Enhancing the effectiveness of the Thaumatotibia Leucotreta (Lepidoptera: Tortricidae) sterile insect technique release programme

The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is a key phytosanitary pest in the South African citrus industry. Due to its cryptic nature and its endemic presence in sub-Saharan Africa with a wide array of host plants, and eradication is not possible. However, the sterile insect technique (SIT) has been incorporated into an Area-Wide Integrated Pest Management (AW-IPM) programme to induce widespread population suppression. The successful implementation of the SIT programme required a series of well-researched phases, with one key phase being the determination of an effective overflooding ratio, previously established at 10:1. Despite this, various studies of T. leucotreta SIT programmes have reported higher release ratios than 10:1 in orchards, necessitating an investigation into their efficacy. This thesis aimed to understand the effects of higher release ratios, different combinations of sterile and fertile T. leucotreta of both sexes, compatibility of SIT and the egg parasitoid Trichogrammatoidea cryptophlebiae, and the pre-release mating levels during production and release stages to improve the effectiveness of the T. leucotreta SIT programme. This study initially investigated the impact of different ratios of sterile and fertile adults on fruit damage, sterile male competitiveness, and population growth in laboratory cages using Washington Navel oranges. Sterilised to fertile T. leucotreta adults at ratios of 0:1 (control), 10:1, 20:1, 40:1, and 60:1 were placed inside insect-rearing cages and allowed to mate, oviposit and infest the fruit. Treatment cages receiving sterile T. leucotreta produced significantly fewer damaged fruit, larval entries, and F1 adults compared to the control. The number of damaged fruit, larval entries, and F1 adults negatively correlated with the increase in the overflooding ratio of sterile to fertile T. leucotreta. Control cages had significantly higher fecundity and fertility compared to treatment cages. The 60:1 ratio exhibited the lowest per generation rate of increase (<1× from the parental [P1] to the F1 generation) compared to the 10:1 ratio (current release ratio). The effects of different combinations of both treated (T) and untreated (U) male (M) and female (F) adult T. leucotreta: UM×UF (control), TM×UF, UM×TF, TM×TF, and UM×UF×TM×TF on fruit damage, mating competitiveness, and per-generation rate of increase were tested. The treatments were housed in insect-rearing cages containing Navel oranges and allowed to mate, oviposit, and infest the fruit. Treatment cages with both treated male and female T. leucotreta had significantly fewer damaged fruit, larval entries, and emerged F1 adults compared to the control cages, except for the UM×UF×TM×TF combination. Similarly, control cages and UM×UF×TM×TF treatments had significantly Higher fecundity and fertility compared to other treatments. The TM×UF combination exhibited the lowest rate of increase per generation (<0.57× from the parental [P1] to F1 generation). A field cage study was conducted to evaluate the effects of various overflooding ratios and different combinations of sterile and fertile male and female T. leucotreta. However, the results were limited, and inconclusive due to collection of insufficient data, as the fruit infestation level was low. This could be attributed to the low quality of the moths released or effects of environmental variables on the moths. A laboratory study explored the susceptibility of T. leucotreta eggs resulting from various pairings of sterile and fertile moths to parasitism by Trichogrammatoidea cryptophlebiae. The ratios of sterile to fertile T. leucotreta used were: 0:1, 10:1, 20:1, 40:1, and 60:1. The resulting eggs were then exposed to T. cryptophlebiae for parasitism, and the parasitism rates of newly laid (24 h), 48 h and 72 h old eggs were evaluated. Overall, eggs from all ratios were suitable for T. cryptophlebiae development and acceptable for oviposition. Significantly higher number of parasitised eggs were recorded between the control (0:1) and ratios 40:1 and 60:1 at 48 h old eggs. Additionally, a higher proportion of flying T. cryptophlebiae emerged across the ratios, with a higher proportion of female-to-male sex ratio. Pre-release mating levels were studied during the production and release stages, divided into three stages: moth eclosion, irradiation, and release. A significantly higher number of spermatophores and percentages of mated female T. leucotreta were recorded at the eclosion and irradiation stages in January. Similarly, in May, a significantly higher number of spermatophores and percentages of mated female T. leucotreta were recoded post-irradiation and release stages in the Sundays River Valley region (SRV). Overall results indicated more spermatophores and percentages of mated female T. leucotreta at the irradiation and release stages in the SRV region. In conclusion, the study demonstrated that a release ratio exceeding 40:1 and different combinations of sterile and fertile T. leucotreta, especially the TM×UF combination, has a suppressive effect against T. leucotreta and integrating SIT with T. cryptophlebiae, shows potential for enhancing the effectiveness of the T. leucotreta SIT programme. Additionally, the mating competitiveness of sterile insects in dual-sex releases can be improved by controlling the level of pre-release matings.Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 202

Listening otherwise in the face of gender-based violence in South Africa: a critical exploration of the listening deficiencies in public narratives and a listening-based framework for healing and social change

South Africa has one of the highest rates of gender-based violence (GBV) in the world. This includes femicide, rape and intimate partner violence. Scholars and activists in the space of GBV have challenged society to alter the way we have been taught to engage with rape and gender-based violence. Despite many interventions, gender-based violence remains an intractable social problem. This study uses Lipari’s (2014) concept of “listening otherwise” to respond to the challenge. By interrogating how South Africa’s violent history and patriarchal society has been normalised, the study attempts to see beyond the narrow ideas prescribed by the country’s history and violent cultures. This study uses the grounded theory approach (Glaser & Strauss 1967) to investigate the relationship between listening and gender-based violence in South Africa. The concept of “listening otherwise” is explored alongside the concepts “voice”, “speak out” and “break the silence” that are the most visible and codified strategies in the fight against gender-based violence. Following the exploration, the study then develops a theoretical and methodological framework for “listening otherwise” in the spaces, fields, and engagements that deal with gender-based violence in South Africa. The two central questions of the study ask; how do we reshape the collective emotional response to patriarchal structural violence? And furthermore, how do we listen otherwise when faced with experiences of gender-based violence in South Africa? The data used to construct the framework includes in-depth interviews, studies of actual cases, academic literature, news interviews and newspaper articles. There are a multitude of ways in which people are talking about gender-based violence, exposing perpetrators and “breaking the silence”. There is, in fact, no silence around rape, gender-based violence and femicide. The silence exists around engagements about gender, misogyny and patriarchy when discussing the causes of gendered violence in the country. This research found that the public’s listening practices around gender-based violence are shaped by patriarchal cultures and rape myths which are endemic in media discourses, legal discourses and in general social talk. Building a caring society, in which people play and use restorative justice practices, may alter the communal listening practices and have an impact on the public response to gender-based violence. The framework for listening otherwise, that emerged as a result of the research, is a contribution to listening scholarship and the activism against gender-based violence. The framework considered various aspects of listening and the field of gender-based violence and arrived at six conceptual considerations and six actions for listening otherwise.Thesis (PhD) -- Faculty of Humanities, Journalism and Media Studies, 202

Perceptions and reflections of primary healthcare professionals on mental health services in Makhanda

Primary mental healthcare in South Africa is still in its early stages, despite policies that have been developed, such as the National Mental Health Framework Policy. Provinces such as the Eastern Cape are far behind development, which can be attributed to limited resources. The scarcity has been noted in the literature, but not extensively. Literature concentrated on healthcare professionals’ perspectives towards primary health greatly narrow, particularly in the Makhanda area. With the integration of primary mental health services, healthcare workers’ viewpoints have impacted on service delivery. This study aims to add knowledge and explore the perspectives of healthcare professionals on primary mental healthcare in Makhanda. The ecological systems theory was used as a theoretical framework for the study. Thematic analysis was used to examine the healthcare professionals’ insights and to extract meaning for the participants involved in the study. Thirteen participants were used, using purposive sampling in four primary healthcare settings. Data were collected using semi-structured and one-on-one interviews. The study revealed three themes including, (i) Scarcity of Mental Health Services, (ii) Mental Health Literacy, (iii) Barriers to the Provision and Use of Physical and Mental Health Services. The findings suggest that there are limited mental health care services in primary care and that there is a gap between service provision and physical and mental healthcare. The data also revealed that mental health literacy is limited, which links to the stigma around mental illness. Furthermore, evidence points out that more mental health education, human resources and training of healthcare professionals would further improve the mental health services in the Makhanda area. In addition, there are barriers to the provision of not only primary mental health care but healthcare, as well as a lack of medical equipment, human resources, and structural space that make it difficult for healthcare professionals to perform their jobs and affect clinic functioning, at times. Another barrier is that the perception of mental health service provision is simultaneously viewed in a positive and negative light and mainly received negatively by service users. In conclusion, healthcare professionals experience a deficiency of resources and a limited provision of mental healthcare, which highlights the lack of implementation of policies that have developed nationally and globally.Thesis (MA) -- Faculty of Humanities, Psychology, 202

Exploring the development of computational thinking among pre-service teachers using visual programming: an interventionist case study

Due to its cognitive effect on learners, computational thinking (CT) has gained significant attention and has been increasingly integrated into primary and secondary education worldwide. The integration of CT into educational curricula offers several benefits, including improved learning outcomes, enhanced problem-solving abilities, and the development of skills necessary for the digital landscape of the 21st century. Recognizing these benefits, South Africa introduced CT in primary schools in 2023 through a dedicated subject, coding and robotics. However, teacher upskilling remains a major challenge, as many teachers lack the necessary skills to teach this subject effectively. This problem is particularly pronounced at the foundational phase, where delivering similar content to young learners presents additional pedagogical complexities. Thus, this study explored the development of CT skills with visual programming among foundational phase pre-service teachers. Situated within the interpretive paradigm, a qualitative case study methodology was employed, owing to its effectiveness in exploring contextual factors and complexities that influence human experiences. The study involved 49 first-year pre-service teachers in an Introduction to Technology module at Rhodes University. Purposive sampling was used to select the foundational phase pre-service teachers at Rhodes University. Data was collected using CT reflective tool, semi-structured interviews, focus-group discussions, and reflective journals. This study was grounded in Vygotsky’s sociocultural theory (SCT) to understand and mediate the development of CT through visual programming. It utilized the “Code, Connect, Create” professional development (PD) model as a structured teacher training approach for CT development through visual programming. Additionally, the “Use, Modify, Create” pedagogical model was implemented as a CT framework specific to visual programming to guide and regulate pedagogical decisions during the intervention. Brennan and Resnick’s 3D CT framework was employed to identify and analyse the CT concepts and skills incorporated in the study. Thematic analysis, which involved coding was used to generate themes from qualitative data to address the research questions. Results indicated that visual programming approach enhances CT by fostering interest, creativity, and collaboration. Key enablers included contextualised project-based learning, a clear rationale for CT, and prior programming exposure. Conversely, lack of a clear CT rationale, prior programming experience, and the multimedia nature of Scratch were identified as hindrances. The study concluded that visual programming effectively enhances CT among foundational phase pre-service teachers and recommended its early integration into their training programs to enhance CT skills.Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 202

Evaluating the effectiveness of Work Integrated Learning (WIL) from the perspective of its key stakeholders: a case study of a TVET college

This research aims to evaluate the effectiveness of a Work Integrated Learning (WIL) programme from the perspective of its key stakeholders, using stakeholder theory as the framework. Stakeholder theory suggests that organisations should consider the interests and needs of various stakeholders who have a vested interest in or are affected by the organisation's activities (Freeman 1963;1984). In the context of WIL, stakeholders include students, the Technical and Vocational Education and Training College, and host employers. The study uncovers the experiences, perceptions, and recommendations of students, educators, employers, and institutions involved in the WIL programme by collecting data through interviews, focus groups, and documents. Through evaluation research, valuable insights emerge regarding the success and potential areas for improvement of WIL within TVET Colleges. The findings indicate issues like inadequate resources and uneven student readiness, and they offer helpful suggestions for better communication, resource distribution, and support systems. Additionally, this calls for more research on curriculum integration, industry collaborations, and long-term career outcomes evaluation.Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 202

New insights on classical radio galaxies from MeerKAT and uGMRT

The morphology of low and high-power sources has been the subject of a classification method for over four decades, leading to a comprehensive understanding of extragalactic radio sources. The morphological classification of radio galaxies is again a hot topic. This project aims to revisit the current classification scheme for classical radio galaxies and investigate the properties and origin of the new filamentary features which are becoming standard within and outside the radio lobes and which are suggestive of so far unexplored interactions between the radio plasma and the external medium. This thesis presents high-resolution and sensitivity studies of the nature of ten known radio galaxies: three FRIs (4C -03.43, 3C 403.1, 3C 198), three FRIIs (3C 105, 3C 227, 3C 445), tailed radio sources (CGCG046-067, NGC7503) and the FR0s (SDSS J 09157+1331, SDSS J 1120+0407). The total sample was selected from the 4C catalogue with well-defined criteria. To this aim, we are using the μJy sensitivity offered by the combination of uGMRT and MeerKAT in a frequency range from 500−1712 MHz. The radio images present several new morphological features in the radio emission at a ∼4′′ −10′′ angular resolution. Our radio maps validate the morphological classification. The sources exhibit remarkable features that raise new questions regarding the complex interaction between radio plasma emitted by host galaxies and the surrounding medium through which the jet propagates. The wealth of morphological details includes, for example, the detection of filaments in the emission from the lobes, the existence of diffuse emission beyond the hotspots, and multiple knot-like structures along the jet spine in some sources in the sample. Detailed descriptions of the overall radio structures are presented. We derived the equipartition parameters for each source in the sample, and after fitting their integrated spectrum, we estimated their global radiative ages. We find a broad range of radiative ages, i.e. 40.19−242.85 Myr. We derived in-band spectral index imaging for a few radio galaxies in the sample. This allowed us to make some preliminary considerations on the origin of the various radio features.Thesis (PhD) -- Faculty of Science, Physics and Electronics, 202

Exploring organisational learning in water resource protection: activity system analysis of social learning among resource directed measures role-players in South Africa

Globally, there are policy and practice efforts to mainstream inclusive education in different sub-fields of education. Part of the efforts have focused on investigating and finding practical mechanisms for the mainstreaming process in teacher education. Anecdotally, Education for Sustainable Development (ESD), with its focus on transformative education, collaborative learning, the community of practice and the whole institution approach, has the potential to mainstream inclusive education in teacher education practices if grounded in sociocultural realities rather than mere ideological framing. This situation is related to the need for more transformative capabilities for teacher educators to prepare teachers for inclusive pedagogical proficiency. However, in a southern African context, the outlook of the potential of pedagogical proficiency from the nexus of inclusive education, ESD and teacher education is disjointed. As such, this study focused on investigating the mainstreaming of inclusive education in teacher education practice for pedagogical proficiency through ESD Change Projects in Southern Africa, examining cases from Malawi, Tanzania and Eswatini. The study intended to gain an understanding of inclusive education and ESD in these countries, identify areas for strengthening inclusive education in teacher education practice, collaborate with teacher educators to develop strategies for mainstreaming inclusive education, and generate indicators for monitoring and evaluating inclusive education in teacher education contexts. The study used Urie Bronfenbrenner’s bioecological theory of human development and Lev Vygotsky’s sociocultural theory of learning as theoretical and analytical frameworks. The study also employed Roy Bhaskar’s critical realism philosophy as an underlabourer or a meta-theoretical framework. The study further adapted the Vygotsky-informed Engestrom’s expansive learning as a methodological torch. Together, these frameworks were used to analyse selected Change Projects within Sustainability Starts with Teachers (SST) programme, which focused on ESD capacity building in teacher educators from 11 southern African countries. In this regard, the research utilised a qualitative nested case study design. A formative interventionist research approach supported the cases in Malawi, Tanzania and Eswatini, with the study selecting SST Change Projects dealing with inclusive education through an initial scoping questionnaire. Data were generated through 12 in-depth interviews, nine workshops (involving 24 participants), document reviews, observations and reflective journals. Thematic ii analysis, employing a critical realist approach with abductive and retroductive reasoning, guided the reflexive presentation and discussion of research findings. The research findings revealed a common understanding of inclusive education as providing equal educational opportunities, ESD as supporting sustainable development, and teacher education as skill development. The research findings also highlighted the influence of teacher educators’ biopsychosocial characteristics on their perceptions of inclusive education, ESD and teacher education. Areas requiring improvement in teacher education systems included resources, attitude change, financing, cooperation, collaboration and leadership. Strategies for mainstreaming inclusive education in teacher education practice for pedagogical proficiency included curriculum implementation, policy shift, contextualisation and interactive systems. Monitoring and evaluation in all three cases focused on teaching practice, assessment, feedback tools, forums and curriculum implementation, but the absence of specific indicators for monitoring and evaluation was evident. These findings suggest multi-layered and complex implications for policy formulation, implementation practices and future research. Therefore, this thesis argues that, in a southern Africa context, the potential of pedagogical proficiency from the nexus of inclusive education, ESD and teacher education involves considering biopsychosocial characteristics to facilitate the capabilities of teacher educators. This situation necessitates utilising inclusivity mechanisms in pre-service teacher training grounded in biosocial and psychocultural realities of the region’s educational challenges. Consequently, this thesis proffers the Sustainable Inclusive Pedagogical Proficiency Process (SIP3) model as a framework to actualise the nexus of inclusive education, ESD and teacher education, and bring into focus its pedagogical proficiency potential which eventually helps with the mainstreaming process in teacher education practice via ESD. The study reported in this thesis contributes to international theory and practice development for inclusivity and ESD in teacher education practice, provides indicators for monitoring inclusive quality education in teacher education practice, and introduces a contextual dynamics model for comparative education research. The thesis is structured in eight chapters, introducing the study context, addressing literature gaps, presenting the theoretical framework, detailing research design, exploring specific cases in Malawi, Tanzania and Eswatini, discussing the research findings and its implications, and concluding with recommendations for change and future research.Thesis (PhD) -- Faculty of Education, Secondary and Post School Education, 202

The effect of Afrocentric missense variations on the structural dynamics of CYP2B6

Cytochrome P450s are a superfamily of enzymes with over 50 members involved in metabolizing 90% of xenobiotics. Among the these, families 1, 2, and 3 are responsible for approximately 80% of clinical drug metabolism. This study investigates the effect of Afrocentric missense variants on the structural dynamics of CYP2B6. Molecular dynamic simulations reveal that specific variants affect the enzyme’s flexibility and stability, potentially altering catalytic activity and drug binding properties. These findings highlight the importance of considering genetic variants in personalized medicine and drug development. By investigating CYP2B6’s function and structural changes induced by missense variants, this research advances our understanding of the enzyme’s role in drug metabolism. The study utilized computational tools such as GROMACS and AMBER for pre- and post-simulation analysis, with clustering and DSSP used to assess protein structures. Variants I328T, K282R, P428T and R140Q exhibited significant deviations in enzyme dynamics, while other variants caused minor shifts. Overall, the findings provide insight into the relationship between genetic variants and enzyme function, contributing to bioinformatics and molecular modelling approaches in drug discovery. Future studies could explore the structural and fuctional impacts of CYP2B6 bound to substrates such as antimalarials, expanding the investigation to a broader range of missense variants.Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 202

Pre-release evaluation of stem-galling and seed-feeding midges (Diptera: Cecidomyiidae) from South Africa as biological control agents for Guinea grass (Megathyrsus maximus) in Texas, United States

Guinea grass (Megathyrsus maximus) is a tall-statured C4 grass with a native range spanning sub-Saharan Africa. Intentionally exported for centuries for its grazing value, it has become a near-global invasive. Texas, USA is the first territory to initiate a biological control program for Guinea grass, targeting an invasive population with genetic origins that have been traced to South Africa. This study focuses on the identification and evaluation of biological control agents for Guinea grass. Native-range natural enemy surveys were performed in South Africa, resulting in the identification of several undescribed species of phytophagous midges (Diptera: Cecidomyiidae) on Guinea grass, including stem-galling taxa (gall midges) and seed-feeding taxa (seed midges). These taxa are expected to be highly host-specific based on the known biology of this family of insects, but the difficulty of rearing them in the laboratory necessitated field-based assessments. Field host range assessments of stem gall midges resulted in the rejection of one candidate (the horn gall midge, undescribed sp.) due to feeding on a relative of the target plant, Batochloa deusta, and the prioritization of another candidate (the blister gall midge, Arabukodiplosis vesicaria) that feeds only on Megathyrsus maximus. Combined field host range evaluations and phylogenetic analysis of a cryptic species complex of seed midges resolved this as a new genus containing up to seven species, with five species that are likely to be specific to their respective Panicoideae grass hosts, including Megathyrsus maximus and Cenchrus ciliaris (buffelgrass – also invasive in the USA). Climate matching models for the blister gall midge and seed midge on Guinea grass predicted high likelihood of establishment and nearly complete coverage of invaded sites in Texas, and identified northern KwaZulu-Natal, South Africa as an ideal source region for Guinea grass biocontrol agents. The nascent sub-field of grass biocontrol research has developed slowly because of inaccurate perceptions that grasses lack host-specific herbivores, and faces a severe taxonomic impediment given the large number of undescribed insect species feeding on grasses, especially in Africa. This study has contributed to resolving both challenges by identifying several new host-specific insect species, showing that the prospects for future success and discovery in grass biological control are promising.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202

Investigating the Transparency of Language for Place Value Understanding Comparing Indigenous Southern African Languages and European-based Languages

In this article we investigate the transparency of language in learning place value in either a Southern African indigenous language (isiXhosa, Setswana, Oshiwambo or Emakhuwa) or a European-based language (Afrikaans, English, German or Portuguese). Since language is a key mediator in developing place value understanding, it is important to investigate the ways in which the transparency of various languages may impact place value learning. A review of pertinent literature and an analysis of literal translations of number words (to thousands) of our eight languages lead us to the conclusion that Southern African indigenous languages are more accessible in their meaning, in relation to place value, than the four European-based languages spoken in Southern Africa, which we analysed. We identified two key advantages in the indigenous languages: (i) there was transparency of the ‘places’ in how numbers are named; and (ii) there was logical alignment between the spoken and symbolic representation of numbers. Despite this, many Southern African learners learn mathematics in English, Afrikaans or Portuguese even though this is not their home language (L1). This means that many learners are denied access to the transparency of the place value concepts that exist in their L1 and must manage learning place value, not only in a yet to be learned ‘foreign’ language, but also in one where they must learn to decode the idiosyncratic ‘irregularities’ of the way those languages name numbers. We conclude this article by discussing the implications of these findings for the teaching of place value in Southern African classrooms, in which indigenous learners are often learning in a European-based language that is not their L1