Masters Degrees (Biological Sciences)

Permanent URI for this collectionhttps://hdl.handle.net/10413/12380

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The effect of edible insects on the colour and nutritional value of maize porridges.
(2025) Zondo, Sindiswa.; Hlongwane, Zabentungwa Thakasile.; Munyal, Thinandavha Caswell.; Slotow, Rob.; Siwela, Muthulisi.
Food and nutrition insecurity are global problems, particularly in Sub-Saharan Africa. The limited access to nutritious food contributes to various forms of malnutrition, including undernutrition, micronutrient deficiencies, obesity, and stunting. Edible insects were recommended by the Food and Agriculture Organisation (FAO) as a cheap and sustainable solution to address food and nutrition insecurities in developing countries because they are high in protein, zinc, iron, and essential amino acids. Therefore, fortifying commonly consumed staple cereal grain food products such as uphuthu (crumbly maize meal porridge) and thin maize porridge with edible insects should significantly improve their nutritional value. This study aimed to assess the effect of edible insect meal on the nutritional value and colour of maize porridges. This was done by (1) reviewing and analysing the existing literature on the nutritional value of food products supplemented with edible insects globally (2) determining the effect of insect meal on the colour of thin and crumbly porridges supplemented with edible insects (3) determining the effect of the addition of different insects’ meals on proximate composition, mineral, and amino acid profile of thin and crumbly maize porridges. A search was conducted following the PRISMA guidelines to identify relevant peerreviewed publications on food products enriched with edible insect meal. Three edible insect types: mopane worm, termite (workers of an unidentified species of genus Macrotermes) and caterpillar in an unidentified species of genus Gynanisa, were selected and processed into separate insect meals. Each of these was used to supplement thin and crumbly maize porridges at different concentrations. The thin and crumbly porridge samples were prepared using the standard methods, but maize meal was partially substituted with 5% and 10% (w/w) edible insect meals. The systematic review search resulted in 61 eligible papers listing 26 edible insects that were used to supplement 12 different food products across different locations in the world. Bakery products were the most used food products, followed by snacks, whilst roti and soup were the least used food products, supplemented with insects. Results of the assessment of the edible insect meal on the colour and nutritional value of the maize porridges showed that the thin and crumbly porridge became darker as the concentration of insect meal was increased. A 10% termite meal concentration resulted in the darkest thin and crumbly porridge, followed by 10% mopane worm, whilst 10% of Gynanisa caterpillar meal caused the lowest darkening of the thin and crumbly porridges. Supplementing thin and crumbly porridges with edible insect meals significantly increased their protein, zinc, and iron content compared to the control. The highest protein levels were observed in porridges with 10% termite meal, while the highest zinc and iron content were found in porridges with 10% mopane worm and Gynanisa caterpillar, respectively. However, termites caused the most darkening, potentially reducing consumer acceptability. Therefore, the two insect types (mopane worm and Gynanisa caterpillar) are suitable candidates for fortifying maize food products without causing unacceptable darkening of the porridges. This increase in nutritional value upon the addition of insect meal indicates that edible insects can play a role in mitigating the risk of malnutrition in rural and resource-poor communities of South Africa, where thin and crumbly maize porridges are popular staple maize food products. Further studies are recommended to evaluate nutrient bioavailability and consumer acceptability of the insect meal supplemented maize porridges.
Phenotypic and physiological responses of Zebrafish (Danio rerio) to three commonly used anaesthetics: clove oil, 2-Phenoxyethanol (2-PE), and MS-222.
(2025) Sosibo, Langelihle Nkanyiso.; Vosloo , Andre.; Vosloo, Dalene.
The use of chemical anaesthesia in fish reduces the risk of mechanical injuries or stress in any husbandry practices or handling procedures in aquaculture, research, transport, surgery, or other veterinary practices. However, the type of the anaesthetic agent needed, the dosage required to induce a desired level of anaesthesia, and the physiological effect incurred can differ between species of fish. Since zebrafish are the most held lab fish and widely used in the aquarium trade, it is essential to determine protocols to anaesthetise zebrafish to reduce the risk of injury and stress due to their high demand and importance in these fields. It is also key to understand the physiological consequence of the anaesthetics for the benefit of studies centred around the use of physiological endpoints. This study focussed on assessing the efficacy and the metabolomic consequence of the three most used anaesthetics for fish: clove oil, ethyl 3-aminobenzoate methane sulphonic acid (MS-222), and 2-phenoxyethanol (2- PE). The study exposed adult zebrafish to various concentrations of the three anaesthetic agents and recorded the anaesthetics induction times and made observations of the phenotypic responses to each concentration. The time it took to recover from each exposure was recorded along with the phenotypic changes that occurred. The exposures were repeated using only dosages that induced the fish to stage IV (surgical) anaesthesia in 60-90 s and samples were taken for metabolomics analyses. Clove oil at 60 mg/L and 100 mg/L was the recommended anaesthetic for fast induction of surgical anaesthesia. For maintaining fish in surgical anaesthesia for an extended duration without artificial respiration, 2-PE at 500 mg/L was most effective, and for fish transport, 2-PE at 100 mg/L was suitable. Induction time was faster at higher concentrations across anaesthetics. Anaesthesia with clove oil yielded the shortest induction time at effective concentrations but required longer for full recovery at lower doses. However, recovery was comparably rapid at higher concentrations. Fish anaesthetised with MS-222 recovered quickly, as did those with 2-PE. The metabolic consequence of clove oil anaesthesia was less widespread and severe than that of 2-PE and MS-222-anaesthised zebrafish, while MS-222 affected a wider range of metabolic pathways and metabolites in comparison to 2-PE and clove oil. While all three anaesthetics elicited a stress-related metabolic response, 2-PE and clove oil did not induce a response indicative of acute or life-threatening physiological disruption. These findings serve as a basis for selecting suitable anaesthetics and dosages for zebrafish, striking a balance between physiological safety and procedural requirements to promote both animal welfare and the integrity of scientific findings.
Histopathology-based health assessment of two tilapia species in the Shongweni Dam, and metal accumulation, and human health implications.
(2024) Ncayiyana, Smangele Pretty.; Lebepe, Jeffrey.
The Shongweni Dam serves as a repository for pollutants from the upper uMlazi River catchment in KwaZulu-Natal. The uMlazi River catchment is characterized by wastewater treatment plant, agricultural, and industrial activities. Despite the aforementioned anthropogenic activities in the catchment, little is known about their impact on the aquatic biota in the Shongweni Dam and human depending on these biotas for their livelihood. Therefore, this study aims to assess the health of the commonly occurring fish species, Coptodon rendalli and Oreochromis mossambicus in relation to water quality, metal accumulation and human health risks associated with the consumption of these two species. Sampling was conducted during dry (July – August) and wet seasons (November and December) in 2021. Sampling involved collecting surface water, sediment, and fish samples. The water was analysed for physical properties, nutrients and metal concentrations. Metals were also analysed in sediment to get a comprehensive understanding on their behaviour between the two matrices. Fish were sampled and each individual was weighed and total lengths were measured. Fish were euthanized by severing the spinal cord and opened ventrally. The length and weight measurements were used to calculate the condition factor. Liver and gonads were also weighed and their weights were used to calculate hepatosomatic and gonadosomatic indices, respectively. The general health of fish was assessed using the Health Assessment Index (HAI) protocol. The liver, gill and gonads were cut out, and fixed in 10% buffered neutral formalin for histopathological examinations. A piece of muscle was wrapped with aluminium foil and frozen for metal analyses. Most physical variables were within the guidelines whereas some nutrients; nitrates (NO3-) and orthophosphates (PO43-), exceeded the guidelines indicating a eutrophic condition. Metal concentrations such as aluminum (Al), iron (Fe) and lead (Pb) exceeded guidelines whereas all metals exceeded the guidelines in sediment. Moreover, most metals in the water were higher during dry seasons whereas a contrasting trend was observed for sediment. Biometric indices and health assessment index showed no significant difference between species (p > 0.05) and seasonal variation was observed for each species (p > 0.05). Histopathology revealed regressive changes and circulatory disturbances in gills and livers were prominent and no seasonal variation was observed for both species (p > 0.05). However, gonadal lesions varied between species (p < 0.05), with pigmented melanomacrophages being the most prevalent. Among organs, gills were most affected, followed by the liver. Muscle exhibited significant concentration of chromium (Cr) and Pb exceeding the permissible limit for safe consumption for both species. Moreover, the non-carcinogenic health risks showed the Target Hazard Quotient (THQ) > 1 for Pb and Cr, with arsenic (As) and antimony (Sb) being on the verge of reaching THQ of 1. Cancer risk (CR) values, exceeding the 10-4 to 10-6 range for carcinogens As, Cr, Pb, and cadmium (Cd) indicated unsafe levels for human consumption regardless of season. It is evident that anthropogenic activities in the uMlazi River catchment are impacting the water quality and fish are also responding to the water quality deterioration. Moreover, consumption of fish from this dam should be exercised with caution as frequent consumption could result in human health risks.
Mucuna pruriens L. (DC) and Arachis hypogaea (L.) enhance soil biological and chemical properties of nutrient-deficient small-scale sugarcane soils.
(2025) Khwela, Sikhanyiso Bright.; Magadlela, Anathi.; Ramdhani, Syd.
Most of the rural population in South Africa rely on agriculture for food security and livelihood. In KwaZulu-Natal, sugarcane production plays a significant role in the livelihoods of smallscale farmers in rural areas. However, there has been a decline in sugarcane productivity and yield due to soil-health-related problems caused by long-term monoculture and excessive chemical fertilizer use. Legume cover cropping is an attractive and sustainable alternative to reduce overreliance on synthetic nitrogen (N) fertilizers since legumes increase soil N levels through symbiotic N fixation. Mucuna pruriens L. (DC) and Arachis hypogaea L. have been reported to fix approximately 34-242 kg N ha-1 and 150-200 kg N ha-1, respectively. Furthermore, these legume species have been reported to provide ecosystem services such as nutrient cycling, weed suppression, soil erosion control, increased organic matter, and microbial diversity. Therefore, this study investigated the effects of cultivating M. pruriens and A. hypogaea on the soil chemical characteristics, bacterial community composition, and enzyme activities of five different acidic and nutrient-deficient sugarcane plantation soils in KwaZulu-Natal, South Africa. Additionally, the study evaluated the N-source preference, biomass accumulation, and plant nutrition of M. pruriens and A. hypogaea growing in these acidic and nutrient-deficient sugarcane soils. Post-harvesting, the soil pH increased across all study sites for both legume species. Both M. pruriens and A. hypogaea sanctioned for Ncycling, N-fixing, and P solubilizing bacteria with the dominant strains belonging to the Burkholderia and Pseudomonas genera. The increase in P solubilizing bacteria, alkaline and acid phosphatase activity assisted with the demands of biological N fixation, allowing M. pruriens and A. hypogaea to fix 26-58% and 40-70% of N from the atmosphere, respectively. Overall, the findings of this study showed that M. pruriens and A. hypogaea contribute to soil health improvement by reducing soil acidity and increasing the diversity of nutrient-cycling bacteria and their associated enzyme activities in small-scale sugarcane soils.
Epigenetic priming and in vitro mutagenesis in sugarcane (Saccharum Spp. Hybrids) for resistance to fusarium species and Eldana saccharina (Lepidoptera: Pyralidae).
(2022) Govender, Eshani.; Watt, Maria Paula.; Snyman, Sandra Jane.; Rutherford, Richard Stuart.
In the South African sugar industry, there have been substantial economic losses of R1 billion/annum caused by the indigenous pyralid borer, Eldana saccharina (Lepidoptera: Pyralidae). To develop control measures for E. saccharina in sugarcane, it is important to understand the interactions between the stalk borer and Fusarium spp. In previous studies, in vitro assays have shown that Fusarium strains may be antagonistic (e.g., F. sacchari PNG40) or beneficial (e.g., F. pseudonyamai SC17). F. pseudonyamai SC17 is a potential endophytic indicator of E. saccharina infestation, as the association between borer infestation and infection by the fungus causes Fusarium stalk rot in sugarcane. Studies have reported that the presence of endophytic fungi may have several benefits to the host plant, e.g., the production of phytohormones such as indole-3-acetic acid (IAA), which promotes plant development. The study aimed to: 1) choose a suitable resistance priming agent between hexanoic acid (Hx) and cis-jasmone (CJ); 2) determine an appropriate culture filtrate (CF) concentration for in vitro screening of calli and plantlets for tolerance to F. pseudonygamai; 3) develop a protocol (epigenetic priming and mutagenesis) to generate mutants: primed only (0.6 mM Hx), a combination of priming and mutagenic agents (100 μM 5-AzaC + 16 mM EMS-induced); 4) screen for indole-3-acetic acid production by F. pseudonygamai; and 5) characterise in vitro selected mutants for E. saccharina and F. pseudonygamai resistance by comparing the levels of resistance between unprimed, primed, and primed + mutagenic plantlets through ex vitro screening. When cis-jasmone (CJ) and hexanoic acid (Hx) were investigated for their effect on priming for pathogen resistance, 0.6 mM Hx was selected as the optimum priming agent concentration for both the callus and plantlet regeneration stages. At the highest CF concentration (100 ppm) at the embryo germination stage, the number of plantlets was greatly reduced to 58 and 98 plantlets/0.1 g of callus, for cultivars 88H0019 and N41 respectively, compared to more than 600 plantlets/0.1 g of callus in the no CF control. Unexpectedly, in the plantlet regeneration stage all the tested CF concentrations had a significant positive effect on the percentage of plantlets that re-rooted compared with the control. Both cultivars showed a 95 - 100 % rooting ability of the plantlets, which was significantly higher than the percentage of plantlets that rooted in the embryo germination media (EGM1) containing no CF (60 - 70 %) (p < 0.001). Likewise, all the concentrations of the CF had a positive effect on the root length of plantlets, with 1500 ppm CF resulting in the highest root length of 31.5 mm ± 4.3 for 88H0019 and 34.05 mm ± 3.9 for N41. Hence, F. pseudonygamai SC17 could not be used as an in vitro selection agent in a root re-growth assay. Due to the enhanced effect of F. pseudonygamai SC17 CF on root growth, the fungal isolate’s potential to produce indole acetic-3-acid (IAA) was assessed. F. pseudonygamai produced the highest IAA concentration (743.1 nM) in the presence of L-tryptophan than in the treatment without L-tryptophan (457.2 nM). This suggests that the observed enhanced root growth may be due in part to the production of auxin (IAA) in the F. pseudonygamai SC17 CF. Acclimatised in vitro plantlets (8-9 months old) were inoculated only with F. pseudonygamai SC17 or dual inoculated: firstly, with F. pseudonygamai SC17, then 1-2 2nd instar E. saccharina larvae that were placed into the leaf whorls 2 weeks later. To confirm tolerance of the putative mutants, fungal isolations were performed on the stem sections above the inoculation lesion from symptomatic and asymptomatic plants. The results revealed that the putative mutant plants that were primed with Hx only and treated with a combination of mutagens (EMS and 5-AzaC) and priming agent exhibited a significant decrease in lesion severity as compared with controls. For both treatments, a mild lesion severity rating was recorded for plants inoculated with only SC17 for cultivars N41 and 88H0019. For the plants that were dual inoculated there was a significant difference in the lesion severity ratings between the two treatments (p < 0.001). The lesion severity rating was moderate for cultivar 88H0019 (primed with Hx) and mild for cultivar N41 (primed with Hx). Plants from the combined treatment for both cultivars resulted in a mild lesion severity rating. This protocol could be valuable in generating commercially important cultivars that are tolerant and resistant to F. pseudonygamai SC17 and possibly other sugarcane pathogens. Planting resistant cultivars is recommended as an economical and the best method for controlling diseases and pests. This approach used in this study will have the least impact on the environment and increase yields without the need for expensive chemical applications and labour.
The importance of flies for pollination at high elevation: a case study of Erica caffrorum.
(2023) Thupsie, Viren.; Van der Niet, Timotheus.; Cozien, Ruth Jenny.; Jordaens, Kurt.
Pollinator communities typically vary across elevation gradients. In particular, the contribution of bee pollination typically declines at higher elevations in favour of other pollinators, such as birds, butterflies and flies. Erica caffrorum occurs at high-elevation sites in the South African Drakensberg Mountains and has floral traits suggestive of pollination by short-tongued insects. Most Erica species with similar floral traits studied to date occur in the Cape Floristic Region at low elevations and are pollinated by honey bees. I present a case study of pollination in Erica caffrorum, including characterization of the breeding and pollination system, quantification of the associated floral traits, and experimental determination of the significance of flower colour and scent for pollinator attraction. Hand-pollination experiments confirmed that similar to most Erica species, E. caffrorum is self-incompatible. At five study sites, between 1800 and 2500 meters above sea level, pollinator observations revealed that most visitors were not honey bees but Diptera, which were identified into morphospecies and identifications verified using DNA barcoding. Assessment of pollinator importance based on pollen loads and visitation frequency identified Muscidae, Rhiniidae and Scatophagidae as the most important pollinators. Analysis of floral scent using GC-MS indicated that benzaldehyde and 2-methyl butanoic acid dominated the odour bouquet across all populations. In bioassays, a significant preference for white colour in the presence of scent was found for flies across all three experimental sites and for other visitors at one of two sites, but no other consistent preferences for colour or scent alone were detected. Across three sites, a combination of acid and benzaldehyde attracted significantly more flies than the unscented control. A similar pattern was observed for acid alone but not for benzaldehyde. This study provides novel evidence for short-tongued fly pollination in an Erica species, mediated through a combination of floral scent and colour. The similarity in traits between E. caffrorum and several other distantly related plant species in the highelevation ecosystems of the Drakensberg mountains suggests that the pollination of scented, small, white flowers by short-tongued flies found here likely represents a more widespread pollination system whose importance in southern African mountain regions is currently underestimated.
The marine aquarium trade in South Africa: a vector for alien invasive species?
(2019) Wehr, Gitte Kirsten.; Macdonald, Angus Hector Harold.; Sink, Kerry.
Biological invasions are increasingly recognized as a primary threat to biodiversity. Global transport and trade play an important role in the movement of alien species around the world, and as transport and trade have intensified over the decades, so too has the number of alien species introductions. As preventing the introduction of harmful species is a more cost-effective and efficient method to managing biological invasions, it is imperative that scientific studies are aimed at identifying the pathways responsible for introductions. The marine aquarium trade is an ever-growing business globally and only up until recently has been identified as a major pathway for the introduction of alien species. Except for the notorious cases of the invasive lionfish, Pterois volitans, and seaweed, Caulerpa taxifolia, the role of the aquarium trade towards the introduction of alien marine organisms has been largely unevaluated. With popularity rising for the marine aquarium hobby in South Africa, it is of concern that the trade remains predominantly unregulated. This study aims to investigate the risk posed by the marine aquarium trade as a pathway for the introduction of alien invasive species in South Africa. One such vector examined in this study is live rock: any type of rock or dead coral skeleton encrusted with, and containing within its crevices, a wide variety of marine organisms, including colourful sessile invertebrates and encrusting algae. A combination of morphological and DNA barcoding molecular identifications, based on the phylogenetic inference of mitochondrial cytochrome c oxidase subunit 1 (COI) and internal transcribed spacer region (ITS) sequence data, was used to assign identifications to 174 taxa harvested from imported Indonesian and Kenyan live rock. Of the 6 diverse phyla identified, one alien species was flagged as harmful due to its successful invasion of other ecosystems in the world: the glass sea anemone Aiptasia pulchella. Non-target DNA amplification of live rock associated taxa exposed the coral pathogenic bacteria Vibrio spp., further suggesting that the marine aquarium trade is also a pathway for the introduction of pathogens. A second component of the study involved the assessment, via formal survey, of the role that pet stores and hobbyists play in the introduction and transmission of marine organisms around South Africa. Irresponsible aquarium pest disposal methods and informal trading pathways were revealed highlighting the need for an education intervention to promote responsible aquarium ownership skills. The third part of the study entailed a national stock inventory of marine aquarium traded fish and revealed that the number of species traded is vast (n = 228) and that 60 % are alien to South African waters. Although the strength of this vector was not defined, this study confirms that the marine aquarium trade is a pathway for the introduction of alien and potentially invasive organisms and serves as the foundation for future research into marine aquarium trade vectors in South Africa. The findings and conclusions presented here should be considered by biosecurity monitoring and management initiatives.
Microbial community study of brine evaporation ponds: identification and analysis of the total organic carbon problem.
(2021) Rambaran, Vrishthi.; Nemukula, Aluwani.; Joslin, Paul Anthony.; Naidoo, Yougasphree.
Salt is an important compound as it is used by humans for everyday life. Salt production can occur from two processes: the use of seawater which is evaporated leaving the salt behind or the use of brine which is obtained from underground sources and undergoes the same process of evaporation as the seawater. The focus for this research will be on the microorganism population in salt produced from underground brine sources such as the source used by Botswana Ash (Pty) Ltd (Botash) which is the salt works that provided the samples for this research paper. The most important microorganism found in salt evaporation ponds is the green algae Dunaliella salina (D. salina) as discovered by previous studies. The main focus of this study was the identification of the microorganisms that are found within the salt evaporation ponds and the effect that the dominant D. salina population will have on the salt production process and also whether the dominant D. salina species can be used for production of important by-products to generate another source of income. The population genetics study on the samples from the various evaporation ponds at Botash has revealed the presence of many different microorganisms such as the bacterium Salinabacter, and the green algae Dunaliella salina which was revealed to be the dominant species. Other species such as archaea were also discovered within the salt evaporation ponds at Botash. The green algae D. salina was focused upon due to its dominance within the higher salinity ponds where it serves as the primary producer. The growth rate of the dominant D. salina species was observed in different conditions such as saline concentrations and different nitrogen sources. The results found that D. salina grows best at 3M salinity with NO3 or Urea as the nitrogen source. A study of the growth of D. salina when environmental factors were controlled showed that D. salina prefers high temperatures and high saline conditions for growth. D. salina also produces high value products such as beta carotene and Extra Polysaccharides (EPS). The production of these compounds are linked to the environmental conditions as it was found that beta carotene production is optimized when the cells are placed under stress during nitrogen starvation. EPS production occurs under all environmental conditions. The results from this research paper show that if the microbial community is controlled and optimized useful by-products can be produced, whilst minimal harm is done to the quality of salt produced.
Identification of Macrourus species (Teleostei: Gadiformes) found near Prince Edward Islands in the Southern Ocean using molecular and morphological analyse.
(2021) Shadamorgan, Vineshree.; Miya, Tshoanelo Portia.
The genus Macrourus belongs to the family Macrouridae that consist mainly of deep-sea fish. Macrourus contains five species that have a polar distribution, with one species, M. berglax, found in the Atlantic Ocean, and the other four species, M. carinatus, M. holotrachys, M. whitsoni and M. caml, found in the Southern Ocean. The species found in the Southern Ocean are morphologically similar to each other and have overlapping distributional patterns, as a result there have been instances of misidentifications within this genus. Based on morphological characteristics, previous studies have grouped the Southern Ocean Macrourus species into two pairs, viz M. carinatus and M. holotrachys, and M. whitsoni and M. caml. Despite overlapping occurrence elsewhere, morphological studies conducted in the Prince Edward Islands (PEIs) located in the Southern Ocean, have identified only one Macrourus species, M. carinatus. Since there are known cases of species misidentification using morphological identification and distribution overlap within this genus, there is a need for a molecular study that will complement the morphological data. There are no published molecular studies that reviewed species identification in these islands. This study aimed to identify Macrourus specimens found near the PEIs using molecular and morphological analyses. This assessment was done by sequencing the cytochrome c oxidase subunit 1 gene, and by measuring and counting morphometric and meristic characters. The BLAST search which had a sequence similarity of 99 – 100%, showed that there are two species represented in this dataset which were identified as M. carinatus and M. holotrachys. This observation was supported by both the phylogenetic and haplotype network trees, which formed two distinct clades. On the other hand, the morphological data did not separate the two species, supporting previous studies that discovered high levels of morphological similarity between M. carinatus and M. holotrachys, which ultimately led to their grouping and/or misidentification. It can therefore be concluded that there are at least two Macrourus species inhabiting waters around PEIs, which are morphologically similar.
Phytochemical and pharmacological analyses of Embelia ruminata (E.Mey. ex A.DC.) Mez.
(2021) Rambaran, Neervana.; Naidoo, Yougasphree.; Baijnath, Himansu.
The discovery of novel phytoconstituents to treat a plethora of ailments has become urgent as the demand for phyto-resourced products has intensified. To complement the search for new phytoceutical products, the current dissertation propelled an investigation into the phytochemical and biological potential of a South African plant, Embelia ruminata (E.Mey. ex A.DC.) Mez. The vegetative structures (leaf and stem bark) and the reproductive organs (fruit and seed) of E. ruminata were sequentially extracted using hexane, chloroform and methanol. The subsequent phytochemical analyses, which included phytochemical tests, Fourier transform infrared (FTIR) and gas chromatography-mass spectroscopy (GC-MS) of the crude extracts revealed the presence of various pharmacologically bioactive compounds. Furthermore, the data from the radical scavenging investigations demonstrated that the methanolic seed and stem bark extracts (IC50 of 3.54 and 37.47 μg/mL, respectively) displayed potent scavenging activities compared with the standard butylated hydroxytoluene (IC50 of 91.09 μg/mL). Evidently, the radical scavenging results corroborated with the cytotoxic effects of the crude extracts, which indicated that the methanolic seed and stem bark extracts had strong anticancer activities against the cancer cell lines, i.e., breast cancer (MCF-7) and human lung cancer (A549). Additionally, silver nanoparticles (AgNPs) using the aqueous extracts of the leaf, stem bark and fruit of E. ruminata were synthesised and characterised by adopting a series of standard tests. The antibacterial potential of both the AgNPs and the crude extracts were evaluated and were distinctively more effective against the Gram-positive than the Gram-negative bacterial strains, with the AgNPs of fruit extracts synthesised at room temperature (23±2 °C) and the methanolic stem bark crude extracts showing the most promising activity. Two biomonitor strains, Chromobacterium subtsugae CV017 (short chain) and Chromobacterium violaceum ATCC 12472 (long chain), were used to test the quorum sensing (QS) violacein inhibition capacity of the respective extracts. Overall, the AgNPs and crude extracts displayed more effective QS inhibition against the long chain than the short chain biomonitor strain. Interestingly, the chloroform leaf, hexane and methanol seed extracts showed QS violacein inhibitory activities against both biomonitor strains, indicating the potential of these extracts against multiple bacterial strains. These findings provide evidence that E. ruminata is a possible source of potential medicinal compounds.
Feeding dynamics of invasive (Tarebia granifera) and native (Melanoides tuberculata) freshwater gastropods.
(2020) Naidoo, Senine.; Carrasco, Nicola Kim.; Miranda, Nelson Augusto Fernandes.
Tarebia granifera has invaded several South African estuaries, outnumbering native gastropods such as Melanoides tuberculata. Comparative feeding dynamics can aid in estimating and understanding invasion impacts. This study aimed to explore the feeding dynamics of these gastropods with the use of two different approaches. Stable Isotope Analyses (SIAs) were used to investigate the dietary preferences and niche overlaps in the St Lucia Estuary, while Functional Response Experiments measured the relationship between the consumption rate of a food resource and its availability. These experiments were run both with and without the presence of heterospecific chemical cues (secondary metabolites secreted by either species) to determine whether chemical cues influence the functional responses of T. granifera and M. tuberculata. Mixed species experiments were also conducted to observe individual behaviour (active, inactive and feeding) over time and measure resource consumption when both species are placed together under high and low food availability. The SIA showed that both gastropods exhibited generalist diets, however, due to niche partitioning, there was no significant difference in their dietary niche overlap. In the FR experiments, both species exhibited Type II FRs and had similar feeding rates. However, in the presence of heterospecific chemical cues, M. tuberculata exhibited a higher feeding rate at high food availabilities, whereas T. granifera showed efficient feeding dynamics under limited food resources. In the mixed species experiments, T. granifera spent more time feeding under low food availability while M. tuberculata spent more time feeding under high food availability. This study showed that in certain conditions (e.g. high resource availability) the alien species did not always have a feeding advantage. A multiple method approach is recommended when assessing ecological impacts of invasive species.
Decadal changes in rocky shore communities in KwaZulu-Natal and survey methods for future monitoring.
(2020) Mvula, Philile Emelda.; Macdonald, Angus Hector Harold.; Pfaff, Maya Catherine.
Intertidal rocky shores form part of the sea during high tides and part of the land during low tides. They are therefore subjected to diverse anthropogenic pressures, including climate change, pollution, coastal erosion and harvesting. Due to their accessibility, rocky shores are among the most heavily exploited marine ecosystems. The rocky shores of the East and the South coasts of South Africa have been exploited for thousands of years. With growing coastal populations, they require management practices that ensure their ecological integrity and function. Rocky shore community structure along the KwaZulu-Natal (KZN) coast has been well studied between the years 1996 and 2000 when surveys were conducted at 39 sites. A monitoring Programme has since been established by Ezemvelo KwaZulu-Natal Wildlife in partnership with the Department of Environmental Affairs, Forestry and Fisheries (DEAFF) to inform the management of these heavily impacted ecosystems. This study aimed to contribute to the monitoring Programme in two ways: Firstly, by characterising and evaluating changes in rocky shore communities that have occurred since 2000, which was done by resurveying historical sites and comparing community structure and diversity between decades. Secondly, by comparing and evaluating different rocky shore sampling methods to identify the most suitable sampling protocol for a long-term monitoring programme of KZN rocky shores. This required statistical analyses of parallel surveys conducted using different methods. Significant changes in the community structure were observed with increased species richness and evenness. A decline in the abundance of harvested mussels was also noted, coupled with an increase in coralline algae and the arrival of two species of alien barnacles. Even though more long-term studies will be required to determine the status of the intertidal communities under anthropogenically induced change, the current study can be used to initiate better managementpractices in order to maintain species diversity and distribution.
Population connectivity of stylophora pistillata and sinularia brassica between KwaZulu-Natal marine protected areas.
(2021) Gilmore, Jessica Rose.; Pearton, David James.; Macdonald, Angus Hector Harold.
Marine Protected Areas are a valuable tool for ecosystem protection and to enhance resilience in the face of global stressors such as global warming and ocean acidification. There is currently an incomplete understanding regarding the level to which MPAs in KwaZulu-Natal protect existing biodiversity and provide benefits beyond their boundaries. The focus of this study was to determine the extent to which the current MPA network acts to facilitate connectivity of sessile benthic species, the role of oceanographic processes, and whether these processes will persist under global change. The population connectivity of two coral species, a hard coral (Scleractinia), Stylophora pistillata, and a soft coral (Alcyonacea), Sinularia brassica, within and between the MPA network on the east coast of South Africa was studied using both traditional markers and RADSeq, a reduced representation genomic sequencing technique. Sampling locations were selected in three existing MPAs and on a representative reef located in the “gap” in between. These MPAs span the tropical Delagoa and subtropical Natal Bioregions. Stylophora pistillata in South Africa is split into two non-hybridizing clades with clear differences in distribution. Clade 2 was confined to the subtropical Delagoa bioregion whereas clade 3 was found throughout the study region from the tropical Delagoa bioregion down to the southern boundary of the warm temperate Natal bioregion. ITS data indicated that there is a complex population structure of the clade 2 potentially driven by a combination of currents, ecological selection, and distance. A subset of Stylophora clade 2 samples was analysed using a RADSeq approach which clarified the structure suggested by the ITS data and clearly identified three distinct populations across four reefs (Leadsman Shoal, Blood Reef, Aliwal Shoal and Aliwal Deep) spanning the Delagoa/Natal biogeographic break. These populations did not appear to be structured solely by geographic distance, with one population comprising samples from two sites (Blood Reef and Aliwal Deep) that were non-adjacent and at different depths (12-18 m vs >30 m), while a geographically adjacent population (Aliwal Shallow) at 12-18 m constituted a distinct population. This suggests that ecological selection might be involved in structuring the population over short distances for this coral. Sinularia brassica was not found south of the iSimangaliso Wetland Park in this study, despite it being recorded in the southern sites in previous surveys. Analyses of COI and mtMutS sequences revealed that there are potentially multiple clades present in the IWP population and that there is a poleward decrease in genetic diversity. Neither of these clades showed any clear geographical or genetic population structure between the reef complexes but additional studies using RADSeq may help to clarify the situation.
Morphological and molecular characterization of Fasciola hepatica and Fasciola gigantica phenotypes from Mpumalanga and KwaZulu-Natal provinces of South Africa.
(2020) Haridwal, Sayurika.; Mukaratirwa, Samson.
Fascioliasis is a food- and waterborne disease. It is one of the most common helminthic infections in domesticated ruminants. The disease is caused by liver flukes, Fasciola hepatica and Fasciola gigantica. Increased attention has been geared toward studying these flukes due to their ever-expanding geographical distribution, enormous economic impact, increased human infections, increased resistance to treatment and the existence of hybrid forms. Both these species are co-endemic in the Mpumalanga and KwaZulu-Natal provinces of South Africa and even though, hybrids have been reported in other areas where both species exist it has not been attempted in South Africa. Therefore, this study was conducted to determine the existence of Fasciola hybrids in South Africa using morphological and molecular characterization. A total of 71 flukes were collected from naturally infected cattle slaughtered at abattoirs located in Enhlazeni and Nelspruit in Mpumalanga province and Pietermaritzburg in KwaZulu-Natal province of South Africa as well as control samples from Zimbabwe (Bulawayo abattoir) where only F. gigantica exist. The samples were categorized morphologically as either F.hepatica, F.gigantica, or Fasciola sp. The morphometrics (body length, body width, and length/width) were analyzed through a PCA and produced three distinct groups. A one-way ANOVA indicated that the length and length/width could be used to differentiate the species (P < 0.05) and the width was not useful in differentiating the species (P > 0.05). Molecular analysis based on ITS-1/5.8S/ITS2 marker showed that specimens morphologically identified as Fasciola sp were F.gigantica, with one sample morphologically identified as F.gigantica was molecularly identified as Fasciola sp. Similar results were observed with the CO1 marker, however, one sample came up as unknown, this sample however, formed a well-supported sister clade to F. gigantica. . It was also observed that aspermatic specimens are not only limited to hybrids, as some individuals that were molecularly identified as F. hepatica lacked sperm in their seminal vesicles. This study confirms species identification of F. hepatica and F.gigantica cannot be solely based on morphological characters where both these species are co-endemic. This was also the first study to report the existence of hybrid Fasciola spp. in South Africa.
The evaluation of the health status of Clarias gariepinus from the Inanda and Nagle dams in KwaZulu-Natal, South Africa.
(2021) Mdluli, Siphosakhe.; Lebepe, Jefferey.; Vosloo, Dalene.
The uMgeni River is one of the most polluted freshwater ecosystems in KwaZulu-Natal. This river is home to about 48 fish species. The study aims to determine the effects of water quality on the health of Clarias gariepinus from the Nagle and Inanda dams. Water variables were measured in situ using a YSI meter. Water and sediment samples were collected at three sites in each dam. Fish were collected and euthanized by severing the spinal cord. Different fish biometrics were measured. Fish tissues were preserved based on the analysis to be carried out. Neutral to alkaline water pH was recorded at both dams. Although the Inanda Dam exhibited higher total nitrogen concentration, both dams were mesotrophic, whereas the phosphate concentration at the Inanda Dam was eutrophic. Generally, the Nagle Dam showed good quality water compared to the Inanda Dam. The Inanda Dam fish population showed a relatively higher prevalence of alterations in the gills and liver than fish from the Nagle Dam. The degree of alterations showed some variability within each population, however, there was no significant difference (p>0.05) between the two populations. Both populations exhibited organ indexes less than 20, hence, moderate alterations. Fish ovaries and testis showed slight alterations at both dams. Acetylcholinesterase (AChE) brain activity recorded no significant difference in between the dams (p>0.05). Male populations recorded no significant difference in vitellogenin (VTG) induction between the dams (p>0.05). Despite, AChE activity and VTG induction showing no significant difference between the two populations, there was a great variability within each population. The lowest AChE activity as well as the highest VTG level were observed in the Inanda Dam fish populations. Both histopathologic and biochemical biomarkers are signs of increased pollution effect at the Inanda Dam. Nevertheless, it is evident that the uMgeni River system which is supposed to be providing sanctuary to aquatic biota is becoming deteriorated. These findings provide baseline data or a point of reference for future studies as it is the first of its kind in this river system.
Morphology, phytochemistry, and medicinal properties of South African Mangifera indica L. leaves for summer and winter seasons.
(2021) Maharaj, Arvish.; Naidoo, Yougasphree.; Dewir, Yaser Hassan.
Herbal preparations of plants continue to present mankind with novel remedies as many of these plants contain important secondary metabolites. Plant species of the family Anacardiaceae are rich in bioactive phytochemicals. Mangifera indica (Anacardiaceae) is an introduced and naturalised species to South Africa. Herbal use of this plant has not been fully documented; however, it is used in traditional medicine. This study aimed at characterizing the morphology, phytochemistry, and biological activity of Mangifera indica leaves harvested in winter and summer. The foliar biology of the plant was conducted by various microscopy techniques such as stereo- and Scanning electron microscopy. The length and diameter of the different trichome types were measured using ImageJ. The non-glandular trichome lengths range between 70 - 200 μm. The peltate gland trichomes consist of 2 rows of 8 oblong cells each with a size ranging from 32- 48 μm. Morphological observations using stereo- and SEM revealed the presence of non-glandular trichomes with cuticular warts and glandular peltate trichomes on the leaves of Mangifera indica. Transmission electron micrographs showed the presence of numerous mitochondria, starch grains, plastoglobuli, and plastids. The results for summer and winter leaves resembled somewhat similar-to-identical morphological characteristics on all fronts. For the phytochemical and biological assays, this study aimed to investigate some of the phytochemical and biological properties using different solvents (hexane, chloroform, and methanol) for extraction of the leaves of Mangifera indica for the summer and winter seasons. Preliminary phytochemical screening for the hexane, chloroform and methanolic extracts was done using a reflux extraction apparatus to uncover the presence of different metabolites and the anti-oxidant screening was done by the radical scavenging activity, which was established using the 2,2-diphenyl-1-picrylhydrazyl assay. Potent radical scavenging activity was exhibited for both summer and winter seasons with hexane and methanolic extracts for summer (IC50 of 19.53 μg/mL and 12.71 μg/mL respectively) and winter (22.32 μg/mL and 14.35 μg/mL respectively) in comparison to the control ascorbic acid which produced an IC50 of 3.20 μg/mL. The summer extracts had better radical scavenging IC50 capacity than winter extracts. The antibacterial activity of the methanolic leaf extracts for summer and winter of Mangifera indica were evaluated against the bacterial species: Gram-negative Escherichia coli (ATCC 25922) and Gram-positive: Staphylococcus aureus (ATCC ATCC 43300). For S. aureus (ATTC 43300), the summer crude extract displayed lower antibacterial activity than the control streptomycin, the summer extracts had a zone of inhibition of 14.17 mm while streptomycin had a 16.67 mm zone of inhibition. winter extracts had a zone of inhibition of 12 mm while streptomycin had a 13.67 mm zone of inhibition. For E. coli (ATCC 25922), the summer crude extract displayed higher antibacterial activity than the control gentamycin; the summer extract had a zone of inhibition of 18.05 mm while gentamycin had a 17.5 mm zone of inhibition. The winter extracts had a zone of inhibition of 8.5 mm. while gentamycin had a 14.5 mm zone of inhibition. Between seasons, summer had better antibacterial activity compared to winter for both Gram-positive and Gram-negative bacteria. Phytochemical screening showed the presence of phenols, flavonoids, tannins, and terpenoids, alkaloids, phytosterols, saponins, steroids, and carbohydrates. Potent radical scavenging activity was exhibited for the hexane and methanolic extracts for summer and winter, indicating that Mangifera indica is a potential source of medicinally important compounds. Antibacterial screening showed positive results with antibacterial properties for both summer and winter samples revealing its valuable biological activities. Summer overall performed better than the winter season. Future studies on this plant species are recommended to advance the use of indigenous herbal medicine or produce novel drug leads. To our knowledge, this study represents the first recent investigation in South Africa describing key foliar micromorphological features, phytochemicals, and biological activities of Mangifera indica L.
Potential use of bacterial community observed during decomposition of pig (Sus scrofa domesticus) and sheep (Ovisaries) carrion in estimating the post-mortem interval during the cold season in KwaZulu-Natal Province of South Africa.
(2021) Durgapersadh, Aarthi.; Mukaratirwa, Samson.
This study was aimed at identifying and describing the bacterial communities present during the decomposition stages of both pig and sheep carcasses, with the potential use of these bacterial communities aiding in estimating the post-mortem interval (PMI). One pig (Sus scrofa domesticus) and one sheep (Ovis aries) carcasses were used for this study during the cold season and the study location was Ukulinga Research Farm, University of KwaZulu-Natal, Pietermaritzburg, South Africa. Five stages of decomposition fresh (0-1 d), bloat (2-6 d), active decay (7-12 d), advanced decay (13-51 d) and dry (5258 d) were observed and described for both the pig and sheep carcasses at the same duration from June till August 2019. Temperatures of the carcass and soil (surrounding environment) was recorded. Temperatures of the individual carcasses changed during each stage of decomposition which was influenced by the surrounding environment temperatures. Five bacterial genera (Bacillus, Leclercia, Myroides, Pseudomonas and Providencia) were identified using 16S rRNA gene. During the pig decomposition Myroides and Pseudmonas spp. were absent and Leclercia sp. was absent in the sheep decomposition process. Providencia vermicola was observed during the fresh till the advanced decay of pig decomposition. On a phylum level Proteobacteria was persistent from the fresh till the end of advanced decay stage of the pig carcass, while on the sheep carcass it was persistent till the end of the active stage. Bacillus cereus belonging to the phylum Firmicutes was observed only during the dry stage of the pig decomposition process. During sheep decomposition Providencia sp. were observed during the fresh till the end of active decay stage and Bacillus cereus was observed during the advanced decay and dry stages. Results showed that Proteobacteria was present on both carcasses at the beginning and were absent at the end of decomposition, Firmicutes was present only on the later (advanced decay and dry) stages of decomposition. The presence and absence of different bacterial species during different stages of decomposition on pig and sheep carcasses, indicates their importance in potentially estimating the post mortem interval (PMI), in forensic investigation in KwaZulu- Natal, South Africa. Although this research indicates that bacterial communities can be utilized for PMI estimations, further research is required to better understand the role of bacteria during the decomposition process. This research is especially needed in the different regions of South Africa, as results cannot be extrapolated beyond the countries/regions of study since the bacterial species spectrum vary with geographical regions and conditions.
Spatio-temporal patterns of hover fly (Diptera: Syrphidae) diversity across three habitat types in KwaZulu-Natal, South Africa.
(2022) Mva, Luhlumelo.; Van der Niet, Timotheus.; Midgley, John.; Jordaens, Kurt.
Hover flies (Diptera: Syrphidae) are poorly studied in southern Africa and as a result, little is known about their abundance throughout the year. Hover fly abundance is generally expected to vary according to vegetation types, due to differences in the type and diversity of floral resources, but this has not yet been investigated in South Africa. This study aims to investigate temporal and spatial patterns of hover flies across three different, but adjacent habitats (forest, grassland, and plantation) in KwaZulu-Natal (South Africa). This was done in two ways, first, by analysing occurrence data from the Global Biodiversity Information Facility’s (GBIF) database across months of the year. Second, by quantifying fly presence and abundance using Malaise traps set up in three different habitats and supplemented with hand-netting data. The Malaise traps were set up from October 2020 - September 2021 and were generally serviced weekly. Hover flies were sorted and identified using available keys at the KwaZulu-Natal Museum. The KZN GBIF database contained 11 tribes that represented three distinct phenological patterns. The Karkloof GBIF dataset contained seven tribes that represented two distinct phenological patterns. The field collection dataset contained eight tribes that represented two distinct monthly patterns, although these slightly differed from the patterns found in the GBIF data. Most records were from January, September and December whereas few records were from May, June and July. Minimum-minimum, average-minimum, average maximum and average temperature showed a positive correlation with hover fly abundance. In terms of spatial patterns, grassland had the highest number of adult hover fly individuals (154), followed by forest (106) and plantation (20). There was an overall effect of habitat type on both the mean number of species and the number of individuals per trap per week. In addition, Shannon’s diversity showed variation among the three habitat types whereas Simpsons Evenness index showed no variation. The results show that hover fly populations remain active throughout the year, but with distinct fluctuations in their abundance. They also show that heterogeneous indigenous habitats such as grassland and forest represent high abundance, diversity, evenness and richness of hover flies and this may be due to the diversity in available microhabitats, compared to the plantation, which is a modified habitat that lacks microhabitat diversity. Nonetheless, further studies should be undertaken in different regions of South Africa to better understand the monthly patterns as well as the effect of habitat type on hover fly diversity.
The importance of sunbirds as pollinators of the southern African plants Alberta magna and Streptocarpus dunnii.
(2023) Jansen, Cally Julia.; Johnson, Steven Dean.; Cozien, Ruth Jenny.
Bird pollination is important for plant reproduction and is found in about 65 flowering plant families. I studied putative bird pollination systems of two southern African plant species, Alberta magna (Rubiaceae), which grows above cliffs and Streptocarpus dunnii (Gesneriaceae), which occurs among boulders in open grassland. A special emphasis of this study was to test the utility of close-focusing motion-activated camera traps for documenting bird pollination of plant species that are rare and occur in habitats that present challenges for conventional bird pollination studies. The aims of this project were to 1) quantify floral traits for comparison with other bird-pollinated species; 2) establish the breeding systems, including reliance on pollinators for reproduction; 3) identify floral visitors and measure their contribution to reproductive success; and 4) determine if seed production is pollen limited. Floral traits of S. dunnii, including large volumes of dilute nectar and long tube lengths, also aligned with an ornithophilous pollination syndrome. In naturally-pollinated plants, overall fecundity was high, with 80% of flowers developing fruits with large numbers of seeds. Malachite sunbirds (Nectarinia famosa) were the only legitimate visitor to flowers of S. dunnii. Greater double-collared sunbirds (Cinnyris afer), which have shorter bills than malachite sunbirds, occasionally rob flowers of nectar. Streptocarpus dunnii was found to be fully self-compatible but does not self-autonomously. Selective exclusion experiments showed that the species is almost entirely reliant on birds for seed production. The species did not experience pollen limitation, indicating that sunbirds are effective pollinators. Measured floral traits of A. magna, including large volumes of dilute nectar and long tube lengths, were consistent with an ornithophilous pollination syndrome. Motion triggered cameras and observations showed that southern double-collared sunbirds (Cinnyris chalybeus) and olive sunbirds (Cyanomitra olivacea) were the most common visitors to A. magna, while amethyst sunbirds (Chalcomitra amethystina) were occasional visitors. Selective exclusion experiments showed that bird visitors are important for reproductive success which was found not to be pollen-limited. The low levels of fecundity in A. magna indicate that there may be other potential factors that limit seed production in this species and the degree of self-compatibility in this species was not firmly established. I conclude that both species are specialized for pollination by sunbirds and that close-focusing camera traps are effective for documenting bird pollination systems of rare plant species which occur in habitats that are challenging for conventional human observations.
Assemblages of surface-active arthropods in pristine and disturbed savannah.
(2022) Mavasa, Risuna Wain.; Tsvuura, Zivanai.; Yekwayo, Inam.; Mwabvu, Tarombera.
Savannahs are structurally complex ecosystems rich in biodiversity, and the conversion of savannahs into human-modified landscapes poses a significant risk to organisms with limited dispersal abilities. Surface-active arthropods have limited dispersal abilities and are sensitive to changes in their environment; as a result, they are restricted to specific habitats with the resources that they need. Surface-active arthropods are essential in ecosystem processes, such as playing a direct or indirect role in water infiltration into the soil and its storage, decomposition of plant and animal matter, nutrient cycling, humification and biological pest control. Many landscapes of natural vegetation in South Africa have been transformed into croplands, residential and commercial areas. In Mpumalanga province, croplands (including fruit plantations) dominate the landscape where savannah vegetation occurred previously. This study investigated the influences of disturbance (transformed savannah vs pristine savannah) and season on the diversity of four groups of surface-active arthropods (ants, beetles, millipedes and spiders) in the savannah biome in Mpumalanga province. The objectives of the study were to determine 1) whether flightless arthropod assemblages differ between disturbed and pristine savannah, and 2) whether functional guilds of flightless arthropod assemblages differ between summer and winter. Field sampling using pitfall traps was done to collect the surface-active arthropods in pristine and disturbed savannah during summer and winter. All samples were sorted into morphospecies and identified into family or genus where possible and then assigned into functional guilds. Functional guilds were allocated based on the feeding habits of the surface-active arthropods, resulting in three distinct functional guilds (detritivores, herbivores and carnivores) being identified. Surface-active arthropods with diverse feeding habits were lumped to form a fourth functional guild, the “diverse functional guild”. I found significant differences in the species composition of ants, beetles and spiders between disturbed and pristine savannahs. The species richness and abundance of ants was significantly greater in the disturbed than pristine savannah, while beetles and spiders had similar species richness and abundance between the two habitat types. The number of unique species of the surface-active arthropods in the disturbed savannah were two times more than those in the pristine savannah. The species richness and composition of all functional guilds of the surface-active arthropods differed between summer and winter, with greater species richness in summer than in winter. Herbivorous and carnivorous arthropods had significantly higher abundance in summer than in winter, while the abundance of detritivores and the “diverse functional guild” was similar between the two seasons. This study shows that different vegetation types support different compositions of surface-active arthropods and that there may be a positive relationship between vegetation structure and the assemblages of surface-active arthropods in the savannah. Furthermore, the study highlights a potentially positive relationship between the assemblages of herbivorous and carnivorous arthropods. I recommend that it may be essential to consider both disturbed and pristine habitat types in the conservation of surface-active arthropods, especially in South Africa where most of the land is outside of formal conservation areas. This assertion is supported by the greater number of unique species of surface-active arthropods found in the disturbed than in the pristine savannah. My study provides relevant baseline information because little is known about the assemblages of surface-active arthropods in savannah landscapes dominated by croplands. Furthermore, my study gives some insight on how the assemblages of surface-active arthropods may respond to disturbance in the savannah.

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