Non-Geographic Variation in Aethomys chrysophilus (De Winton, 1897) and A. namaquensis (A. Smith, 1834) (Rodentia: Muridae) from Southern Africa

Prior to a systematic revision of African rock rats (genus AethomysThomas) in southern Africa, the nature and extent of non-geographic variation due to sex and age in two samples each of A. chrysophilus (De Winton, 1897) and A. namaquensis (A. Smith, 1834) were examined using both univariate and multivariate statistical procedures. Results of Model I two-way analysis of variance, % sum of squares and a series ol multivariate procedures were congruent and showed a lack ol sexual dimorphism in all samples examined, but marked variation between seven age categories based on the degree ol tooth wear on the maxillary tooth row. When univariate and multivariate results were considered together, pooling of sexes as well as individuals of tooth-wear classes IV, V and VI for subsequent recording and analysis was justified. Very few tooth-wear class VII individuals were available and their exclusion was largely arbitrary. Few measurements showed sexage interaction. The largest per cent contribution to the total variance was due to error. In general, variance partitioning indicated that if comparisons are to be made, caution needs to be exercised on the type of characters, number of factor levels and methodology used

Effect of cowpea flour processing on the chemical properties and acceptability of a novel cowpea blended maize porridge

Childhood growth stunting is a pervasive problem in Malawi and is in large part due to low quality complementary foods and chronic gut inflammation. Introducing legumes such as cowpea (Vigna unguiculata) into the complementary diet has the potential to improve childhood growth by improving diet quality through improvements in macro- and micronutrients and also by reducing gut inflammation. However, cowpea is relatively underutilized in complementary feeding in Malawi due to its strong taste, long processing time, and high energy requirements for processing. Effective utilization of cowpea in complementary feeding requires processing which may affect chemical composition as well as sensory quality. The present study evaluated the effect of processing on the retention of zinc, crude fibre, and flavonoid in roasted, boiled, and dehulled cowpea flours, and assessed the acceptability of maize porridge (70%) enriched with one of the three cowpea flours (30%). Roasting, dehulling, and boiling did not have any effect on zinc content. Crude fibre content increased after processing by all methods. Processing had no effect on measurable flavonoids. Roasted, boiled, and dehulled cowpea blended maize porridges were acceptable to children with mean quantities of leftover food of less than 3g from the given 100g. Caregivers also rated the blended flours to be highly acceptable to them as well, with maize porridge blended with dehulled cowpea flour the most acceptable to both children and caregivers. These results demonstrate that cowpea flour, processed by any of these three different methods, could serve as a useful addition to maize porridge for complementary feeding of children in sub-Saharan Africa

A Systematic revision of Southern African Aethomys Thomas, 1915 (Rodentia :muridae)

Five species of African rock rats of the genus Aethomys, A.namaquensis, A. granti, A. silindensis, A. chrysophilus and A. ineptus, are recognized in southern Africa. Morphometric analyses indicated that A. namaquensis, A. granti and A. silindensis differ markedly in cranial size and/or shape. Morphometric analyses involving cytogenetically known specimens of A. chrysophil us revealed the presence of two sympatric, morphologically similar species, A. chrysophilus and A. ineptus. This is in agreement with observations on cranial morphology and earlier investigations involving cytogenetics, protein electrophoresis and sperm morphology. Contrary to published reports, the morphometric data show that the Central African A. nyikae does not occur in southern Africa, and the single previous record from eastern Zimbabwe is probably based on a misidentification. Four subspecies, A. n. namaquensis, A. n. lehocla, A. n. alborarius and A. n. monticularis, which broadly coincide with major biomes of southern Africa, are recognized within A. namaquensis. Two subspecies, A. c. chrysophilus and A. c. imago, which broadly coincide with altitudinal limits of the eastern part of southern Africa, are recognized within A. chrysophilus. Intraspecific variation in A. ineptus is clinal, with size positively and significantly correlated with longitude. Variation within the geographically restricted A. granti suggests a southwesterly-northeasterly cline. A cladistic appraisal of phylogenetic relationships among the 11 recognized species of Aethomys in Africa, based on qualitative cranial characters, suggests the retention of Micaelamys and Aethomys as subgenera.Thesis (PhD)--University of Pretoria, 1997.Zoology and EntomologyPhDUnrestricte

Bioregion heterogeneity correlates with extensive mitochondrial DNA diversity in the Namaqua rock mouse, Micaelamys namaquensis (Rodentia: Muridae) from southern Africa - evidence for a species complex

<p>Abstract</p> <p>Background</p> <p>Intraspecific variation within the diverse southern African murine rodents has not been extensively investigated, yet cryptic diversity is evident in several taxa studied to date. The Namaqua rock mouse, <it>Micaelamys namaquensis </it>Smith, 1834 is a widespread endemic murine rodent from the subregion. Currently, a single species with four subspecies is recognised, but in the past up to 16 subspecies were described. Thus, this species is a good candidate for the investigation of patterns and processes of diversification in a diverse but under-studied mammalian subfamily and geographic region. Here, we report genetic differentiation based on mitochondrial DNA (mtDNA) cytochrome <it>b </it>(cyt <it>b</it>) sequences among samples collected over an extensive coverage of the species' range.</p> <p>Results</p> <p>Cytochrome <it>b </it>sequences of 360 widely sampled individuals identified 137 unique maternal alleles. Gene tree and phylogeographic analyses of these alleles suggest the presence of at least eight lineages or haplogroups (A-H), with varying degrees of intra-lineage diversity. This differentiation is in contrast with the most recent taxonomic treatment based on cranial morphometrics which only recognised four subspecies. The mtDNA diversity strongly supports earlier views that this taxon may represent a species complex. We further show statistical support for the association of several of these lineages with particular vegetation biomes of southern Africa. The time to the most recent common ancestor (TMRCA) dates to the Pliocene (~5 Mya) whereas coalescent-based divergence time estimates between lineages vary between 813 Kya [0.22 - 1.36] and 4.06 Mya [1.21 - 4.47]. The major diversification within lineages occurred during the Pleistocene. The identification of several regions of sympatry of distinct lineages offers future opportunities for the elucidation of the underlying speciation processes in the suggested species complex.</p> <p>Conclusions</p> <p>Similar to other African murine rodents, <it>M. namaquensis </it>radiated during the Pliocene and Pleistocene coinciding with major periods of aridification and the expansion of savanna habitats. The suggested species complex is represented by at least eight lineages of which the majority are confined to only one or a few neighbouring biomes/bioregions. Contrasting intra-lineage phylogeographic patterns suggest differences in adaptation and responses to Plio-Pleistocene climatic and vegetation changes. The role of ecological factors in driving speciation in the group needs further investigation.</p

Modelling water temperature in the lower Olifants River and the implications for climate change

Freshwater systems in southern Africa are under threat of climate change, not only from altered flow regimes as rainfall patterns change, but also from biologically significant increases in water temperature. Statistical models can predict water temperatures from air temperatures, and air temperatures may rise by up to 7 °C by 2100. Statistical water temperature models require less data input than physical models, which is particularly useful in data deficient regions. We validated a statistical water temperature model in the lower Olifants River, South Africa, and verified its spatial applicability in the upper Klaserie River. Monthly and daily temporal scale calibrations and validations were conducted. The results show that simulated water temperatures in all cases closely mimicked those of the observed data for both temporal resolutions and across sites (NSE&gt;0.75 for the Olifants River and NSE&gt;0.8 for the Klaserie). Overall, the model performed better at a monthly than a daily scale, while generally underestimating from the observed (indicated by negative percentage bias values). The statistical models can be used to predict water temperature variance using air temperature and this use can have implications for future climate projections and the effects climate change will have on aquatic species. Significance:• Statistical modelling can be used to simulate water temperature variance from observed air temperature, which has implications for future projections and climate change scenarios.• While there are many other factors affecting water temperature, air temperature accounts for up to 95% of water temperature variance.• The model used can successfully simulate water temperature variance for different rivers

Partitioning of Evaporative Water Loss into Respiratory and Cutaneous Pathways in Wahlberg's Epauletted Fruit Bats ( Epomophorus wahlbergi

Please read abstract in the article.National Research Foundation.http://www.journals.uchicago.edutoc/pbz/currenthb201

Non-invasive monitoring of adrenocortical activity in free-ranging Namaqua rock mice Micaelamys namaquensis from South Africa in response to anthropogenic land use and season

Stress in animals has been linked to behavioural and physiological changes in response to environmental, social and anthropogenic stimuli. Hence, stress-related responses in animals, especially in rodents, have been used as biological indicators of ecosystem health. This study aimed to establish an enzyme immunoassay (EIA) for monitoring adrenocortical activity in free-ranging Namaqua rock mice (Micaelamys namaquensis) (Rodentia: Muridae) using faeces as a prerequisite for assessing the effects of anthropogenic land use and season on faecal glucocorticoid metabolite (fGCM) concentration. Rodents were live-trapped seasonally across four land use types: an agricultural crop farm, an agricultural livestock farm, a human-populated site, and a nature reserve; all situated in Limpopo Province, South Africa. Determined fGCM concentrations from capture and recapture events were used for biologically validating an EIA detecting steroids with a 5α-3β-11β-diol structure. Recapturing resulted in a significant overall 40% elevation of individual fGCM concentrations demonstrating the effectiveness of the chosen EIA to reliably detect glucocorticoid output in the study species. Neither land use type nor season affected fGCM concentrations in the species, suggesting that land use and season-related environmental changes do not necessarily act as stressors for M. namaquensis, presumably due to their adaptive and resilient nature. Such species can be used to identify ecosystems affected by human-mediated disturbances and allow insights into the management and restoration of these threatened ecosystems and their associated species.Centre of Excellence for Invasion Biology (CIB)http://www.wildlifebiology.orgpm2020Zoology and Entomolog

Seasonal reproduction in the female spiny mouse from South Africa

Many mammal species reproduce seasonally because of annual fluctuations in temperature, rainfall and photoperiod in often nutritionally challenging habitats. The reproductive biology of many small southern African mammals is largely unknown and in critical need of study. We investigated the breeding pattern of the female spiny mouse (Acomys spinosissimus) from South Africa. We examined the ovarian development, follicular growth, circulating plasma progesterone concentrations and the reproductive status of wild-caught adult female spiny mice sampled over a 12-month period while also correcting for body mass and age. From these data, we conclude that female A. spinosissimus breed seasonally. The main breeding season of the spiny mouse is between September and January, with plasma progesterone concentrations being elevated, ovarian volume and primary, secondary, tertiary and Graafian follicle numbers as well as the corpora body number being the highest and pregnancies occurring during this period. Females were reproductively inactive from February through to August. The breeding season coincides with the onset of the rainy season in the habitat, which starts around September and ends in April. Rainfall, in association with an increase in primary productivity and hence higher food availability, might be the most important factor shaping reproduction in the female spiny mouse.Centre of Excellence for Invasion Biolog

Faecal glucocorticoid metabolite concentrations and their alteration post-defaecation in African wild dogs Lycaon pictus from South Africa

Non-invasive techniques for the monitoring of animal well-being, such as faecal hormone analysis, are increasingly becoming some of the most desirable methods for addressing practical conservation questions. Despite the widespread use of faecal hormone measurements for monitoring responses to stressors and its known applicability to African wild dogs Lycaon pictus, the potential influence of time of collection post-defaecation on stress-steroid concentrations in faecal matter has not yet been investigated. In the present study, we determined the rate at which African wild dog faecal glucocorticoid metabolite (fGCM) concentrations change over a 16-day period post-defaecation, in order to provide recommendations for best sampling practice. No significant changes in fGCM concentrations were found for the first 48 h post-defaecation. However, an approximately 30% increase in fGCM concentrations were already noted between day 1 and day 2, followed by a significant 150% increase at 96 h post-defaecation. We therefore suggest that respective faecal material should be collected within the first 24 h post-defaecation to ensure the reliability of fGCM analysis. In addition, we collected baseline data denoting the fGCM concentrations of captive African wild dogs sampled across three South African captive sites. Determined baseline fGCM concentrations differed between African wild dogs at the sites sampled. These data could be used in future studies aimed at identifying the key stressor complexes perceived by captive African wild dogs in order to improve management strategies.This study was funded in part by the National Research Foundation (NRF).am2019Anatomy and PhysiologyZoology and Entomolog

Faecal glucocorticoid metabolite concentrations and their alteration post-defaecation in African wild dogs Lycaon pictus from South Africa

Non-invasive techniques for the monitoring of animal well-being, such as faecal hormone analysis, are increasingly becoming some of the most desirable methods for addressing practical conservation questions. Despite the widespread use of faecal hormone measurements for monitoring responses to stressors and its known applicability to African wild dogs Lycaon pictus, the potential influence of time of collection post-defaecation on stress-steroid concentrations in faecal matter has not yet been investigated. In the present study, we determined the rate at which African wild dog faecal glucocorticoid metabolite (fGCM) concentrations change over a 16-day period post-defaecation, in order to provide recommendations for best sampling practice. No significant changes in fGCM concentrations were found for the first 48 h post-defaecation. However, an approximately 30% increase in fGCM concentrations were already noted between day 1 and day 2, followed by a significant 150% increase at 96 h post-defaecation. We therefore suggest that respective faecal material should be collected within the first 24 h post-defaecation to ensure the reliability of fGCM analysis. In addition, we collected baseline data denoting the fGCM concentrations of captive African wild dogs sampled across three South African captive sites. Determined baseline fGCM concentrations differed between African wild dogs at the sites sampled. These data could be used in future studies aimed at identifying the key stressor complexes perceived by captive African wild dogs in order to improve management strategies.This study was funded in part by the National Research Foundation (NRF).am2019Anatomy and PhysiologyZoology and Entomolog