Abstract: This thesis reports on the number of individuals in Macrotermes natalensis (Hav.) colonies, their biomass and food consumption in the northern Kruger National Park (KNP). The ecology of M. natalensis is largely undocumented despite the abundance of colonies in southern African savannas. New approaches to mound excavation, sub-sampling and data management are introduced. Via the intracolonial demography of colonies the contribution of each caste in number or proportion is determined...
Abstract: All previous taxonomic studies on the Ectemnorhinus group of weevils have been based primarily on morphological data. While these studies are invaluable, some questions can only be addressed adequately through molecular studies. This is especially true when studying the genetic relationships and phylogeograpic patterns of taxa endemic to the South Indian Ocean Province (SIP) biotas that have long been controversial. The Ectemnorhinus group of genera is a monophyletic unit of weevil...
Abstract: Despite an IUCN conservation status of critically endangered, Juliana’s golden mole (Neamblysomus julianae) has received no ecological research attention to date. The species urgently requires conservation attention, but a poor understanding its biology, ecology and distribution makes effective conservation planning almost impossible. In light of this, a thorough understanding of the habitat requirements for this habitat specific species was needed. Additionally, the cryptic life...
Abstract: This study focused on the dispersal and dispersion of southern elephant seals, Mirounga leonina, at Marion Island in relation to their natal site, and to their site of first reproduction. Movements from the natal site to terrestrial haulouts used for reproduction, and between successive reproductive sites, were defined as dispersal, while movements from the natal site to sites used for purposes other than reproduction, were defined as dispersion. Some 33000 records collected over 1...
Abstract: No abstract available.
Abstract: Methods used to estimate the prey consumption by large carnivores include direct continuous observation, stomach content analysis, carcass observations and scat analysis. Continual observations are widely considered the best approach to estimate large carnivore diets, with lions (Panthera leo) being no exception. Continual observation allows the recording of all prey encounters and biases inherent in the other approaches are minimised. However, continuous observations are not alway...
Abstract: The ecologically sensitive, but relatively simple sub-Antarctic mouse-colonised Marion and mouse-free Prince Edward Islands represent ideal ecosystems for addressing questions relating to the partitioning of potential influences of anthropogenic changes, such as climate change and alien species on ecosystem functioning. Consequently, weevil species were used in the present investigation to address questions of morphological change over time with reference to climate change and mous...
Abstract: Xylose is an unusual nectar sugar found in the nectar of Protea and Faurea (Proteaceae). Since nectar composition is an important floral characteristic in plant strategies for ensuring reproductive success, the unexplained presence of xylose in Protea nectar prompted this study of the interaction between pollinators and Protea species. Among pollinators that visit Proteaflowers in the south-western Cape Floral Kingdom, South Africa, insects and birds show an aversion to, and are po...
Abstract: Please read the abstract in the section 00front of this document
Abstract: Group size affects individual and collective vigilance levels of prey species. As individual vigilance decreases with increasing group size, the indirect risk of predation to each individual and the group as a whole will also decrease (dilution and many-eyes effect) which may have a decreasing effect on stress responses on group level as well. Where predation risk is low, other factors like group size might influence stress-related glucocorticoid output in prey species. I test the ...
Abstract: Water balance in insects is under neuroendocrine control, and both diuretic and antidiuretic factors are thought to be involved. Despite being the largest and most diverse order of insects, the Coleoptera have been largely neglected in studies of hormonal control of excretion. However, the only insect from which both diuretic and antidiuretic peptides, acting on Malpighian tubules, have been isolated, is a beetle: the mealworm Tenebrio molitor. This study reports the effects of dif...
Abstract: Genetic variation, structure and dispersal among Cape buffalo populations from the Hluhluwe-Imfolozi and Kruger National Parks of South Africa Barend Jacobus (Ben) Greyling Doctor of Philosophy (Zoology) Department of Zoology and Entomology Supervisor: Prof. Armanda Slager-Bastos Co-supervisor: Dr. Pim van Hooft 2007 The research reported on in this thesis is aimed at quantifying and qualifying, using a molecular genetics approach, some of the factors that influence the population ...
Abstract: Please read the abstract in the section 00front of this document.
Abstract: Sweetpotato, Ipomoea batatas (L.) Lamarck was introduced into Lesotho in 1992 in the hope that it would help alleviate poverty levels. Efforts are being made to learn the potential constraints to optimal production of this crop. Insect pests especially the sweetpotato weevils, Cylas species are a major production constraint worldwide. Hence the main objective of the study was to predict if these pests have potential to establish themselves in Lesotho. Two Cylas species, C. formicar...
Abstract: Please read the abstract in the section 00front of this document