The wetlands on the Eastern Shores of Lake St Lucia are primarily groundwater fed and exhibit a variety of hydrological regimes that give rise to a high degree of habitat and species diversity. Hydrologically unstable systems experience ecophasal shifts that can disrupt an established steady state within the wetland ecosystem. Communities of both plants and animals can accordingly disintegrate into more or less isolated populations, open to re-invasion by preceding or "new" species when conditions change again. Given the ephemeral and episodic nature of much of the surface water on the Eastern Shores, ecological dynamics of this type are likely. Fish and aquatic invertebrates were sampled from a number of routine and other sites between May 2002 and April 2003. Measurements of various environmental and abiotic factors (including pH, ionic conductivity and dissolved oxygen levels) were taken with each sample in order to establish relationships between environmental changes and the assemblages of aquatic fauna occurring within the Eastern Shores wetlands. Conditions on the Eastern Shores during the study were somewhat anomalous, as the region experienced drought conditions during this period. The Eastern Shores wetlands support a diversity of aquatic fauna, including at least four species of freshwater fish listed as rare or threatened by the IUCN. The aquatic organisms existing within this dynamic system exhibited changes in abundance and distribution that reflected the spatial and temporal changes in their environment. The relationships between aquatic organisms and their environment were complex, with assemblages being affected by combinations of changing environmental and habitat variables as well as other factors such as the environmental stability of habitats and stochastic effects. Given the complex nature of these interactions, aquatic macrofauna on the Eastern Shores are likely to be best conserved through the preservation a heterogeneous mix of wetland habitats, maintaining the diversity of wetland structure and function on the Eastern Shores that can facilitate an element of lottery in the development and structure in biotic assemblages. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

The synanthropic molossid bat, Mops leucostigma (Allen 1918), is widely distributed across Madagascar and has recently been described from the Comoros. M. leucostigma individuals from eastern Malagasy populations are markedly larger than those from the west, and Mops leucostigma populations from Madagascar are morphologically distinct from populations of its putative sister species, Mops condylurus from mainland Africa (Ratrimomanarivo et al. in press, Genetic diversity was assessed by sequencing the mitochondrial cytochrome b (n = 56) and displacement loop (D-loop) (n = 64) regions of Mops leucostigma individuals from a broad range of locations across Madagascar, and Mohéli and Anjouan in the Comoros. Specimens of Mops condylurus (n =3), Mops midas (n =3) and Otomops martiensseni (n = 1) were included in the study for comparative purposes as outgroups. Phenetic and cladistic analysis of cytochrome b and D-loop sequences strongly supported the reciprocally-monophyletic status of Mops condylurus and M. leucostigma. Comorian (Mohéli and Anjouan) and Malagasy M. leucostigma samples formed a monophyletic Mops leucostigma group, within which Comorian samples formed a poorly-supported subclade in the cytochrome b analysis only. Cytochrome b genetic distances of 13.8 % separated M. midas from M. condylurus and M. leucostigma, which formed reciprocally-monophyletic sister groups separated by genetic distances of 2.5 % for cytochrome b and 13 % for the D-loop. 49 M. leucostigma cytochrome b sequences yielded seven haplotypes, two of which were exclusive to the Comoros. D-loop haplotype analysis did not support the distinctiveness of the Comorian samples. Genetic distances within M. leucostigma samples were low (0.22 % for cytochrome b and 1.91 % for the D-loop). Comorian samples were found to be genetically attributable to M. leucostigma. Clear phylogenetic separation between M. condylurus and M. leucostigma was found in all analyses, consistent with their status as phylogenetic species within the genus Mops. There was no clear correlation between haplotype distribution and aspect (east/west-facing slopes), elevation or gender. Low mtDNA variation (cytochrome b and D-loop) and lack of phylogeographic concordance indicates that the observed morphometric variation between eastern and western Mops leucostigma populations may possibly be explained in terms of adaptation to local environmental conditions. / Thesis (M.Sc.)-Univeristy of KwaZulu-Natal, 2008.

The continual increase in elephant numbers across southern Africa raises concern, though the interventions to manage these populations are more contentious. Within small, enclosed reserves active management is necessary to limit elephant impact. Various management tools exist with which to control fluctuations in elephant population numbers or density and simulate natural large stochastic events to control population growth. During this study, undertaken in the Munyawana Conservancy, KwaZulu-Natal, and Pilanesberg National Park, North West Province, South Africa, several management options were implemented. In order to lower the population numbers, family groups were translocated from the Munyawana Conservancy to other reserves, while to reduce population growth rate an immunocontraception was implemented. Both conservation areas introduced older bulls to normalise the bull population age structure, and expanded the conservation area by inclusion of new land to reduce population density. The influence of these management interventions on the elephant population were measured by their social, behavioural, spatial and movement responses. The older bull introduction was successful as bulls set up exclusive bull areas. There was a quick, subtle affect on the bull groups' size immediately after the older bull introduction, while there was no immediate change within the resident bulls' musth behaviour or duration. During area expansion, elephants appeared to perceive the new unexplored area as a threat although this threat became reduced through time as they became more familiar with it. The spatial scale of response was relatively small, while the temporal scale of response was relatively large. Rotational immunocontraception was shown to be a successful tool to alter herd structure by aging the population and maintaining a low population growth rate. The process of immunocontraception darting had no significant effect on herd associations and movement rates, accordingly the duration of the disruption effects were short lived. During multi-management interventions, no differences were found within the elephant social grouping. Management interventions may pose unforeseen social risks and different populations may respond differently to management induced stress. Therefore, interventions need to be considered for each elephant population which will achieve the conservation area's objectives with the most effective outcome, but with lowest holistic impact. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

Recent evidence suggests that avian facultative hypothermic responses are more common than previously thought. Traditionally, several categories of avian hypothermic responses have been recognized, and are frequently differentiated on the basis of minimum body temperature (T[b]) The available data suggest that the capacity for shallow hypothermia (rest-phase hypothermia) occurs throughout the avian phylogeny, but that the capacity for pronounced hypothermia (torpor) is restricted to certain taxa. However, there are currently too few data to test hypotheses concerning the evolution of avian hypothermic responses. Facultative hypothermia occurs over most of the avian body mass (M[b]) range, but is most common in small species. Minimum body temperature during hypothermia (T[min]) is continuously distributed from 4.3 °C to ca. 38°C. The continuous T[min] distribution, as well as recent evidence that the T[b] ranges of different avian physiological states may overlap, question the biological reality of specific T[b] limits. Pattens of thermoregulation during avian hypothermic responses are relatively variable, and do not necessarily follow the entry-maintenance-arousal patterns that characterize mammalian responses. Avian hypothermic responses are determined by a suite of ecological and physiological determinants. I investigated normothermic thermoregulation and hypothermic responses to restricted food in the speckled mousebird Colius striatus in the context of the distinction between normothermia, rest-phase hypothermia, and torpor. The lowest T[b] recorded in a bird which was able to arouse spontaneously was 18.2°C. However, I was unable to clearly discern between normothermic, hypothermic and torpor T[b] ranges. Furthermore, hypothermic responses did not accord with the patterns typically observed in birds and mammals. Metabolic suppression normally associated with entry into torpor and the defence of a torpor T[b] setpoint was largely absent. Laboratory data for C. striatus, as well as published data for Colius colius suggest that clustering behavior plays an important thermoregulatory role in mousebirds. Hence, I investigated thermoregulation under semi-natural conditions in C. striatus. In particular, I was interested in the interaction between clustering behavior and hypothermic responses during energy stress (restricted feeding). In contrast to clustering birds, rest-phase thermoregulation in single birds was characterised by linear decreases in T[b] and the birds did not appear to defend a specific T[b] setpoint. During restricted feeding, both clustering and single birds exhibited significant decreases in rest-phase T[b]. The extent of these facultative hypothermic responses was greater in single birds than in clustering birds, supporting the prediction that clustering behavior moderates the use of facultative hypothermia. I also tested the prediction that in free-ranging C. colius, the use of heterothermy should be rare, even at the coldest time of the year. I recorded mid-winter rest-phase body temperatures (T[b]) in a flock of free-ranging C. colius in an arid habitat in the Karoo, South Africa. The mousebirds' rest-phase T[b] was fairly labile, but was maintained above 33°C, despite T[a]s as low as -3.4 °C. The mousebirds showed no evidence of torpor under natural conditions; a facultative hypothermic response, during which T[b] was reduced to 29 - 33°C, was only observed on one occasion. The observed patterns of thermoregulation supported my predictions, and suggest that thermoregulation in clustering C. colius in the wild is significantly different to that of single birds under laboratory conditions. My results also suggest that the pronounced capacity for heterothermy usually associated with mousebirds is not necessarily representative of their patterns of thermoregulation under natural conditions. The capacity for avian torpor appears to be dependent on phylogeny. To investigate phylogenetic constraints on the capacity for torpor, I measured metabolic responses to food deprivation in a small, arid-zone passerine, the red-headed finch (Amadina erythrocephala). I observed significant reductions in rest-phase energy expenditure and body temperature (T[b]) in response to restricted feeding. The maximum extent of T[b] suppression (ca. 5°C) and energy savings (ca. 10%) were consistent with those reported for a number of other passerines. The lowest T[b] I observed in a bird able to arouse spontaneously was 34.8°C. My data support the hypothesis that the capacity for heterothermy in passerines is phylogenetically constrained, and that the majority cannot employ torpor in response to energetic stress. Selection for the capacity for torpor is presumably similar to the selection pressures acting on other avian energetic traits, such as basal metabolic rate (BMR). I tested the generality of a recent model linking the slow-fast mammalian metabolic continuum to global patterns of climatic predictability using BMR data for 219 non-migratory bird species. Avian BMR varied significantly between zoogeographical zones, with Afrotropical, Indomalayan and Australasian species generally exhibiting lower BMR than Holarctic species. In addition, the magnitude of differences between arid and mesic species varied between zones. In the Nearctic, these differences were pronounced, whereas no significant differences were evident for Afrotropical or Australasian species. A slow-fast metabolic continuum similar to that described in mammals appears to exist for birds, with higher BMR associated with predictable, seasonal environments and lower BMR with less predictable environments, in particular those affected by the El Niño Southern Oscillation. I constructed a generalised, conceptual model which attempts to predict the occurrence of torpor using phylogeny, M[b] constraints, a trade-off between energetic benefits and potential ecological costs, and specific ecological factors. A recent hypothesis suggests that endotherm heterothermy is monophyletic, and predicts that torpor should be more widespread in phylogenetically older taxa. Once phylogeny is considered, the most important determinant of avian torpor is M[b]. I used an existing model of endotherm torpor to predict the relationship between M[b] and minimum T[b] during torpor. The available data show that the lower limit of torpor T[b] is determined by the M[b]-dependent costs of rewarming following a torpor bout. Finally, I constructed a model based on the assumption that torpor is adaptive if the energetic benefits exceed the potential ecological costs. The model predicted that torpor should be more prevalent in species near the extremes of the avian metabolic continuum. The available data provide tentative support for this prediction. In addition to generalised factors such as phylogeny and M[b], specific aspects of a particular species' ecology need to be considered when predicting the occurrence of avian torpor. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2001.

This study investigated the effects of temperature and relative humidity (both controlled and natural) on the lifecyle and morphology of adults of members of the Anopheles gambiae complex in northern KwaZulu-Natal, South Africa. Laboratory investigations into the effects of simulated temperature and relative humidity regimes concentrated on seasonal differences in longevity, egg hatchability, reproductive potential and adult survivorship of An. arabiensis. Differences were found in the life table parameters when these mosquitoes were reared under conditions of seasonal temperature and relative humidity. During the cool season the lifespan and adult survivorship of mosquitoes were greater than those reared during the warm season. In summer, the egg hatchability and reproductive potential were greatest whereas in winter An. arabiensis underwent gonotrophic dissociation although these females were found to take blood meals readily. The influence of seasonal temperature and relative humidity on the body size of An. arabiensis was investigated, both in the laboratory and under field conditions. In both environments, these factors were found to significantly influence body size. In winter, there was a 13% increase in wing size compared to summer bred mosquitoes. A comparison of body size of An. arabiensis, An. merus and An. gambiae reared under laboratory conditions of seasonal temperature and relative humidity showed that the wing size of An. arabiensis was greater than that of An. merus and An. gambiae. The effect of temperature and relative humidity on morphological criteria used in species separation was also investigated. Seasonal differences in wing spot size were compared for An. arabiensis, An. merus and An. gambiae. From this investigation it was concluded that the pale and dark spots on the wing of Anopheles mosquitoes could not be used in species identification due to the large degree of inter-species overlap in the wing spot measurements. The measurement of the pale band at the junction of the 3rd and 4th tarsomere on the hind leg was also investigated for its use in species separation and were found to be useful within the An. gambiae complex. The implications of this study on the transmission and control of malaria are discussed with reference to the late season transmission during March to May that is characteristic of the region. / Thesis (Ph.D)-University of Natal, Pietermaritzburg, 1996.

Nematicides are not only expensive and unaffordable to small-scale farmers but are also harmful to the environment as they kill both the target organisms and non-target micro and macro-organisms, thereby destabilising the ecosystem. Most developed countries have or are in the process of banning use of chemicals for pest management, implying that agricultural products from developing countries using pesticides will not be marketed in the developed countries. In former studies, it was shown that plant parasitic nematodes posed serious problems in sugarcane fields as their attacks on sett roots during germination period decreased sett root weights, delayed bud germination or led to fewer buds germinating as most buds abort. Those that germinate later are then faced with competition for food, space and light from the "older" shoots and often die. The attacks on shoot roots may lead to inefficient uptake of water and nutrients by the plant thereby leading to stunted plants. Fewer and shorter sugarcane stalks due to nematode attacks result in poor yield. In this study, it has been shown that a large number of endoparasites would be needed to reduce sett root weights. Agricultural systems based on monoculture are rarely successful in the long term and because sugarcane fields have been monocultured for a very long time, they are losing their productive capacity and this is termed "Yield Decline". Instead of using nematicides, alternative methods can be used for the management of nematode communities. Research has shown on other plants that nematode communities dominated by Helicotylenchus dihystera are less pathogenic to the plants than other ectoparasitic nematodes, e.g., Xiphinema elongatum and Paratrichodorus spp. A study conducted as a pot experiment showed that sugarcane grown in soil with high H. dihystera grew taller and produced greater root and aerial biomass than one grown in X elongatum infested soil. To induce a nematode community dominated by H. dihystera in the field, two strategies were followed: (i ) abiotic factors that influence the nematode's environment were identified. Certain elements found in soil and sugarcane leaves were found to be correlated to certain species, e.g., H. dihystera was negatively correlated to soil sulphur, medium and coarse sand while X elongatum was positively correlated to these soil types and soil elements. Sugarcane leaves with high levels of Ca, Zn, Cu and Fe were found in areas with high percentages of H. dihystera while the reverse was true for X elongatum. (ii) organic amendments were used to improve the sugarcane growth, modify the environment and decrease competition among species within a community. Application of organic matter to the soil improves soil properties such as water infiltration, water holding capacity, erodibility and nutrient cycling, increases suppressiveness of soils to plant parasitic nematodes and stimulates other anti-nematode micro-organisms, e.g., nematode-trapping fungi. Organic amendments were therefore used in this study not only as screens to protect sugarcane roots from nematode attacks but also to manipulate nematode communities for the less pathogenic species, H. dihystera. In a field study where organic amendments were used, plots treated with filter cake, thume + filter cake, trash + filter cake, filter cake + furfural and Temik (aldicarb) had high percentages of H. dihystera while control plots had high percentages of X elongatum. However, the change in relative proportion of H. dihystera by certain treatments was not followed by an average increase in yield, probability because of the overall variability. The yield results, however, showed that for all treatments, including control, the highest yields corresponded to plots with higher H. dihystera proportions, conflicting the initial hypothesis. As a result, if an organic amendment that can substantially increase the relative proportions of H. dihystera can be found, a substantial increase in yield can be expected. Although the organic amendments did not successfully manipulate the nematode communities for the less pathogenic species, H. dihystera, plots with higher yield were those that had high H. dihystera percentages in their nematode communities. / Thesis (Ph.D.)-University of Natal, Durban, 2004.

The successful conservation management of African elephants depends largely on understanding the fundamental processes driving the population regulation of this species. Southern Africa’s increasing populations have raised concern over the impact of high elephant densities on the system, in stark contrast against the elephant’s more precarious position in other parts of Africa. As we search for solutions from the processes of historical elephant regulation, we realise that there is a decided lack of empirical evidence to explicitly direct our efforts. In this PhD, I attempt to investigate the application of the classic pattern of large herbivore population limitation, which mainly involves high juvenile mortality in response to stochastic environmental events, to African elephant population dynamics. Firstly, I evaluated the magnitude and frequency of mortality events that would be required to prevent elephant population growth. The death of 85 % of infants and weaned calves would need to occur twice a generation, while a single severe mortality event (causing the death of all infants and weaned calves and 10 % of the rest of the population) once a generation would be sufficient. However, the severity of these events is not matched in natural occurrence in Africa today and only a single recorded event in Tsavo National Park, Kenya, in the 1970’s has come close when more than 7 000 died during a very severe drought. Secondly, I evaluated the potential role of fire as a stochastic, massmortality event limiting elephant populations. I found that fire functions in a similar manner to other environmental catastrophes and primarily causes high juvenile mortality. However, this catastrophic event also highlighted the extreme behavioural and physiological impacts experienced by the elephant population involved. The potential role of these types of events on long-term female fecundity needs further investigation. In isolation, this type of mortality event would need to occur with high frequency to prevent population growth. However, in combination with a decrease in female fecundity, these stochastic events may have a much greater impact on population demography than first thought. Thirdly, I investigated a potential mechanistic link between stochastic mortality events and juvenile susceptibility to resource limitation. Allometric relationships dictate that juveniles select a diet of higher quality than adult elephants. We found that this was achieved by weaned calf selection of higher quality plant parts, although use of plant types and plant species was similar to that of adult females, who they move across the landscape with. The strong sexual dimorphism exhibited by this species was reflected in adult male use of lower quality forage than adult females (or juveniles) in both dry and wet seasons. Diet quality scaled negatively with body size, but adult females consistently selected a higher quality diet than adult males, irrespective of body size. The nutritional and reproductive demands placed on an individual during different life-history stages therefore influence foraging strategies, together with nutrient requirements, e.g. phosphorus for pregnancy/lactation selected consistently by females when unrestricted in the wet season, protein for growth selected consistently by weaned calves. Competitive displacement of adult females to feed at higher levels in the canopy by calves also influenced feeding behaviour. Therefore intraspecific body size, nutritional requirements (in terms of nutrients and energy) and competition had a strong influence on foraging strategy employed by age-sex classes of elephants in response to seasonal environmental change. More selective juvenile foraging requirements means that juveniles are most susceptible to resource limitation, for example during stochastic environmental events such as droughts. In small, closed systems, juvenile mortality is likely to have a strong influence on elephant population regulation, with a slight, temporary decrease in female fecundity possibly acting in conjunction with juvenile mortality effects. Therefore, stochastic environmental events such as drought and fire may be the only natural incidence of population regulation to occur in these systems, where populations continue to grow exponentially and there is no evidence of density-dependence (as in the case of many small, fenced reserves in South Africa). In large, open, high-density systems in other parts of southern Africa, density dependence acts strongly on female fecundity and causes low levels of juvenile mortality in areas of local population aggregation. Therefore, in isolation, natural juvenile mortality is unlikely to regulate African elephant populations, but in conjunction with decreased female fecundity in response to density-dependent feedbacks and stochastic environmental events, population regulation may occur. The management of long-lived megaherbivore species with similar demographic drivers must include an appreciation of the complexity of population response to manipulation of mortality or fecundity effects. Small changes can potentially result in large shifts in population dynamics. Further insight into the mechanisms driving these processes will allow sound scientific support of megaherbivore management decisions to be made throughout Africa. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2008.

Endothermy in birds and mammals is invariably associated with homeothermy. However, homeothermy can only be maintained if sufficient energy is obtained to meet the animals' maintenance budget. In mammals, daily torpor and hibernation have evolved to conserve energy when energy inputs from the environment are insufficient to meet maintenance requirements. Several studies have suggested that daily torpor and hibernation do not represent distinct physiological responses but are components of a continuum of heterothermy. Under laboratory conditions, even within phylogenetically ancient eutherian mammals, such as elephant shrews, it is unclear whether daily torpor or hibernation is used. Furthermore, an interpretation of the torpor patterns observed under laboratory conditions is complicated by the fact that torpor patterns often differ between laboratory and free-ranging conditions. Within the more recent mammal lineages, torpor has been observed in strepsirrhine primates. The occurrence of torpor in strepsirrhines is interesting as it pertains to arguments relating to the colonization of Madagascar by strepsirrhine primates as well as implications for human physiology. The first aim of this study was to investigate and quantify parameters that characterize torpor in a phylogenetically ancient eutherian mammal (Macroscelidae: Elephantulus myurus) under free-ranging conditions. This was done mainly to resolve whether daily torpor and hibernation were physiologically discrete responses. The second aim was to investigate torpor occurrence in a more recently evolved eutherian mammal (Primates: Galago moholi). The objective was to gain insights into the phylogenetic distribution of torpor and to provide a physiological verification of torpor occurrence in a mainland strepsirrhine relative to arguments about the colonization of Madagascar. I measured body temperatures in three monthly cycles between May 2001 - May 2002 in 22 free-ranging E. myurus. I recorded a total of 467 torpor bouts throughout the study period. The elephant shrews were capable of daily torpor throughout the year, with torpor most prevalent during winter and correlated with ambient temperature, photoperiod and invertebrate abundance. Only two torpor bouts were observed during summer. I suggest that although torpor use was most prevalent during winter, summer torpor might also be important for energy conservation in this species during drought years. This highlights the need for long-term physiological data in free-ranging animals. The mean torpor Tbmin and the mean bout length for the whole year were in the range expected for daily heterotherms. However, there was some marginal overlap with hibernation characteristics; a few torpor bouts were longer than 24 hrs in duration indicating that the animals were capable of opportunistically extending torpor bouts longer than 24 hours in response to unpredictable energetic shortfalls. Tbmin also decreased below 10°C. However, a consideration of behavioural and ecological factors argues against hibernation in E. myurus. Instead, these results support the idea of a physiological continuum for heterothermy. A return to normothermic body temperatures requires considerable energy expenditure, and this is perceived to be one of the major disadvantages of torpor. E. myurus offset the high cost of arousal from low body temperatures by using exogenous passive heating. This is achieved by coupling of the timing of arousal with ambient temperature cycles. Laboratory studies that quantify torpor energetics are usually conducted under constant temperature conditions and are likely to underestimate the energetic benefits accrued through the use of ambient temperature cycles during arousal. Torpor is often displayed during the animal's rest phase. However, nocturnal small mammals that utilize passive heating to assist arousal from torpor may enter torpor during the nighttime, thus effectively advancing the onset of the rest phase. I investigated the functional significance of daily and seasonal rhythms of body temperature in normothermic and torpid free-ranging E. myurus. Daily patterns of Tb, in normothermic E. myurus suggested polyphasic Tb patterns that nevertheless indicated a rest phase coincident with the daytime. I suggested that the principal benefit of a flexible daily rhythm of Tb, is that it facilitated torpor use during the nighttime and arousal by passive exogenous heating using ambient temperature cycles. It has been suggested that the evolution of endothermy precluded the need for homeothermic mammals to be sensitive to Ta cycles because they could maintain physiological function despite fluctuations in the ambient temperature. Elephant shrews utilize passive heating and provide excellent models with which to investigate whether mammals can entrain their body temperature rhythms to ambient temperature cycles. I experimentally tested whether food restricted E. myurus can entrain torpor cycles to shifts in the Ta cycle while holding the light-dark cycle constant. Food restriction and short photoperiod were only sufficient to induce torpor in E. myurus if photoperiod and Ta, cycles are in phase with each other. Shifting the cold T, into the photophase prevented the expression of torpor. I concluded that the body temperature rhythm is most probably tightly coupled with the photoperiod cycle and that although Ta and photoperiod usually act synergistically in nature, photoperiod is probably the stronger zeitgeber. The evolution of endothermy is thought to have been facilitated by the advent of endothermic energy sources such as brown adipose tissue (BAT), the principal site of nonshivering thermogenesis (NST). Rock elephant shrews are amongst the smallest members of the Afrotheria, the most basal of the eutherian lineage. I determined whether the phylogenetic placement of E. myurus and reliance on passive heating might result in a decreased capacity for NST relative to other eutherians. I investigated the capacity for NST in winter acclimated E. myurus by measuring the thermogenic response to noradrenalin (NA) injection. I used phylogenetically independent analyses to compare E. myurus NST capacity with other eutherians. E. myurus had an NST capacity that was no different from other eutherian mammals. Although they displayed a NST capacity that was 74% of that expected on the basis of body mass, this value was not significantly different from phylogenetically independent allometric predictions. Although heterothermy is almost always considered in the context of how the environment affects function , its use may offer insights into topics such as island biogeography and species dispersal. For example, there have been suggestions that heterothermy might have played an important role in the successful colonization of Madagascar by strepsirrhine primates. To my knowledge no studies exist as yet that provide a physiological verification of this suggestion. Currently no data exist on thermoregulation and heterothermy in any free-ranging African strepsirrhines. The lesser bushbaby, Galago moholi, is a small nocturnal strepsirrhine primate that experiences severe winters and drastic food reduction during winter and is a candidate employer of torpor. I measured body temperatures of 11 free-ranging lesser bushbabies, Galago moholi, captured at different times between February 2002 - September 2003. I did not record any incidents of heterothermy throughout the study period. Why does G. moholi not employ heterothermy? I consider several alternatives; phylogenetic placement, physiological and ecological factors that might preclude the use of torpor in this species. I suggest that the breeding pattern observed in G. moholi obviates torpor use whilst increasing fecundity, which would be adaptive if the animals are confronted with high predation risks. Much is currently known about the advantages of torpor use. This study highlights the need to consider and investigate those physiological, ecological and phylogenetic factors that might constrain species from utilizinq heterothermy. Furthermore, this study highlights the potential for thermoregulatory studies to offer insights into topics as widely separated as evolution of endothermy to species dispersal and island biogeography. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Proponents of the recognition concept of species hold that isolating mechanisms, including chromosome rearrangements, play no role in speciation while the more commonly accepted biological species concept proposes that isolation mechanisms are instrumental in the formation of new species. Moreover, some adherents of the biological concept of species, reject the hypothesis that chromosomal rearrangements can be instrumental in causing reproductive isolation and, hence, speciation. Evidence to the causative role played in speciation by chromosome changes can be obtained from cytogenetic investigations of sibling species, in parallel with analyses of gene products, DNA polymorphism and premating behaviour. This study reports the results of a cytogenetic investigation of 97 specimens of the vlei rat 0. irroratus, from 18 South African localities, and 11 samples of the Angoni vlei rat 0. angoniensis from two geographically distant populations. All 0. angoniensis individuals showed a constant karyotype with 56 acrocentric chromosomes but extensive variation was detected in 0. irroratus. Five cytotypes could be recognized within the latter. In the south-eastern parts of its South African range, 0. irroratus had a diploid number (2n) of 30 chromosomes in whicll all autosomes were acrocentric (cytotype A) while further east (cytotype A2), the diploid number was 30-32 with, again, acrocentric autosomes, A further acrocentric cytotype (AI) with 2n = 24-27 occupied the southern and south-eastern slopes of the Drakensberg range. A type with 2n = 28-30 (cytotype B), with eight pairs of biarmed autosomes, was found in the southern Cape region while in the Cape of Good Hope and in the north-eastern parts of South Africa, 0. irroratus had 2n = 28 with only four pairs of biarmed autosomes (cytotype C). Most of the numerical changes were due to variation in the number of copies of Bchromosomes which were small, biarmed and partly heterochromatic. C-banding analysis revealed that the short arms of bianned autosomes were totally heterochromatic. On the other hand, G-banding patterns of acrocentric autosomes were, with two exceptions (AI and A2 types), similar in all cytotypes while G~banding of the long arms VII of biarmed chromosomes matched the pattern of their homologues in acrocentric cytotypes. A potentially heterotic rearrangement was detected in the Al localities where a unique acrocentric autosome was identified as the product of a fusion between chromosomes 7 and 12. The geographic distribution of these groups of karyotypes correlated, by Discriminant Function Analysis, with bioclimatic regions of South Africa. The Al cytotype was shown to occupy the coldest and wettest region of the montane Drakensberg while the B type is found in the hot area of the eastern Cape with an unpredictable rainfall pattern: group C occupies regions of intermediate climate. Gene product analysis was carried out using the novel approach of subjecting liver homogenates to "Western blotting". This method was first assessed at supraspecilic level using specimens of various southern African rodents, and allowed the generation of phylogenies essentially similar to those produced by allozyme studies of the same taxa. At intraspecilic level, immunobloHing analysis did not reveal synapomorphies congruent with karyotype groups. This was interpreted, in conjunction with available allozyme data from the same populations, as evidence of low genetic differentiation between 0. irroratus cytotypes, A measure of genetic divergence was indicated in two populations from the Cape province and this was in agreement with existing data from allozyme electrophoresis and mitochondrial DNA polymorphism. The cytogenetic results were related to available data on breeding and premating behaviour concerning some of the O. irroratus populations investigated here. The presence of the 7/12 chromosome fusion in the Al cytotype correlated with a dramatic reproductive impairment of FI individuals originated from Al/A2 and Al/B cytotype crosses. Evidence of partial premating behavioural barriers has been reported by others, but information on premating behaviour between populations which are not chromosomally isolated is lacking. Therefore, it was not possible to establish if behavioural premating barriers preceded, or followed, the fixation of negatively heterotic chromosomal rearrangements. It was, nevertheless, suggested that the existence of such impaired mate recognition may be an example of reproductive character displacement which may have followed the fixation of the t(7: 12) typiVIII cal of the Al populations. In conclusion, the existence of chromosome changes in the AI, and possibly A2, populations accompanied by low genetic divergence and severely impaired hybrid reproductive success, are consistent with a hypothesis whereby chromosomal reproductive isolation causes speciation. Nonetheless, other speciation mechanisms mediated by genetic divergence and/or mate recognition failure, are possible in other populations where no chromosome changes of negatively heterotic potential were found. / Thesis (Ph.D.)-University of Natal, 1996.

The ecology of blue duikers Philantomba monticola and red duikers Cephalophus natalensis was studied in three lowland coastal evergreen forests in Natal. Variation in population densities, estimated with numerous census techniques and between and within study areas permitted comparisons of habitat parameters. Both species are strictly diurnal, and are active between 18 and 40% of the nycthemeral cycle. Usually a pair of blue duikers occupy a permanent territory of about 0,7ha while red duiker home ranges, between 2 and 15ha, overlap extensively with each other and those of blue duikers. Habitat quality of both species is determined by canopy cover (stem densities, spatial patterning, and, diversity of the tree and shrub layers), tree to shrub ratios, and, bedsites. The main dietary item, freshly fallen leaves, is not that of a highconcentrate feeder as hypothesised. Food appears to be abundant while condensed tannins have no influence on duiker densities. Management recommendations include land acquisition, forest ecology research, monitoring interaction with other species, genetic aspects, translocations and captive propagation. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1990.