Abstract: Earthworms have an important role to play in turfgrass. They aerify and enrich the soil, enhance water infiltration and break down thatch. Turfgrass managers are advised to select pesticides non-hazardous to earthworms to maintain the long-term stability of a healthy turf An artificial soil test was used to assess the toxicity of five insecticides, used for turf grass pest management, on the Pheretima group (Megascolecidae). The recommended application rates of carbaryl, chlorpyrif...
Abstract: Morphological variation was examined in 58 species of Canthon and 18 species of other genera of the subtribe Canthonina (Anisocanthon, Canthonella, Cryptocanthon, Deltochilum, Hansreia, Holocanthon, Malagoniella, Melam canthon, Scybalocanthon, and Sylvicanthon). A total of 667 specimens was used for examination of morphological characters. Variation in head structures such as clypeus, eyes, labium, gula, and epipharynx is described. Thoracic structures examined include the pronotum...
Abstract: In South Africa, the genus Eucalyptus plays an important role as a plantation tree and hence forms a major economic component in the forest sector. An insect pest of these Eucalyptus species, Gonipterus scutellatus, causes periodic defoliation in the plantations. Plants have extraordinary array of chemicals (secondary metabolites), which defend them from herbivores. This study reports on the seasonal variation of the tannin concentration and carbohydrate content of the leaves of ni...
Abstract: Please read the abstract in the section 00front of this document. Also note that an abstract is provided for each chapter as well
Abstract: Spirocercosis is a canine disease caused by the nematode parasite Spirocerca lupi (Rudolphi, 1809) (Spirurida: Spirocercidae) and is a potentially fatal condition in domestic dogs (Canis familiaris). The larval life cycle of this parasite involves intermediate and paratenic (transport) hosts. Various species of coprophagous dung beetles (Scarabaeidae: Scarabaeinae) serve as the principle intermediate hosts. Despite extraordinary advances in biomedical research, it is unlikely that ...
Abstract: The eight southern African King Cricket genera, namely Bochus, Borborothis, Henicus, Libanasa, Libanasidus, Nasidius, Onosandridus, and Onosandrus are redescribed from type and museum material and a key to the genera is provided. Additionally, the status of Libanasidus impicta is investigated and species characteristics confirmed. A key to the two Libanasidus species is also provided. No morphological support for these eight southern African anostostomatid genera was attained with ...
Abstract: Please read the abstract in the section 00front of this document
Abstract: The discovery of the honeybee-specific ectoparasitic mite Varroa destructor in South Africa in October 1997 raised the spectre of massive honeybee colony losses as has occurred in most parts of the world where the varroa mite has been found. This was particularly concerning in Africa because of the importance of honeybees in the pollination of indigenous and commercial crops, and because of the numbers of small-scale beekeepers in Africa. The mite has now spread throughout South Af...
Abstract: Termites are considered to be major ecosystem engineers in tropical and sub-tropical environments, and fire in savanna systems is regarded as a major and necessary disturbance for the maintenance of biodiversity. However, most fire ecology studies have focused on vegetation dynamics with little attention given to other taxa, especially invertebrates. This thesis has addressed several aspects of savanna termite ecology. First, based on a review of studies examining the relationship ...
Abstract: The banana weevil, Cosmopolites sordidus, is an economical pest of Musa, distributed to most areas where the crop is grown. The beetle larvae produce feeding tunnels in the pseudostem and rhizome, reducing bunch weight and causing toppling or snapping of plants. In developing an integrated pest management system for South Africa, specific aims of the study were to quantify the genetic diversity of the species around the world, investigate the population dynamics of the insect, dete...
Abstract: The systematic status and geographic distribution of spiny mice of the genus Acomys I. Geoffroy, 1838 in northern Tanzania is uncertain. This study assesses the systematic and geographic distribution of Acomys from northern Tanzania using a multidisciplinary approach that includes molecular, cytogenetic, traditional and geometric morphometric analyses, and classical morphology of the same individuals. The molecular analysis was based on 1140 base pairs (bp) of the mitochondrial cyt...
Abstract: Please read the abstract provided for each separate chapter and the General Summary (Chapter 9) added to the section 00front
Abstract: At its inception, taxonomy simply provided guidelines for nomenclature. It has since developed into a science applied to problems relating to economics, conservation and even law. Taxonomy is arguably one of the most important pillars of the biological sciences, providing the framework from which all other studies are conducted. We expand this essential foundation by describing four new species of Trox in Chapter 2 of this dissertation - the first to be recorded in South Africa sin...
Abstract: The diversity of the Eriophyoidea is largely unknown and their systematic study mostly entails alpha-taxonomy which is critically important for these mites. Eriophyoid morphology is almost exclusively studied on slide-mounted specimens, and truly permanent specimen slides cannot be prepared and are eventually lost. Shortcomings in taxon descriptions are persistent, and too few morphological characters are available for systematic use, particularly for phylogenetic studies. The frag...
Abstract: The taxonomic composition, structure, and diversity of current local species assemblages results from an interacting complex of historical, regional ecological and local ecological factors. Structural differences between such current species assemblages are primarily determined by changing ecological conditions across spatial gradients. These conditions may change abruptly or they may represent a gradual divergence. Across the Botswana Kalahari basin there is a gradual northeast-so...