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Rhiniidae (Diptera: Oestroidea) diversity in South Africa. Taxonomic review and phylogenetic advances for the Afrotropical regionThomas, Arianna 24 November 2020 (has links)
La familia de dípteros Rhiniidae (Diptera: Oestroidea) se encuentra distribuida fundamentalmente en las areas tropicales y subtropicales de las regiones Afrotropical, Australiana, Oriental y Paleártica. Tradicionalmente era considerada con el rango taxonómico de subfamilia de la familia Calliphoridae. No obstante, estudios filogenéticos recientes, basados en el análisis de caracteres morfológicos y moleculares, evidencian que Calliphoridae no es un grupo monofilético. Esto provocó diversos cambios sistemáticos, considerando a los rhiniidos con el rango taxonómico de familia independiente. Actualmente, se reconocen casi 400 especies de Rhiniidae agrupadas en dos subfamilias y 30 géneros. La región Afrotropical alberga la mayor diversidad de rhiniidos a nivel mundial, con un total aproximado de 170 especies comprendidas en 5 géneros de la subfamilia Rhiniinae y 11 de Cosmininae. Existe muy poca información sobre la diversidad, biología y distribución geográfica de la familia Rhiniidae. El ciclo biológico y en particular los hábitos y morfología larvaria es desconocido para la mayoría de las especies. La mayor parte del conocimiento se limita a unas pocas especies restringidas a enclaves geográficos muy concretos. En general, se conoce que tienen una fuerte asociación ecológica a ambientes naturales, que los adultos frecuentan flores por lo que se cree que son importantes polinizadores y que algunas especies parecen tener una estrecha relación con termitas. En cuanto al estudio de su diversidad y taxonomia, desde los años setenta muy pocas investigaciones se han realizado en relación a Rhiniidae en la región Afrotropical, por lo cual el conocimiento del grupo se encuentra desactualizado. Además, su identificación morfológica, en muchos casos, depende exclusivamente de la terminalia masculina y por lo tanto muchos ejemplares femeninos permanecen sin identificar o inadecuadamente identificados. El objetivo general de esta tesis doctoral es contribuir y actualizar el conocimiento de la familia Rhiniidae en la región Afrotropical, a través del estudio de su diversidad, taxonomía y filogenia en la región, con especial énfasis en Sudáfrica. Para ello, en primer lugar se realizó un estudio taxonómico y de la diversidad de la familia en Sudáfrica, país que a nivel mundial se considera como un hot-spot de biodiversidad. Se examinaron más de 4.000 especímenes de Rhiniidae depositados en colecciones entomológicas de África, Europa y los Estados Unidos. Se generó una lista actualizada de las especies presentes en el país, así como se revisó el estatus taxonómico de las mismas. Adicionalmente, se generaron mapas de distribución histórica y fotografías de alta resolución del habitus para la mayoría de las especies estudiadas. Entre los resultados más importantes que se han obtenido destacan nueve citas nuevas para el país, para un total de 73 especies de Rhiniidae, alrededor de 15 nuevas especies a ser descritas en trabajos futuros y la compilación de información bionómica novedosa para varias especies (Capítulo I). Posteriormente profundizamos dentro de la familia con la revisión taxonómica del género Fainia Zumpt, 1958, exclusivo de la región Afrotropical. Este género incluye siete especies descritas, pero el estatus taxonómico de algunas de ellas es controvertido. Se realizó un estudio morfológico de la terminalia masculina de las especies descritas, junto a la revisión de su respectivo material tipo disponible, para así aclarar el estatus taxonómico de sus especies. De esta forma, se aportan nuevas herramientas de identificación para el género, tales como claves de identificación para ambos sexos, redescripciones, y fotografías de alta resolución de la morfología general del adulto y terminalia masculina, así como nuevas sinonimias. Este estudio se complementó con la homogenización y actualización de la nomenclatura morfológica utilizada para la familia Rhiniidae, así como con la proposición de posibles sinapomorfias para la diagnosis de las dos subfamilias actuales Cosmininae y Rhiniinae (Capítulo II). Finalmente, empleamos herramientas moleculares con el fin de corroborar las identificaciones basadas en morfología, asociar los morfotipos femeninos a sus masculinos conspecíficos, explorar las relaciones filogenéticas entre géneros y especies, y generar la primera biblioteca de códigos de barras de ADN (CO1) para las especies de Rhiniidae. Para ello, generamos fragmentos de códigos de barras de ADN (CO1) de 138 especímenes de Rhiniidae. Para inferir los límites entre especies y su monofilia se utilizaron árboles de Inferencia Bayesiana y Máxima Verosimilitud. Esto se complementó con las variaciones genéticas intraespecíficas e interespecíficas reconstruidas con distancias por pares utilizando el modelo de sustitución de nucleótidos de Kimura-dos-parámetros (K2P) y la delimitación de especies mediante el análisis ABGD. La mayoría de las especies delimitadas a nivel morfológico se lograron recuperar como monofiléticas. Se determinaron entre 65 y 68 posibles especies de Rhiniidae presentes en nuestro estudio, así como 31 morfotipos femeninos se vincularon con éxito a sus machos conspecíficos (Capítulo III). Esta investigación demuestra la importancia de revisar las colecciones entomológicas para mejorar el conocimiento de la diversidad y de usar la información que aportan las etiquetas de los especímenes como un valioso recurso de datos para interpretar: ocurrencia temporal y espacial, preferencias ambientales y asociaciones con plantas u otros organismos como termitas, que a su vez son relevantes para estudios de biología de la conservación, polinización e interacciones ecológicas. Además, los códigos de barras de ADN mostraron eficiencia como medio complementario para la revisión taxonómica de Rhiniidae; sin embargo, entre especies muy similares a nivel morfológico no tuvo el éxito esperado, lo que sugiere una posible divergencia evolutiva reciente y la necesidad de realizar más estudios moleculares. / Parcialmente financiada por H2020 Research and Innovation Staff Exchange Programme of the European Commission (RISE), project 645636: ‘Insect-plant relationships: insights into biodiversity and new applications’ (FlyHigh).
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1 Long Term Impact of Microimplant Assisted Rapid Palatal Expansion on Soft Tissue Nasal MorphologyChew, Laura, Suh, Heeyeon, Park, Joorok, Oh, Heesoo 01 January 2021 (has links)
Introduction: When skeletal transverse discrepancies exist between the maxilla and mandible, they commonly manifest in dental malocclusion. If left uncorrected, the malocclusion can lead to periodontal issues, tooth fractures, tooth loss, or other significant dental problems. Utilization of microimplants in palatal expansion aims to correct transverse discrepancies between the maxilla and mandible by separating the palatal suture in a parallel manner aimed at maximizing skeletal changes and minimizing dental side effects. Overlying soft tissue changes can be affected by the induced skeletal changes. The purpose of this study is to evaluate skeletal expansion and the overlying soft tissue change that occurs using MARPEs (microimplant assisted rapid palatal expanders) at the end of orthodontic treatment in skeletally mature (Cervical Vertebral Maturation (CMV) ≥ 5) patients using cone-beam computed tomography (CBCT) imaging and to evaluate soft tissue changes that occur at the time of orthodontic treatment completion using CBCT imaging. Materials and Methods: CBCT scans from 19 patients who were treated using microimplant assisted rapid palatal expanders were traced and evaluated at three time points: Before orthodontic treatment (T1), post MARPE expansion with MARPE in place (T2), and after orthodontic treatment with MARPE removed. Fourteen hard tissue landmarks and six soft tissue landmarks in the midface and nasal cavity regions were traced by three judges at each time point. The traced landmark points were averaged among all three judges and comparisons were made between the three time points to see the amount of expansion that occurred at various anatomical 2 regions. Intraclass correlation coefficient (ICC) was used to evaluate inter-judge reliability for all measurements. A repeated measures ANOVA test was used for statistical comparison across all three time points and a Tukey post hoc test was used for comparison between time points. Significance was set to .05 and ICC was set to >.70. Results: Expansion with microimplant assisted rapid palatal expanders can affect the hard tissue of the midface region as well as the overlying soft tissue. Increases in skeletal width from the ANS down to the maxillary alveolar bone were statistically significant in both the short term (T1-T2) and long term (T1-T3). The nasal cavity width at inferior turbinate area increased significantly after expansion (T2) and remained increased at treatment completion (T3) and the increased soft tissue width of the alar base that presented after expansion therapy remained increased at treatment completion. Conclusion: Maxillary expansion with microimplant assisted expanders resulted in skeletal changes throughout the maxilla and led to a significant long-term increase in nasal cavity width. The soft tissue changes associated with MARPE treatment show that a widening of the base of the nose may be expected after expansion and can remain at treatment completion.
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Pathophysiology and recovery of myotis lucifugus affected by white nose syndromeFuller, Nathan W. 13 February 2016 (has links)
Critical to our understanding of wildlife diseases is the recovery phase, a period during which individuals clear infections and return to normal patterns of behavior and physiology. Most research on effects of white nose syndrome (WNS), an emerging fungal disease in bats, has focused on the pathophysiology of winter mortality and the effects of WNS on hibernating populations. The period immediately following emergence from hibernation has received little attention, but is a critically important time for survivors of the disease. During this time, survivors face significant physical and physiological challenges as they migrate to summer habitats, potentially begin gestation in the case of reproductive females, and begin to recover from wing damage caused by the fungus, which can be extensive and may greatly increase the energetic cost of flight. In this study, I (1) test the hypothesis that free-ranging bats heal from WNS-induced wing damage, (2) determine how WNS-induced wing damage changes skin surface lipid profiles on free-ranging bats, and (3) describe the temporal process of disease recovery in a colony of captive bats, including analyses of body mass, wing damage, pathogen load, skin surface lipid profiles, and histopathological metrics of WNS. I find that bats can quickly heal from wing damage in the wild and appear healthy as early as mid-July in New England. Analysis of skin surface lipids does not reveal any striking differences between bats with wing damage and those without, although there are trends towards lower total surface lipids and increased levels of cutaneous cholesterol in bats with severe wing damage. Finally, I show that within 40 days of emerging from hibernation, bats quickly clear the fungal infection and gain body mass, undergoing rapid healing of wing damage and changes in skin surface lipid composition. Bats depend on their wings for a variety of vital processes including physiological regulation, locomotion and feeding. To fully understand the consequences of WNS and develop actionable management strategies, it is important to consider the long-term effects of this disease. My study helps fill critical knowledge gaps and will aid in the future conservation and management of affected bat species.
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IMPACT OF TRIBOSYSTEM COMPATIBILITY ON TOOL WEAR AND SURFACE INTEGRITYArif, Taib 11 1900 (has links)
H13 tool steel is widely used in the mold and die industry. Due to tighter geometric tolerances and higher quality expectations, the use of hard machining has increased over the years. Hard machining refers to the machining of materials in their hardened state. The challenges with hard machining are rapid tool wear and maintaining a high surface integrity of the machined surface. Surface integrity is measured in terms of surface roughness, residual stresses, presence of surface and subsurface cracks, and the quality of the developed microstructure. In order to minimize wear and improve product quality, researchers are working on the development of different tool coatings. Some of the recent tool coatings function by adapting to their environment using heat to form thin layers of oxides, referred to as ―tribo-films‖, on the surface of the tool. If engineered properly, these tribofilms can prolong tool life and improve the surface integrity of a hard machined surface. A titanium based nano multi-layered coating (TiAlCrSiYN/TiAlCrN) has been developed by researchers at the MMRI. The tribological performance of two different coatings TiAlCrSiYN/TiAlCrN and TiAlCrN were tested in a hard machining metal cutting process. The impact of these coatings on tool wear, Cutting process (Chips) and Surface Integrity (Quality of machined surface) was assessed. This research involves characterizing the coating to understand how the formation of different oxide films (tribofilms) effect tool wear and surface integrity. The generation of these tribofilms is sensitive to coating composition and cutting condition (temperature/pressure). Next, an in-depth characterization of the chips produced during machining was carried out as part of studying the effect of different tribological conditions between the tool and workpiece. The chip's hardness, oxidation, chip formation mechanism and topography as the chip slid against the cutting tool surface was studied. Also, the Surface integrity of the machined part was investigated, considering its microstructure, residual stresses and surface roughness. Lastly, tests were performed in an attempt to accelerate the generation of beneficial tribofilms. Results indicate significant improvement in wear life and surface integrity of the machined surface due to the generation of tribo-films in this machining application. / Thesis / Master of Applied Science (MASc)
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Molecular Techniques for the Identification of Commensal Fungal Populations on Cave Roosting BatsNjus, Kelsey Anne 16 September 2014 (has links)
No description available.
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Effect of Foliar Nitrogen and Sulfur Applications on Aroma Profile of Vitis vinifera L. cv. Petit Manseng using Modified Quantitative Descriptive Analysis, SPME GC-MS and Electronic Nose TechnologyKelly, Molly Kathleen 12 June 2013 (has links)
Petit Manseng grapes harvested in 2011 and 2012 were fertilized with soil nitrogen at 0, and 30 kgN/ha, foliar nitrogen at 15kg/ha and foliar nitrogen plus sulfur at 15kg/ha and 5kg respectively. Point quadrat analysis demonstrated foliar nitrogen alone and nitrogen plus sulfur treatments increased percent gaps and lower leaf layer numbers. Berry juice samples differed in ammonia, arginine and yeast assimilable nitrogen concentration. Total glycosides were 25 percent higher in the foliar nitrogen treatment versus the control treatment. Electronic nose measurements on field clusters and laboratory berry analyses was different among treatments in volatile content. Harvest samples underwent acid or enzyme hydrolysis of precursor fractions. Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC/MS) analysis identified 27 free aroma and flavor compounds and 52 bound compounds. Lactones and carboxylic acids were the major components of the free fractions while bound fractions had increased concentrations of alcohols, esters and terpenes compared to the free fraction. With nitrogen fertilization, acid and enzyme hydrolysis had reduced concentrations of some higher alcohols and carboxylic acids. Acid hydrolysis released more terpenes with nitrogen treatments versus enzymatic hydrolysis. Ester content was increased in both acid and enzyme hydrolysis fractions in vines receiving nitrogen treatments. For descriptive analysis, eight trained panelists described aroma, flavor, texture/mouthfeel and aftertaste attributes. Analysis of Variance (ANOVA) demonstrated that wines were a significant source of variation with 23 of the 24 attributes used. Wine principal component analysis (PCA) of aroma attributes explained 23.5% of the variation from PC1, while flavor-by-mouth and texture/mouthfeel attributes explained 26.3% of the variation due to PC1. The aim of this study was to develop descriptive terms for Petit Manseng and determine the influence of fruit nitrogen levels on the aroma and flavor profile of this cultivar. / Ph. D.
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Instrumental Methods for Determining Quality of Blue Crab (Callinectes sapidus) MeatSarnoski, Paul J. 11 June 2007 (has links)
The purpose of this study was to find an alternative instrumental method to sensory analysis and to further investigate the aroma properties of spoiling blue crab meat. This was accomplished by use of a Cyranose 320™ Electronic Nose, Draeger-Tubes®, and solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). These techniques were compared to the more established techniques for determining quality of blue crab meat of sensory and microbiological analysis. Three different electronic nose methods were used to evaluate five sequentially spoiled groups of crab meat. The manufacturer's recommended setup only resulted in a 30 % correct separation of the known groups, and only 10 % of the samples were correctly identified when coded unknown samples were used to validate the electronic nose training results. The compressed air method which utilized compressed tank breathing air, filtered through activated carbon and moisture traps resulted in 100 % separation of the known groups, but only correctly identified 20 % of the coded unknown samples. Draeger-Tubes® were found to be more accurate and precise compared with the electronic nose. All 5 groups of samples analyzed using Draeger-Tubes® were found to be significantly different at α = 0.05 using a Tukey-Kramer ANOVA statistical procedure. The coded unknown samples were correctly identified at a rate of 83 %. The simplicity and rapidness of this procedure allows it to possibly be an alternative for the crab industry as an alternative to sensory analysis.
SPME-GC-MS found trimethylamine (TMA), ammonia, and indole to best correlate with spoilage of blue crab meat. TMA was found to be sensitive to the minor changes in the early stages (0 - 4 days of refrigerated storage) of spoilage for blue crab meat. Indole corresponded well with sensory results, which suggests that indole may be a promising indicator for detecting early, mid, and highly spoiled samples. It is feasible that these methods can be applied to other crustaceans to determine spoilage level. / Master of Science in Life Sciences
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Seasonal activity patterns of bats in the Central AppalachiansMuthersbaugh, Michael S. 27 March 2018 (has links)
Two threats to bats are especially pervasive in the central Appalachian Mountains of the eastern United States: a fungal disease called White-nose Syndrome (WNS) and wind energy development. White-nose Syndrome has caused the death of millions of bats in North America, and multiple hibernating bat species are affected in the central Appalachians. Wind energy is one of the most rapidly-growing energy sources in eastern United States, and bats are often killed when they fly near wind turbines. Fatality rates at wind turbines is highest in bat species that migrate instead of hibernate. There is limited data on bats during the autumn and spring seasons in the central Appalachian Mountains, and the impacts of WNS and wind energy development may be exacerbated during these seasons. Therefore, I sought to determine patterns and drivers of activity for hibernating bat species during autumn and spring around hibernacula. Similarly, I set out to determine patterns and drivers of activity for migratory bat species during autumn and spring along mountain ridgelines in the central Appalachians. Lastly, I searched for evidence of potential WNS-induced changes in the summer ecology of the once common northern long eared bat. This study can help elucidate patterns of bat activity during largely understudied seasons. Furthermore, it can provide useful information needed by land managers to implement actions that could help alleviate and/or avoid potential additive negative impacts on bat species with existing conservation concerns. / MS / Two threats to bats are especially pervasive in the central Appalachian Mountains of the eastern United States: a fungal disease called White-nose Syndrome (WNS) and wind energy development. White-nose Syndrome has caused the death of millions of bats in North America, and multiple hibernating bat species are affected in the central Appalachians. Wind energy is one of the most rapidly-growing energy sources in eastern United States, and bats are often killed when they fly near wind turbines. Fatality rates at wind turbines is highest in bat species that migrate instead of hibernate. There is limited data on bats during the autumn and spring seasons in the central Appalachian Mountains, and the impacts of WNS and wind energy development may be exacerbated during these seasons. Therefore, I sought to determine patterns and drivers of activity for hibernating bat species during autumn and spring around hibernacula. Similarly, I set out to determine patterns and drivers of activity for migratory bat species during autumn and spring along mountain ridgelines in the central Appalachians. Lastly, I searched for evidence of potential WNS-induced changes in the summer ecology of the once common northern long eared bat. This study can help elucidate patterns of bat activity during largely understudied seasons. Furthermore, it can provide useful information needed by land managers to implement actions that could help alleviate and/or avoid potential additive negative impacts on bat species with existing conservation concerns.
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Ecology of Mid-Atlantic bats after white-nose syndrome: communities, reproduction, and diet within an urban-to-rural gradientDeeley, Sabrina Maris 27 January 2020 (has links)
White-nose syndrome (WNS) has reduced the abundance of many bat species within the United States' mid-Atlantic region, including the endangered Indiana (Myotis sodalis), threatened Myotis septentrionalis (northern long-eared bat) and other bats of conservation concern, such as Perimyotis subflavus (tri-colored bat), Myotis leibii (eastern small-footed bat) and Myotis lucifugus (little brown bat). Impacts to Eptesicus fuscus (big brown bat) populations have been negative, positive or neutral. Migratory bat species such as Lasiurus borealis (eastern red bat) are not impacted by WNS. To determine changes within the National Park Service National Capital Region bat communities, I surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. I documented a significant reduction in the numbers and distributions of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in Eptesicus fuscus. Documented M. septentrionalis reproduction suggests that portions of the National Capital Region may be important bat conservation areas.
To explore the relationship between bat life history and passive acoustic sampling echolocation call data, as well as to review the sampling effort required to detect the presence of extant species, I used mist-netting captures and acoustic call data collected 2015 – 2018 within the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia. Based on locally estimated scatterplot smoothing line calculations, I determined that the highest levels of maternity season acoustic activity for Eptesicus fuscus and Lasiurus borealis corresponded primarily to lactation periods. To determine sampling effort, I developed simulations based on species accumulation curves for individual species within different physiographic regions and land-cover types. I determined that the smallest sampling efforts typically corresponded to sampling additional sites versus sampling the same sites with more nights. Detection effort varied greatly by species, physiographic region and land-cover type.
Eptesicus fuscus diet has been well-studied throughout North America with visual identification methods from fecal and stomach content samples. Next-generation sequencing provides large genetic data sets analyses in a cost-effective manner and has been used to identify bat prey items. I collected Eptesicus fuscus fecal samples from mid-Atlantic regions and used next-generation sequencing to identify their prey. I documented high variation between survey areas, but did not note a clear pattern of urbanization or fragmentation impacts upon Insecta diversity. All order-level taxa that I documented had been previously documented in morphological studies; however, I did document new families, genera and species. However, I would suggest caution in using next-generation sequencing technologies as authoritative sources for documenting new diet taxa, as I noted frequent occurrences of confounding environmental DNA within the samples. / Doctor of Philosophy / White-nose syndrome (WNS) has reduced the abundance of many bat species within the United States' mid-Atlantic region, including the endangered Indiana (Myotis sodalis), threatened Myotis septentrionalis (northern long-eared bat) and other bats of conservation concern, such as the Perimyotis subflavus (tri-colored bat), Myotis leibii (eastern small-footed bat) and Myotis lucifugus (little brown bat). WNS-impacts to Eptesicus fuscus (big brown bat) populations have been negative, positive or neutral. Migratory bat species such as Lasiurus borealis (eastern red bat) are not impacted by WNS. To determine changes within the National Park Service National Capital Region bat communities, I captured bats with mist-netting techniques and recorded bat echolocation calls with active acoustics (20-minute periods; 2016–2018) and compared findings to pre-WNS (2003–2004) data. I documented a significant reduction in the numbers and distributions of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in Eptesicus fuscus. Documented M. septentrionalis reproduction suggests that portions of the National Capital Region may be important bat conservation areas.
To explore the relationship between bat echolocation calls recorded with passive (over-night) acoustic data and bat reproduction trends, as well as the amount of effort required to document bat species, I sampled 849 sites with passive acoustics and 482 sites with mist-netting during 2016 – 2018 within the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia. I determined that the highest levels of acoustic activity for Eptesicus fuscus and Lasiurus borealis (eastern red bat) within the maternity season are associated with the period of highest levels of lactation. To determine sampling effort, I used simulations to detect species in different landscape conditions. I determined that sampling additional sites requires less sampling effort than sampling more nights. The amount of effort required to detect each bat species varied, as did the impact of different landscape conditions.
Eptesicus fuscus diet has been well-studied throughout North America by identifying insect parts in feces and stomach contents. Next-generation sequencing is a process which produced large amounts of genetic data sets in a cost-effective manner, and it can be used to identify prey within bat feces. I collected Eptesicus fuscus fecal samples from mid-Atlantic regions and used next-generation sequencing to identify potential prey. I determined that bat diet varied greatly based on survey area and number of feces analyzed. At the order-level, I did not document new taxa: however, I did document new families, genera and species. However, I would suggest caution in using next-generation sequencing technologies as authoritative sources for documenting new diet taxa, as many taxa apparent within my samples were subsequently excluded, as the bats may have been incidentally ingested them.
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Changing Relationship Between Temperature and Pathogen Growth on Bats with White-nose SyndromeFife, Josh 22 April 2024 (has links)
Emerging infectious diseases (EID) pose significant threats to biodiversity. Human influence over the environment has increased opportunities for the introduction of novel pathogens to naïve hosts, potentially leading to host extinction. Understanding mechanisms of host persistence is critical for effectively conserving species affected by EIDs. Our study investigated the disease dynamics of white-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans (Pd), in little brown bats (Myotis lucifugus) across a spatiotemporal gradient. We explored the relationship between bat roosting temperatures and Pd growth rates across three phases of pathogen invasion comprising years since WNS has been present at sites: invasion (0-3), established (4-8), and endemic (9+ years). Data used by this study comes from a combination of field-based data collection in New York where WNS has been present the longest and data from a long-running project which includes from other locations in the Northeast and Midwest regions of the United States. Our results reveal a weakening interaction between temperature and fungal growth rates time with WNS progresses. We additionally observed a decrease in early hibernation fungal loads and variation in infection prevalence over time, suggesting the onset of a coevolutionary relationship between bats and Pd. This study highlights the importance of investigating changing disease dynamics when understanding the reasonings for host persistence. / Master of Science / Emerging infectious diseases threaten species with the risk of extinction. Human activities have altered habitats which has increased the spread of new pathogens to vulnerable host populations. This research focuses on white-nose syndrome (WNS), an emerging disease caused by the fungal pathogen Pseudogymnoascus destructans (Pd). The arrival of Pd to North America resulted in widespread declines in little brown bat (Myotis lucifugus) populations, however, some populations persist at stable or growing rates. This study aims to investigate how the relationship between the growth rate of Pd and bat hibernation temperature may have changed over time. We used a combination of contemporary data collected in New York and a long-running dataset that documents the invasion and establishment of Pd across the Northeast and Midwestern regions of the United States to investigate fungal growth rates during different phases of Pd invasion: invasion, established, and endemic phases. Our results indicate the relationship between temperature and pathogen growth rate has weakened over time, suggesting potential changes in the host-pathogen relationship. Additionally, we found changes in fungal loads and infection prevalence throughout hibernation, suggesting the foundation of a coevolutionary relationship between bats and Pd. This research highlights the importance of understanding changes in disease dynamics to help understand how other species at risk of emerging infectious diseases may be able to persist.
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