Masters Degrees (Zoology and Entomology)
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Item Open Access Anthelmintic, anticancer and phytochemical screening of Cotyledon orbiculata; Hermannia depressa; Nicotiana glauca and potassium permanganate(University of the Free State (Qwaqwa Campus), 2013-12) Molefe, Nthatisi Innocentia; Thekisoe, O. M. M.; Ashafa, A. O. T.; Tsotetsi, A. M.Cotyledon orbiculata, Hermannia depressa and Nicotiana glauca are widely used plants in traditional medicine for treatment of various infections and diseases. C. orbiculata is mostly used in treatment of epilepsy, earache and the removal of warts while H. depressa is used to relieve toothache, nerves and diarrhoea. Lastly, N. glauca has been mostly used as pain killer in relieving earache, toothache and seldom applied on body in treatment of soreness and inflammation. Traditional usages of these plants by indigenous people and local traditional healers have not yet been scientifically reported, that is why the current study was aimed at determining the anthelmintic and anticancer activity of these plants. The anthelmintic activity of acetone and water extracts from the shoots of Cotyledon orbiculata, Hermannia depressa and Nicotiana glauca were investigated using the egg hatch, larval development and larval mortality assays. In all extracts tested, C. orbiculata water extract at 7.5 mg/ml prevented nematode eggs from hatching with 82.63% success rate. Other extracts exhibited egg hatch inhibition in a degree of less than 50%. Similarly, C. orbiculata water extracts suppressed nematode larval development with 85.32% at the concentration of 2.5 mg/ml followed by 66.69% of H. depressa extract at 7.5 mg/ml concentration. However, N. glauca water and all acetone extracts induced the 100% larval development inhibition. The in vitro larval mortality rate revealed that the water extracts from all the plants were able to kill all larvae at 2.5 mg/ml within 48 to 96 h. The results from this study have shown that the extracts from the three plants have the potential to prevent and ameliorate diseases associated with gastrointestinal nematodes. The anticancer activity of the above mentioned plants was tested on two cancer cell lines, the MCF-7 and HeLa cells. All plants possessed anticancer activity at different durations and concentrations. The N. glauca demonstrated an activity against both cell lines, however, the plant acetone extracts were much effective on the MCF-7 line at 48 hours with inhibition percentages > 80% at all concentrations. The N. glauca acetone extracts were effective at 24 hours. The H. depressa acetone extracts also possessed much activity than water extracts at 24 hours, whereas C. orbiculata showed no activity at all on this cell line. The C. orbiculata acetone extracts followed by the water extracts were the most effective on the HeLa line ranging from 12 to 84% and 0 to 77% inhibition. H. depressa activity was observed at 48 hours of experimentation at all concentrations in both extracts. N. glauca exhibited significant inhibition percentages at 24 hours of water extracts and 48 hours of acetone extracts. This study has showed that the three plants are potential candidates for cancer treatment. Brine shrimp lethality test was conducted on the nauplii stage of the shrimps. Furthermore, two assays, MTT and LDH cytotoxicity assays were conducted on the MDBK cells. None of the plants was toxic on the brine shrimps as most of them survived through 24 and 48 hours. C. orbiculata and H. depressa brine shrimp larval mortality was observed at 96, 72, 72, 96 and 96 h at 0.2, 0.4, 0.6, 0.8, and 1.0 mg/ml of water extracts respectively and 72 h at all concentrations of acetone extracts while N. glauca larval mortality was observed at 120 and 96 hours at all concentration of both extracts. There was a cell survival decrease of 50% at 0.65 mg/ml and 50-60% in C. orbiculata water and acetone extracts treated wells, respectively. No significant cell decrease was observed from both H. depressa and N. glauca water and acetone extracts except for N. glauca acetone extract at 2.50 mg/ml. None of the plants induced a significant toxicity on both the brine shrimps and the bovine cells. Alkaloids, saponins, tannins and phenols were the constituents tested for in order to identify constituents responsible for observed activity of the whole study. No alkaloids were detected from all plants for both extracts, only saponins, tannins and phenols were present even though N. glauca acetone extracts possessed none of the tested constituents. Tested plants are therefore good candidates in treating parasitic gastrointestinal nematodes and cancer disease. Potassium permanganate (KMnO₄) is a widely used chemical substance in the rural communities as prophylaxis or in treatment of various infections and diseases; however, there is no scientific validation of its usage. Anthelmintic activity of potassium permanganate was tested against parasitic gastrointestinal nematodes in comparison to anthelmintic commercial drugs, Tramisol®, Noromectin® and Valbazen®. There was no egg hatch inhibition induced (<10%) by potassium permanganate at all concentrations as compared to >80% inhibition of commercial drugs, however, 85.24, 98.10 and 90.91% of larval development was induced at 0.5, 1.0 and 1.5 mg/ml, respectively. Larval mortality was observed at 216, 144 and 144 hours at 0.5, 1.0 and 1.5 mg/ml, respectively. The cytotoxicity of this chemical was tested on the brine shrimps and MBDK cells as well. Within 24 hours all the brine shrimps larvae treated with KMnO₄ died. A significant decrease in MDBK cell survival was observed at 0.65 mg/ml at 24, 48 and 72 hours. This study has therefore showed that potassium permanganate have anthelmintic activity and concentration dependent cytotoxicity on the mammalian cell lines. In conclusion Cotyledon orbiculata, Hermannia depressa, Nicotiana glauca and potassium permanganate have the potential to supress the aggressiveness of parasitic gastrointestinal nematode and cancer diseases. These substances are therefore potential candidates in treatment of tested pathogens.Item Open Access Aspects of bio-intensive pea aphid, acyrthospihon pisum (Harris) management on lentil, lens culinaris (Medikus)(University of the Free State, 2001-11) Andarge, Alemtaye; Van der Westhuizen, M. C.Damage caused by the Pea aphid, Acyrthosiphon pisum (Harris) is a limiting factor in lentil production in Ethiopia. Although application is minimal, losses are combated with the application of synthetic pesticides like Primicarb®. However, the continuous application of synthetic pesticides may result the development of insect resistance to insecticides, adverse effect on non-target organisms and environmental pollution. It is therefore necessary to implement a multi-faceted approach in order to keep A. pisum populations below economic threshold level. This thesis highlights aspects of an integrated pest management approach to this pest. The components studied were host plant resistance, biological control and chemical control with bio-rational pesticides. All the trials were done under glasshouse condition in the University of the Free State, Bloemfontein, South Africa. The host plant resistance study was completed in two phases. The first phase dealt with the preliminary screening of fifty entries of lentil introduced for such purposes. One entry appeared to be resistant while six were moderately resistant to A. pisum. The resistant entry and four of moderately resistant entries selected randomly were chosen for the next study. The second phase thoroughly examined and identified the mechanisms of resistance of each entry previously identified as moderately resistant and/or resistant. With in the field of microbial control of agricultural pests, the effect of Beauveria bassiana on population of A. pisum was evaluated. This method appeared to be effective in significantly reducing the population of A. pisum compared with the control. The last component investigated the influence of the botanical product Neemolin® and extracts of Wild sering, Burkea africana on the fecundity of A. pisum. A. pisum populations treated with Neemolin® produced significantly fewer offspring than the control and proved to be an effective control measure. On the other hand, application of extracts of Wild sering, Burkea africana did not affect A. pisum population. The result does not indicate the failure of this extract against the pest rather highlights the need to keep the extract in water for long hours so that the extract can dissolve and the insecticidal property can be enhanced. The results of this study therefore indicate that the components of an integrated pest management approach included in this study will serve as a base towards effective management of this pest.Item Open Access Aspects of geophagia amongst dairy cattle in a feedlot system(University of the Free State, 2017-03) Wiid, Emmarentia Elsabe; Butler, H. J. B.English: Modern confinements imposed on animals limit their access to natural resources required for optimal nutrition. This lack of resources may lead to nutrient deficiencies and one of the hypotheses for the deliberate consumption of soil is to supplement mineral deficiencies. Counteraction of acidosis, detoxification, buffering of unpalatable plant compounds as well as the use of soil as anti-diarrhoeal agent are other suggested motivations for geophagy. By means of direct observation as well as camera traps, the behaviour of geophagy amongst dairy cows in a confined feedlot system was documented. In addition, soil analysis was done to determine the geochemistry of ingested as well as excreted soil. Geophagy amongst cows at Amperplaas constituted less than 2% of daily activity. The non-lactating individuals invested less time in this behaviour than lactating individuals and the frequency as well as time spent on this behaviour decreased as the lactation phases progressed. Recorded geophagy occurrences were most during winter and thereafter spring and peak soil ingestion occurred during mid-day. At Amperplaas, all but one of the mineral licks were situated on the undisturbed elevated areas underneath the fence wire or around the wooden and iron poles. The average size of a typical mineral lick was about 40 cm by 15 cm with a depth of 10 cm. The soil collected from the mineral licks was alkaline and classified as sandy clay loam. Quartz, Plagioclase and K-Feldspar were identified in all samples while Ilmenite was quantifiable in all but one of the control sites. Silica concentrations were supportive of quartz dominance in the soil collected from mineral licks as well as soil from the stomachs and faecal matter. The most recent mineral lick contained the lowest silica, arsenic, copper, lead, scandium, and zirconium content. But this site had elevated calcium, iron, potassium, magnesium, sodium and phosphorus as well as bromine, nickel, strontium and zinc levels. When offered soil combined with different minerals, the preference of most cows was sodium chloride mixture and thereafter calcium-phosphorus. When comparing the estimated amount of soil ingested per second with the excreted amount of soil, it appears that the daily excretion rate of soil is almost equal to the ingestion rate, therefore not posing any threat for sand impaction. Milk collected at Amperplaas had low levels of calcium as well as potassium and therefore, soil is possibly ingested to supplement this deficiency. Results of this study confirm the ability of some animals to detect deficiencies in the body and to attempt to correct these deficiencies from available resources. Results also support the theories that this nutritional wisdom is partly from cultural transmission as well as innate behaviour.Item Open Access Aspects of the behaviour and ecology of Gurney's Sugarbird Promerops Gurneyi verreaux, 1871, in Protea Woodland, South Africa(University of the Free State, 1998-11) De Swardt, Dawid Herklaas; Kok, O. B.English: Several aspects of the ecology of Gurney's Sugarbird were studied in the Lydenburg area (Mpumalanga) and at Sterkfontein Dam Nature Reserve and Qwaqwa National Park (Free State) during the period April1980 to June 1998. The distribution pattern of Gurney's Sugarbird is closely associated with that of Protea roupelliae along the Drakensberg escarpment in the Grassland Biome. Nectarivore densities at Protea clumps were affected by the size of clumps, flower availability and grasssland fires. Sugarbird densities were higher during winter, spring and early summer when sufficient flowers were available. Male sugarbirds were significantly larger than females in all body measurements, except tarsus length. Significant correlations were recorded between culmen/total head length and wing/tail length of the two sexes, and between maximum width of the bulged P6/wing length in males. Monthly variations in body mass were recorded in both sexes, and birds were heaviest during the November-March breeding season. Adults with long, fully-grown tail ornaments usually had longer wings, while males had wider bulged P6. Primary moult occurred between November to March, coinciding with the breeding season. Tail moult also occurred during this period and were replaced as soon as their condition worsened. The sugarbirds have a September-March breeding season, with a peak from November to December in the Lydenburg area. P. roupe/liae were usually selected for nesting sites, while P. caffra was also occasionally used. Nests were completed within five days by the female; mean nest height was 1,85 m. Nests were lined with the brown, fluffy seeds of P. roupelliae. Incubation period was 16-17 days, nestling period 21-23 days, and post-nestling period 20-30 days. Breeding success was 41,4%, higher than that of the Cape Sugarbird. Sugarbirds foraged mostly on the nectar of P. roupelliae, but during winter they fed on A/oe arborescens in nearby suburban areas and on mountain cliffs. Insect orders which predominated in the diet of Gurney's Sugarbird were Coleoptera and Hymenoptera. These insects also comprised the main arthropod fauna in P. roupelliae flowers. Bees and ants were recorded in both stomachs of sugarbirds and Protea flowers. Sugarbirds foraged on P. roupe/liae flowers by probing several times into a flower whilst moving clockwise on it. Beetles were taken from flowers and small flying insects hawked from the air. Movement and survival data for 93 individuals were obtained from 553 captured sugarbirds in the Lydenburg area. Recaptures showed fidelity to mountain sites, local movements between mountain sites, seasonal movements and individuals recaptured at the same suburban localities during winter. Peak in occurrence in suburban areas was from late May until early July, coinciding with the flowering season of Aloe arborescens. Sugarbird movements were after the peak flowering periods of P. roupelliae, birds leaving burnt Protea veld after fires and after seasons characterised by low annual rainfall. Annual survival in the Lydenburg area was estimated at 80,7%. Life expectancy was 4,6 years. Two individuals were recaptured after periods of 88 months and one after 74 months. Recapture data suggests a longevity of beyond seven years for this species. This longevity data represents the first of its kind for the species. The conservation of Gurney's Sugarbird and the' management of its Protea roupelliae habitat is a priority. Uncontrolled fires in grassland with P. roupe/liae trees, and logging of wood for fuel, have negative influences on bird and protea populations. The recommended fire regime for P. roupelliae woodland is during dry winter periods (June/July), rotated biennially, or as late winter-spring fires (August/September). The application of regular block burns or firebreaks in montane grassland will ensure less damage to tree canopies during accidental fires.Item Open Access Aspects of the bio-ecology of the biting louse, Damalinia Limbata(University of the Free State, 2000-05) Brown, Leslie; Van der Linde, T. C. de K.; Fourie, L. J.English: Biting lice are well known ecto-parasites of vertebrates. Most wild and domesticated animals have one or more louse species, living on them. Although lice are a source of irritation to the host, they are not generally considered as economically important because they do not cause much physical damage. The sheep biting louse (Damalinia avis) has, however, been shown to cause losses in wool production and quality. Damalinia limbata are ecto-parasites on Angora goats and can cause the same type of losses to the farmer as the sheep biting louse. Very little research has been done on these lice and their impact on mohair production can therefore not be objectively assessed. The objectives of the current study were to investigate aspects of the biology and distribution of D. limbata and to promote more effective and economical management of these lice on commercial farms. The following were investigated: (1) Aspects of the morphology of D. limbata and D. avis. (2) Environmental temperatures prevalent on the body of Angora goats. (3) The number of nymphal instars of D. limbata. (4) Seasonal changes in the populations of D. limbata. (5) The influence of D. limbata on the body mass of Angora goats and the production and quality of mohair, as well as the efficacy of different control methods. Field experiments were conducted on the farm Preezfontein (29°50'S, 25° 19'E), situated 10 km from the town Fauresmith, about 130 km southwest of Bloemfontein in the south-western Free State. The veld type of this area is defined as 'False Upper Karoo' and falls in the Karoo biorne. The Free State is a summer rainfall region with an average precipitation of 450-500 mm per annum, with hot summers and cold winters and droughts occurring regularly. D. limbata and D. avis were compared using general morphological characters, morphometric measurements of various body regions and placement of dorsal and ventral abdominal sclerites. D. limbata has a more robust appearance than D. avis. Females of both D. limbata and D. avis were on average 1.611 mm long and the males had average lengths of 1.378 mm and 1.255 mm, respectively. Male D. ovis had solid dorsal plates where as D. limbata males had dorsal plates, which were transversally split, on segments IV and V. Temperature studies, on the micro-habitat of D. limbata, showed that the temperature against the skin of an Angora goat is relatively constant at approximately 35°C. All attempts to establish a laboratory colony of D. limbata were unsuccessful. D. limbata was found to have three nymphal instars before reaching adulthood. Instar 1 had average head-capsule widths and lengths of 0.252 mm and 0.202 mm, respectively. The second and third instars had head-capsule widths of 0.364 mm and 0.467 mm and lengths of 0.305 mm and 0.425 mm respectively. The louse populations increased during spring and early summer, peaking in mid summer. Mid winter shearing seemed to have a greater impact on the louse populations than mid summer shearing. D. limbata moves around the body of Angora goats, being more abundant on the ventral areas of the body during summer and more evenly dispersed over the body during winter. It was found that D. limbata does not have an adverse influence on the body mass of Angora goats, but does adversely affect mohair production and quality. The average loss in mohair production was 12 % and individual losses of as much as 25 % were recorded, representing substantial financial losses to the farmer. D. limbata was effectively controlled by Deltamethrin when applied as either a backline treatment or as a lateral application with a Tikspray applicator.Item Open Access Aspects of the morphology and life history of Oculotrema hippopotami (Polystomatidae: Monogenea)(University of the Free State, 1999-01) Moeng, Itumeleng Amos; Du Preez, L. H.; Kok, D. J.Being the only monogenean known from a warm-blooded animal and from a mammal Oculotrema hippopotami Stunkard (1924) took a major leap in monogenean evolution. After its description in 1924 various researchers rejected the claim that it came from the hippopotamus and made it out as a mislabeled specimen. It was only 40 years later that this parasite received full recognition. In spite of the fact that it was described more than seven decades ago, only a few papers on this parasite have seen the light. During 1996 this parasite was rediscovered in South Africa. A hippopotamus culling program in Kwazulu-Natal gave an opportunity to study this parasite. The present study is the first detailed attempt to study the morphology and life history of Oculotrema hippopotami. The approach in this study was as follows: 1. Background on the host's morphology, behaviour and phylogeny is given. The hippopotamus' eye is situated deep in the orbit with the result that a deep crevice is present all around the eye, which serves as habitat for the parasites. 2. The external morphology of the egg, oncomiracidium and adult parasite was studied USIng scannmg electron rrucroscopy. This is the first ever scanrung electron microscopical study of 0. hippopotami and this study revealed many new information. 3. The internal morphology of the adult parasite was studied histologically using wax sections. This revealed unique musculature in the mid piece that has never before been reported for any polystomatid parasite. 4. Sperm morphology and the ultrastructure of the musculature in the mid piece was studied at transmission electron mieroeope level. Indications are that the sperm morphology is very similar to that reported for other polystomatids. 5. Infection levels for different seasons were compared. In contrast with most other polystomatids that reproduce during the warmer summer months, 0. hippopotami lays eggs during the cooler winter months. 6. The parental care and behaviour of a pair of hippopotami with a newborn calf were studied. A very close bond with long periods of physical contact was observed. This could give an ideal opportunity for parasite transmission from mother to calf.Item Open Access Aspects of the morphology, life cycle and epidemiology of Toxocara species and Toxascaris Leonina(University of the Free State, 2003-03) Tekele, Girma Mekete; Kok, Dawie J.; Basson, LindaEnglish: The present study has provided detailed and comprehensive information on the morphological aspects, life cycle, and epidemiology of Toxocara canis, Toxocara cati and Toxascaris leonina. The overall results of the study results are briefly summarized as follows: 1. In the morphological studies of these parasites, it has been observed that there are gross morphological similarities in the developmental stages of T. canis, T. cati and T. leonina. However, closer and detailed observations have revealed that the various developmental stages differ from one another in their fine morphological features. The observed morphological differences were: a. Eggs of T. canis and T. cati look very similar under the light microscope, in some eggs it seems that the surface pits and ridges of T. canis are larger and coarser than in the eggs of T. cati. However, unlike the eggs of Toxocara spp., eggs of T. leonina have no surface pits and ridges but are smoother on the surface. b. Second-stage larvae of T. canis recovered from the eggs and from the infected tissues of mice were stumpy and vigorously motile. The larval stages from both sources were similar in their morphological features and had comparable size measurements indicating that larval stages did not undergo development in the paratenic host. Like the larvae of T. canis, second-stage larva of T. cati recovered from the eggs and from the infected tissues of mice were stumpy and vigorously motile. The larval stages from both sources were similar in their morphological features and had comparable size measurements. The second-stage larvae of T. canis recovered from eggs or from tissues of mice had a greater width than the comparable second-stage larvae of T. cati. Unlike the larval stages recovered from the embryonated eggs of T. leonina, larvae recovered from infected tissues of mice were longer and wider and had more distinct morphological features. This indicated that larval stages recovered from the tissues of infected mice had probably undergone development to third-stage larvae. c. Adults T. canis, T. cati and T. leonina resemble each other in their gross morphological features, but also differ in their detailed and fine structural features. The major differences were on the shape of cervical alae, the presence or absence of an esophageal ventriculus, the position of the vulva in the female worms, as well as the number and arrangement of papillae on the tail of the male worms. d. Precloacal median papilla were recorded and described in males of T. canis and T. cati. Previous researchers did not describe the presence of these structures in male Toxocara spp. worms. In the present study, a female T. canis worm with a length of 27.5 cm was recovered from an infected dog and it was larger than any recorded in the literature. 2. In the study of the modes of transmission of ascarids, it has been observed that transplacental transmission of T. canis occurred in mice infected during but not before pregnancy. Transmammary transmission of T. canis and T. cati larvae had also occurred in mice infected prior to or during pregnancy. However, unlike in T. canis and T. cati, had neither transplacental nor transmammary transmission occurred in T. leonina. Larval stages were recovered from most tissues and organs of infected mice, and the larvae gradually accumulated in various extraintestinal tissues for the three ascarid species and especially in the brain of mice infected with T. canis. 3. The study on T. leonina transmission to the definitive hosts through experimentally infected mice as paratenic host, has indicated that dogs can be infected by ingesting infected tissues of mice that were infected with T. leonina infective eggs originally obtained from dogs. However, in cats this was not possible and it has been suggested that cats may not be the proper definitive host for T. leonina originating from dogs. 4. In an epidemiological survey of Toxocara spp. T. leonina, and other intestinal helminths of dogs and cats in Jimma, Southwestern Ethiopia, it was shown that the overall prevalence rates for parasitic infection were 60.78% in faecal samples of dogs from the environment, 78.60% in faecal samples of dogs taken from the rectum, 66.23% in faecal samples of cats and 33.38% in soil samples were recorded. Parasite species identified were Toxocara canis, T. cati, Toxascaris leonina, hookworms, Spirocerca lupi, Trichuris vulpis, taeniids, Ascaris species and Strongyloides species. A relatively high mean egg count of 15.25 was observed for T. canis in dog faecal droppings collected from the environment. The potential of these parasites as a cause of zoonotic infections, ways of prevention of infection and control measures were discussed.Item Open Access Aspekte van die bio-ekologie van Aedes aegypti (Diptera: Culicidae)(University of the Free State, 2001-07) Brown, Deodanda; Van der Linde, T. C. de K.English: Aedes aegypti (Linnaeus) was reported for the first time in 1996 in the Bloemfonteinregion. Due to the fact that this was not the normal distribution area of this species, the main objective of the study was to do research on the bio-ecology of Ae. aegypti in order to determine whether it can get established in the Free State. Trapping of both adult and immature mosquitoes were done at two weekly intervals from 1996 - 1998. This was done at three localities in the Bloemfontein urban area viz the "Dam van Trane", Valley of Seven Dams and the Pony Club Dam, in the region where this species was recorded for the first time. The aim of these trappings was to get a general idea of the species diversity, relative abundance and seasonal fluctuations of the mosquitoes in this area. Ten mosquito species were collected during the study. Aedes juppi McIntosh was the most abundant species, accounting for 36,6% of the total catch followed by Culex theileri Theobald (32,4%) and Aedes aegypti which constituted only 0,5% of the total catch. The seasonal fluctuation and abundance of all the species that were caught, were analyzed and correlated with meteorological parameters such as temperature, rainfall and relative humidity. From these is was concluded that no parameter can be singled out, but that a combination of all the above parameters playa role in the occurrence and distribution of the mosquito species.An Ae. aegypti laboratory colony was established. Results originating from various experiments contributed to the sucessful colonization of this species. Adults were kept in electronically controlled rearing rooms at a temperature of 25°C ± 1°C and a relative humidity of70% ± 2%, with a day-night cycle of 12 hours light and 12 hours darkness including a dawn and a dusk period of one hour respectively. For carbohydrate feeding, adults were fed on 7% sugar water and pigeons were used for bloodmeals. Oviposition occurred on white strips of paper towel which were placed in black plastic containers filled with 300ml of 0,02M NaCl-solution and a small amount of larval food. These containers were placed inside the mosquito cages and left for three days.Eggs had to be dried for at least four days at 25°C and a relative humidity of >68% before they were submerged in the water for hatching to occur successfully. Larvae were held in shallow pans filled with O,02M NaCI-solution and kept in the rearing rooms at 25°C_ They were fed a mixture of brewer's yeast and an infant cereal. Carbohydrates play an important role in the bloodfeeding, ovipositioning and survival of the females. Females that were fed on cane sugar as carbohydrate source, performed significantly better in taking a bloodmeal and producing eggs than females that fed only on fruit. The fruit-fed females also had a significantly lower survival. If Ae. aegypti females have regular access to bloodmeals, they are capable of surviving on protein from the blood. Ae. aegypti larvae are able to take up NaCI from diluted solutions (O,OIM - O,02M) and are able to survive and develop in distilled water. NaCl-solutions above O,08M had a negative impact on larval development and at concentrations above O,12M NaCl survival is negatively influenced Successful development and survival of the immature stages occurred at temperatures between 15°C and 35°C. The optimum development temperature was 30°C. A constant temperature of 35°C however, had a negative influence on the physical size of the adults. The results obtained from the laboratory studies were used in an attempt to explain the occurrence of Ae. aegypti in the Free State and to try and determine whether this species will be able to establish itself permanently in the Free State.Item Open Access Aspekte van die biologie van tuinduiwe (Columba livia) in die Bloemfonteinse stadsgebied(University of the Free State, 2007-05) Le Roux, Pieter Daniël Stephanus; Kok, O. B.; Butler, H. J. B.English: Owing to the increase of complaints in the city of Bloemfontein concerning the damage being caused to buildings by birds, different aspects of the biology of feral pigeons (Columba livia) was investigated. Close to 400 pigeons, which included nearly 50 lost racing pigeons, were collected on a regular basis within the city boundaries over a period of one year (March 2005 - February 2006). Although slightly more male birds were obtained, no significant variance from a balanced sex ratio in the population structure was distinguished. Feral pigeons moult continuously throughout the year at a relatively low intensity rate. Conspicuous peaks in the moulting of primary, secondary and tail feathers were observed for both sexes, however, the period for replacement was slower for females. Leucism was displayed by more than a quarter of the birds. Feral pigeons are more frequently infected with parasitic louse flies compared to local rock pigeons (Columba guinea), with the highest infection occurring during the summer months. Apart from measurements of the beak, the standard body measurements of adult males are significantly larger compared with their female counterparts. A similar trend applies in the different sexes of juvenile feral pigeons as well as racing pigeons. The seasonal variation in the body weight and visible fat deposits of adult feral pigeons probably coincides with the birds' breeding activity and the temporary availability of abundant food supplies. A prominent peak in the activity of the ovarian cycle of female birds, based on the weight and diameter of macroscopic follicles, coincides with the gonad cycle of male feral pigeons which occurs during the early winter months, followed by a smaller peak during spring. Based on the presence of nests, eggs and chicks, feral pigeons breed throughout the year with a decrease in breeding activity during the wetter summer months. Nest types vary from dried droppings on which eggs are laid to firmly-built, dry stick nests. After hatching from a typical clutch of two eggs the weight of the chicks increase daily on a linear scale. Both parents are involved in the hatching and raising of the chicks. Second or subsequent clutches are laid regularly throughout the year at the same nesting site. Rock and feral pigeons may interbreed, however this phenomenon is rarely documented. Agricultural crops including maize (Zea mays), sunflower (Helianthus annuus) and wheat (Triticum aestivum) are the most important components of the diet of feral pigeons living at the SASOL library on the campus of the University of the Free State. The diet of birds living within the city centre consists mainly of natural vegetation of which seeds of the Camdeboo stinkwood (Celtis africana) constitutes the most important component. The low percentage of animal matter consists largely of pupae of Diptera and egg cocoons of unidentified earthworms, while grit constitutes the largest component of inorganic matter. No significant statistical difference was found in the composition of the different sexes' diet. Under experimental conditions feral pigeons show a definite affinity towards maize in comparison with sorghum (Sorghum almum), sunflower and wheat. Associated with the latter, yellow food items are preferred above blue, green and red coloured items. Single birds eat on average more over a short term (10 minutes) than individuals which feed in groups, but almost equal amounts of food are ingested by individuals over a longer period (2 hours). Feral pigeons living on the university campus leave their nesting sites daily just after sunrise to go and feed on agricultural crops on the surrounding farmlands, returning approximately two hours later. Birds feeding in the city were mainly found on the ground during the early morning hours and to a lesser extent during the afternoon. The birds usually spend the hot midday hours in the shade. Lost racing pigeons regularly join local feral populations in urban areas. With the consideration of appropriate national and/or municipal laws, the shooting of feral pigeons with airguns and/or the provision of alpha-chloralose treated bait seems to be the most effective way in which their numbers in urban areas may be controlled. The introduction of natural enemies such as owls and/or falcons into urban areas could also be considered as a method of control of feral pigeon numbers.Item Open Access Assessment and improvement of molecular diagnosis of Theileria parva of African buffalo (Syncerus caffer) in Southern Africa(University of the Free State, 2015-10-30) Pienaar, Ronel; Thekisoe, Oriel M. M.; Man, Ben J.English: Buffalo-adapted Theileria parva causes Corridor disease in cattle. Strict control measures therefore apply to the movement of buffalo in South Africa and include mandatory testing of buffalo for the presence of T. parva. The official test is a real-time hybridization PCR assay that amplifies the V4 hypervariable region of the 18S rRNA gene of T. parva, T. sp. (buffalo) and T. sp. (bougasvlei). The effect that mixed T. parva and T. sp. (buffalo)-like infections have on accurate T. parva diagnosis was investigated. In-vitro mixed infection simulations indicated PCR signal suppression at 100 to 1000-fold T. sp. (buffalo) excess at low T. parva parasitaemia. Suppression of PCR signal was found in field buffalo with mixed infections. The T. parva-positive status of these cases was confirmed by selective suppression of T. sp. (buffalo) amplification using a locked nucleic acid clamp and independent assays based on the p67, p104 and Tpr genes. Conventional and SYBR® Green touch-down PCR methods were developed for each protein coding gene and buffalo from the endemic Kruger National Park were screened. The protein gene assays compared well with the negative and T. parva positive samples diagnosed on the current real-time assay however, they did detect additional positive samples diagnosed as negative on the real-time hybridization. These samples were all T. sp. (buffalo) positive. This confirmed the suppressive effect on PCR signal due to template competition in the current real-time PCR assay. Some positive samples were not detected by the protein genes, possibly due to sequence variation in the primer regions. These independent markers proved useful as supplementary assays in the accurate diagnosis of T. parva infections where mixed infections occur in the buffalo host. The development of the Hybrid II assay, a real-time hybridization PCR method, which compared well with the official hybridization assay in terms of specificity and sensitivity revolutionized the diagnosis of the disease for the main reason that it is not influenced by mixed infections of T. sp. (buffalo)-like parasites and is as such a significant improvement on the current hybridization assay. While the incidence of mixed infections in the Corridor disease endemic region of South Africa is significant, little information is available on the specific distribution and prevalence of T. sp. (buffalo) and T. sp. (bougasvlei). Specific real-time PCR assays were developed and a total of 1211 samples known to harbor these parasites were screened. Both parasites are widely distributed in southern Africa and the incidence of mixed infections with T. parva within the endemic region is similar (~25-50%). However, a significant discrepancy exists with regard to mixed infections of T. sp. (buffalo) and T. sp. (bougasvlei) (~10%). Evidence for speciation between T. sp. (buffalo) and T. sp. (bougasvlei) is supported by phylogenetic analysis of the COI gene, and their designation as different species. This suggests mutual exclusion of parasites and the possibility of hybrid sterility in cases of mixed infections.Item Open Access The bio-ecology of the blue tick (Boophilus decoloratus) in the central Free State(University of the Free State, 2002-05) Phalatsi, Moeketsi Solomon; Fourie, L. J.; Kok, D. J.English: Boophilus decoloratus is the most dominant and economically important tick that infests cattle in the central Free State. Very little research on this tick in the central Free State has, however, been conducted. The broad objectives of this study were to investigate aspects of the oviposition and reproduction, tolerance of engorged females to sub-zero temperatures, and microhabitat selection, survival and seasonal abundance of non-parasitic larvae, and the seasonal dynamics of B. decoloratus parasitic on cattle in Botshabelo, central Free State. Engorged B. decoloratus females exposed to 10°C did not lay eggs whereas those kept at 15, 20, 25, and 30°C, respectively laid eggs. The shortest (3.5days) mean pre-oviposition period was recorded at 30°C and 75% RH and the longest (13.2 days) at 15°C and a RH of 35%. The developmental zero temperature for pre-oviposition was calculated at 9.138°e. The oviposition period was more extended at lower temperatures. The shortest mean oviposition period (8 days) was recorded at 30°C and 35% RH. Incubation was also more extended at lower temperatures. The developmental zero temperature for incubation was calculated at 4.73°C. This value was lower than expected and probably due to a smaller sample size or lack of values for eggs incubated between 10 and 15°C. Relative humidity did not affect the oviposition period or the pattern in daily egg production. Peak egg production (533) was reached within five days from the start of oviposition. B. decoloratus females lay average sized eggs. Females weighing more than 200mg produced an average of 11.4 eggs per mg of body mass. The average conversion efficiency index (Cêl) values recorded in this study recorded nutrient index (NI) values were 10-15% less than the recorded values for specific weight classes of B. microplus. Females exposed during May 1998 to naturally fluctuating conditions died during late winter (August) without laying eggs. Eggs which were laid during April and May did not accumulate sufficient temperature for eclosion to take place. Larval survival periods were inversely dependent on increased temperature accumulation. The results of this study have shown that engorged female ticks do not dig into the soil. The ticks seek refuge in cracks or openings in between gravel particles, or underneath debris. B. decoloratus is able to withstand exposure to sub-zero temperatures. Mortality, however, increased with an increase in exposure time. At an exposure temperature of -10°C and an exposure time of 8 hours, 40% of the females still managed to survive and lay eggs which hatched normally. The results further indicated that direct chilling injury could occur at <- 8°C, which may also be indicative of the supercooling point for engorged B. decoloratus. Investigations on the longevity of larvae under laboratory conditions have shown that temperature to a great extent affected survival as manifested by a relatively short survival period (2 days) of larvae kept at 30°C. In general the survival periods for the larvae were less than those reported in the literature. The differences are believed to be related to different methodologies that were used. The results of this study also indicated that B. decoloratus displayed an appetence behaviour by preparing an ambush for its hosts. The larvae migrated vertically and showed a preference for longer (45cm) compared to shorter (5 and 25cm) questing substrates. The larvae formed clusters at the tips of the questing substrates. B. decoloratus ticks were present on cattle all year round. The numbers were, however, low during July to September. Peak adult numbers were collected from cattle during April and May, respectively. Nymphs and larvae displayed peaks during February and April, respectively. It was surmised that B. decoloratus can complete three generations per year in the central Free State. The overall sex ratio of the ticks collected from cattle did not differ from unity. This did not conform to the general pattern of male dominance observed for other metastriate ticks. B. decoloratus was the most abundant larvae collected from the drags. The off and on host seasonal abundance of B. decoloratus larvae correlated well. Drag sampling provided a fairly accurate indication of, not only the seasonal abundance of questing larvae, but also the species conditiosition in the Botshabelo area.Item Open Access The bio-ecology of the grass leaf miner, Agromyza ocularis (Diptera: Agromyzidae), on wheat and barley in the Northern Cape Province, South Africa(University of the Free State, 2010-06) Adendorff, Joan; Prinsloo, G. J.; Louw, S. vdM.English: The grass leaf miner fly, Agromyza ocularis (Spencer) (Diptera: Agromyzidae) was first described from specimens collected at Ceres (1959), Giant's Castle (1961) and the Maseru (1963) district. These specimens were collected with a sweep net from grass and no information was recorded on the host range and biology of the species. During 2000, A. ocularis was recorded on irrigated wheat in the Prieska district, Northern Cape and since then the species has spread to many wheat and barley fields in the Prieska and Douglas area. Two distinct types of injury are caused by A. ocularis, namely feeding punctures and leaf mining. The adult femail cause's circular punctures on the upper leaf surface of the host plant with her ovipositor, the ovipositor puncture can provide a feeding or egg-laying site. Mines are caused by the larvae feeding on tissue inside the leaf. The mine commences at the egg laying site where the larvae hatch. The mines are usually linear in the direction of the stem attachment or apex of the leaf. The area mined is dead, necrotic tissue and could not be revived through plant growth compensation. Photosynthesis rate by the leaves is therefore diminished. A mature larva cuts a slit in the leaf epidermis, escapes from the mine, drops to the ground and burrows into the damp soil adjacent to the plant and pupates. The pupal stage can last 23 days at 25°C under laboratory conditions. A pupal diapause stage which lasts for ±10 months in the laboratory can occur. The function of this stage is not clear, but it could be a mechanism to survive through periods when food resources are not readily available and extreme high temperatures occur. The lifespan of the adult fly is 30 days at 25°C, also under laboratory conditions. This can lead to overlapping generations of flies in a field and increase of damage to the crop. The flies were found to be active in the field when mean daily temperatures ranged between 10°C and 30°C and high relative humidity prevailed due to irrigation. This could be the optimal conditions the flies need to survive and thrive. A number of alternative host plants for A. ocularis were identified, i.e. Phalaris minor (small canary grass), Bromus catharticus (rescue grass), Lolium perenne (perennial rye grass) and Avena fatua (common wild oats). These grasses were recorded on the edges of the wheat fields during the wheat growing season, but not during the peak of the summer or in the natural vegetation surrounding the fields. The appearance of the flies in the cultivated fields differed by 14 days between 2008 and 2009 growing seasons. In spite of this difference, the crops in both years were older than plant growth stage (GS) 5 (Joubert scale) and the plants had already entered the stem elongation phase when the leaf miner outbreak occurred. It thus seems as if the appearance of flies is not linked to the specific plant growth stage, but rather to climatic conditions. At plant GS 5 the number of tillers per plant is already set and the plants' energy is utilized to initiate the number of heads per plant and the number of florets per head. If the plant is heavily damaged by this time, the number of heads and florets per plant will be influenced. The leaf miners commence oviposition on the lower older leaves of the plant, which are then obviously mined first. The rest of the leaves are attacked as they develop. In 2008, 100% of both barley and wheat plants sampled in the Douglas area were damaged by leaf miners when evaluated at GS 5. This damage intensity continued in all subsequent investigations. The number of damaged tillers per wheat plant increased from 48% - 63% between GS 5 and GS 17, the latter being the stage immediately prior to flowering. The number of damaged wheat leaves per tiller increased from 33% - 58% between GS 5 and 17, whilst indices ranging from 10% to 100% of leaf area damage were recorded. This amply demonstrates the severity of damage that is caused by the leaf miner. The damage varies, however, between fields and between years and could be due to specific spatial and temporal parameters. Damage to the crop and its yield is thus expected. However, insecticide trials conducted under similar conditions during 2008, demonstrated no difference in yield, albeit that a number of larvae were still present per tiller. The plant therefore seems to be able to compensate for the damage inflicted by the leaf miner. If the optimal conditions under which the crop is produced, i.e. sufficient water and fertiliser, is considered, this could be possible. The testing of different insecticides in field trials between 2007 and 2008 provided variable results, with a double dosage of Unimectin® resulting in 80% reduction in larval numbers on barley, which is the only reduction figure which is according to the pesticide registration application (Act 36 of 1947). In 2008 only Abamectin® double dosage met these standards and was the most successful in larval reduction, resulting in figures of 53% - 85% on barley. In spite of all these variables no significant decrease or increase in yield could be measured on any of the treatments in any of the years, suggesting that the plants could absorb the damage levels through compensatory growth.Item Open Access The bio-ecology of the sheep scab mite Psoroptes ovis (Acari: Psoroptidae) Hering (1835)(University of the Free State, 1999-09) Meintjes, Theresa; Fourie, L. J.; Kok, D. J.English: Sheep scab, which is caused by the mite Psoroptes ovis, has been and is still today an impediment to sheep husbandry in many countries throughout the world. Despite the economic impact, sheep scab remains a serious veterinary problem in South Africa. The broad objectives of this study were to determine the adverse effects of P. ovis on the host, with special reference to Merino and Dorper sheep, and to examine various possible foci of infestation and host specificity. Furthermore, the effects of abiotic factors (relative humidity and temperature) on the off-host survival of P. ovis were determined. The nature and extent of sheep scab in small scale, predominantly black farming communities, were assessed and compared to commercial predominantly white farming communities. The results revealed the following: With the exception of neutrophils, haematological values remained within the normal range for infested Merino and Dorper sheep, during a 14 week assessment period. For both sheep breeds the albumin and globulin values were higher than the normal range during the entire 14 week observation period. Both sheep breeds displayed a slight decrease in albumin values and a slight increase in globulin values. At the termination of a 16 week assessment period, uninfested control Merino sheep gained a mean ·body mass of 3.44 kg which represented a Il. 60% increase in body mass, compared to the mean body mass decrease (6.4 kg) of infested Merino sheep. This represented a 23.43% decrease in body mass. The mean body mass of the infested Dorper sheep increased over the 16 week period by 4.56 kg (15.11%) compared to the 5.88 kg (18.28%) of the uninfested control Dorper sheep. Comparative studies on the rate of sheep scab lesion development indicated that there were profound differences between sheep breed and season. During the summer assessment of 1997 the mean lesion size on the Merino sheep expanded from 1.0 cm2 at two weeks post infestation to 342.2 cm2 at eight weeks post infestation, compared to the mean lesion size of 0.406 cm2 and 59.0 cm2, respectively, recorded at two and eight weeks post infestation on the Dorper sheep. Lesion growth for both sheep breeds were greater during the winter. Attempts to artificially infest Boer and Angora goats failed. No clinical signs of sheep scab developed on the goats during a nine week observation period. When a single artificially infested Merino and Dorper sheep were introduced during winter into a flock of nine uninfested sheep for each breed, it took 14 and 8 weeks, respectively, before all the sheep in the flocks displayed clinical signs of sheep scab. During summer it took 10 and 12 weeks, respectively, before all sheep in the two flocks displayed clinical signs of sheep scab. All developmental stages of the mites were found in proximal and distal parts of wool / hair tufts clipped from Merino and Dorper sheep. Immature and mature mites were readily transferred to wool/hair tufts placed onto, and later removed from infested sheep, confirming that direct contact between hosts is most probably the main means of transfer. A maximum mean off-host survival time of 15 days (T = 10°C and RH = 33% and 75%), 10.5 days (T = 10°C and RH = 75% and 90%) and 11.25 days (T = 10°C and RH = 90%) were recorded for nymphs, males and ovigerous females, respectively. The mean egg incubation time varied from 5.9 (±2.58) to 22.14 (±6.53) days. The longest time eggs took to hatch was 31 days (T = 10°C and RH = 75%). The longest mean larval longevity was 9.25 days (T = 10°C and RH = 90%). Under natural fluctuating conditions ovigerous females in glass vials containing Merino wool survived 20 days, compared to a maximum of 17 days of females in glass vials without Merino wool. A survey indicated that 36.36% of the sheep flocks in Botshabelo and 38.46% in Thaba Nchu, respectively, were infested with sheep scab. This high incidence was believed to be due to factors such as communal grazing systems, ignorance on the part of the farmers and the lack of financial means to purchase effective remedies to treat their sheep flocks.Item Open Access Biology and control of the mango seed weevil in South Africa(University of the Free State, 2008) Louw, Cornelia Estelle; Van der Merwe Louw, S.English: The mango seed weevil (MSW), Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae), generally causes few problems on early-season cultivars, since the fruit are marketed and consumed before adult emergence from the fruit. Adult emergence from late-hanging cultivars, however, results in unattractive lesions that influence the marketability of the fruit. There is little evidence that MSW influences yield, although some authors argue that MSW development in the seed may lead to premature fruit drop. The economic impact of the MSW is primarily based on the fact that it is a major phytosanitary pest, restricting access to new foreign markets and contributing to substantial rejections of fruit destined for existing export countries. The MSW has no natural enemies, is monophagous on mango and completes its entire life cycle within the mango seed. The impact of this pest can, therefore, be greatly reduced by orchard sanitation. Sanitation practices, however, are labour intensive, necessitating producers to rely on alternative or additive control measures. Several semi-penetrant and contact pesticides are registered for MSW control. However, with trans-laminar products it is imperative that treatments coincide with, or are applied just after, the onset of weevil oviposition. This requires intensive and accurate scouting programmes, with an in-depth knowledge regarding the duration of oviposition necessary to ensure seasonal control. When using contact insecticides, applications should coincide with seasonal and daily activity peaks to ensure direct contact. Since adult weevils are extremely inactive, this necessitates an in-depth knowledge of MSW activity patterns. It is also imperative to understand the development cycle and life strategies of the insect in order to know at which time intervention would prove to be the most effective. The product most generally used for MSW control in the Hoedspruit magisterial district of the Limpopo Province is fenthion (Lebaycid® EC 500g/ℓ a.i.). This product is very effective, but does not provide 100% control and can lead to secondary infestations of mango scale, Aulacaspis tubercularis (Newstead) (Hemiptera: Diaspididae), and mealybug (various species). The use of organophosphates on fruit destined for certain overseas markets is also under investigation by the EU. It is for this reason that Westfalia Technological Services, over the past four years, investigated various aspects of MSW general biology, reproduction and control. The investigation into the activity patterns of adult weevils indicated that MSW were crepuscular – nocturnal insects. For this reason, applications with contact insecticides aimed at controlling the adult weevil would be expected to be more efficacious when applied at dusk. During the study investigating MSW development, it was found that the majority of MSW eggs hatched between 7 and 14 days, with some of the first instar larvae already having penetrated into the seeds between 7 and 14 days after oviposition, depending on whether the eggs were laid early or late in the season. This implies that chemical control with contact and semi-penetrant chemicals, aimed at controlling the MSW larvae, should preferably not commence later than 7 days after observing the first eggs in the orchards. However, it was found during the course of this study that MSW oviposition commenced during the latter part of September and continued up to the latter part of January, a period considerably longer than previously stated in the literature. For this reason, more than one chemical application would be warranted. While investigating alternative chemical control measures, it was found that a single application with the systemic insecticide, thiamethoxam (Actara™ SC 240g/ℓ a.i.), applied during flowering in the root zone, rendered seasonal MSW control. The use of this product, therefore, negates the necessity of tedious fruit inspections and an in-depth understanding of the pest in order to determine the most appropriate time for chemical intervention.Item Open Access Biology and transmission potential of malaria vector mosquitoes in Elabered sub-zone, Eritrea(University of the Free State, 2001-11) Okbaldet, Yohannes Bein; Coetzee, M.; Van der Linde, T. C.; Hunt, R. H.This study was intended to assess the biology and transmission potential of the malaria vector mosquitoes in Elabered sub-zone, Eritrea. Field collected Anopheles mosquitoes sampled during the malaria transmission season, from September to November 2000, were identified morphologically in the field. Morphological identification revealed that members of the An. gambiae complex were the most abundant and the only malaria vector species present during the study period. All the members of the An. gambiae complex were subjected to polymerase chain reaction (peR) assay and results showed An. arabiensis was the only member of the An. gambiae complex found in this area. Blood meal ELISA tests showed that 16.9% and 66.9% of 266 An. arabiensis were human and bovine fed, respectively. The percentage of mixed feeds, on both on human and bovine was only 3.8%. A total of 12.4% of the samples failed to react either to human or bovine anti-sera. None of the non-vector anophelines tested positive for human blood. Anopheles arabiensis in this particular area preferred to feed and rest outdoors rather than indoors, and biting was more intensive in the first half than in the second half of the night. Plasmodium falciparum infection was also determined using ELISA for 589 An. arabiensis specimens. There was no apparent monthly variation in infection rate, 0.5%, 0.8% and 0.7% for September, October and November, respectively. Based on the entomological inoculation rate derived from the hourly night bait catches carried out, during the whole transmission season, a villager could be exposed to 0.08 infective bites/night. Anopheles arabiensis in this particular area is susceptible to deltamethrin, lambdacyhalothrin, propoxur and DOT. However, permethrin resistant strains might be present and more tests at field level are required to verify the result and monitor the situation.Item Open Access Blood parasites of Free State and Lesotho reptiles(University of the Free State, 2003-07) Van As, Johann; Davies, Angela; Basson, LindaEnglish: The study of blood parasites of reptiles is a relatively new and unexplored field of research in South Africa. The Free State province and the Lesotho highlands provide a range of reptiles in which their intraerythrocytic parasite fauna were explored. Objectives of this study were to set a baseline of blood parasite diversity and to identify the enigmatic Sauroplasma Du Toit, 1937 and Serpentoplasma Pienaar, 1954 infections in lizards and snakes, respectively. Surveys were conducted in various localities in the Free State and Lesotho. Although low in diversity, 204 specimens representing 14 species of lizards, and 59 specimens representing 13 species of snakes were investigated for the presence of blood parasites. Three known infections were found: Sauroplasma thornasi Du Toit, 1937, Sauromella haemolysus Pienaar, 1954 and Hepatozoon (Haemogregarina) sebae (Laveran and Pettit, 1909) Smith, 1996. These were redescribed and S. thomasii and H. sebae were examined by aid of transmission electron microscopy. The investigation led to the discovery of six new records and possibly new species of haemogregarines named Hepatozoon sp. A-F, four new records and possibly new species of lizard malaria named Plasmodium sp. A-D, and a viral infection possibly of the Pirhemocyton type. Furthermore nine new host and distribution records for Sauroplasma in lizards and nine for Serpentoplasma in snakes are described. Ultrastructural investigations of S. thomasi in Cordylus giganteus A. Smith, 1844, Serpentoplasma in Bitis arietans arietans (Merrem, 1820) and H. sebae in Python sebae natalensis (Gmelin, 1789) were the first to examine the nature of infections in this manner. This is the first comprehensive survey of the biodiversity of blood parasites in reptiles in the Free State and Lesotho highlands.Item Open Access Caligid fish parasites from the South and East coast of South Africa(University of the Free State, 2000-03) Grobler, Nicolaas Johannes; Van As, J. G.; Olivier, P. A. S.English: Caligus Muller, 1785 are caligid copepods found almost exclusively on marine fish hosts. This genus is represented by more than 200 species in the oceans of the world and is the largest genus of parasitic copepods. A total of 39 species of Caligus parasites have been recorded off the coast of Africa, and 26 species are found along the South African coastline. Surveys carried out from 1992 to 1998 in Lake St Lucia and from 1997 to 1999 at De Hoop Nature Reserve and Jeffreys Bay along the coast of South Africa, revealed the presence of caligid copepods, of the genus Caligus MilIler, 1785, occurring on the body surfaces and gills of many estuarine and intertidal fish species. Four different species were collected from marine hosts namely, Caligus acanthopagri Lin, Ho & Chen, 1994, Caligus confusus Pillai, 1961, Caligus engraulidis Barnard, 1948, and Caligus mortis Kensley, 1970. The first three species mentioned were collected in Lake St Lucia, KwaZulu-Natal, on the east coast of South Africa, and C. mortis were collected at De Hoop Nature Reserve and Jeffreys Bay on the south coast of South Africa. In the present study, males of C. engraulidis and C. mortis are described for the first time and is new to science. Further studies revealed that interesting hypersymbionts were found attached to the caligids. Sessiline ciliophorans were found on both C. acanthopagri and C. engraulidis and represents a first record for South Africa. Udonella caligorum Johnston, 1835 were found on the caligid host C. engraulidis. This monogenean worm have a complicated history, for it was placed in different taxa and families since it was first described in 1835. Phylogenetic analysis as well as morphological analysis places this worm firmly as a polyonchoinean monogenean alongside the Gyrodactylidae. These hypersymbionts do not feed on the copepods and have no detrimental effects on their hosts.Item Open Access Characterization of macro- and micro-invertebrates and assessment of water quality in dams and rivers of Qwaqwa(University of the Free State (Qwaqwa Campus), 2016) Motholo, Lisemelo Francina; Thekisoe, O. M. M.; Tsotetsi, A. M.This study was aimed at assessing water quality status and documentation of waterborne invertebrate organisms in freshwaters (rivers and dams) of Qwaqwa area of Maluti-A-Phofung municipality. Water samples were collected seasonally from rivers and dams to test water quality parameter levels and the variability of the South African scoring system (SASS) bioassessment method. Variable parameters were assessed using the multiparameter equipment and spectrophotometer for water quality and nutrient assessment respectively in all sampled rivers, namely; Metsimatsho, Namahadi, Khoptjwane, Kollatshwene and Elands as well as in two dams namely; Metsimatsho and Fikapatso. The mean electrical conductivity (EC) levels were the highest in Kollatshwene (0.268 μS/cm); Elands (0.231 μS/cm) and Khoptjwane (0.214 μS/cm) rivers between February and June 2014. The EC levels varied widely across the rivers ranging from 0.017 to 0.298 μS/cm in spring. Therefore there were no significant differences (p > 0.05) of the EC levels between the rivers. The EC levels of Fikapatso dam have been higher than those of Metsimatsho dam throughout the sampling period. The pH levels between the rivers were slightly significantly different (p ≤ 0.06). There were no significant differences (p > 0.05) on the temperature levels between the rivers. The salinity and TDS levels between the rivers were significantly different (p < 0.001). The highest winter temperature level was observed in Namahadi river (9.07 ºC) with the lowest winter temperature observed in Kollatshwene river (6.22ºC) which is the highest elevated sampled river (1675m). Meanwhile, with Fikapatso Dam (8.13 ºC) compared to Metsimatsho dam (9.07 ºC) is the opposite since temperature levels were relatively higher than those of most rivers. The pH average levels were high in the Elands river (7.57) than in Kollatshwene river (7.12) being the least of them all. On the other hand, pH average levels were high in Metsimatsho dam (7.42) than Fikapatso dam (7.25). The highest salinity levels between rivers and dams were observed in Metsimatsho river (0.223 mg/l) as compared to 0.01 mg/l in Metsimatsho dam. Lastly, the TDS levels were high in rivers ranging from 21 mg/l (Metsimatsho river) to 297 mg/l of Elands river; than that of dams ranging from 13 to 60 mg/l in both dams. Of the various macroinvertebrate diversity indices, the South African scoring system version 5 (SASS5) index and the average score per taxon (ASPT) were the most consistently used among all biotopes. On the other hand, of the biotopes examined the Gravel/Sand/Mud (GSM) and vegetation combination is the most variable with respect to the SASS score and number of taxa encountered. The comparative SASS scores among the sampled sites were the highest in Metsimatsho Dam (SASS score = 125; No. of Taxa = 20 and the ASPT = 6.3) followed by Elands River (SASS score = 118; Number of Taxa = 21 and ASPT= 4.8); Metsimatsho River (SASS score = 117; No. of Taxa = 17 and ASPT = 6.8); and the least was Kollatshwene River (SASS score = 64; No. of Taxa = 14 and ASPT = 4.8). The lowest ASPT score of 4.8 was observed in both Kollatshwene and Elands rivers and was indicative of poor ecological category, hence poor water quality. Aquatic insects were identified to family level. The most occurring taxa was Baetidae with 102/298 (34.22%) and was the found in all sites; followed by Corixidae with 36/298 (12.08%) and the least being Ceratopogonidae 18/298 (6.04%). Occurrence of macroinvertebrates in water sources depends on their sensitivity to water pollution, while microinvertebrates (total and faecal coliforms) are tolerant to water pollution. Of many sampled sites, Kollatshwene, Elands and Khoptjwane rivers had the highest percentage occurrence of tolerant families (71.4%; 61.9% & 60.0% respectively). The coliform bacteria such as Escherichia coli, Aeromonas hydrophila, Acinetobacter baumanii, Serratia marcescens, Vibrio fluvialis, Pseudomonas putida, Enterobacter cloacae, and Burkholderia cepacia were also identified from Qwaqwa waters. Organisms like fish and frogs (Ameitia spp) as well as ,crabs (Potamonantes spp) occurred in water sources with good water quality mainly in Fikapatso dam since they are highly sensitive to high levels of water pollution. All studied parameters classify the Qwaqwa river water quality status to be poor as compared to the potable water from Fikapatso and Metsimatsho dams.Item Open Access Colour variation of African bovidae: consequences for conservation and the wildlife ranching industry(University of the Free State, 2015-07) Olivier, Phillip Arnold; Butler, H. J. B.English: Colour variant game species have become a common sight on game farms and at auctions, as a result of their oddity and high monetary value. Currently there are more than 40 colour variants of African Bovidae. Even though these colour variants have become very sought after and profitable to farm with, it has been warned that colour variants do not contribute to conservation since colour variants normally do not survive in nature. Consequently the intentional breeding of colour variants is causing concern, as they may be a threat to conservation. The objective of this study was to collect data to facilitate decision making in the game ranching and conservation industry. Statistical analysis showed that there were significant behavioural differences between four springbok colour variants studied. Black springbok were less active and utilised much more shaded areas compared to other colour variants or normal coloured animals. The darker coloured animals presented less body surface area to the sun during the warmest times of the day than the white springbok. Springbok were also found to form herds based on phenotype, preferring to associate with homogenous individuals. This phenomenon was likely due to the odd-prey effect. Wildlife auction turnover grew from R62 million to over R1 billion in the last ten years. In conjunction with this growth, record prices for animals are being recorded every year. However in most cases colour variant game are reaching much higher prices than the normal coloured nonspecific's. Colour variants also achieve annual growth which is greater than inflation often providing better return on investment than stock market shares. Even though a normal Kalahari springbok ram set a new record at R1.2 million it was far exceeded by coffee coloured springbok that sold for R4 million. Financial gain then seems to be the main motivator behind the breeding of colour variants as they have become sought after by game ranchers. There is however concern amongst various stakeholders that the breeding of colour variant wildlife is unsustainable. This is as a result of the increasing opposition against the selective breeding of these animals and a general disinterest in these animals from end-users which include hunters and eco-tourists. No significant proof could be found during this study that there will be large-scale interest in the consumptive or non-consumptive use of colour variants. Little published scientific data is available concerning colour variants and most of the available information is in the form of popular magazine articles, newsletters and websites. The lack of published scientific data has resulted in a debate concerning colour variants. Opinions on this issue are much divided and can also evoke strong emotional responses from those involved; particularly from ranchers that are concerned their livelihoods may be threatened by any control measures. Most wildlife ranchers feel that they should be allowed to breed with any animal that provides the best return on investment and that, since colour variants are a natural phenomenon, they do not threaten conservation. Survey results showed that although many respondents did not consider colour variants to be a threat to conservation the majority did not support breeding of such colour variant wildlife. The vast majority of respondents indicated that financial gain was the main reason for the popularity of colour variants. Many stakeholders also expressed great concern about potential damage being done to the conservation and eco-tourism image of South Africa as many, specifically foreign hunters, consider colour variants wildlife to be unnatural. The ultimate conclusion of this study is that the existence of colour variants does not pose a threat to conservation but it is rather the management of these animals which pose a potential threat to conservation of South Africa’s wildlife as well as South Africa’s conservation image.Item Open Access Comparative bone histology of stigmochelys pardalis (leopard tortoise), with specific reference to ontogeny and biomechanics(University of the Free State, 2017-01) Botha, Alexander Edward; Botha-Brink, JenniferTestudines are a group of reptiles characterised by the presence of a shell comprised of bony shields. Stigmochelys pardalis is the most widely distributed terrestrial testudine in southern Africa. Although relatively common with some life history traits (e.g. lifestyle, reproduction, longevity) being well known, the growth of this species has yet to be studied in any detail. This study is the first to use bone histology and microanatomy to examine the growth and biomechanics in an ontogenetic series of S.pardalis. The study also indicates clear short-comings in the determination of lifestyle using a single section on the diaphysis in S. pardalis and possibly in other testudines. The bone microanatomy of this clade differs from that found in other amniotes. In other amniotes, aquatic species tend to display large osteoporotic bone with large infilled medullary cavities and thin cortices. Semi-aquatic species have thick bone walls with small or no medullary cavities whereas terrestrial species tend to have thinner bone walls, open medullary cavities and a sharp transition from cancellous to compact bone. A detailed histological analysis of the limb bones of S.pardalis reveals extensive variation through ontogeny. Cortical bone becomes increasingly thicker through ontogeny and is finally resorbed in the late sub-adult stage, resulting in a thin cortex and a large infilled medullary cavity. The predominant bone tissues are parallel-fibred and lamellar-zonal for forelimb and hind limbs respectively. In certain cases parallel fibred bone tissue transitions to lamellar-zonal bone tissue later in ontogeny. A few older individuals exhibit and External Fundamental System indicating that the growth rate had decreased substantially by this stage. However, these individuals are between 56% and 60% maximum known size indicating that this slow growing species takes many more years to reach its maximum body size. Inter-elemental variability is most prevalent between the forelimb and hind limb. Forelimb elements exhibit characteristics such as faster growing parallel-fibred bone tissue, slightly higher vascularisation and a predominance of annuli over Lines of Arrested Growth compared to the hind limb which exhibits poorly vascularised, slower growing lamellar zonal-bone interrupted by LAGs. These differences indicate that the forelimb grew more rapidly than the hind limb, possibly due to the method of locomotion typical in chelonians. Lifestyle inferences using Bone Profiler indicate an aquatic lifestyle for this species despite it being clearly terrestrial. Sections from individuals of various ontogenetic stages were tested and although the microanatomy of the bone changes dramatically with age, the lifestyle readings remained inaccurate. The extensive bone resorption that occurs from the early sub-adult stage destroys much of the primary cortex, thus destroying the ecological signal. This supports the results from other studies that have found that using bone microanatomy to determine lifestyle in testudines is inaccurate.