideologies produces a complex and unstable tension with persisting legacies of communism and socialist ideologies. This dissertation is a critical analysis of the ways in which various tensions are manifested within the changing physical culture in Romania, particularly through performative bodies and constructed spaces of leisure and physical activity. In addition, participation in sports and other physical activities related to fitness and health are examined to reveal disciplinary techniques that reinforce normalized constructions of gendered and classed bodies. Using a qualitative, multi-method approach, empirical data was primarily collected in gyms and fitness clubs of three major cities in Romania. Through a contextual, interpretive, and theoretically-informed analysis of the empirical findings, this project intends to expand upon and articulate theories of postcommunist transition, gender, and physical culture in the Eastern European context--opening new lines of inquiry that consider both the empowering and problematic implications of creating and negotiating new subject positions within postcommunist environments.Item Fitness of the transgenic malaria-refractory mosquito Anopheles gambiae(2004-11-11) Ladner, Deborah Tillman; Hawthorne, David J; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The African mosquito Anopheles gambiae is the insect vector responsible for half of worldwide malaria infections. One option for reducing malaria is genetic manipulation of the vector. By creating transgenic mosquitoes incapable of spreading the malaria pathogen, the human-mosquito-human cycle of infection may be interrupted. In order for the engineered Plasmodium-refractory mosquitoes to be effective they need to be able to thrive in nature and to compete successfully with nontransformed conspecifics. Two lines of transgenic An. gambiae were used in this study to evaluate the fitness consequences of transgenesis in this insect. Life table characteristics of two transformed An. gambiae lines were compared to a control line to determine if fitness costs were present. Specific traits measures between transgenic and control mosquitoes were not significantly different, and the transgenic lines had no evidence of position effects.