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Thermal biology of the two-spotted stink bug, Bathycoelia distincta (Hemiptera: Pentatomidae) a major pest of macadamia
No full textPhD (Zoology)Department of Biological SciencesThe physiological functions of insects are mainly dictated by temperature because they rely on the
external environment to regulate their body temperatures. This temperature dependence drives their
performance, with profound implications on abundance and distribution. Daily environmental
temperature fluctuations may outpace an insect’s thermal tolerance capacity, which requires
physiological plastic mechanisms to survive. In the context of global warming, insects may be vulnerable
to temperature variations, and may ultimately determine their population dynamics. The two-spotted
stink bug, Bathycoelia distincta (Distant) (Hemiptera: Pentatomidae) is an important pest of macadamia
in South Africa. It causes damage by direct feeding on the kernel and comprises more than 80 % of the
shield bugs in the orchards. Increased crop losses due to stink bug damage threaten macadamia nut
production. Modern pest management practices require an understanding of the biology of pests and
ecology. An important question to pose is, how does an organism's thermal plastic traits affect its
ecological population dynamics? First, this study aimed to quantify the effects of temperature on
biological parameters of B. distincta life stages, such as the development rate, development duration,
survival, adult longevity, pre-oviposition period, oviposition period, and life table parameters, to
determine its thermal requirements and population growth at constant temperatures ranging from 19 to
29 °C. In addition, the effect of diet (macadamia nut and sweetcorn) on development, survival, and sex
ratio was investigated at 25 °C (Chapter 2). Second, to quantify the phenotypic plasticity of B. distincta life
stages. Two thermal tolerance indices were explored: rapid hardening (rapid heat hardening: RHH and
cold hardening: RCH) and acclimation (critical thermal maximum: CTmax and minimum: CTmin). RHH and
RCH were determined by exposing B. distincta life stages to extreme temperatures of 41 and -8 °C,
respectively. Acclimation effects on CTmax and CTmin were quantified by exposing B. distincta life stages to
48 h at 20, 25, and 30 °C. Temperature was ramped up and down at a rate of 0.2 min-1 to score survival at
high (CTmax) and low (CTmin) critical temperature points (Chapter 3). Thirdly, the development rate was
monitored (on the host plant) at temperatures ranging from 18 to 40 °C to acquire the total heat required
to complete development (degree-days) and thermal requirements of each life stage of B. distincta.
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Lastly, the physiological traits, degree-days, and thermal requirements were used to predict seasonal
generation turn-over, heat and cold thermal stress, thermal safety margin (TSM), and relative fitness in
macadamia orchards along an elevational gradient (705 - 1493 m a.s.l.) to determine the effects of climatic
zones (Cwa climate zone: Monsoon-influenced humid subtropical climate, Cwb: Subtropical highland
climate or Monsoon-influenced temperate oceanic climate, and Bsh: Hot semi-arid steppe climate)
(Chapter 4). B. distincta developed at a wide range of temperatures on sweetcorn (18 to 29 °C) and
macadamia nut (18 to 35 °C). The survival rate was high (51 to 100 %) between temperatures with a
monotonic increase of population growth from 19 to 29 °C. The total number of heat units required to
complete development was 783 DD. All life stages of B. distincta displayed thermal plasticity, but instar 2
was the most plastic stage except in response to cold acclimation. Response to extremes varied more at
low extreme temperatures compared to high extremes. As expected, the number of generations
decreased with increasing elevations from the Cwa (Arbor: 2.4 generations) to the Cwb climate zone
(Highfield: 1.1 generations). None of the life stages experienced thermal stress. TSM and relative fitness
were highest at the Cwb climate zone of the highest elevation. These findings suggest that B. distincta will
potentially cause more damage in response to global warming because of its estimated population growth
rate at elevated temperatures. Although relative fitness was highest in the Cwb climate zone, damage
could be expected in the Cwa zone due to increased number of generations. This study can also help
identify macadamia orchards in climate zones vulnerable to climate-related consequences such as
outbreaks. Climatic data combined with the DD model can be used to predict the phenology of B. distincta
and timing of chemical applications. The impacts of global warming on crop losses due to insect pests are
evident worldwide, and this study has shown that macadamia orchards in certain climatic zones (e.g., Cwa
climate zone) could be at risk of increased abundance of B. distincta. Thus, integrated pest management
strategies should be of priority to macadamia farmers for effective management of B. distincta. Given that
South Africa is the largest producer of macadamia globally and its major pest is thermal plastic, linking the
physiological traits of B. distincta life stages to climatic conditions of all macadamia growing regions in
South Africa will help understand its distribution limits.National Research Foundation (NRF
Assessing the effects of MACADAMIA ORCHARD pesticide inputs on recipient aquatic ecosystems
No full textPhDENVDepartment of Geography and Environmental SciencesAquatic environments, while not the target of many pesticide applications, often receive chemicals
through catchment runoff dynamics. In this regard, the use of pesticides in agricultural systems
may have deleterious effects on aquatic ecosystems within the same catchment area. Here using a
series of in–situ and ex–situ experiments, the study assessed (a) pesticide concentrations of
acetamiprid and chlorpyrifos across MACADAMIA ORCHARD and communal area reservoirs
using liquid chromatography tandem mass spectrometry (LC–MS/MS), (b) the behavioural
responses of Mozambique tilapia, Oreochromis mossambicus, following exposure to three
commonly used macadamia pesticides (i.e., Karate Zeon 10 CS, Mulan 20 SP, Pyrinex 250 CS at
different concentrations, (c) macadamia Macadamia integrifolia leaf litter decomposition and
mosquito colonisation following pesticide exposure, and (d) macroinvertebrate colonisation
associated with introduced stone substrates in cages within the MACADAMIA ORCHARD and
control reservoirs to explore whether macadamia pesticides affected on macroinvertebrate
colonisation dynamics.
Firstly, analysis of acetamiprid and chlorpyrifos associated with sediments in MACADAMIA
ORCHARD reservoirs revealed mean pesticide concentrations of 14.48 μg L–1 and 5.67 μg L–1,
respectively, whereas, in communal area reservoirs outside of agricultural catchments, both
pesticides were not detected. Acetamiprid was not detected across reservoir water, whereas the
mean pesticide concentration of chlorpyrifos of 6.51 μg L–1 (MACADAMIA ORCHARD) and
0.13 μg L–1 (communal area) were detected. Secondly, O. mossambicus demonstrated different
onset behavioural responses, i.e., swimming erratically, surfacing, vertical positioning, loss of
equilibrium, being motionless and mortality with high mortality at increased mortality. Thirdly,
macadamia leaf litter tended to decompose faster when exposed to pesticide treatments, whereas
chlorophyll–a were reduced. Furthermore, pesticide treatments seemed to promote mosquito (i.e.,
Culex spp.) and pupal abundances. Finally, a total of 644 macroinvertebrate individuals were
recorded across macadamia and communal reservoirs, mostly dominated by Chironominae (55.1
%), Ostracoda (14.4 %), Trithemis sp. (5.2 %), Anax sp. (5.2 %) and Radix natalensis (5.0 %).
The results indicate that MACADAMIA ORCHARD reservoirs are highly contaminated by
acetamiprid and chlorpyrifos and that these contaminants have implications for the ecological
functioning of aquatic ecosystems. Reduction of species diversity adjusted community structure
and altered energy flow and nutrient recycling were all demonstrated. The results of the study
collectively show how common pesticides used in the macadamia plantation may be exert pressure
on adjacent freshwater ecosystems. Future studies should examine effects on trophic interactions,
pesticide accumulation in faunal groups and allochthonous trophic transfer dynamics to terrestrial
environments. Such information would be useful for managers tasked with mitigation plans for the
region.National Research Foundation (NRF
An urban planning perspective on the readiness of Thohoyandou CBD public spaces in dealing with the COVID-19 pandemic: a case study of Thohoyandou CBD
No full textMURPDepartment of Urban and Regional PlanningThohoyandou CBD public spaces need to be ready in the future to urgently react to pandemics. This study aims to introduce urban planning measures that must be taken into consideration to improve the current performance of public spaces in reducing the spread of COVID-19. The study is guided by four research objectives which are as follows, (i) To analyse urban planning and urban management attributes that are critical in limiting the spread of COVID-19 in public spaces. (ii) To identify and categorize public spaces that are likely to pose a threat to limiting the spread of the COVID-19 pandemic in Thohoyandou CBD. (iii)To determine urban management factors that are significant to COVID- 19 in public spaces of Thohoyandou CBD and (iv) To come up with an urban planning-based resilience framework that will boost the ability of public spaces to respond to the challenges of a pandemic. Twenty-five public spaces were analysed based using five study constructs, which included waste management attributes, water provision attributes, ecological/environmental attributes, demographic attributes, and public space management and behaviours. Data was analysed using Hierarchical Cluster Analysis (HCA), Multiple regression Analysis (MRA) and analysis of standardised mean score z-values. Data screening procedures were employed using normality test measures of skewness and kurtosis. Results revealed that there are five critical issues that need to be addressed if we are to limit the spread of COVID-19 in public spaces. These include waste management, water provision, public space user demographics, public space management behaviors and environment integrity issues. HCA results revealed two unique categories of public spaces based on their responsiveness to the spread of COVID -19. Cluster 1(one) is made up of 10 public spaces accounting for 40 % of the total and Cluster 2 is made up of 15 public spaces accounting for 60 %. Cluster 2 type of public spaces are generally performing relatively well in responding to the COVID-19 pandemic as evidenced by positive and high standardized mean score z values when compared to cluster 1 (one) type of public spaces. MRA results revealed that the most significant (P value <0.05) attribute capable of reducing the spread of COVID-19 is water provision. The study concluded by recommending a resilience framework aimed at reducing the risk and exposure to COVID- 19 as well as building public pace capacity to withstand challenges posed by future pandemics. Critical interventions for building resilience should focus on such issues as building functional waste management and water facilities, redesigning of some public spaces, deployment of smart technologies, improved infrastructure maintenance and public space monitoring as well as rolling out of education campaigns. More
intervention efforts should be directed to 40 % of public spaces belonging to cluster 1 as they were found to be severely compromised.National Research Foundation (NRF
Determinants of Maize Seed Selection for Climate Change Adaptation among Emerging Farmers in Mopani District, Limpopo Province, South Africa
No full textMSCAGR (Agricultural Economics)Department of Agricultural Economics and AgribusinessMaize is a crucial crop in the Mopani District of South Africa, playing a vital role in food
security, economic development, and alleviation of poverty. As a staple crop in the
region, maize is an important source of food for the local population and a significant
economic activity for farmers. Farmers tends to select seed varieties for desired
benefits such as adapting to the changing climatic conditions. The main aim of the
study was to investigate the determinants of maize seed selection for climate change
adaptation among emerging farmers in Mopani district. The study used quantitative
research method. A simple random sampling was used to select the participants of the
study. Data was collected through structured questionnaire from a sample of 208
emerging maize farmers. Descriptive Statistics was used to analyze and describe
socio-economic characteristics of farmers within the study area. A multinomial Logit
Model was used to examine factors influencing choice of maize seed varieties among
emerging farmers and to determine the influence of climate change knowledge on
selection of maize seed varieties. The results of the study showed that the majority of
farmers were males, with the dominating age group being between 41 to 50 years and
had between 6 and 10 years of farming experience. Grading and standardization of
maize during the marketing phase had a significant impact on the selection of the red
seed variety, and that awareness of climate change also had a significant impact on
the selection of seed varieties. It was recommended that continuous efforts be made
to promote awareness of climate change among farmers.NR
The effect of tris aloe vera (barbadensis miller) gel on chilled and frozen-thawed bull spermatozoa quality
No full textDepartment of Animal ScienceSemen extenders protect sperm from cold shock, osmotic stress, and alterations in membrane fluidity and permeability plus provide energy substrates for sperm metabolism. Egg yolk is one of the most common additives of animal origin that are used for semen preservation, however, it has become a suspect for facilitating the transmission of diseases. Tris-aloe vera gel have several beneficial properties, such as anti-inflammatory, antioxidant, antiviral and antibacterial features. The aim of this study was to determine the effect of Tris-aloe vera gel (TAG) extender on the quality of bull spermatozoa. In experiment 1, the effect of Tris-Aloe vera gel extender was assessed after the semen was chilled at 5 0C in a refrigerator for different storage times up to 120 hours, and frozen in liquid nitrogen at -196 0C for 5 days in experiment two. Assessment was done for morphology, motility, and viability of bull spermatozoa. Semen samples were collected from four (4) Nguni bulls with proven fertility records, aged between 6 and 8 years kept at the University of Venda Experimental Farm under intensive farming practice. Collected semen samples were pooled and diluted at a ratio of 1:5 (semen to extender) in Tris-egg yolk (TEY) as a control and TAG at three different concentration levels 12%, 16% and 20% of Aloe vera gel (AVG). In experiment one, diluted semen samples were evaluated immediately after the extension using computer aided sperm analyzer (CASA) before storage at 5 0C, followed by sperm analysis after every 24 hours for 120 hours. In experiment two, freshly collected and diluted semen samples were cryopreserved and stored at (-196 0C) in LN2 for 5 days and evaluated thereafter. The results were subjected to the analysis of variance (ANOVA) for statistical analysis using a general linear model (GLM) procedures of Minitab 19 program. Tris-egg yolk extender (TEY) with 0% aloe vera gel was used as a control. In experiment one, it was found that TEY showed consistency in keeping motility at an average of 100% (p<0.05) after 120 h of chilling semen samples. Semen samples extended in Tris-aloe vera gel had a decrease in spermatozoa motility as storage time increased. Experiment two discovered that AVG can equally be used to substitute
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egg yolk in tris-based extender and be able to cryopreserve Nguni bull semen for a period of 5 days, this is due to a fact that there was no significant difference (P<0.01) in spermatozoa progressive motility, from both TEY and TAGs post thaw. It was also found that morphological normal spermatozoa were above 80% post thaw. Semen extended in TEY shows a great deal of consistency in maintaining high spermatozoa viability throughout the chilling process.NR
The effects of local economic development in poverty alleviation: a case of Lepelle-Nkumpi Local Municipality, Limpopo Province
No full textMAdminDepartment of Public and Development AdministrationThe focus of this study is to evaluate the effects of local economic development (LED) in poverty alleviation in municipalities using Lepelle-Nkumpi Local Municipality as a case study. LED is essential as it involves identifying and using primarily local resources and skills to ensure or stimulate local economic growth and community development. Municipalities are responsible to ensure the promotion of LED projects to alleviate poverty. This study was motivated by fact that there is lack of promotion of LED projects, high rate of poverty and unemployment and other socio-economic related issues that is occurring in communities within Lepelle-Nkumpi Local Municipality. Although the Municipality is continuing with the implementation of LED strategies but high rate of poverty and unemployment persist. Lack of capacity, incorrect interpretation or implementation of LED and resource constrains are some of the factors that contribute to failure of LED implementation in municipalities even though they are policies or guidelines in place.
The study adopted a qualitative research approach with the aim of interpreting and analysing the responses in thematic method. The data was obtained through semi- structured interviews from the identified municipal officials who are responsible for LED implementation, other municipal officials, economic development agency officials, project beneficiaries, community stakeholders and project leaders. The study used face-to-face interviews as a more natural way of interacting with the respondents. The purposive sampling was appropriate for this study, because the researcher wanted participants who have knowledge about the topic and who can give reliable information which will help to reach the objectives of the study. The study findings revealed LED implementation in Lepelle-Nkumpi Local Municipality is constraints by many factors which hinder it to achieving economic development and poverty alleviation. The Municipality have challenges such as lack of budget, political interference in the allocation of LED projects, double dipping of projects, dependency syndrome of LED projects, LED strategies do not address socio-economic challenges of communities, absence of monitoring and evaluation. Local economic development must contribute effectively on poverty alleviation and should have strong social focus.NR
E-commerce framework for sustainable development: A case study of SMME's in Limpopo, Mpumalanga and Northern Cape
No full textPhDBISDepartment of Business Information SystemsDigital technologies have brought about a turnaround in business, with big companies in developed countries now depending on the internet to support their business activities. While Small, Medium, and Micro Enterprises (SMMEs) contribute much to the economies of developing countries, e-commerce has not been considered as a support for sustainable development by SMMEs, in post-colonial Southern Africa. E-commerce strategies have been established and implemented successfully by big businesses in the developed world, however, these strategies fail to address issues arising from the different contexts for SMMEs in developing countries, such as South Africa. This research will contribute to the discipline of Business Information Systems by establishing a framework for implementing e-commerce for SMMEs in South Africa. Underpinned by the pragmatism philosophy, the study takes an in-depth case study approach, in which SMMEs in three provinces of South Africa were used as the population of the survey, to champion an e-commerce framework for SMMEs in South Africa. A mixed-methods research approach was applied, and both secondary and primary data were used in this study. The secondary data aided in establishing the research gap on advancing e-commerce frameworks, while quantitative data were collected using structured questionnaires, from SMMEs in Limpopo, Mpumalanga, and Northern Cape Provinces. The quantitative data was used to test the causal effect of identified factors of e-commerce in SMMEs. The SPSS software was used to analyse the quantitative data. The qualitative strand of the mixed-methods approach using semi-structured interviews, served the purpose of method triangulation with the quantitative strand enabling the gathering of further insights on how e-commerce in SMMEs can foster sustainable development. The ATLAS.ti software package was used to code and interpret the qualitative data collected from interviews, using thematic analysis. Based on the findings, an e-commerce framework for SMMEs was established, tested, and refined. The framework is intended to contribute to the formulation of government policies that will facilitate sustainable development, through e-commerce in SMMEs.NR
A Dynamic Capabilities Perspective of Big Data Analytics in Healthcare in South Africa
No full textMCom (Business Information Systems)Deparment of Business Information SystemsThe healthcare domain has constantly been swamped with a vast amount of complex data coming in swiftly. Big Data could be a term for tremendous data sets with expansive, more shifted, complex structures with troubles putting away, analyzing, and visualizing distinctive processes or results. Big Data Analytics may be a modern era of innovations and models planned to financially extract value from large volumes of a wide variety of data by empowering high-velocity capture, discovery, and analysis.
An immeasurable sum of data is created in several healthcare industry divisions, such as data from clinics, hospitals, healthcare suppliers, medical insurance, medical equipment, life sciences, and medical research. With the progression in innovation technology, there is endless potential for utilizing this data to transform healthcare.
The study aims to analyze how Big Data Analytics can be used for Data Management in Healthcare Organizations in South Africa to improve service delivery. The study reviewed the concept of BDA in healthcare, sources of Big Health Data, potential benefits and challenges, BDA capabilities, BDA technologies and techniques within healthcare, and Dynamic Capabilities Theory. The Dynamic Capabilities Theory was used as a theoretical lens to study Big Data Analytics in Healthcare.
This research used primary data. A positivist research paradigm was used in this study. To achieve the aim of the study, 170 questionnaires were distributed for data collection, but only 102 responded. SPSS 25 was used to analyze data.
The study found that the healthcare sector can spot, interpret, and pursue environmental opportunities. It can oversee and ideally synchronize resources, partners, deliverables, and tasks concerning tasks or necessities. It moreover can gather, understand, and exploit knowledge to make progressed decisions. Furthermore, it has processes that permit more effective problem-solving by combining different organizational resources. The findings further revealed that the healthcare sector could make strategic decisions and rapidly enact or execute against these by repositioning resources better to adjust the organization to the external or market environment.NR
The correlation between patients HIV status, multiple types of violence and children's future behavioral outcome in Mpumalanga and Western Cape Province
No full textMPHDepartment of Public HealthThis study investigated the correlation between Parent's HIV status, multiple types of violence and children's future behavioural outcome in Mpumalanga and Western Cape Province. The study objectives were to determine parent’s HIV status and childhood violence exposure, to determine the prevalence of multiple types of violence, to investigate children’s future behavioural outcomes and to establish the correlation between parent’s HIV status, multiple types of violence and children’s future behavioural outcomes.
Methods: Using a cross sectional survey design, a total number of 3515 were selected to participate in the study. 751 were males and 913 were females residing in Mpumalanga, while 772 males and 1079 were females residing in the Western Cape areas. Teenagers from the urban and rural areas of Mpumalanga and Western Cape Province were selected (MP=urban 848 and WC=930) (MP=rural 816 and WC=921).
Their age range was 13 - 17 years and was teenagers. The study employed a secondary data analysis of the data collected in the selected areas of Mpumalanga and Western Cape Provinces by the University of Oxford. This was in collaboration with the University of Witwatersrand, University of KwaZulu-Natal, University of Cape Town, and the Department of Social Development and Department of Health and Education in Pretoria about Violence in the study Teen Talk 2 South Africa 2011 (www.youngcarers.org.za).
Secondary data were analysed using SPSS version 27 software. Descriptive and inferential statistics were employed during data analysis. Furthermore, a cross-tabulations were used to determine differences in multiple types of violence and HIV status.
Results: Positive relationships between variables were seen. There was an influence of the independent variable on the dependant variable. Parent’s HIV status had a positive relationship with multiple types of violence and children’s future behavioural outcome.
Recommendations: Parents and community members should be psycho-educated about childhood violence exposure to create an enabling environment for their children’s mental health and development. Programs that enhance the children’s mental health should be implemented in the Mpumalanga and Western Cape Province, if not the rest of the country.
Conclusion: The study concluded that childhood violence exposure results negatively. It affects children psychologically and disrupting their daily functioning and exposing them to psychological conditions that last longer.
Keywords: Violence exposure, Parents HIV status and children’s future behavioural outcome.NR
An analysis of Fourth Industrial Revolution (4IR) and entrepreneurship in South Africa: opportunities and challenges
No full textMCom (Business Management)Department of Business ManagementAfrica and the rest of the world have witnessed plethora of changes in the way we do things, by the introduction of the fourth industrial revolution. This is not just true for the way people live, for the fourth industrial revolution has also impacted the manner in which businesses operate and perform. Its introduction presented changes, challenges and opportunities on the operations of small businesses; these have not been sufficiently tested in the body of knowledge. It is against this background that this study investigates the changes, challenges and opportunities brought by the 4IR on entrepreneurship with special focus on small businesses. The study was guided by the radical humanists‘ paradigm, the phenomenological design and the qualitative research method. Data was collected from 10 small business owners purposively sampled from Gauteng at the Ekurhuleni Local Municipality and Mpumalanga at Bushbuckridge Local Municipality. A structured interview guide was used to collect data through face-to-face interviews while an audio recorder and a notebook were used to capture the responses of the participants. The collected data was transcribed using Microsoft Word version 26 and analysed thematically. Results indicate the fourth industrial revolution applicable technologies, potential changes, challenges and opportunities facing small businesses and entrepreneurship. The value of this dissertation is that it is among the first studies contributing towards understanding of the changes, challenges and opportunities presented by the 4IR to small businesses and entrepreneurship in South Africa. The scope of the study was restricted to Bushbuckridge Local Municipality and Ekurhuleni Local Municipality; therefore, findings might not be generalisable to other areas in South Africa, to the rest of Africa or other developing countries/emerging economies. There is an opportunity to conduct similar study with other municipalities in other provinces in South Africa to gain different views. The researcher recommended that entrepreneurs should search for more information from relevant and reputable sources in order to avoid misinformation and misunderstandings as well as enrolling on 4IR education and skills programme and policymakers should implement necessary tech-related policies that will work towards providing adequate tech-support to small businesses.NR