The impact of soil water and nitrogen variability on the fitness and performance of Neolema abbreviata Larcordaire (Chrysomelidae) a biological control agent for Tradescantia fluminensis.

Master of Science in Entomology. University of KwaZulu-Natal, Pietermaritzburg, 2018.Tradescantia fluminensis Vell. (Commelinaceae) is a plant of Neotropical origin native to the southern parts of Brazil bordering Argentina. In South Africa, it is classified as a category 1B invader species in the National Environmental Management Biodiversity Act (NEMBA) owing to its incipient phase of invasion. The occurrence of naturalised populations of T. fluminensis has so far been confirmed in all provinces except the Free State, Northern Cape and North West. In cognisance of the devastating effects of invasive alien plants on native biodiversity, ecosystem health and ultimately provision of ecosystem services, several control methods have been employed with varying degrees of success. Classical biological control, which involves the release of exotic natural enemies (pathogens and herbivorous insects), is one such method widely-used because of its relatively low costs and minimal non-target effects. For T. fluminensis, Neolema abbreviata (Larcodaire) Coleoptera: Chrysomelidae) is one agent that is earmarked for release in South Africa following a successful introduction in New Zealand. However, little is known how novel environments presented by soil water and nutrient gradients may indirectly influence its herbivore performance and life-history through alterations in host-plant quality. In this era of global climate change where anthropogenic activities have led to changes in rainfall patterns and biogeochemical cycles of major elements such as nitrogen, investigation of species responses to such is important. Results from my study show that both water and nitrogen (N) variability influenced plant biomass accumulation, foliar N content and subsequent herbivore performance, and life-history traits of both adult and larval N. abbreviata. The longest vines were on plants that had optimal irrigation under excess fertiliser whilst severely water stressed plants that had excess fertiliser had the shortest vines. Foliar N content was highest in plants that had excess fertiliser under both pulsed and optimal irrigation whilst lowest foliar N content was in plants under optimal irrigation without any fertiliser. Optimally irrigated plants that received moderate fertiliser had their highest rate of egg deposition in both no-choice and multi-choice conditions suggesting quality-based host ranking behaviour in N. abbreviata. The consequent larval performance traits which included weight gain and time to pupation were superior in this treatment thereby providing support for the preference-performance hypothesis (PPH). Feeding patterns between larvae and adults among plant treatments were largely similar suggesting uniform nutritional requirements across the life-stages. There were limited parental effects of plant quality on the life-history traits in both larvae and adults across F1 and F2 generations. In reciprocal diet transplant experiments, there were no significant responses to parental diet effects on larval weight, mortality, feeding damage, pupal weight and days to pupation. However, there were significant parental diet x test diet interactions with offspring from parents fed on high N plants generally performing better on low N test plants in traits such as larval weight gain and final pupal weights. Oviposition selection, feeding weight and longevity did not respond to the effects of parental diet nor its interaction with test diet, unlike the case with larval traits. There were significant correlations between pupal weight and number of days to pupation, pupal weight and eclosion success. I conducted a 3 x 3 full factorial experiment to determine the impact of water and fertiliser variability on the performance of Neolema abbreviata (and its host plant Tradescantia fluminensis. My results show differential responses to parental diet between larvae and adults of the same generation among an insect species with both actively feeding larval and adult life-stages. However, there was no correlation between adult weight and longevity. Overall, my thesis contributes to the growing body of literature on the impacts of anthropogenic global change on plant-insect interactions. It will also assist land managers when applying biological control of T. fluminensis. Furthermore, my results show the implications on the successful biological control (mass-rearing and field release) of T. fluminensis resulting from variable nitrogen and water conditions

Fishes in the Mngazi and Mngazana estuaries, with particular emphasis on the community structure and primary carbon sources

The fish community structure of two contrasting estuaries, one with a well developed mangrove forest (Mngazana) and the other without mangroves (Mngazi) was compared. Both the Mngazi and Mngazana estuary fish communities were dominated by marine species, reflecting the importance of these systems as nursery areas for marine fishes. The Mngazi Estuary contained 18% more estuarine fishes in terms of catch per unit effort (CPUE) than the Mngazana Estuary. The reduced tidal influence due to the narrow mouth opening is a possible reason for the heightened CPUE of estuarine species in the Mngazi estuary. The recorded higher diversity of fish species in the Mngazana Estuary when compared with the Mngazi Estuary was attributed to the greater influence of the marine environment due to the wide permanently open mouth, as well as the presence of a variety of habitats in this system. In both estuaries tropical and temperate species were captured, confirming the transitional nature of their biogeographic location which is situated close to the boundary between the subtropical and warm temperate regions of the Southern African coastline. Contrary to previous studies, which recorded seasonal changes in the proportions of tropical and temperate species, the proportions of tropical species remained unchanged at approximately 70% during the January and June sampling occasions. Global warming as a possible reason for the increased dominance of tropical species is discussed. Although several studies in southern Africa have investigated estuarine food web structure, none have compared mangrove and non-mangrove estuaries. In this study, the primary sources of carbon utilised by the fish fauna in the Mngazi and Mngazana estuaries was investigated. The carbon isotopic values of fishes in both estuaries displayed a continuum rather than a tight clustering around particular energy sources. Most detritus feeders of the family Mugilidae (mullets) from both estuaries were relatively more enriched than other fish taxa. The isotopic values of the mullet species suggest a diet derived from relatively enriched carbon sources such as benthic microalgae, the eelgrass Zostera capensis and associated epiphytes. Based on the isotopic values, piscivorous fishes from both estuaries could not be linked to specific prey fish taxa, but clearly the mullet species were not their main food source. The invertebrate feeders that were found in both estuaries showed greater isotopic variations in the Mngazana Estuary than in the Mngazi Estuary, probably reflecting the higher diversity of habitats (carbon sources) and invertebrate prey species in the Mngazana system. Generally the isotopic signatures of fishes from the Mngazi Estuary were more enriched than those from the Mngazana Estuary, thus indicating the possible effect of δ¹³C depleted mangrove derived carbon in the latter system

An assessment of the role of Education Development (EDO) officers in promoting quality teaching and learning in selected secondary schools in the King Williams Town (KWT) District

Globally, concern have been raised against the quality of teaching and learning driven by international institution such as the United Nations Educational, Scientific and Cultural Organization and agenda of the Education for All policy. In South Africa, the QTL in secondary school remains low and compromised despite the implementation of EFA policy and use of EDOs in South Africa generally and King Williams Town (KWT) in particular. The drive of this study is to assess the role played by EDOs in supporting QTL in selected secondary schools in King Williams Town District. The study used a qualitative approach, a case study design was followed and the case in point for this study is EDOs in KWT district. Their roles where assessed between two secondary schools namely Enoch Sontonga high school and Nosizwe high school. Ten (10) interviews using face-to face and telephonic method. The study managed to conduct five face-to-face interviews among EDOs as they were conveniently located during a period of workshops in the circuit and two educators and three principals were interviewed electronically. Purposive and convenience sampling techniques were used to select participants. Using the Popper’s theory of learning perspective the study found out that quality teaching and learning in KWT schools is dependent on factors such as time on task, scope of learning, learning environment, teaching methods and strategies, support and monitoring programmes, the teacher preparedness and their motivation and availability of attractive incentives to retain quality practitioners in their classrooms. The study found out that presently the EDOs are performing various roles such as offering support to the SMT through helping them understand their function within the school and the broader education system and helping in developing systems for monitoring and recording progress made by learners towards achievement of targets set. However, there are challenges encountered by EDOs when supporting schools to improve the QTL that were discussed namely, lack of human resources and material resources; educator resistance; non-academic activities; learner and teacher absenteeism; programmes alignment; and work overload. These challenges can be addressed using strategies such as human resources training and recruitment; programmes coordination and stakeholder cooperation; transport provision; consequence management; attitude change and policy alignment and implementation. The study recommends investment in leadership, Monitoring and evaluation, stakeholder engagement and training.Thesis (MPA) -- University of Fort Hare, 202

An assessment of the role of Education Development (EDO) officers in promoting quality teaching and learning in selected secondary schools in the King Williams Town (KWT) District

Globally, concern have been raised against the quality of teaching and learning driven by international institution such as the United Nations Educational, Scientific and Cultural Organization and agenda of the Education for All policy. In South Africa, the QTL in secondary school remains low and compromised despite the implementation of EFA policy and use of EDOs in South Africa generally and King Williams Town (KWT) in particular. The drive of this study is to assess the role played by EDOs in supporting QTL in selected secondary schools in King Williams Town District. The study used a qualitative approach, a case study design was followed and the case in point for this study is EDOs in KWT district. Their roles where assessed between two secondary schools namely Enoch Sontonga high school and Nosizwe high school. Ten (10) interviews using face-to face and telephonic method. The study managed to conduct five face-to-face interviews among EDOs as they were conveniently located during a period of workshops in the circuit and two educators and three principals were interviewed electronically. Purposive and convenience sampling techniques were used to select participants. Using the Popper’s theory of learning perspective the study found out that quality teaching and learning in KWT schools is dependent on factors such as time on task, scope of learning, learning environment, teaching methods and strategies, support and monitoring programmes, the teacher preparedness and their motivation and availability of attractive incentives to retain quality practitioners in their classrooms. The study found out that presently the EDOs are performing various roles such as offering support to the SMT through helping them understand their function within the school and the broader education system and helping in developing systems for monitoring and recording progress made by learners towards achievement of targets set. However, there are challenges encountered by EDOs when supporting schools to improve the QTL that were discussed namely, lack of human resources and material resources; educator resistance; non-academic activities; learner and teacher absenteeism; programmes alignment; and work overload. These challenges can be addressed using strategies such as human resources training and recruitment; programmes coordination and stakeholder cooperation; transport provision; consequence management; attitude change and policy alignment and implementation. The study recommends investment in leadership, Monitoring and evaluation, stakeholder engagement and training.Thesis (MPA) -- University of Fort Hare, 202

Accumulation from Below : Smallholders and public irrigation investments in Kilombero Valley, Tanzania

Smallholders in Tanzania and elsewhere in Africa are increasingly differentiated. This thesis contributes to the empirical and conceptual understanding of the differentiation processes in irrigation by following the internal dynamics among smallholders linked to public investments in improving smallholder initiated small scale irrigation schemes in Kilombero district, Tanzania. The aim of the thesis is to examine the role of public investments in irrigation in transforming rural smallholder farmers and how inclusive these investments are likely to be, specifically, in the current context where policies in irrigation are widely focused on poverty reduction among the smallholders. In this thesis I have used data collected from both irrigating and non-irrigating villages in Kilombero district, Tanzania so as to capture overall transformations in the area and how irrigation contributes to agricultural development and differentiation among smallholders. A combination of methods was used in this thesis, these includes participatory wealth rankings, interviews and walking interviews, focus group discussions, questionnaire survey, and remote sensing data. This thesis consists of four papers and an introductory “kappa”. The study mainly problematizes the general conception within agriculture and irrigation policies that smallholders are homogenous and builds on theories of ‘accumulation from above’ and ‘accumulation from below’ to analyse development and differentiation among the smallholders in irrigation.  In following processes of accumulation among the smallholders, the study links public investments in smallholders’ small-scale irrigation with the processes of ‘accumulation from below’. Findings of this thesis indicate that public investment in smallholders’ small-scale irrigation builds on pre-existing social differences among the smallholders. In all sub-cases in Kilombero, initial development of irrigation was done by farmers through their own initiatives as a form of a ‘farmer-led’ irrigation development. These developments were mainly traced from the late 1970s to early 1980s, and attracted state investments in lining the canals later in the 1990s onwards. However, it was until the late 1990s to early 2000s where there was increased cultivation in the irrigated areas. The increase went hand in hand with neo-liberalisation of the Tanzanian economy since late 1980s and privatisation of agriculture in the area from 1998. As smallholders were responding to market stimuli and increased productivity in both irrigated and rain-fed cultivation, they became increasingly differentiated. The wealthier farmers were cultivating mostly extensively in relatively larger pieces of land, and the less wealthy farmers were combining cultivation in smaller rain-fed fields and providing labour to other wealthier farmers. Most of the middle wealthy farmers were concentrated in irrigation, and therefore investment in irrigation was clearly benefiting the middle wealthier farmers. The thesis argues that expansion of rice irrigation in Kilombero plays a crucial role in the current agricultural transformations in Kilombero as rice is both a food and commercial crop in the area. In conclusion, the thesis argues that the current investments in smallholders’ small-scale irrigation are fueling processes of ‘accumulation from below’ which are more inclusive as they benefit middle smallholders rather than the large wealthier farmers. These findings points to the importance of focusing on smallholders’ in agriculture and irrigation development for a more inclusive agricultural transformation

Accumulation from Below : Smallholders and public irrigation investments in Kilombero Valley, Tanzania

Smallholders in Tanzania and elsewhere in Africa are increasingly differentiated. This thesis contributes to the empirical and conceptual understanding of the differentiation processes in irrigation by following the internal dynamics among smallholders linked to public investments in improving smallholder initiated small scale irrigation schemes in Kilombero district, Tanzania. The aim of the thesis is to examine the role of public investments in irrigation in transforming rural smallholder farmers and how inclusive these investments are likely to be, specifically, in the current context where policies in irrigation are widely focused on poverty reduction among the smallholders. In this thesis I have used data collected from both irrigating and non-irrigating villages in Kilombero district, Tanzania so as to capture overall transformations in the area and how irrigation contributes to agricultural development and differentiation among smallholders. A combination of methods was used in this thesis, these includes participatory wealth rankings, interviews and walking interviews, focus group discussions, questionnaire survey, and remote sensing data. This thesis consists of four papers and an introductory “kappa”. The study mainly problematizes the general conception within agriculture and irrigation policies that smallholders are homogenous and builds on theories of ‘accumulation from above’ and ‘accumulation from below’ to analyse development and differentiation among the smallholders in irrigation.  In following processes of accumulation among the smallholders, the study links public investments in smallholders’ small-scale irrigation with the processes of ‘accumulation from below’. Findings of this thesis indicate that public investment in smallholders’ small-scale irrigation builds on pre-existing social differences among the smallholders. In all sub-cases in Kilombero, initial development of irrigation was done by farmers through their own initiatives as a form of a ‘farmer-led’ irrigation development. These developments were mainly traced from the late 1970s to early 1980s, and attracted state investments in lining the canals later in the 1990s onwards. However, it was until the late 1990s to early 2000s where there was increased cultivation in the irrigated areas. The increase went hand in hand with neo-liberalisation of the Tanzanian economy since late 1980s and privatisation of agriculture in the area from 1998. As smallholders were responding to market stimuli and increased productivity in both irrigated and rain-fed cultivation, they became increasingly differentiated. The wealthier farmers were cultivating mostly extensively in relatively larger pieces of land, and the less wealthy farmers were combining cultivation in smaller rain-fed fields and providing labour to other wealthier farmers. Most of the middle wealthy farmers were concentrated in irrigation, and therefore investment in irrigation was clearly benefiting the middle wealthier farmers. The thesis argues that expansion of rice irrigation in Kilombero plays a crucial role in the current agricultural transformations in Kilombero as rice is both a food and commercial crop in the area. In conclusion, the thesis argues that the current investments in smallholders’ small-scale irrigation are fueling processes of ‘accumulation from below’ which are more inclusive as they benefit middle smallholders rather than the large wealthier farmers. These findings points to the importance of focusing on smallholders’ in agriculture and irrigation development for a more inclusive agricultural transformation

Thermal tolerance in Spodoptera frugiperda: Influence of age, sex, and mating status

Temperature plays a key role in shaping the physiology and behavior of ectotherms where responses can depend on age, sex and ontogeny. We investigated the effects of age, sex and mating status on thermal tolerance of Spodoptera frugiperda 3-, 6- and 9-days old adults heat shocked at adult, pupal and larval stages, at 40 °C for 2 h. Our results showed varied significant critical thermal maxima across mating status, age, sex and life stage in tested insects after heat shock. The virgin females CTmax increased with age while it fluctuated in males and 6 days old virgin females had higher CTmax than males. The 3 day old mated females had the highest heat tolerance while 6 days old virgin males the lowest heat tolerance. There was no significant difference in CTmax recorded between virgin males and females aged 3 and 9 days as well as 3, 6 and 9 day mated males and females. There was also no significant interaction between mating status and sex but there was a significant interaction effect between life stage and age. Mated males had higher CTmax than females across all heat shocked developmental stages. The results show a high level of fitness and survival in S. frugiperda females, which may be advantageous in invasion. This study also showed “carry over” effects in adults heat shocked at juvenile stage, with aged adults showing decline in CTmax. This study suggests that plasticity of thermal tolerance may be an important approach for S. frugiperda invasion

Mtsitso 1

Venancio Mbande's solo timbila xylophone musi

Mabandla

One of Venancio Mbande's new Mgodo dance song accompanied by the timbila xylophone for analysis by Andrew Trace

Mgeniso

One of Venancio Mbande's new Mgodo dance song accompanied by the timbila xylophone for analysis by Andrew Trace