Thesis (M. Med. Sc.)--University of Hong Kong, 2007.

Thesis (Ph. D.)--Illinois State University, 2007. / Title from title page screen, viewed on April 8, 2008. Dissertation Committee: Sabine S. Loew (chair), Steven A. Juliano, Charles F. Thompson, Angelo P. Capparella, William L. Perry. Includes bibliographical references (leaves 143-173) and abstract. Also available in print.

Thesis (Ph.D.)--Murdoch University, 2007. / Thesis submitted to the Division of Health Sciences. Includes bibliographical references (leaves 146-165).

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 109-115). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 109-115). Also available on the Internet.

Honors Project--Smith College, Northampton, Mass., 2010. / Includes bibliographical references (p. 52-65).

Thesis (Ph. D.)--Illinois State University, 1998. / Title from title page screen, viewed July 5, 2006. Dissertation Committee: Carleton J. Phillips (chair), Elmer C. Birney, Angelo P. Capparella, Sabine S. Loew, Charles F. Thompson. Includes bibliographical references (leaves 61-74) and abstract. Also available in print.

Thesis (M.S.)--University of Massachusetts Amherst, 2008. / Includes bibliographical references (p. 33-40).

M.Sc. / Two species of multimammate mice occur in South Africa, namely Mastomys natalensis and M. coucha. These species, both reservoirs for different and equally important disease pathogens, are morphologically identical with variations described in chromosome number, sperm morphology, pheromones, ultrasound and allozyme and isozyme markers. Their identical macro morphologies also raise problems where habitat and distribution is concerned. The need to identify various disease threats based on the carrier organism makes their identification important because they occur sympatrically in many areas of South Africa. Both species were expected to occur within the Roan Camp, Kruger National Park, South Africa and therefore toe samples were obtained from D. MacFadyen who was able to capture the Mastomys genus during his biodiversity survey of the area. He was unable to assign species designations to the captured individuals based on external morphology, but identification would allow exploration into the habitat preferences of each species when compared to the vegetation data gathered by MacFadyen using cross tabulation methods. DNA was extracted from 90 toe samples obtained during August 2003 (30 samples) and 2004 (60 samples) and the cytochrome-b region was amplified using the polymerase chain reaction (PCR). Amplified PCR products were cut using the restriction enzyme BsmAI to produce restriction fragment length polymorphism (RFLP) profiles from which the two species were identified. Once identified, the species were associated to vegetation data received from MacFadyen and samples were selected for further analysis using 5 microsatellite loci. Mastomys natalensis was found in very low numbers, as expected, based on the average rainfall and altitude of the sample area, which is preferred by M. coucha. Further insight was gained into the preferences of each species concerning habitat and their respective status as pioneer species in habitat recolonisation. Genetic differences were obtained within the two species with 100% and 80% polymorphic loci for M. coucha and M. natalensis respectively. Allele classes at most of the loci deviated from Hardy-Weinberg equilibrium, probably due to small sample sizes, null alleles and/or heterozygote deficiencies with average heterozygosities of 0.754 for M. coucha and 0.526 for M. natalensis. The genetic distance between the two species was 0.465 and an Rst value of 0.503 indicated a significant differentiation between the two species. Fixed allele differences between the species were not obtained, but private alleles were found at four loci in M. coucha and one locus in M. natalensis. This study therefore contributes to the global information on species identification, genetic variation and ecology of the two cryptic Mastomys species; the three pillars on which the Convention of Biological Diversity (of which South Africa is a signatory) rests upon.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy, 2017 / Under current and previous global climate change, environments are changing and have changed at a rapid rate. Species with the potential to undergo adaptive radiation are likely to survive environmental change. The genus Rhabdomys is widespread in southern Africa, occurring along the east-west rainfall gradient in South Africa. Rhabdomys may have undergone adaptive radiations in the past, which may have resulted in the current suite of species in various habitats of different aridity. Some Rhabdomys species also occur in sympatry in some locations in South Africa. The aim of my study was to investigate adaptive variation in Rhabdomys by studying the behaviour of 5 populations, representing 3 Rhabdomys species, across South Africa. Using selected taxa, my approach was, firstly, to describe variation in two traits, personality and spatial cogntion, well known for showing environmentally-linked (i.e. adaptive) variation. Secondly, I manipulated the development of exploratory and anxiety behaviour to assess the limits of the adaptive variation (i.e. test the nature of the reaction norm of the characters measured). I first established the taxon-level personality of 4 taxa (2 sympatric) in 5 standard behavioural tests. Generally, the semi-desert living R. pumilio was the boldest together, surprisingly, with R. d. dilectus occurring in grasslands of central South Africa, contradicting previously published results. Comparatively, R. bechuanae from central South Africa and R. dilectus from far north-eastern South Africa, also occurring in grasslands were less bold, even though R. bechuanae is sympatric with R. dilectus in central South Africa. My data indicate adaptive variation at the extreme populations and possibly character displacement in the sympatric populations. In the next chapter, I investigated whether early rearing environment shapes exploratory behaviour and anxiety responses of R. pumilio and R. bechuanae. I predicted that using an interspecies cross-fostering protocol would reveal a gene x environment interaction on behaviour, so that fostered offspring would display an intermediate behaviour phenotype compared to their non-fostered siblings. I showed that a novel rearing environment mostly did not influence the adult behaviour of cross-fostered inidividuals. This indicates genetic constraints on exploratory behaviour and anxiety responses. Next, I tested whether physical rearing environment shapes exploratory behaviour and anxiety responses. I reared semidesert R. pumilio, sympatric R. bechuanae and R. dilectus and allopatric R. bechuanae under either no cover or high cover for 2 generations. The taxa were mostly similar and altering the phyical housing condition did not alter behaviour, but there were small differences between the taxa in exploratory behaviour. In the final experimental chapter, I established whether the environment predicts the spatial cognition in semi-desert R. pumilio, sympatric R. bechuanae and R. dilectus and an allopatric population of R. dilectus from far north-eastern South Africa. The populations showed very similar performance in a modified Barnes maze, indicating a possible phylogenetic constraint on spatial cognition. Overall, my study suggests that there is adaptive variation in personality but not spatial cognition. In contrast to previous studies in the genus, alterations to the social and physical environments failed to separate out genetic and environmental effects (i.e. reaction norm) that would potentially provide the mechanisms for adaptive variation within and between species. The similarity in spatial cognition between taxa and similar responses to environmental modification indicate phylogenetic constraints on traits that were predicted to vary geographically. / XL2018