Zoology and Entomology

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Open Access
Activity patterns of birds in the central Free State, South Africa
(University of the Free State, 2009-11) Van Niekerk, Daniël Johan; Kok, O. B.
Activity patterns of bird species were studied at Glen Agricultural College within the grassland area of the central Free State, South Africa, during a period of 11 years (July 1997 - July 2008). The study focused on a specific grassland locality where 5-minute checklists were compiled continuously from dawn to dusk at least once a week for a total of 656 days. Data were also collected each minute for selected species. Additional observations in an adjacent tree and shrub dominated drainage line included I-minute checklists compiled during transects over a two-year period (late autumn 2000/1 to mid-autumn 2002/3) as well as surveys from a fixed position from dawn to approximately 70 minutes after sunrise during 2007/8. The central aim of the study was to quantify and explain annual, seasonal and daily activity patterns of all bird species recorded in the study area. This data is summarised in separate species accounts where aspects of the annual cycle, particularly breeding and moulting, were also considered. In addition, the potential influence of rainfall was investigated. The study reveals, for the first time, how the activity patterns of a southern African bird community change through time, and how the amount and timing of rainfall can influence these patterns. In spite of similarities amongst species when daily, seasonal and annual patterns are considered separately, the study also shows that each species is unique when all its data is considered simultaneously. Because activity patterns can have a substantial influence on the detectability of a species, the accuracy and usefulness of surveys aimed at estimating bird numbers is consequently questioned. The study at Glen also shows how activity patterns can be used to help unravel the annual cycle of species in a time and cost effective way.
Open Access
Advances in the systematics and ecology of African Corinnidae spiders (Arachnida: Araneae), with emphasis on the Castianeirinae
(University of the Free State, 2012-01) Haddad, Charles Richard; vdM Louw, Schalk; Dippenaar-Schoeman, Ansie
English: The Corinnidae is one of 76 families of spiders (Arachnida: Araneae) presently recognised in the Afrotropical Region. By the end of the last century their taxonomy and systematics had been very poorly studied and no modern revisions existed on the group. At that time, 110 species in 22 genera were known from the region, making it a family with moderate species richness. The description of the new genus Hortipes Bosselaers & Ledoux, 1998 in the family Liocranidae signalled the start of modern systematics studies in that family, and following the transfer of Hortipes to the Corinnidae, of that family by default too. Since that time, 20 taxonomic papers have been published on the Afrotropical Corinnidae and 10 new genera (all endemic to the region) and 164 new species have been described, of which three species form part of the current study (Chapters 7 and 9). Several genera have also been transferred to or from the Corinnidae in those papers. Presently there are 35 genera and more than 270 species known from the region, with the Corinnidae now ranking eighth in species richness in the region. Most of the revisionary work so far has focused on the subfamilies Trachelinae and Phrurolithinae, while the Corinninae sensu lato and Castianeirinae have largely remained neglected. The broad aim of the current study was to focus on the systematics of the latter group, treat the taxonomy of each of the currently known genera, at least in part, and provide a basis for future work on the subfamily. As such, many of the smaller genera in the subfamily were revised in the Afrotropical Region and two new genera were described. The genus Apochinomma Pavesi, 1881, the only described genus of accurate antmimicking castianeirines from the region, is revised and separated into two species groups based on genitalic and abdominal morphology. The type species, A. formicaeforme Pavesi, 1881, is redescribed and three new species are described in the A. formicaeforme species group: A. malkini sp. nov., A. parva sp. nov. and A. tuberculata sp. nov.. Two new species, A. decepta sp. nov. and A. elongata sp. nov., are described in the A. decepta species group, although an additional species only known from juveniles can also be placed in the latter group. Members of the A. formicaeforme species mimic Polyrhachis ants and are mainly arboreal, while members of A. decepta species group are ground- or grass-dwelling and probably mimic ponerine ants. The genus Cambalida Simon, 1909 is revised and three species are transferred from Castianeira Keyserling, 1879 to Cambalida: C. deminuta (Simon, 1909) comb. nov., C. fulvipes (Simon, 1896) comb. nov. and C. loricifera (Simon, 1885) comb. nov.. An additional species is transferred from Brachyphaea Simon, 1895 to Cambalida: C. fagei (Caporiacco, 1939) comb. nov.. All of these species are redescribed, as is Cambalida coriacea Simon, 1909. Two species, Castianeira depygata Strand, 1916 syn. nov. and C. mestrali Lessert, 1921 syn. nov., are considered junior synonyms of C. fulvipes. The type material of the type species of the genus, C. insulana Simon, 1909 from Annobon Island, is lost, and only immature specimens have been subsequently collected from a nearby island. The species is regarded as a nomen dubium until fresh adult material can be collected. A replacement name, Cambalida simoni nom. nov., is proposed for Cambalida fulvipes Simon, 1909, the latter being a secondary junior homonym of Cambalida fulvipes (Simon, 1896) comb. nov.. The type material of C. simoni is also lost and it too is considered a nomen dubium. Five new species are described: C. compressa sp. nov., C. dippenaarae sp. nov., C. griswoldi sp. nov., C. lineata sp. nov. and C. unica sp. nov.. Castianeira Keyserling, 1879 is the largest genus in the Corinnidae with 131 described species, of which 22 are presently known from the Afrotropical Region. There is a very rich undescribed fauna known from the region, and the variable morphology of its component species would suggest it is polyphyletic and should be divided into several genera. For example, six species are misplaced and have been transferred to or synonymised with species in Cambalida or the new genus Copuetta gen. nov.. In the present study, five species are redescribed and illustrated for the first time based on the type material: C. delicatula Simon, 1909, C. formosula Simon, 1909, C. majungae Simon, 1896, C. phaeochroa Simon, 1909 and C. thomensis Simon, 1909. The female holotype of C. bicolor (Simon, 1890) lacks an abdomen and the species is considered a nomen dubium. The types of several Afrotropical species could not be traced as yet and the species should be redescribed, if possible, based on recently collected material from near their type localities. The ground-dwelling genus Copa Simon, 1885 is one of four genera in the Afrotropical Region that have cryptic colouration that bears a resemblance to that of wolf spiders (Lycosidae), hereafter referred to as cryptic lycosiform colouration. The type species of the genus, C. flavoplumosa Simon, 1885, is redescribed and proposed as a senior synonym of C. benina Strand, 1916 syn. nov. and C. benina nigra Lessert, 1933 syn. nov.. This is possibly the most widespread corinnid in the Afrotropical Region albeit that is has not yet been recorded from any of the islands. A new species, C. kei sp. nov., is described from South Africa. Copa agelenina Simon, 1910, originally described from a subadult female from southern Botswana, is considered a nomen dubium. Although the Madagascan fauna was not included in this revision, nearly 30 new species have been distinguished from museum collections, and once that fauna is revised it will provide an exceptional example of island radiation. In a revision of the Afrotropical species of the ant-mimicking genus Corinnomma Karsch, 1880, Apochinomma semiglabrum Simon, 1896 is redescribed from both sexes, and based on these descriptions it is transferred to Corinnomma as C. semiglabrum (Simon, 1896) comb. nov.. A new species, C. lawrencei sp. nov., is described from Mozambique, Tanzania and South Africa. The taxonomic status of C. olivaceum Simon, 1896 is discussed and the first illustrations of the female genitalic structures are presented. Since no fresh material of this species is available and the female holotype is badly faded, it is not thoroughly redescribed. An English translation of Simon’s (1896) Latin description of C. olivaceum is provided with the intention of more accurately describing the colouration of this species. The arboreal cryptic lycosiform castianeirine genus Echinax Deeleman-Reinhold, 2001, previously known only from South-East Asia, is recorded from the Afrotropical Region for the first time. Copa longespina Simon, 1909 is redescribed and the species is transferred to Echinax as E. longespina (Simon, 1909) comb. nov.. Six new species are described from both sexes: E. clara sp. nov., E. hesperis sp. nov., E. natalensis sp. nov., E. scharffi sp. nov., E. similis sp. nov. and E. spatulata sp. nov.. The genus Graptartia Simon, 1896, presently known only from Africa, is revised. The type species, G. granulosa Simon, 1896, is redescribed and the first genitalic sketches of the species are provided. Two new species, G. mutillica sp. nov. and G. tropicalis sp. nov., are described. Unique amongst African castianeirines, all species of Graptartia are mimics of wingless female velvet ants (Mutillidae). Although the genus Merenius Simon, 1909 is not revised, a single common species, Merenius alberti Lessert, 1923, is redescribed. The species was previously known only from South Africa, and is recorded for the first time from Mozambique, Swaziland and Zimbabwe. While most populations of M. alberti comprise the typical black morph of the species, a red morph is described for the first time here. As part of a field study to identify the potential models of the two colour morphs of M. alberti, spiders were collected by hand and ants by pitfall trapping in the Ndumo Game Reserve in northern KwaZulu-Natal, South Africa. The ants assemblages sampled at 20 sites in the reserve seem to indicate that the black morph is a generalised mimic of black ground-dwelling ants, most likely Camponotus cinctellus (Gerstäcker, 1859), Streblognathus peetersi Robertson, 2002 and Polyrhachis gagates F. Smith, 1858, while the red morph is a mimic of Anoplolepis custodiens (F. Smith, 1858) ants. Lastly, the genus Messapus Simon, 1898, presently placed in the Castianeirinae, is reviewed. The type species, M. martini Simon, 1898, clearly represents two different species, one a corinnine (female lectotype) and the other a castianeirine (male paralectotype). The female is redescribed and the true male described for the first time. Based on the redescription, Messapus is transferred to the Corinninae. Corinna natalis Pocock, 1898 is misplaced and is transferred to Messapus as M. natalis (Pocock, 1898) comb. nov., while Messapus secundus Strand, 1907 is misplaced and transferred to Merenius as M. secundus (Strand, 1907) comb. nov.. A new cryptic lycosiform genus, Copuetta gen. nov., with the type species C. maputa sp. nov., is established to accommodate the castianeirine male paralectotype of M. martini, and its matching female is described for the first time. Castianeira kibonotensis Lessert, 1921 syn. nov. is considered a junior synonym of Copa lacustris Strand, 1916 and the species is redescribed and transferred to Copuetta gen. nov. as C. lacustris (Strand, 1916) comb. nov.. An additional eleven new species of Copuetta gen. nov. are described: C. comorica sp. nov., C. erecta sp. nov., C. kakamega sp. nov., C. kwamgumi sp. nov., C. lesnei sp. nov., C. litipo sp. nov., C. lotzi sp. nov., C. magna sp. nov., C. naja sp. nov., C. uzungwa sp. nov. and C. wagneri sp. nov.. A second new cryptic lycosiform genus, Wasaka gen. nov., is described for four new species from tropical Africa: W. imitatrix sp. nov., W. montana sp. nov., W. occulta sp. nov. (type species) and W. ventralis sp. nov.. A phylogenetic analysis of the subfamily Castianeirinae from the Afrotropical Region was carried out. Forty-one ingroup taxa (Castianeirinae) were included, of which 39 were Afrotropical, one Australasian and one Brazilian. Outgroup taxa included three species of Trachelinae, one Phrurolithinae, two Corinninae and two Corinnidae incertae sedis, with Drassodes sesquidentatus Purcell, 1908 used to root the trees. Only species of Castianeirinae treated in this thesis and known from both sexes were included in the analysis. Analyses performed in Winclada, TNT and PAST all produced similar but very unsatisfactory results, with the outgroups grouping together with part of the Castianeirinae. Consequently, a second analysis was conducted with the exclusion of most of the outgroup taxa (except D. sesquidentatus and Corinninae). These results improved the resolution of the results considerably. but still did not resolve the placement of the Medmassa–Messapus clade within Castianeirinae; these genera can be considered to belong to Corinninae and should hypothetically have been placed outside the Castianeirinae clade. A single analysis produced in PAST produced the most parsimonious tree, with Medmassa–Messapus placed outside the Castianeirinae and each of the Afrotropical castianeirine genera as monophyletic. The results are inadequate to support any systematic changes in the Corinnidae, but future analyses need to include a more diverse range of castianeirine genera from outside the Afrotropical Region to better understand the relationships of the Afrotropical fauna. In the final chapter, the role of Castianeirinae as components of arthropod mimicry complexes is described for three species of ants, Anoplolepis custodiens (F. Smith, 1858), Polyrhachis gagates F. Smith, 1858 and Camponotus fulvopilosus (De Geer, 1778). There are respectively two out of 10, four out of six, and zero out of five species of Castianeirinae forming part of the arthropod complexes associated with these ants. All of these castianeirines are inaccurate (weak/ generalised) mimics of their models except for Apochinomma formicaeforme, which is an accurate (good/specialised) mimic of P. gagates. Colour polymorphism is also described for the first time in four species of Afrotropical Castianeirinae, i.e. Corinnomma semiglabrum, Merenius alberti, Castianeira cf. venustula (Pavesi, 1895) and Copa flavoplumosa. Three of these species are inaccurate mimics of ants, while C. flavoplumosa is a species with a widespread variant with cryptic lycosiform colouration and a nigrito form restricted mainly to tropical forests. High Castianeirinae biodiversity and endemism corresponds to most of the main Biodiversity Hotspots and Centres of Endemism (CE) in the Afrotropical Region: Maputaland-Pondoland-Albany CE (five endemics), Madagascar and Indian Ocean Islands CE (>30 endemics), East African Afromontane Forests CE (four endemics), East African Coastal Forests CE (five endemics), Guinean Forests of West Africa CE (seven endemics) and the Horn of Africa CE (one endemic). No endemic castianeirines have been recorded in the Succulent Karoo and Cape Floristic Region CE’s in southern Africa, although this corinnid fauna of these two CE’s is largely dominated by Trachelinae, most of which are endemics.
Open Access
Alternative methods of controlling the brown locust, Locustana pardalina (Walker)
(University of the Free State, 2003-07) Price, Roger Edward; Van der Westhuizen, M. C.
Outbreaks of the brown locust, Locustana pardalina (Walker), occur almost annually in the semi-arid Karoo region of South Africa and southern Namibia. Current suppressive control strategy relies on the application of fast-acting, synthetic pyrethroid insecticides, applied as ultra low volume drift sprays, to control gregarious brown locust targets at source within the Karoo outbreak region. However, the negative impact that the repeated application of insecticides may have on the rich diversity of endemic invertebrates and reptiles found in the Nama-Karoo biome is of great concern to landholders and conservationists. How to reduce the insecticide load and minimise the environmental impact in the Karoo and yet at the same time control this serious agricultural pest has become a controversial issue. There is thus an urgent need for more environmentally benign methods of locust control, as an alternative to the current spraying of insecticide. As part of a locust research project initiated by the Plant Protection Research Institute, Pretoria, the potential of various alternative methods of controlling the brown locust were evaluated against gregarious hopper populations in the laboratory and in the field. It was first important to update the available information on the background level of control provided by natural enemies and diseases of the brown locust. Although a range of natural enemies were found to prey upon the various life stages, their impact on brown locust populations in the present study was negligible. Of particular interest was a study of the impact of the sarcophagid fly, Wohlfarhtia pachytyli, which is a well-known facultative parasite of late instar brown locust hoppers and fledglings. However, field data suggested that the potential of the fly as a biological control agent may have been over estimated in the past, as the fly failed to cause more than 6% mortality of fledgling swarms in the present study. Before the first insecticides became available at the turn of the zo" century, farmers had to resort to mechanical methods to protect their crops and pastures from the ravages of locusts. Turning back the clock, the destruction of locust egg beds and the harvesting of locusts were re-examined as control methods. Excavation of locust eggs gave effective control, but the disturbance of the friable soils in the Karoo would damage the vegetation cover and cause severe erosion problems and is therefore not advocated. Harvesting of live locusts using nets or vacuum machines was not practical due to the avoidance behaviour of locusts. However, the harvesting of locust cadavers lying on the soil surface following insecticide spraying, once they had dried out and insecticide residues had broken down, was possible. With their high protein and fat content, the processing of locust cadavers into animal feed may become economically viable in future. Before organo-chlorine insecticides became available in the 1940s, bran bait containing sodium arsenite was extensively used for brown locust control. The baiting technique was re-evaluated in the present study using minute dose rates of the phenyl-pyrazol insecticide, fipronil, dissolved in water and mixed into wheat bran as the edible carrier. Bran bait containing 0.02% fipronil 200Se (Regent®) was prepared on site and was broadcast by hand onto the soil surface around bushes occupied by hopper bands as overnight roosting sites. Excellent control (>95%) of small and medium sized hopper bands was achieved, as long as baiting was undertaken shortly after sunrise, before hoppers scattered from the baited area. Baiting large band targets, or baiting later in the day once hoppers became active, was not effective. Baiting with 0.02% Regent® proved very effective if applied to compact, roosting hopper bands. It was also inexpensive and was easy to prepare and apply, requiring basic equipment and limited training. However, the logistics of the bulk transport, preparation and application of locust baits under operational conditions appear daunting. Insecticide barrier treatments using fipronil (Adonis® 5UL), applied to 21m-wide strips of Karoo vegetation at a dose rate of 12.5g a.i./ha, were used to intercept gregarious brown locust hopper bands marching through the veld. Barriers of Adonis® proved very effective against mobile L2-L3 bands and against small L4-L5 bands, giving >90% control within 48 hours. However, barriers sometimes failed to adequately control large and mobile L5 bands that had sufficient momentum to march through barriers before the majority of hoppers acquired a lethal dose of Adonis®. Barriers also proved less effective where the vegetation density was sparse or where the vegetation was unacceptable to locusts. The size and density of the hopper bands and the time of day when bands made contact with the barriers also appeared to influence efficacy. Despite these factors, Adonis® barriers were still considered to have potential for the control of brown locust hopper bands in the more remote areas of the Karoo, especially during the early stages of an outbreak when hopper bands are still young. However, barriers would have to be judiciously applied to restrict the environmental impact of Adonis® against non-target organisms. Large-scale operational trials are recommended. Insect Growth Regulators (IGRs) have shown promise when applied as barrier treatments against various locust and grasshopper species. However, laboratory experiments with the IGRs, flufenoxuron and teflubenzuron, applied to leaf discs and fed to L5 brown locust hoppers at dose rates of 3-l5Ilglg, gave variable mortality of 30-70%, with most mortality occurring as the hoppers attempted to moult. In another experiment, diflubenzuron (Dimilin OF6®), was sprayed onto maize plants at volume rates of l-3.f;ha and subsequently fed to L2 brown locust hoppers in the laboratory. Dimilin OF6® produced 100% mortality of L2 hoppers within Il days at all application rates, as long as hoppers were continuously exposed to treated vegetation. However, irregular exposure to Dimilin® during the inter-moult period produced unsatisfactory mortality, as the product is evidently non-accumulative and is readily excreted. The fact that brown locust hoppers have to be regularly exposed to IGR-treated vegetation, combined with the sporadic feeding behaviour and high mobility of brown locust hopper bands in the Karoo, would probably make IGR barriers unsuitable for brown locust control operations. In collaboration with nBC and the LUBILOSA programme (CABI Bioscience, Ascot, UK), the locust-killing fungus, Metarhizium anisopliae var. acridum, was imported and evaluated by PPRI locust researchers as a myco-insecticide agent in laboratory and field trials against the brown locust. Under suitable application conditions the myco-insecticide, applied at a standard dose rate of lOOgconidia/ha, regularly produced >90% mortality of hoppers maintained in cages, although speed of kill was slow, with median lethal times of 10.3 and 13.4 days for the ground and aerial application trials respectively. In most cases, acceptable >90% mortality was not achieved for at least three weeks after application. Despite the slow speed of kill, the myco-insecticide agent was considered a significant advance in locust control and the product was subsequently registered as Green Muscle® in South Africa in 1998. However, the lack of a knock-down action and the slow kill currently makes Green Muscle® unsuitable for operational use in the Karoo. The thousands of individual hopper bands treated during control campaigns, and the high mobility of bands, would make the recognition of treated and untreated targets by locust officers impossible. The hot and dry Karoo climate is also usually detrimental for the survival and transmission of fungal conidia, while the thermoregulation behaviour of brown locust hoppers enables them to effectively delay the onset of Metarhizium mycosis. An alternative application strategy needs to be developed and tested before Green Muscle® can be recommended for brown locust control. Other pathogenic micro-organisms evaluated in the laboratory for brown locust control were certain acid-tolerant strains of Bacillus thuringiensis and an entomopoxvirus isolated from a West African grasshopper, Odaleus senegalensis (De Geer). Unfortunately, none of these microorganisms proved virulent to the brown locust. The alternative locust control methods evaluated against the brown locust were all ranked according to various performance criteria and compared with the conventional spraying of ULV insecticides. Of the alternative control methods, only Adonis® barrier treatments and Regent® bait showed sufficient promise for brown locust control. However, none of the alternatives were considered suitable under all locust control situations to entirely replace the spot spraying of conventional ULV insecticides, which will thus remain the backbone of brown locust control strategy. Recommendations on the development of an lPM strategy for brown locust control, to incorporate barrier treatments and baiting in certain areas of the Karoo in order to complement conventional insecticide spraying, are given.
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.
Open Access
Anthropogenic light, noise, and vegetation cover differentially impact different foraging guilds of bat on an opencast mine in South Africa
(Frontiers, 2022) Cory-Toussaint, Dawn; Taylor, Peter J.
Bats are known to be sensitive to changes in their environment. The impact of natural vegetation cover, artificial light intensity and noise (dBA) were investigated on the bat community on the opencast Venetia diamond mine using mixed-effects models. Clutter-feeding bats were virtually absent compared to surrounding natural habitats, suggesting the negative impact of vegetation removal and/or light and/or noise pollution. Mixed-effect models revealed that natural vegetation was the most important factor impacting species richness and overall bat activity. In general, bat activity of both open-air and clutter-edge foragers was negatively impacted over areas close to mining operations that were devoid of vegetation cover. Artificial light only significantly affected feeding activity with less feeding activity in the lit areas. Anthropogenic noise had no significant impact on bat activity and species richness. Our study highlights the importance of vegetation cover and the complexity of the interaction between bats and the environment incorporating anthropogenic factors (artificial lighting, continuous noise, and habitat degradation) and natural factors such as minimum temperature, moon phase, and season that confound trends in bat species richness and responses in relation to opencast mining.
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.
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.
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.
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.
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.
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, Linda
English: 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.
Open Access
Aspekte van die algemene biologie van Culex (culex) theileri Theobald (Diptera: Culicidae)
(University of the Free State, 1984-01) Van der Linde, Theunis Christiaan De Klerk; Van Pletzen, R.; Hewitt, P. H.
English: Since little is known of the occurence, distribution and possible vector roles of mosquitoes in the western Orange Free State, a trapping survey was undertaken to determine the species richness, relative abundance and seasonal fluctuations of mosquitoes in this region. Trapping of mosquitoes was done at weekly intervals from 1976 to 1978 on the farm Daniëlskuil, 30 km west of Bloemfontein. Twentyfive species were found to be present, of which eight had not previously been recorded from the Orange Free State. Culex (Culex) theileri Theobald was the most abundant species, accounting for 55,44% of the total catch. The temporal distribution and abundance of the seven dominant species viz. Aedes caballus, Ae. juppi, Ae. lineatopennis, Ae. durbanensis-group, Anopheles squamosus, Cx. theileri and Cx. univittatus were analyzed in terms of meteorological parameters such as air temperature, water temperature, relative pumidity and rainfall, all of which were recorded continuously. From these it was concluded that temperature and saturation deficit proved to be the most important variables. A Cx. theileri colony was established in the laboratory. Field observations and laboratory experiments led to the following rearing procedure and environmental conditions: Adults were held at 27°C and 65% RH with a day-night cycle of 12 hours each, which included a dawn and a dusk of one hour each respectively. Adults were fed on 7,5% sugar water and pigeons were used for bloodmeals. Optimum oviposition occured when individual gravid females were placed in pill vials containing 10 ml of water in which larvae had developed. Larvae were held in 0,02 M NaCI in shallow pans at 27°C. They were fed a mixture of brewer's yeast and an infant cereal. An electronmicroscopic study of the surface structure of the eggs revealed that the exochorion of the egg can be divided into four main regions viz. an anterior pole, a transitional region, an attachment region and a posterior pole. A cup-shaped corolla filled with gelatine-like material is present on the anterior pole and a prominent oil droplet on the posterior pole. In the attachment area the exochorion bears knobs with gaps between them. The knobs of adjacent eggs are arranged in such a way that adjacent eggs are joined to one another in a similar way as a press-stud operates. The eggs are thus held together to form a raft. Mating before or after a bloodmeal had no significant effect on the number of eggs produced. Intake of sugar after a bloodmeal had a detrimental effect on the number of egg-rafts produced, but not on the number of eggs per raft. Females which fed on white rats produced significantly more eggs than those which had fed on pigeons. The females, however, which fed on male rats produced large numbers of nonviable eggs. Aging prior to a bloodmeal resulted in decreased egg production. Repeated bloodmeals and oviposition by young females did not cause a decline in egg production or viability. Females oviposited during late dusk. They preferred 0,01 - 0,08 M NaCl solutions with a dark background. Furthermore, solutions in which larvae or pupae were reared, or which contained bacteria, were even more attractive. If offered no choice females oviposted on the available aqueous solution. Although temperatures below 15°C and above 33°C had a detrimental effect on oögenesis, no effect on selection of a suitable oviposition site could be established. The eggs are not particularly temperature sensitive during embryogenesis, but hatching does not occur below 12°C or above 36°C. The optimum developmental temperature was 27°C. NaCI concentrations above 0,08 M led to a decrease in the hatching percentage, while above 0,16 M no hatching took place. The temperature extremes of 12°C and 36°C were lethal to the larvae. The optimum temperature was 27°C. Increases in NaCI concentration up to 0,06 M had only a slight effect of larval developmental time. Thereafter a rapid increase in mortality occured. A direct correlation between survival of adults, temperature and saturation deficit was established. Sugar and bloodfed females survived longer at temperatures 6°C - 24°C and saturation deficits of 0,4 and 0,8 kPa. The results obtained form both field and laboratory studies were used in an attempt to explain the occurrence, temporal distribution and abundance of Cx. theileri.
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.
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.
Open Access
Aspekte van die ekologie van avifauna op 'n binnelandse lughawe
(University of the Free State, 1999-11) Kok, Alettta Catharina; Kok, O. B.; Van der Linde, T. C. de K.
English: Owing to the world-wide increase in air traffic the number and intensity of collisions between birds and aircraft have increased accordingly. Bird strikes are not only responsible for considerable physical damage and fmancial losses, but also endanger human lives unnecessarily. Aspects of the ecology of avifauna at the Bloemfontein airport were, therefore, investigated in order to reduce hazards posed by birds at inland airports. Plant surveys conducted during 1994 and 1995 confirm the classification of the study area as a chy Cymbopogon-Themeda veld type. Based on botanical composition and basal cover the veld is in a relatively good condition. Regularly mowed experimental plots were characterised by a greater variety of plant species consisting of a lower percentage of climax grasses and a larger component of pioneer grasses, forbs and dwarf shrubs compared to undisturbed tall grass areas. A total of 270 pitfall traps were used over a continuous period of 15 months to determine the diversity, relative abundance and seasonal variation of terrestrial invertebrates in the study area. Members of seven classes, 23 orders and 57 families were identified of which insects comprised the most important component by far. As .opposed to this, flying and plantliving invertebrates which were monitored on a monthly basis by means of sweep-nets were represented by only two classes, comprising 13 orders and 70 families. Mouse trapping and incidental catches of smaller vertebrates in pitfall traps suggest a limited presence of amphibia, reptiles and small mammals. Broadly speaking significantly more invertebrates were collected during the wet than during the dry season. Evidently, the opposite trend applies with regard to the sampling of reptiles and small mammals. Although no direct relationship between catches and rainfall as environmental factor could be demonstrated, a significant correlation with temperature was indicated. Over a period of eleven years approximately 5 000 individuals representing 51 bird species which, potentially, posed a threat to aviation were collected at the Bloemfontein airport. More than half of the species concerned can be considered as I medium-sized terrestrial birds of which the crowned plover (Vane/Ius coronatus) is by far the most important. A similar species composition occurred at the Kimberley airport, in contrast to the greater percentage of water associated birds at the Johannesburg airport. Indirectly, food availability appears to be one of the main environmental factors involved in the presence of, amongst others, the five dominant bird species at the Bloemfontein airport. Analyses of the stomach contents of 3 544 bird carcasses from the Bloemfontein airport, supplemented by 906 stomach contents from the Johannesburg and Kimberley airports, indicate that insects can generally be considered the main food source of the birds concerned. Based on dry mass composition the Isoptera, followed by the Coleoptera and Orthoptera, constitute the most important component in the diet. The Isoptera, more specifically the harvester telmite (Hodotermes mossambicusi), is, moreover, the only important prey taxon showing a conspicuous utilisation peak during the relative food shortage of the dry season. Evidently, temporary superabundant food sources which periodically come about in grassland habitats are opportunistically utilised by the birds. Indications are that habitat manipulation at airports can serve as an effective long-term bird control strategy. Based on the superabundant availability of invertebrate prey species in short grass areas compared to that in tall grass, a socalled tall grass policy would not only lead to the reduction of available food sources, but would also hamper the prey searching abilities of the largely insectivorous avifauna. According to results obtained, chemical manipulation can also be successfully employed to limit the presence of harvester termites, the staple food of the majority of terrestrial bird species in grassland habitat, thereby bringing about a reduction in bird numbers. At the same time, a five layered model is discussed setting out the responsibilities of all the role players associated with the implementation of a successful bird control programme. Key words: Airport, avifauna, bird hazard, feeding ecology, harvester termites, pitfall trapping, grassland, habitat manipulation, management.
Metadata only
Assessing small-scale fisheries potential of Gariep Dam, South Africa's largest impoundment
(University of the Free State, 2022-07) Swanepoel, Pieter Johannes; Van As, L. L.; Ellender, B. R.; Barkhuizen, L. M.
South African inland fisheries are considered poorly developed and fish resources are mainly utilised by recreational and subsistence fishers. The South African government has identified inland fisheries as an opportunity to contribute to food security, job creation and economic development, and has established a mandate to develop this sector. The Gariep Dam is South Africa’s largest freshwater reservoir, and its fish resources can potentially be utilised by the small-scale fisheries sector. The objectives of this study were to assess the fisheries potential of Gariep Dam by determine the viability of small-scale fisheries development by establishing up-to-date utilisation rates, determining fish abundance and catch rates, and assessing the viability of various harvest strategies. To assess resource status, a fisheries-independent multi-method approach was applied using gillnets, fyke nets and longlines to determine relative abundance, population structure and harvest potential. Fisheries-dependent roving creel surveys and angler counts were conducted to assess the recent utilisation of fish resources. To complement previous biological assessments of other species, Clarias gariepinus was studied to understand the biology, ecology, and population dynamics of this species in Gariep Dam. To assess potential development, a fisheries management plan that determined harvest costs, fish prices and financial viability was included. Labeobarbus aeneus dominated gillnet catches, with an average catch per unit effort of 5.7 ± 4.1 kg.net-1.night-1, which comprised 63% of the species composition. The remainder of gillnet catches comprised C. gariepinus (16%), Labeo capensis (10%), Labeobarbus kimberleyensis (10%) and Labeo umbratus (1%). Longlines proved to be successful in harvesting C. gariepinus, with an average catch per unit effort of 35 ± 24 kg.20-hooks-1.night-1, with very low catch rates for fyke nets. The longline catches were dominated by C. gariepinus (99%) with low numbers of L. kimberleyensis (1%). Roving creel surveys revealed that the Covid-19 pandemic had a major effect on the current hook-and-line fishery that was dominated by subsistence anglers, while recreational fishing disappeared during this period. A large proportion of the subsistence fishing sector were found to be out of work with unemployment rates of 70.9% and 34.5% in the two angling areas. Angler catches were dominated by L. aeneus (37.3%), followed by Cyprinus carpio (32.7%), C. gariepinus (13.7%), L. capensis (14.1%) and L. kimberleyensis (1.4%). The angling effort was estimated at an average of 42 ± 1 anglers.day-1 for the Gariep Dam which harvested an estimated 27 tonnes.year-1 during the sampling period. Clarias gariepinus from the Gariep Dam represents a stable population that matures late (5.2 years for males and 3.3 years for females), is dominated by old fish (Amax = 32 years) and exhibits slow growth (Lt = 1 013.28 (1-e0.092(t+7.78)) and a low natural mortality rate (0.369 year-1). These characteristics point towards a species that is likely to be utilised by inland fishers; however, spawning stock should be protected through special refuge areas. e study has revealed that the existing hook-and-line fishery is very important to the local communities surrounding the Gariep Dam and should be recognised and protected from future inland fisheries development. Results of the study indicate that a sustainable small-scale fishery is possible in the form of a longline fishery harvesting 40 tonnes.year-1 of C. gariepinus and a gillnet fishery using a 100 mm mesh size to harvest L. aeneus if they are separated by area to protect the current fishery. The financial analysis, however, indicated that substantial fishing effort will be required to harvest the projected amount of fish. With the recent price of freshwater fish (ZAR 13.50–16.00), a longline fishery is likely to be feasible, but a gillnet fishery is unlikely to generate sufficient revenue based on catch rates for a small-scale sector. The results of this study have been used to inform specific recommendations to develop inland fisheries for Gariep Dam, which can be used by government for decision-making.
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.
Open Access
An assessment of fish and fisheries in impoundments in the upper Orange-Senqu River Basin and Lower Vaal River Basin
(University of the Free State, 2016) Barkhuizen, Leon Martin; Weyl, O. L. F.; Van As, J. G.
South Africa is an arid country that, as a result of the need to store water for domestic, industrial and agricultural use, has invested heavily in the construction of impoundments which now cover a total of approximately 3 000 km2. Faced with high levels of poverty and unemployment, South Africa is increasingly considering developing fisheries in freshwater impoundments to provide economic opportunities and food security in rural areas. To be effective, such development needs to be guided by information on current utilisation, fish species composition and abundance, as well as the impact of potential harvest methods. Unfortunately, inland fisheries have received limited interest in a country with large marine fisheries and a history of failures in developing inland commercial fisheries. As a result, there is a general lack of even basic information on fish communities in impoundments and their utilisation. This thesis attempts to address this paucity of information in the Free State Province (FSP) by conducting a rapid appraisal of the fisheries potential of impoundments using empirical approaches; collating a 35 year time series of catch returns from recreational angling tournaments and commercial fisheries; conducting surveys to determine fish species composition in 21 impoundments and testing a new fishing gear. The FSP has the largest inland water surface area (145 677 ha) in South Africa and is situated centrally within the Orange-Senqu River Basin that is drained by the Orange-Senqu and Vaal River Systems. As a result of complete lack of data on inland fisheries in the FSP, a scoring system (based on empirical estimations of potential fish yield and water level fluctuations) was developed to provide information on the potential of impoundments for the development of commercial fisheries. Applying different models to Morphoedaphic index (MEI) data provided the first estimates of yields ranging from very conservative to highly opportunistic (e.g. for Gariep Dam from 5.0 to 58.5 kg ha-1 y-1). As predicted by most MEI-based models, impoundments situated at high altitudes with large average depth, with least fluctuation in water levels, had the least potential for the establishment of fisheries. Data on commercial fisheries were collated from various field stations and digitised. This provided the first complete database of commercial fisheries yields in South Africa. Between 1979 and 2014, a total of 9 036 tons of fish were harvested by commercial fishery enterprises operating sporadically at seven impoundments. Commercial fisheries yields were dominated by Bloemhof Dam (73%) and Kalkfontein Dam (23%) with sporadic attempts to develop commercial fisheries in the five other impoundments, contributing only 4% to the total yield over the 35 year period. The gear used to harvest fish determined which species were caught, with the indigenous cyprinids, namely Orange River mudfish Labeo capensis, moggel Labeo umbratus and smallmouth yellowfish Labeobarbus aeneus dominating catches when gill nets were used, while common carp Cyprinus carpio dominated when seine nets were used. Only two commercial ventures operated at one impoundment (Bloemhof Dam) on a continuous basis for more than 32 years. Prior knowledge, skills and experience and most importantly a pre-existing and self initiated market were identified as determinants of success. Data from license sales demonstrate that the recreational fishery sector in the FSP comprises 7 710 licensed recreational anglers. Of these, 748 are affiliated with 30 angling clubs. An analysis of historical data indicated that there has been a decrease of 76% in the number of recreational anglers since 1971 (based on license sales). Over the period 1974 to 2014 available data show that at least 4 817 angling tournaments were held at 17 impoundments. Historical analysis of participation indicates a decline in angling tournament participation. This was in support of the trends observed using license sales data. The total recorded catch for these tournaments was 414 tons. The recreational fishery was dominated by C. carpio that contributed 81% to the total weight and 77% of the total number of fish landed. Experimental fishing surveys conducted during this study, sampled 23 831 fish from the 21 impoundments surveyed. Sixteen species were sampled, with the bulk of the catches consisting of four large cyprinid species (L. capensis, L. umbratus, L. aeneus and C. carpio), and the sharptooth catfish Clarias gariepinus. On average, 7.6 ± 1.4 and 6.0 ± 1.1 species were sampled per impoundment in the Vaal River and Orange-Senqu River Systems respectively. Fish assemblages in different impoundments were similar (average Jaccard’s Index of Similarity of 64.2%). Examination of population structure (using length frequencies) indicated that most species sampled were established with evidence of several year classes of adults as well as young of year. An assessment of fyke nets as a potential harvesting gear demonstrated that this gear might be a suitable passive gear for small-scale fisheries. Eleven fish species were caught with fyke nets, with catches dominated by four large cyprinid species (L. capensis, L. umbratus, L. aeneus and C. carpio), and C. gariepinus of which most are important angling species, except L. umbratus. The preliminary assessment of the suitability of fyke nets as gear for smallscale fisheries has revealed a number of research questions and once these have been addressed, fyke nets might become the gear of choice in future inland fisheries development in central South Africa. With the new interest in the development and promotion of inland fisheries in South Africa to address government’s policy objectives of job creation and poverty alleviation, this thesis will contribute to the knowledge base, as for the first time in South Africa such a comprehensive study on an assessment of fish and fisheries within impoundments has been done. This thesis will provide baseline information which may support and inform the policy development process for inland fisheries in South Africa that was initiated during February 2015 by the National Department of Agriculture, Forestry and Fisheries.
Open Access
The bio-ecology and control of Coproica vagans and Coproica hirtula (diptera: Sphaeroceridae) in cattle feedlots
(University of the Free State, 1998-12) Badenhorst, Daniel; Van der Linde, T. C. D. K.; Louw, S. V. D. M.
English: Sphaeroceridae are generally known as "lesser dung flies". These are small to medium sized dark-brown to blackish flies ranging from about 0.5 mm to 6 mm in length. They are saprophagous and occur throughout the tropical and subtropical regions of the world. A unique scenario involving Sphaeroceridae flies that constitute a serious problem at South African feedlots is discussed. Two species, namely Coproica vagans (Haliday) and Coproica hirtula (Rondani) are both associated with cattle dung at feedlots, with the former species reflecting dominance. The flies cause a nuisance to the cattle by forming black clouds of swarming flies. It therefore became imperative to find a way to control these flies. The establishment of separate sphaerocerid laboratory colonies from which experimental studies could be conducted was successful and is described. The seasonal occurrence and relative abundance of the Diptera fauna occurring within undisturbed cattle droppings exposed to shaded and sunny locations in the central Free State was investigated. The Sphaeroceridae was of particular interest, but only five presumably new species were discovered among the 21 fly species reared from these droppings. No C. vagans or C. hirtula specimens were encountered. The influence of physical parameters such as temperature and moisture content of the dung on the development and survival of immature stages and adult flies is described. Temperature had a major effect on all stages of both species, and both too low and too high temperatures led to severe mortality. Optimum developmental temperatures were between 24°C and 30°C. The development time of all stages also increased with a decrease in temperature. Moisture content of the dung had the same influence on all stages of the Sphaeroceridae, and optimum moisture content levels were at approximately 90%. Development times also increased somewhat with a decrease in moisture content levels of the dung. Oviposition by adult females of both sphaerocerid species and the influence of temperature and photo periodicy was determined and is described. Oviposition continued for more than 60 days at colder temperatures, although the number of eggs produced was often very low. Higher temperatures on the other hand resulted in large numbers of eggs produced by sphaerocerid females (up to 607 eggs per female) at 24°C, but the duration of oviposition dropped. Different photoperiods had no severe effect on oviposition or egg production. Development and survival of immature stages and adult Sphaeroceridae were also influenced by the type of dung which they were offered and the effect of this phenomenon on the flies is also described. Some dung types, e.g. horse, buffalo and rhino dung, had a negative influence on larval and adult survival most probably as a result of the higher fiber contents of these dung types. The other dung types such as cattle, sheep and elephant dung, led to successful development and survival of all stages. Biological control was attempted with several Coleoptera (a staphylinid, Philonthus caffer (Boheman) and scarabaeids Aphodius pseudolividus Balthasar and Harmogaster strydomi Endrëdi), Diptera (Musea xanthomelas Wiedemann and Coboldia fuscipes (Meigen)) and mite species. These biological control agents all failed to control Sphaeroceridae numbers mainly because of their inability to survive in wet feedlot dung. Chemical control on the other hand produced positive results and seemed like the only option available. Several insecticides and chemicals were tested but only two, namely Neporex (cyromazine) and Scatterkill (piperonyl butoxide), showed irradication potential. A further advantage of Scatterkill is its long residual effect in feedlot dung.
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.

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