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Includes bibliographical references (leaves 873-896). / xxxvi, 896 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Reports on 2 experiments which investigated exploratory & other behaviour in the laboratory rat during fixed-interval, variable-interval, variable-ration and differential reinforcement of low rates schedules of reinforcement (& subsequent extinction.) A third experiment investigated exploratory & other behaviours in an open-field Skinner box during a fixed-interval schedule, with a concurrently available water source. The final experiments were conducted on a qualitative analysis basis at Adelaide Zoo. A number of novel objects were presented to a group of six chimpanzees, and a different set of objects presented to a pair of caracals, in an attempt to facilitate exploratory behaviour and reduce abberant behaviours. / Thesis (Ph.D.)--Adelaide University, Dept. of Psychology, 2001

Thesis (Ph. D.)--University of Hong Kong, 1993.

Thesis (M.S.)--University of Akron, Dept. of Biology, 2009. / "August, 2009." Title from electronic thesis title page (viewed 10/7/2009). Advisor, Amy Milsted; Committee members, Monte Turner, Richard Londraville; Department Chair, Monte Turner; Dean of the College, Chand Midha; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

The aim of this thesis was to evaluate the effect of increased intake of selenium from the diet of rats with spontaneous hypertension (SHR) on other essential elements. The effect of different diets on the element levels in kidney, liver, testes, and blood of rats was observed under model conditions. Tested rats were divided into five groups, where the first group A was the reference group and feed mixture contained no additive. In groups B and C was soybean meal replaced by defatted rapeseed and into feed mixture of group C was additionally added vitamin E. Diet groups D and E contained added selenium and zinc, and group E contained additionally vitamin E in comparison to reference group A. Se content in kidney, liver, testicles, and blood of animals was determined by inductively coupled plasma mass spectrometry (ICP MS). The other essential elements (Cu, Fe, Mn, P, S, and Zn) were determined by inductively coupled plasma optical emission spectrometry (ICP OES). The content of Ca, K and Mg was determined by atomic absorption spectrometry with flame atomizer (F-AAS). The hypothesis has been that the increased intake of selenium should improve the use of other essential elements by the rat organism. It was expected that there will be influenced elements mainly involved in the defense of the organism against oxidative stress. This was not confirmed by this experiment. Changes in the concentrations of these elements occurred only at very high dose of selenium that is already toxic to the organism. This toxic effect could be also responsible for fifty percent mortality of rats in group E, where perhaps even increased concentration of vitamin E could not sufficiently reduce the toxicity of high doses of selenium.

Les invasions biologiques sont de plus en plus fréquentes, avec des conséquences importantes sur la biodiversité et la santé humaine. Étudier les mécanismes qui les expliquent permet simultanément (i) d’envisager des stratégies efficaces de contrôle et de prévention et (ii) d’étudier divers processus écologiques et évolutifs sur des échelles de temps contemporaines. Plusieurs hypothèses basées sur le parasitisme et l’immunité des hôtes sont proposées pour expliquer le succès des espèces envahissantes. Ainsi, au cours de l’invasion, les hôtes exotiques (1) perdraient leurs parasites naturels (Enemy Release, ER), (2) transfèreraient leurs parasites exotiques aux hôtes natifs (Spill-Over, SO) et/ou (3) amplifieraient les cycles des parasites natifs au sein des hôtes locaux (Spill-Back, SB). En relation avec ces changements dans les interactions hôtes-parasites, l’hypothèse EICA (Evolution of Increased Competitive Ability) prédit une modulation des ressources de l’hôte envahissant via un investissement moins important dans les réponses immunitaires coûteuses (inflammation) au profit de réponses immunitaires beaucoup moins coûteuses (réponses médiées par les anticorps) et de capacités de reproduction et de dispersion des populations sur le front d’invasion. Le but de ma thèse est de tester ces prédictions dans le cadre de deux invasions actuellement en cours au Sénégal : celles du rat noir Rattus rattus et de la souris domestique Mus musculus domesticus, deux espèces envahissantes majeures tant par leurs impacts (économique, sanitaire, écologique) que par leur distribution quasiment mondiale. Mes travaux se basent sur un dispositif d’échantillonnage en populations naturelles et sur le développement d’approches comparatives le long d’un gradient d’invasion pour chacune des deux espèces exotiques. Les patrons de structure (prévalence, abondance, richesse) de deux communautés de parasites (helminthes gastro-intestinaux, bactéries pathogènes) et les profils immunitaires (réponses médiées par les anticorps naturels, inflammation) des rongeurs commensaux exotiques (M. m. domesticus, R. rattus) et/ou natifs (Mastomys spp.) ont été comparés pour des localités situées dans des régions anciennement envahies (depuis plus de 100 ans), récemment envahies (depuis moins de 30 an : front d’invasion), et non envahies. Mes résultats montrent des variations dans la structure des communautés de parasites et les réponses immunitaires des hôtes natifs et exotiques. Les tendances observées, aussi bien pour les communautés de parasites que pour les composantes immunitaires étudiées le long des deux routes d’invasion, attestent de patrons globalement plus complexes qu’attendu sous les hypothèses de départ, suggérant l’existence de relations complexes entre caractéristiques des communautés d’hôtes et de parasites, investissement immunitaire, conditions environnementales et invasions biologiques. Des approches expérimentales doivent être envisagées afin de déterminer les conséquences et les mécanismes sous-jacents aux différents phénomènes observés. / Biological invasions are increasingly phenomenon worldwide having deleterious impacts on biodiversity and human health. Studying the mechanisms explaining them allows both (i) to define efficient strategies for controlling and preventing invaders and (ii) to study ecological and evolutionary processes at contemporary scales. Some major hypotheses rely on parasitism and host immunity to explain invasion success. Thus, exotic host populations (1) may benefit of an " Enemy Release " (ER) through impoverishment of their original parasite communities, and may affect native hosts by (2) transferring exotic parasites (Spill-Over, SO) and/or (3) by increasing transmission risk of native parasites (Spill-Back, SB). In turn, according to the refined “Evolution of Increased Competitive Ability” (EICA) theory, invasive populations should experience immune trade-offs by favouring less expensive antibody-mediated responses over costly inflammation, to increase their competitive ability (dispersion, reproduction). The aim of my thesis is to test these predictions along the invasion routes of two commensal exotic species in Senegal, the domestic mouse (Mus musculus domesticus) and the black rat (Rattus rattus). These rodent species are considered to be major invasive species worldwide inducing high economic, sanitary and ecological damages. My research is based on comparative analyses along one invasion route for each invasive species. We focused on gastrointestinal helminths and pathogenic bacteria as parasite communities, and inflammation and natural antibody-mediated responses as immune estimates. Comparisons were performed for invasive and/or native (Mastomys spp.) rodents between localities of long-established invasion (100-200 years ago), recent invasion (10-30 years ago; invasion front), and non-invaded localities. My findings showed variations along both invasion routes in parasite community structure and immune patterns, but in a more complex way than expected under the initial predictions. The heterogeneity of changes observed highlights the existence of particular relations between host and parasite traits, host immune investment, environmental conditions and biological invasions. Further experimental works are needed to assess the consequences and mechanisms underlying the changes observed along both invasion routes.

The human-abetted introduction of commensal species (i.e. those that opportunistically exploit the anthropogenic environment for food and shelter, e.g. rats, cockroaches etc.) to new areas has occurred throughout history. This has resulted in detrimental ecological changes worldwide but, from a viewpoint of human knowledge, a beneficial corollary of these translocations is that the species in question can be used as proxies to study the movement of the humans who transported them. I reconstruct colonisation histories of three widespread commensal mammalian species in the Western Indian Ocean, the black rat Rattus rattus, house mouse Mus musculus and Asian house shrew Suncus murinus, through phylogeographic studies (the geographic distribution of genetic lineages) of maternally-inherited mitochondrial markers, and zooarchaeological data. The DNA analyses are conducted on samples largely derived from museum specimens collected up to 110 years ago, and from archaeological bones (in the case of rats). I show considerable cryptic diversity in all three species, particularly in mice for which we find a potential major new lineage. Certain lineages within each species predominantly reveal long-distance translocations within the Indian Ocean, but high resolution geographic and genetic clustering is also evident, particularly in Asian house shrews. Phylogeographic structuring of the three species in East Africa and the southern Indian Ocean region (e.g. Madagascar, Reunion, etc.) indicate connections with Arabia, the Middle East, and India in the Islamic period from the first millennium AD, and later European connections during the Age of Exploration. Closer to the origins of the three species (the Indian subcontinent in all cases), range expansions in Eurasia and nearby islands relate to early to mid Holocene human populations, but also with signals of later secondary colonisations. Through ancient DNA studies I found genetic continuity between temporally separated populations of black rats suggesting population persistence, and high levels of diversity in Songo Mnara, a Swahili stonetown in Tanzania. Knowledge of the colonisation history and genetic diversity of an introduced species is essential to understand their resilience in novel landscapes, and to identify pathways of invasion and, by proxy, human trade and exchange networks that facilitated their dispersal. My research contributes significantly to that end for three socially, economically and ecologically important species that are well-established in the Indian Ocean region and beyond.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2007. / Title from PDF cover (viewed February 21, 2008) Includes bibliographical references (p. 79-85)

La leptospirose est une zoonose ré-émergente de distribution mondiale, causée par un spirochète du genre Leptospira. L'OMS rapporte environ un million de cas sévères de leptospirose humaine par an à travers le monde, avec un taux de mortalité de 10 %. Les rongeurs étant considérés comme les principaux hôtes réservoirs de cette bactérie, la transmettent aux Hommes et aux animaux, par un contact direct ou indirect via de l'urine infectée. Le rat brun (Rattus norvegicus) est important d'un point de vue épidémiologique car il est réservoir du principal sérogroupe incriminé dans les cas de leptospirose humaine : le sérogroupe Icterohaemorrhagiae. Chez ce rongeur, l'infection est asymptomatique et a été caractérisée par des modèles expérimentaux centrés sur la colonisation rénale des leptospires faisant appel à une voie d'inoculation éloignée des conditions naturelles. De plus, les détails sur la dynamique de transmission rat-rat restent encore inconnus. Il est donc important de mieux comprendre le rôle du rat dans le maintien des leptospires dans l'environnement, afin de mieux contrôler les épidémies de leptospirose humaine et animale. À partir d'un modèle expérimental avec une voie d'inoculation mimant des conditions naturelles (conjonctivale ou sous-cutanée), nous avons mis en évidence que la réponse sérologique semblerait être indépendante de la mise en place de la colonisation rénale, et que la voie conjonctivale serait plus efficace pour devenir porteur rénal que la voie sous-cutanée. De plus, une étude de l'infection naturelle sur le terrain avec les mêmes méthodes d'analyse, a permis de mettre en évidence la présence de leptospires dans les poumons de manière concomitante à un portage rénal chez le même individu. Grâce à la mise au point d'une nouvelle méthode de typage moléculaire, nous avons identifié les souches circulantes de leptospires dans une population urbaine de rats et leur dynamique de transmission. Toutes les souches portées par les rats appartenaient au sérogroupe Icterohaemorrhagiae et chaque colonie de rat ne semblait maintenir qu'une seule souche de leptospires dans sa population / The leptospirosis is a zoonosis caused by spirochetes of the genus Leptospira, which could infect human and animals. This infection represents a major problem of public health in several countries. The WHO estimates at one million of severe cases of human leptospirosis by year in the world, with a 10 % fatality rate. In the human, the leptospirosis is a mortal infection if it is not treated. The rodents, including the brown rat (Rattus norvegicus), are considered as a carrier and excrete pathogenic leptospires via urine, which becomes the main source of direct or indirect contamination of human and animal. In the rat, the asymptomatic infection was few characterized by experimental model, or only focused on the renal colonization using a no-natural inoculation route. Furthermore, the details of the transmission rat-rat remain still unknown. It is important to know the role of the rat in the persistence of leptospires in rural or urban environments, in order to better control leptospirosis epidemics. With an experimental model using conjunctival and subcutaneous routes, we showed that the antibodies production was independent of the rate of renal colonization and that the conjunctival route was more efficient to become renal carrier than the subcutaneous route. Furthermore, a study of the characteristics of natural infection using the same methods showed the presence of leptospires in lung of rat which are renal carriers. With a new method of molecular typing, we have studied the circulating of the Leptospira strains in the rat’s urban population. All the strains belonged to the Icterohaemorrhagiae serogroup and every colony of rats maintained only one strain of Leptospira. The characterization of the infection with the experimental and field studies, and the epidemiological studies are also important to model the infection in the brown rat, for the prevention of human and animal leptospirosis

The coexistence of humans and rodents lasts from the beginnings of the history of agriculture. Many rodent populations accepted to synanthropic way of life and as commensals accompany human societies until today. In the first study we wanted to find out, how the evolution of non-commensal rodent species, a Cypriot mouse (Mus cypriacus), was influenced by people. This endemic island species evolved on the Cyprus Island without presence of any mammalian competitors or predators. In last 10.000 years humans arrived on the island, bringing several mammalian species, which affected the environment markedly. A black rat (Rattus rattus) is now dominant species there and presumably it is an important competitor for the Cypriot mouse. We supposed that the mice should avoid its odour. Nevertheless the rats odour was preferred by the mouse, probably as an odour of phylogenetically related species. On the contraty, the odour of domestic cat (species, which is also widespread on the island), was avoided. In conclusion, the long-term isolation from mammalian predators did not affect the antipredatory reactions of the Cypriot mouse. Our next study was focuse on changes in behavioural strategies of different populations of mice: the main question was how the commensal way of life affects their exploratory...