University of the Free State

KovsieScholar (Univ. of the Free State)
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    Effective pedagogical practices teaching assistants use in hybrid teaching modes: a community of inquiry approach

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    Dissertation (M.Ed.(Higher Education))--University of the Free State, 2023Scripted lessons serve as guides for instructors in various educational circumstances, promoting pedagogical consistency. This study explored the use of semi-scripted lessons in the context of higher education, specifically on a large module that utilised hybrid teaching methods (online and face-to-face) across two campuses. This large module employs a considerable number of teaching assistants (TAs) to teach sections of the module, despite not being specialised instructors. Using the Community of Inquiry framework as a guide to gathering empirical evidence, a pragmatic, sequential, exploratory, three-phase (quantitative-qualitative-quantitative) mixed-methods research methodology was implemented to explore the effectiveness and implications of semi-scripted lessons. Convenience sampling was used in Phase 1 to observe 31 TAs’ hybrid teaching practices across the two campuses. The four highest-scoring TAs, two per campus and one per hybrid mode were chosen as exemplary TAs to be interviewed in Phase 2. An additional TA who had been awarded the “Best Presenter of the Year’ the previous year was also interviewed. Phase 3 comprised a full population survey sent to all the TAs and staff members involved in the module. The design of this survey was informed by the findings of the previous phases, and its purpose was to examine ways to improve the TA training programme. Descriptive statistics were used to analyse Phases 1 and 3 and thematic analysis for Phase 2. It was found that semi-scripted lessons contributed to the enactment of consistent, effective teaching and cognitive presences across the hybrid classrooms. However, while the semi-script included high-order thinking activities and discussion prompts, the TAs’ capacity to facilitate these were found to be lacking. Furthermore, the semi-script was found to be least effective at promoting the enactment of social presence, primarily due to TA avoidance of the scripted collaborative activities, due to time constraints. The social presence that was observed, largely arose from TA initiatives beyond the script, and these were evidenced considerably more in face-to-face than in online classes. Findings from the third phase provide suggestions for improvements to the TA training programme: optimisation of the training objectives; extending the training to five days; providing early access to the course material; devoting more time for TAs to practise facilitation, and receiving comprehensive feedback. The significance of this study lies in its exploration of semi-scripted lessons in the given context by providing support for this approach, while also highlighting its limitations. The primary limitation of this study is its context, which focused on TAs in a unique higher education setting, using semi-scripted lessons. Although this provided in-depth insights for comparable circumstances, the extent to which the findings could be generalised to other contexts would still need to be determined

    Exploring experiences of visually impaired students on support services in higher education institutions in Lesotho

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    Thesis (Ph.D.(Psychology of Education))--University of the Free State, 2023: Higher education institutions (HEIs) are regarded as the apex of the education system in many countries of the world. These institutions play a leading role in providing qualifications for their students, intellectual and physical skills necessary for innovation, creativity, self-reliance, and to survive societal and economic demands. Inclusion and admission of persons with disabilities has increased diversity in the student population. The admission of persons with disabilities brings with itself a package of factors and demands among the visually impaired students (VIS) who encountered multi-faced experiences. This study aimed to explore the daily experiences of VISs towards various available student support services in two Lesotho higher education institutions to address a significant gap in the existing literature. In the context of Lesotho, much literature has been published on disability issues specifically on visual impairment in educational institutions. However, limited studies and research addressed the support services provided to students. Appreciative inquiry, as a theoretical framework and a human rights-based approach as a conceptual framework were triangulated to establish how VISs are embraced, celebrated and appreciated by support services in their respective institutions. The human rights-based approach was used to uphold the support offered to VISS as education rights holders in higher education institutions. : The philosophical underpinning of this study was the Interpretivism paradigm that enabled the researcher to make reflections on beliefs, views and principles about the world that one lives in. The study was guided by the phenomenological research design to understand the participants‟ perceptions, experiences and perspectives towards support services. Nine (9) VISs and thirteen (13) student support services officials in two higher education institutions participated in this study. In-depth interviews, narrative interviews and an observation adopting complete observer were used as data collection tools. The Interpretive Phenomenological Analysis (IPA) was used to analyse qualitative data which is flexible and participant-oriented to acquire the real-life experiences of visually impaired students. The IPA allowed the interpretation of single units to reflect the general patterns across units. : several findings relating to the experiences of VISs towards support services were made. Higher education institutions have academic and non-academic support services for student in their academic journey. The findings are that disability the units are the most favoured and used support services by VISs in the institutions. The library, health centre, computer lab, counselling and guidance services are the least used support services. Student affairs, student welfare and special education services are partially used by visually impaired students. There are no guiding principles, models or policies guiding and governing disability issues in both institutions. Further findings are that lack of expertise, assistive devices or lack of learning material in the library not only compromise the learning by VISs but they also influence negative perceptions towards the use of these services. Disability units must be equipped with more assistive devices such as desktops with JAWS, screen readers and magnifiers. The relationship and attitude of non-visually impaired students, lecturers and support staff differs from one visually impaired student to the next. The study finds that VISs encounter several challenges in their residences including theft of properties, poor living conditions, and poor security. : The study concludes that the journey and experiences of each student are dynamic. Each student has his or her highs and lows towards different support services that may compromise or enhance one's academic success. To safeguard the academic and social well-being and success of visually impaired students, it is important for institutions to consider developing disability policies that will guide disability issues. This will protect their rights to receiving quality education, eradicating learning and teaching barriers that hinder their academic success. Development of a disability policy and guidelines will be a token of appreciating and embracing diversity in higher education institutions

    The integration of information-handling skills into the South African secondary school curriculum

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    Thesis (Ph.D.(Curriculum Studies))--University of the Free State, 2023The existing research claims that information-handling skills do not receive the necessary attention in some South African secondary schools, even though they are recommended by the National Guidelines for School Library and Information Services. The existing research affirms that this impacts negatively on learners, as a result they perform poorly in certain subjects, and this phenomenon ends up impacting on their tertiary education. The non-existence of the training manual for schools and the lack of the recent research on the integration of information-handling skills into curriculum opened the gap for this study to take place. The study intended to identify insights regarding a step-by-step integration of information-handling skills into the South African secondary school curriculum. Due to non-existence of the National School Library Policy that may provide recommendations on the integration of information-handling skills into curriculum, this study was limited to refer to few educational documents and policies, which had no in-depth information on information-handling skills but on curriculum. This study adopted an interpretivism paradigm to focus on the participants' own experiences in six secondary schools in Bloemfontein with school libraries, from various quintiles to represent the whole population relevant to the study. For this reason, either librarians or library committee members from both quintile (1-3 and 4-5) were interviewed per school during semi-structured interviews to reveal the status of the media centers. Teachers from both quintile (1-3 and 4-5) schools were requested to produce their lesson plans and learners’ research work for analysis during document analysis. Also, learners were observed while accessing the media center resources in quintile (4-5) level schools during structured observation. The study revealed that the concerns raised in the problem statement still exist to this day, and the consequences are that plagiarism is committed, and that learners may not be ready for a tertiary education, according to previous research studies. This study addresses these concerns and contributes to the body of knowledge by proposing the Information-Handling Skills (IHS) enhancement model in secondary schools. The study recommends urgent implementation of this model, this would enable the successful integration of information-handling skills into curriculum by schools at all levels

    An overview of Takayasu Arteritis at an academic hospital in Central South Africa

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    Dissertation(M.Med.(Internal Medicine)--University of Free State, 2023: Takayasu arteritis (TA) is a chronic granulomatous inflammatory vasculitis of large and medium vessels of unknown aetiology. It has a predilection for the aorta and its branches, and can affect the brachiocephalic, carotid, subclavian, vertebral, and renal arteries, as well as the coronary and pulmonary arteries. Expression of the disease is variable, often leading to symptoms of ischaemia due to blood vessel stenosis or thrombus formation within a vessel. An unknown, yet identified antigen, is thought to initiate an autoimmunological response in a genetically susceptible patient, where mononuclear infiltration in the vasa media leads to granulomatous inflammation resulting in medial thickening, intimal proliferation and obliteration of elastic layers and medial smooth muscles with cellular infiltration around the vasa vasorum. Disease progression causes tunica media destruction, often with resultant aneurismal formation or acute aneurismal dissection of affected arteries. The epidemiological distribution of TA is worldwide with the highest prevalence occurring in the Asian population. The disease is more prevalent in younger females with a female to male ratio of 4-9: 1. TA may show heterogeneous disease expression, patterns of arterial involvement and prognosis in different parts of the world. Available data on the African continent and specifically South Africa is limited. The largest study on adults with TA in SA was done in the Western Cape Province at Groote Schuur Hospital. Case reports have been documented in South Africa and Africa. Published literature in South Africa mainly has been focused on TA in the paediatric population group, and, in the Free State Province of South Africa, no published literature has been found. Clinical manifestations are variable, ranging from initially asymptomatic to vague and non-specific symptoms. As the disease progresses, classical features of TA begin to emerge with ischemic symptoms being a prominent feature. The classification of TA requires at least three of the six criteria of the American College of Rheumatology of 1990 to be present. There is often a delay in the diagnosis due to non-specific symptoms and variable clinical presentation. The diagnosis is often missed due to low clinical awareness and suspicion. No standardized criteria to assess disease activity have been formalized, further contributing to the difficulty in managing the disease. Thus far, no definitive biomarker has been found to diagnose TA. Imaging is paramount to making the diagnosis, establishing the extent of arterial involvement, and assessing disease progression and response to treatment. Computerised tomography angiography (CTA) or magnetic resonance angiography (MRA) is used to establish the diagnosis of TA. CTA is most often used in our setting due to restrictions to the accessibility of MRI. CTA and MRA are beneficial for the assessing the aorta and its main branches. Treatment for TA can be subdivided into medical and surgical treatment. The ultimate goal of treatment is to suppress the vascular inflammatory process. The natural history and prognosis of TA remains poorly defined. This is due to lacking data for long term follow up. Prognosis mainly depends on the development of complications, albeit from the disease itself or as a consequence of medical or surgical treatment. Further important prognostic factors are duration and extent of both vascular and systemic inflammation, late presentation and diagnosis and treatment resistance. : Patients who met the 1990 American College of Rheumatology criteria for the diagnosis of TA were included in this retrospective study over a twenty-one-year study period from 2000 until 2021. This study comprised of adult and paediatric patients seen at Universitas Academic Hospital, in the city of Bloemfontein, Free State. They were referred to Universitas Academic Hospital, which is a tertiary institution, from other centrally located hospital in South Africa. The records of patients were reviewed, and data were analysed from the departments Rheumatology, Vascular Surgery and Paediatrics. This included patient demographics (sex, age, and ethnicity), 1990 ACR criteria, clinical features, anatomical classification, surgical interventions, medical treatment, response to therapy, complications, and outcome. Patients were excluded if there were missing data on clinical features, if no imaging studies were performed and if they had an alternate diagnosis. : The mean age at presentation was fourteen years (9-23), with 71.8% (n= 28) female patients, and this correlates with previous studies on sex predominance and age characteristics. The cohort constituted of 71.8% (n=28) patients of Black African ethnicity and 28.2% (n=11) patients of coloured ethnicity. There were no patients of white, Indian, or Asian ethnicities included. The most common clinical features at presentation were cardiac disease (61.5%, n=24), hypertension (56.4%, n=22) and cerebrovascular disease (48.7%, n=19). 17.9% (n=7) and 15.8% (n=6) of patients presented with peripheral vascular disease and constitutional symptoms, respectively. Gastrointestinal, respiratory, and dermatological manifestations were only present in 5.1% (n=2), respectively. Angiography demonstrated the abdominal aorta to be the most frequently involvement (71.8%, 28/39), followed by common carotid artery lesions (58.9%, 23/39), subclavian artery lesions (56.4%, 22/39) and thoracic aorta lesions (48.7%, 19/39). Therefore, Numano type IV was most commonly found in this study followed by Numano type I and type IIa. Type III and Type IIb was the least common. Stenotic lesions were more common than aneurysmal disease. 94.7% (n=36) of patients were treated with glucocorticoids (GCs). 68.4% (n=26) were combined with Methotrexate and 23.7% (n=9) with Azathioprine. 31,6% (n=12) received Cyclophosphamide 2.6% (n=1) were treated with Mycophenolate Mofetil (MMF). No patients were treated with biologics. Surgical interventions comprised mainly of open surgical procedures. : This study revealed that TA, which is a large vessel vasculitis, remains rare, and improving awareness is important for making an early diagnosis and preventing morbidity and mortality. The aetiology remains uncertain although an autoimmune process is implicated. Demographical data and clinical features remain comparable to previous studies worldwide and in previously done South African studies. Cardiovascular and cerebrovascular manifestations were the most frequently seen and lead to significant morbidity. Immunosuppression remains the mainstay of treatment with all patients on glucocorticoids during the course of treatment. Glucocorticoids were still heavily relied upon in the treatment of these patients. : Future studies can be done to focus on ways in identifying patients with Takayasu arteritis earlier and exploring to identify novel biomarkers for use in diagnosis and disease activity assessment. Future research on individuals who were treated with biologics earlier in the course of their disease will be crucial to making improvements in the management of this difficult disease and comparing their outcome with patients on conventional disease modifying agents

    The transformation of diplomacy as an instrument of good governance: higher education internationalisation in South Africa

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    Dissertation(M.A.(Governance and Political Transformation))--University of the Free State, 2023Diplomacy has played a crucial role throughout history, serving as a tool to advance the interests of the countries it represents, foster international relationships, and pursue advantageous foreign policies. It offers a means to enhance a country's position in the global arena without resorting to the use of force. Diplomatic efforts prioritise peaceful dialogue and constructive discussions to reach agreements and resolve disputes between states (Barston 1997: 84). The concept of diplomacy typically involves diplomatic and political cooperation between countries, often through bilateral agreements, aimed at addressing conflicts and promoting peacemaking efforts (Berridge 2010:1). Traditionally, diplomacy has been seen as a means to resolve conflicts through negotiation, serving as an alternative to resorting to war. In extreme cases where diplomacy fails, war is often the result. Therefore, diplomacy can be viewed as an active practice that combines the art and science of collaboration among states to achieve mutually beneficial outcomes through peaceful negotiations. However, it is important to note that diplomacy can also encompass initiatives that may involve both cooperative measures and coercion, including the use of threats or even force if necessary (Du Plessis 2006:124). Diplomacy and its various activities have been present throughout human history, with some evidence and examples dating back to the 5th century and the Treaty of Westphalia (1648) (Van Langenhove 2016: n.p). Following the conclusion of World War II in 1945, a new era emerged, highlighting the significance of diplomacy in its diverse forms and the member states of the newly formed United Nations (UN) recognised the importance of formal collaboration and cooperation through diplomacy and the utilisation of diplomats to foster a more interconnected global community. During this time, the practice and role of diplomacy were significantly influenced by several intricate and interconnected factors, particularly concerning the functions and positions of states in the international arena. This cooperative approach led to the expansion of bilateral diplomacy, which focuses on relations between two sovereign states or countries and further expanded to multilateral diplomacy, involving more than two sovereign states or countries. These diplomatic frameworks became fundamental building blocks for international relations (IR) (Berridge 2005:5).

    The influence of mindfulness on employees’ resilience at Eskom, Northern Cape

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    Dissertation (MBA (Business Administration))--University of the Free State, 2023International trends such as globalisation, epidemics, and rapid technological developments impact individuals locally and internationally on all levels of society, with electricity companies experiencing increased challenges. The various challenges and stressful working conditions lead to employees experiencing exhaustion when trying to cope with the demanding work environment. Therefore, resilience, defined as one’s capability to adapt to changes, adhere to, and accomplish objectives despite existing challenges, is necessary for survival in such a turbulent environment. For Kelly et al. (2019), mindfulness is the antidote to resilience. Mindfulness is one of the individual qualities advocated to assist employees in properly managing psychological stress in the workplace and is a critical psychological resource for improving employee performance. Thus, mindfulness can be viewed as a unique personal feature of employees that protects them from negative emotions connected with a demanding workload and stressful work conditions, thereby reducing emotional tiredness. Therefore, this study aimed to determine if mindfulness influences employees’ resilience at Eskom, Northern Cape (NC). The study also aimed to determine if a relationship exists between mindfulness and resilience among employees at Eskom, NC. Lastly, using a non-experimental research design, the study aimed to determine if gender differences exist in career resilience among employees at Eskom, NC. A non-experimental quantitative survey research design was utilised to obtain the data from employees at Eskom (a large electricity company) in Northern Cape, South Africa (SA). Questionnaires used to obtain the data included the demographic questionnaire, the Adult Resilience Indicator (ARI) questionnaire, and the Mindfulness Attention Awareness Scale (MAAS) questionnaire. Data was analysed using regression analyses, correlational analyses and the t-test for independent groups. The results indicated that mindfulness positively influences career resilience. Furthermore, the results indicated no significant differences in resilience in terms of gender. The study thus provides new knowledge on the relationship between mindfulness and resilience. It also presents the rationale for implementing mindfulness training in organisations to assist employees in positively adapting to the pressures experienced by electricity companies in South Africa

    Christian faith formation and culture: a theological study of the Nsenga people

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    The antithetical antagonistic dichotomy expressed in the saying Chikristu ni Chikristu, Mwambo ni Mwambo chikristu cepeza mwambo niwachinkhalire induces a dualistic approach to Christian faith among some of the Nsenga people belonging to the Reformed Church in Zambia (RCZ), Nyanje Presbytery, Sinda and Petauke districts, eastern province of Zambia. The saying literally translates as Christianity is Christianity and tradition is tradition. Christianity found an established tradition with two implications for the practice of Christian faith. First, it portrays Christianity and the Nsenga culture as antithetical. Secondly, it relegates Christianity to a newcomer and alternative life to traditional culture. This entails that Christianity is welcomed and valued as a 'stranger'. The Christian faith has to be localised for it to transform the Nsenga people and culture from the inside. The Nsenga people belonging to the RCZ face the challenge of localising Christianity and making its teachings part of their conceptual systems. This research proposes that the theological study of the Nsenga people and their cultural formation aims to understand the causes of antagonism between Christian faith and culture, as the starting point for contextual faith formation. Contextual faith formation will strengthen relationships with God, self, and others (humanity and the environment) through knowledge, values, attitudes, beliefs, and praxis. The research explores the possibility of RCZ faith formation to hermeneutically discern possible means of integrating the outcomes from the theological study of the Nsenga people and their cultural formation, in order to address the antagonistic dichotomy. It recommends an integrated, self-theologised and decolonised faith formation conducted by engaging the Nsenga people and their culture to bring about spiritual transformation. This calls for a responsible hermeneutics of the bible, culture, and the RCZ faith tradition

    Assessment of ventricular function using gated blood pool planar and - SPECT imaging: a phantom study

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    Dissertation(MMed.Sc.(Medical Physics))--University of the Free State, 2023In the field of Nuclear Medicine, Gated Blood Pool (GBP) investigations are essential in offering vital insights into cardiac function, specifically the Left Ventricular Ejection Fraction (LVEF). The evaluation of ventricle volume changes during the end-diastolic (ED) and end-systolic (ES) phases plays a critical role in detecting, diagnosing, and managing various cardiac diseases. While the longstanding preference for Gated Blood Pool Planar (GBP-P) methods lies in their validation, non-invasiveness, and straightforward application, challenges such as anatomical overlap and the need for background correction persist. The theoretical superiority of three-dimensional (3D) analogues, specifically Gated Blood Pool SPECT (GBP-S) studies, promises to overcome GBP-P challenges by offering true volumetric representation without the need for background correction. However, this transition introduces complexity in algorithms and processing software needed for GBP-S studies. Accuracy and precision in determining LVEF is paramount in both GBP-P and GBP-S methods to avoid misdiagnosis, improper treatment, or negligence. Rigorous testing and comparison to known or true values are imperative for validating GBP processing software programs to meet set standards. A key advancement in validating these software programs is the use of digital hybrid phantoms, notably the advanced 4D-XCAT model. The model, blending voxelised and mathematical elements, mimics human anatomy and physiology. Paired with the Monte Carlo (MC) code, SIMIND, these 4D-XCAT models can be used to simulate clinically realistic GBP images, generating a database for testing, and validating various GBP software packages. Importantly, this approach avoids radiation exposure to patients and researchers and enhances the reliability of outcomes by providing benchmark input parameters for software evaluation. The primary aim of this investigation was to assess ventricular function using MC-simulated GBP-P and GBP-S images of digital patient phantom studies based on 4D-XCAT models with varying cardiac volumes and functions. The aim was achieved by considering three objectives. Firstly, a Monte Carlo simulated cardiac phantom for planar and SPECT studies was validated. The modelled gamma camera was verified using routine quality control procedures outlined by the National Electrical Manufacturers Association (NEMA). Furthermore, 3D cardiac phantoms were printed and imaged according to GBP-P and GBP-S imaging guidelines. Simulated images of these phantoms were generated using the MC code SIMIND and compared to the gamma camera-acquired images. The successful verification of these simulated images led to the next step, namely verifying the use of the 4D-XCAT model in image simulations. By simulating GBP-P and GBP-S studies of a single 4D-XCAT model, the study demonstrates excellent agreement between known and calculated ventricular parameters, confirming the reliability of the 4D-XCAT model in simulating cardiac imaging. Building on the successful simulation of the 4D-XCAT model, the second objective involved the creation of a comprehensive database comprising 64 clinically realistic GBP patient models. GBP-P simulated images from these models were utilised to evaluate four commercially available GBP-P processing software programs. The study yielded a strong correlation between calculated LVEF values and known values, thereby affirming the reliability and accuracy of the GBP-P processing software. Lastly, the research was extended to include clinically realistic GBP-S studies as part of the third objective. The phase focused on assessing the commercially available GBP-S processing software, Quantitative Blood Pool SPECT (QBS), from Cedars-Sinai. GBP-S images of the 4D-XCAT GBP database were simulated according to established imaging guidelines. The study assessed the accuracy of QBS in terms of LV volumes and EF values for two different reconstruction techniques and found a strong correlation between the calculated and known LV volumes and EF values. This paved the way for future multi-centre studies to validate other GBP-S processing software packages

    Ritual threads: between land and lake: a cultural and nature edge place articulating, facilitating, and preserving the traditional and natural ecotones in the Kosi Bay Nature Reserve

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    Dissertation (M.Arch.(Architecture))--University of the Free State, 2023The Kosi Bay Thonga fish traps are a culturally significant landmark in South Africa. The traps can be described as finely woven “fences” or “kraals” spread around the lake system. These spectacular structures are what enable Kosi Bay’s sustainable fishery. And with these activities, a temporary link between land and lake is formed within the wetland ecotone, interweaving specific ways of human movement, living, and working. The thesis outlines the design of a cultural and nature edge place articulating, facilitating, and preserving the traditional and natural ecotones in the Kosi Bay Nature Reserve. The research focuses on the preservation of the natural and human ecologies situated within the wetland ecotone, guided by the emplaced site phenomena and the community’s particular needs and activities. The focus of the dissertation stems from redefining the edge place has the potential to integrate social and cultural factors by way of an architectural approach. Architecture has the potential to sensitively affect how people use their surroundings, leading to the extension of existing rituals and everyday living that eventually become part of the interweaved phenomena of the park. This idea is implemented into the edge place to connect these concepts with Kosi Bay’s culture. Thus, the dissertation questions if an architectural response to vernacular routines, rituals, and orders, will articulate and preserve the existing cultural and natural ecotones within the coastal community of Kosi Bay. In order to create an interweaved relationship between culture and nature, the proposal grows on the existing chain of memories and ecological grid of the water edge. The theoretical methodologies of a shifting ecological grid and a chain of memories are a representation of a transparent axis that creates a roadmap for the design. The investigation gave form to a variety of methods of making which preserve indigenous knowledge and make use of environmentally friendly materials, assuring a generous and sustainable integration that lightly touches the earth and reduces the built impact on the natural environment

    Evolutionary, physiological and phenological responses of Spodoptera frugiperda to climate change

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    Thesis (Ph.D.(Entomology))--University of the Free State, 2023The threat of biological invasions due to global climate change and anthropogenic activities is growing globally. Environmental changes, such as increasing mean temperatures due to global climate warming, may exacerbate the spread of invasive insect species by improving their voltinism, survival, reproductive success and geographic range expansion. The fall armyworm (FAW) Spodoptera frugiperda is one of the most economically important invasive insect pests attacking sub-Saharan Africa (SSA) staple crops, such as maize and sorghum. First reported in West Africa in 2016, FAW has spread to the rest of SSA. Key questions arising from this rapid geographic expansion is how climate and its physiological attributes aid its invasion potential. This is particularly important in this era of global climate change where phenological mismatches are known to also influence their host utilization and survival across different life-stages and physiological status such as mating or feeding. Evolutionary responses at individual and population also play a pivotal role in survival and population persistence across various temporal scales. This study explored the evolutionary, physiological and phenological responses of S. frugiperda to climate change. First, I measured the effects of short-term exposure to heat shock on physiological responses vis critical thermal limits (critical thermal minima [CTmin] and critical thermal maxima [CT max]), and ecological traits vis reproductive success (fecundity [number of eggs per female] and hatching success) and longevity using virgin adults following heat shock at 32, 35, and 38 °C for 2 hours. Second, I assessed the effects of repeatable exposure to cold (CTmin) and chill coma recovery time (CCRT) for 0; 24; 48 and 72 hours and the body lipid content (BLC) and body water content (BWC) on adult fall armyworm (24 h old). Last, I investigated the thermal tolerance of S. frugiperda at 3, 6 and 9 days old adults heat shocked at adult, pupal and larval stages, at 40℃ for 2 hours. Heat shock improved tolerance to heat (measured as CTmax) but negatively affected cold tolerance (measured as CTmin). Males were more vulnerable to heat stress than females. Interestingly, heat shock also reduced fecundity, hatching success and adult longevity. Cold tolerance measured as CTmin improved with repeated exposure in 5th instar larvae, virgin males, and females while CCRT improved in 4th, 5th and 6th instar larvae following repeated cold exposure. Heat tolerance in virgin females showed highest CTmax in 6 day olds while it fluctuated in males. Mated males had higher CTmax than mated females across all heat shocked developmental stages. This study shows that, under heat stress, reproductive fitness in FAW is largely compromised due to low fecundity and stress resistance that is dependent on mating status, age and life-stage. Taken together, the results show that thermal variation has fitness consequences for FAW at both individual and population level. These results provide valuable data that inform mechanistic models for the geographic distribution of FAW under variable climate scenarios. This will especially be critical in developing early warning systems and area-wide strategies for FAW control

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    KovsieScholar (Univ. of the Free State)
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