In this thesis I investigated the possibility that the kinin system could be involved in the process of ovulation. This study was divided into four parts, these are outlined be 1ow. (1) To determine whether and when the kinin system is activated in relation to ovulation, plasma kininogen levels were estimated in female rats, guinea pigs, and humans at different stages of their estrus or menstrual cycles. Non-ovulating females (women using oral contraceptives,, or post-menopausal women) and male guinea pigs served as controls. The ovulating females of all three species showed a marked decline in kininogen levels shortly before ovulation, suggesting that the kinin system was activated at this time. The fall was absent in the non-ovulating controls, with the exception of women using oral contraceptives. In the latter subjects the fall occurred at a similar time in the 'cycle', and was of a similar magnitude as the fall in normal women. These results showed that the fall is a preovulatory change and raised the possibility that a mechanism more fundamental than the events obstructed by the oral contraceptives could be at least partially responsible for the decline. (2) After establishing the timing of the fall in plasma kininogen levels, an attempt was made to locate the enzymes responsible for the change. The kinin-forming enzymes of the two locations most likely to be involved in kinin release during ovulation, that is, the plasma and the ovary were examined. The evidence indicated that kinin-forming enzymes were present in both locations and suggested that their concentrations increased as ovulation neared. (3) In order to examine the possibility that an ovulatory stimulus can activate the kinin system, female rats were treated with an ovulatory dose of luteinizing hormone (LH) or estradiol -17β one day before the anticipated time of ovulation and kininogen level declines. Estimation of plasma kininogen levels revealed marked declines in the LH-treated animals, estradiol-17β had no observable effect. This evidence suggested that LH, but not estradiol-17β could be responsible, at least in part, for the decreased kininogen values just before ovulation. (4) Lastly, to establish the ability of a kinin to initiate some of the more important events of the ovulatory process, the effects of bradykinin on ovarian smooth muscle contractility and ovarian follicular blood vessel permeability in the rat were examined. Bradykinin stimulated ovarian contractility in in vitro preparations to a significantly greater degree in ovaries isolated during the ovulatory period than at any other stage of the cycle. Also, the degree of movement of the dye Trypan Blue from the general circulation throughout ovarian follicular tissue over a ten minute exposure period was significantly greater in tissue from animals treated with bradykinin than those that were not. This suggests that bradykinin can increase ovarian follicular blood vessel permeability in the rat. Both of these bradykinin-induced effects were reduced, but not eliminated by indomethacin, suggesting that prostaglandins may be involved. Results from this study indicate that the kinin system is activated during the preovulatory period, possibly at the level of the ovary, that LH may be partially responsible for this activation, and that kinins may play a role in triggering increases in ovarian contractility and blood vessel permeability both directly and possibly via the release of prostaglandins. More definite proof awaits the development of a satisfactory kinin antagonist. / Science, Faculty of / Zoology, Department of / Graduate

If spacing behaviour of snowshoe hares limits juvenile survival and recruitment during summer, removal of this behaviour should produce an increase in these parameters. During the summers of 1980 and 1981 I removed all adults from an 8 ha trapping grid and all first litter juveniles from another. Experiments were conducted in the southwestern Yukon during a period when hare populations were at peak densities. The experimental removals did not increase survival, but recruitment relative to control areas was higher to the adult removal grid in 1980 and to both the adult removal and juvenile removal grids in 1981. To determine whether juveniles trapped for the first time were residents or immigrants, I implanted adult females with, calcium-45. This was passed to nursing young and could be detected by scintillation counting of a sample of bone tissue taken from new recruits. Any juvenile without radioactive calcium was classed as an immigrant. The increase in recruitment on the removal areas was due to increased immigration. The number of resident recruits was equal on all study areas. Results support the hypothesis that spacing behaviour limits juvenile immigration but not survival. However, immigration to control areas was also high with immigrants making up 70% of the total number of juveniles present on the areas in October. If food limits snowshoe hare numbers, addition of food should lead to increased numbers through higher survival and immigration. If food supply influences spacing behaviour of hares, home range size should decrease with food addition. I supplied peak (1980) and declining (1981) hare populations on 8 ha grids (one in 1980 and 2 in 1981) with laboratory rabbit chow for 1 - 4 months during March through June. Population size was determined by live-trapping and movements of animals were monitored by radio telemetry. Food addition decreased weight loss and improved survival of hares in both years. Onset of breeding was advanced in males but not females. In 1980, the number of males on the food addition area was 1.4 times higher than those on the control area while the number of females did not differ. In 1981, numbers of males and females were up to 3.6 and 3.2 times higher respectively on the food addition area as compared to those on ;the control area. The differences were due mainly to increased immigration. Residents responded to food addition by decreasing home range size in 1980 but not in 1981. Movement of immigrants, as monitored by telemetry, to the food addition area indicated that some established home ranges there while others returned to their old home ranges. Results support the hypothesis that hare densities are limited by winter food supply during the early decline phase of the cycle and possibly during the peak phase as well. A decrease in home range size was not necessary for immigration to occur. To examine the relationship of dispersal to changes in snowshoe hare numbers, I monitored dispersal of hares during a population increase, peak, and early decline (1978-1982). Two methods were used: 1) a conventional removal grid in which all animals caught each trapping session were removed and 2) telemetry monitoring of radio-collared individuals. The number of animals caught on the removal area was correlated with density on the control area but per capita dispersal rate was not. Both the number of dispersers and the per capita dispersal rate were highest during the period of peak densities on the control area. Dispersal, as measured by the removal grid, was not density dependent. Only 23 of 265 radio-collared animals dispersed during the study. Dispersal accounted for an average of 11% of the losses of radio-collared animals during the population decline. Results from both telemetry and the removal grid indicated that the decline in hare numbers was not due to dispersal. The amount of dispersal as determined by the removal grid was much higher than that determined by telemetry. The difference was more pronounced during the population peak and early decline. This was due to the removal grid over-estimating the average amount of dispersal that was occurring because it attracted animals to it. These results point to the need to be more critical of the underlying assumptions of the removal grid method as a way of monitoring dispersal. / Science, Faculty of / Zoology, Department of / Graduate

The purposes of this thesis were (1) to provide some knowledge of the herptiles and mammals of this area, (2) to clarify the distribution of many of these animals in this section of Texas, and (3) to provide additional ecological information about the area.

Africa’s conservation areas have vast road networks as a result of motorized vehicle game viewing. In conservation areas these roads provide increased accessibility to previously inaccessible areas, often with negative ecological impacts, such as wildlife fatalities and decreased habitat quality and connectivity. Additionally, tar roads often have a greater negative effect on mammal species than dirt roads, altering their spatial distribution and behaviour to a greater extent. The Kruger National Park, South Africa, has 2294 km of public roads within the park, of which 850 km is tarred – carrying a higher traffic density than dirt roads – and 1444 km is dirt. The aim of this study was to compare the ecological impacts of tar and dirt roads on medium to large mammal species in the Kruger National Park, hypothesizing that the tar roads within the park have greater negative impacts on the park’s mammal species. I focused on three response variables: 1. observation likelihoods; 2. species group sizes and 3. distances to the road, comparing tar to dirt roads. Sampling was done at 1 km intervals, for 430 km of tar and 430 km of dirt roads, in savanna vegetation during the Austral winter of 2017 and 2019. In total 476 sampling points were on tar roads (401 systematic and 75 ad hoc) and 451 on dirt roads (369 systematic and 82 ad hoc). At each sampling point, all observed medium to large mammals, their group size, distance of the closest individual to the road, GPS coordinates, traffic volume and percentage cloud cover were recorded. Chi-square analyses were used to identify associations between species presence and road type. To determine the relationship between group size and road type, as well as the observed distance from the road and road type, Generalised Linear Models (GLMs) were used. The results refute the hypothesis of increased ecological impacts associated with tar roads, as the majority of the commonly occurring mammal species were not disproportionately associated with a specific road type. My results indicated that, as a tourist, one has an equal likelihood of observing the majority of the common mammal species from either road type. The results suggest that the increased traffic intensity of tar roads does not decrease one’s chances of viewing game, as hypothesized. The commonly occurring species were also observed at similar distances from both road types, and all were observed on the road, suggesting a limited barrier effect, if any. Previous studies on the impacts of road type on mammals both support and contradict my results. Elephant (Loxodonta africana) was the only species that was associated with a road type, although the complete opposite was found to what was hypothesized. Elephant occurred more often alongside tar roads (albeit only in the north of the park) than dirt roads, in larger groups next to tar roads and closer to tar roads. Potential reasons that are discussed are higher quality forage, plant species richness, group vigilance and predator avoidance. My results can have an influence on park management decisions and communication with tourists. Tourists can be informed that they do not need to make use of dirt roads, which are often less accessible, to view game. In terms of road management, my results suggest that the temporary closure of dirt roads for rehabilitation should not affect game viewing. It is, however, suggested that further research is needed to compare the influence of public to private road areas on animal ecology within the Kruger National Park, as well as to compare the influence of road areas to completely natural areas. / Mini Dissertation (MSc (Environmental Ecology))--University of Pretoria, 2020. / Thuthuka programme - National Research Foundation (NRF) of South Africa (Grant no. 94103). / Zoology and Entomology / MSc (Environmental Ecology) / Restricted

Serine transhydroxymethylase was purified one thousand-fold from bovine brain and one hundred and twenty-fold from bovine liver. Both enzymes were yellow due to the presence of the coenzyme pyridoxal 5'-phosphate. Polyacrylamide gel electrophoresis of the liver enzyme showed one major band containing 95% of the protein, while in the case of the brain enzyme two major bands of nearly equal intensity were observable. The specific activity of the crude liver enzyme was about sixty times higher than that of brain. The liver enzyme was also more heat stable than the brain enzyme. The purified enzymes exhibited L-allothreonine and L-threonine aldolase activities besides serine transhydroxymethylase activity. Electro focusing established the isoelectric point of liver enzyme at 8.75 and a value of 8.90 was obtained from the brain enzyme. The molecular weight of the brain enzyme was found to be 229,000 ± 20,000 while the liver enzyme had a value of 245,000 ± 20,000. pH optima of the enzymes were around 8.0. A similarity in antigenic properties was established for the enzymes from both tissues.

One of the few remaining mysteries in mammalian phylogeny is the issue of Chiropteran phylogeny. In order to further investigate the diphyletic hypothesis that states that Megachiroptera evolved from primate-like gliders and that Microchiroptera evolved from insectivores, the cholinergic, catecholaminergic, serotonergic and orexinergic systems were analyzed in, not only five insectivores (Crocidura cyanea, Crocidura olivieri, Sylvisorex ollula, Paraechinus aethiopicus and Atelerix frontalis) and three prosimian primates (Galagoides demidoff, Perodicticus potto and Lemur catta), but in species from other orders of interest including the Afrotheria (Potamogale velox, Amblysomus hottentotus and Petrodromus tetradactylus), Lagomorpha (Lepus capensis) and Scandentia (Tupaia belangeri). Brains of the mammals were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyltransferase, tyrosine hydroxylase, serotonin and orexin-A. The presence or absence of 93 nuclei within these neuromodulatory systems was entered into modern cladistics software for analysis of the 13 studied species, as well as an additional 40 previously studied mammals. The majority of nuclei revealed in the current study were similar among the species investigated and to mammals generally, but certain differences in the nuclear complement highlighted potential phylogenetic interrelationships. The Afrotherian, A. hottentotus, presented unusual cholinergic interneurons in the cerebral cortex, hippocampus, olfactory bulb and amygdala, and exhibited an unusual foreshortening of the brain, such that a major mesencephalic flexure in the brainstem was evident. The Afrotherian, P. tetradactylus, lacked the catecholaminergic A15d nucleus as in a previously studied member of Macroscelididae. The three Insectivoran shrews lacked the cholinergic parabigeminal and Edinger-Westphal nuclei, had a mediodorsal arch of the cholinergic laterodorsal tegmental nucleus, lacked the catecholaminergic A4 and A15d nuclei and presented an incipient ventral division of the substantia nigra which is identical to previously studied Microchiroptera. All three prosimians presented a central compact division of catecholaminergic locus coeruleus (A6c) surrounded by a shell of less densely packed (A6d) tyrosine hydroxylase immunopositive neurons. This combination of compact and diffuse divisions of the locus coeruleus complex is only found in primates and Megachiropterans of all the mammalian species studied to date. T. belangeri of the Scandentia contained ChAT+ neurons within the nucleus of the trapezoid body as well as the superior olivary nuclear complex, which has not been described in any mammal studied to date. L. capensis of the Lagomorpha presented vi the rodent specific rostral dorsal midline medullary nucleus (C3), while T. belangeri was lacking both the ventral and dorsal divisions of the anterior hypothalamic group (A15v and A15d), and both species were lacking the primate/Megachiropteran specific compact portion of the locus coeruleus. Our neuroanatomical analysis suggests a phylogenetic relationship between the Soricidae (shrews) and the Microchiropterans, supports the phylogenetic grouping of primates with Megachiropterans, confirms previous molecular evidence of the relationship between lagomorphs and rodents within the super-order Glires, and suggests that primates are phylogenetically closer to Megachiroptera than to any members of the Euarchontoglires. The cladistic analysis confirmed the neuroanatomical analysis with the most parsimonious tree placing Megachiroptera into the Euarchontoglires as a sister group to primates and the Microchiroptera next to Soricidae within the Laurasiatheria.

No description available.

ABSTRACT This summarizes a study conducted on the Archie Carr (ACNWR) and Pelican Island (PINWR) National Wildlife Refuges located on the barrier island complex of southern Brevard and northern Indian River counties, Florida. Major objectives of this study were designed to 1) survey the mammals of the ACNWR and PINWR, 2) perform a small mammal population demographic study in coastal scrub and maritime hammock habitats, and 3) document a population monitoring project of Peromyscus po/ionotus niveiventris in northern Indian River County at Treasure Shores Park, within ACNWR Segment 4. A total of7,279 trap nights was compiled during the survey portion of this research: 5,136 on ACNWR and 2,514 on PINWR yielding a combined total of 1,152 captures of 10 species of nonvo lant mammals. Seventeen species of mammals were documented through live trapping, observations, and recorded as road kills. Three species represent additions to the list of mammals once found in the study area, having not been documented in the historical literature. Two are exotic or introduced mammals (Dasypus novemcinctus and Rattus rattus) and one is the native carnivore Lontra canadensis. Seven species of rodents were recorded historically, only five were documented during this study. Two native rodents, Neofiber al/eni and Oryzomys palustris, were not captured while another native species, P. polionotus niveiventris, has dra1natically declined. Capture success ,vas highest on ACN\VR in xeric ha1runock habitat (28.3%) and lovvest in dune habitat (5.9%). On PINWR~ capture success \Vas highest in marititne hanunock habitat ( 14. 7%) and lo\vest in salt marsh/i1npoundment habitat (2.2%). Peromyscus gossypinus was the most abundant mammal, accounting for 55% (481/875) of all captures on ACNWR and 78.7% (218/277) of all captures on PINWR. The second most abundant matnmal was Sigmodon hispidus, accounting for 39.8% (348/875) of all captures on ACNWR and 7.6% (21/277) of all captures on PINWR. Species richness was highest on ACNWR and PINWR in maritime hammock habitat and lowest in salt marsh/impound1nent habitat on both refuges. Five species of native rodents were captured while one species of exotic or non-native rodent was documented through live trapping. Native rodents were distributed in all habitats (eight)~ vvhereas the non-native R. rattus was captured in three of these habitats. Six small 1na1nmals were captured 322 titnes after compiling 5,631 trap nights on three trap grids in two habitats of ACNWR and PINWR. Two s1nall ma1nmals, P. gossypinus and S. hispidus, were the 1nost frequently encountered species. The number of individual P. gossypinus and S. hispidus captured per 100 trap nights and densities varied on the three grids. Density estimates of P. gossypinus ranged from 4.4 to 20.9 individuals/ha in coastal scrub and from 22 to 50 individuals/ha in maritime hammock. Densities of S. hispidus ranged from 0.9 to 15.1/ha on two grids in coastal scrub. Survival rates of P. gossypinus and S. hispidus did not differ significantly among seasons. Weight of adult male P. gossypinus fluctuated seasonally in both coastal scrub and 1naritime hammock habitat. Lowest weights were observed in coastal scrub during spring 1998 while heaviest weights were observed during summer 1998. Adult male P. gossypinus in maritime hammock were heaviest during winter 1999 and lowest during summer 1998. Adult body weights of male S. hispidus varied significantly among seasons. Sex ratios of P. gossypinus were dominated by males on all three grids while sex ratios of S. hispidus in coastal scrub habitat were close to unity. Seasonal reproductive activity of P. gossypinus in coastal scrub habitat was highest during fall 1998 and winter 1999 while reproduction was confined to the fall and winter months in maritime hammock. Greatest seasonal reproductive activity of S. hispidus was exhibited during summer and fall 1998. The age structure of both P. gossypinus and S. hispidus on all three grids was largely dominated by adults. In a total trapping effort of 5,505 trap nights conducted from November 1996 to January 1999 at Treasure Shores Park, 54 captures of28 individual P. polionotus niveiventris were recorded. The number of new individuals captured ranged from a low of two to a high of 13. Recaptures outnumbered new individuals during summer 1997 and winter 1998 however, by spring 1998, recaptures composed 100% ofthe overall captures. Estimates of population size using the Lincoln-Petersen estimator ranged from a low of two to a high of 18 individuals. After three trapping sessions resulted in no captures, further trapping efforts were suspended and it became evident that the Treasure Shores Park population of P. polionotus niveiventris has experienced a tremendous decline. Three individuals were then discovered in oldfield habitat west of SRAlA, opposite the Treasure Shores Park study site. The primary threat to this subspecies' existence in the northern Indian River County portion of ACNWR is habitat loss resulting fro1n the destruction of the pri1nar) dunes b) coastal erosion caused by the jett~ at Sebastian Inlet.

No description available.

No description available.