Dissertations / Theses on the topic 'Zoology'

Majoriteten av Sveriges vattendrag observeras i skogsmark, där en god skogsbruksplanering kan förbättra vattenkvaliteten. Världsnaturfonden (WWF) konstruerade således verktygen Naturvärden, Påverkan, Känslighet och Plusvärde (NPK+) och Blå målklassning, vilka har utvecklats av skogsstyrelsen. NPK+ innefattar en visuell naturvärdesinventering som poängsätter vattendrags befintliga egenskaper enligt ett fältprotokoll. Blå målklassning baseras på NPK+-poängsumman och beskriver ambitionsnivån för vattendragens hänsyn. År 2005 erhöll Kolarebäcken ett av Västra Götalands län största bestånd av den rödlistade flodpärlmusslan (M. margaritifera), men i dagsläget påvisas en markant minskning av arten. Studien ämnar undersöka om Blå målklassning, Känslighet och NPK+-protokollets underkategorier kan förklara var flodpärlmussla förekommer och var höga eller låga tätheter finns i ett vattendrag, samt huruvida variabler inom signifikanta kategorier eller underkategorier i NPK+ gynnar flodpärlmusslans förekomst och täthet. Kolarebäcken inventerades enligt skogsstyrelsens manual av Blå målklassning. Baserat på skogens och vattnets karaktär konstruerades segment med en NPK+-poängsumma och Blå målklass. Flodpärlmusslans förekomst och täthet hämtades från länsstyrelsens inventeringsstationer år 2011 och 2017. Varken Pearson’s Chi-squared test, Fisher’s exact test eller ANOVA påvisar att Blå målklassning kan förklara var förekomst eller höga, alternativt låga, tätheter finns. Oparade t-test och Welch t-test påvisar att flodpärlmusslan främst förekommer i segment som erhåller höga naturvärden i vattendraget och i kantzonen, i synnerhet död ved som genereras av en äldre kantzon. Multipel linjär regressionsanalys påvisar att högre tätheter främst förekommer i segment med höga naturvärden och känslighet samt låg påverkan, i synnerhet en äldre, blöt kantzon. Fler vattendrag behöver dock undersökas för bekräftelse av att Kolarebäckens samband representerar övriga vattendrag.
Streams in Sweden mainly occurs in woodland, where a decent forest management plan can improve the water quality. Thus, the World Wide Fund for Nature (WWF) constructed Conservation value, Impact, Sensitivity and Added values (CISA) and Blue targeting, which were further developed by the Swedish Forest Agency. CISA involves an inventory, which marks visual variables within streams according to a check list. Blue targeting is based on the CISA credits and describes the consideration ambition level. In 2005, Kolarebäcken contained one of the largest populations of the red-listed freshwater pearl mussel (M. margaritifera) in Västra Götaland County. However, a significant reduction of the species is currently detected. The study aims to investigate whether Blue targeting, Sensitivity and the subcategories of CISA checklist might explain where freshwater pearl mussels occur and where high or low densities are found in a stream, plus whether variables within significant categories or subcategories in CISA favor the occurrence and density. Kolarebäcken was inventoried according to the Swedish Forest Agency’s manual. Stream sections, containing one CISA credit and Blue target, were constructed based on fluctuations in forest or water. The mussels’ occurrence and density were obtained from the County Administrative Board’s inventory locations in 2011 and 2017. Neither Pearson's Chi-squared test, Fisher's exact test nor ANOVA indicates that Blue targeting can explain where occurrence or high, alternatively low, densities are found. Unpaired t-tests and Welch t-tests indicates that the occurrence is mainly affected by high conservation values in the stream and riparian zone, especially occurrence of dead wood generated by an old riparian zone. Multiple linear regression analysis indicates that high densities mainly occurs within segments including high conservation values, sensitivity and low impact, especially an old, wet riparian zone. Investigations of several streams are required to confirm that the association in Kolarebäcken represents other streams.

Anthropogenic changes in climate and land use are causing a dramatic erosion of biodiversity. To understand this erosion, and predict future transformations of biodiversity, we need to understand better species’ response to these changes at different spatial and temporal scales. Modeling studies have identified correlations between physical parameters of the environment and species’ distribution at large spatial scales. However, this does not accurately characterize the response of a specific species, since this does not account for the constraints arising from the biology of the species. This thesis shall combine knowledge on the biology of species obtained from laboratory experiments with modeling studies. This will allow us (i) to identify life history traits and biotic interactions that influence species’ adaptive potential, and hence, explain possible differences in species’ distribution, and (ii) to consider, not only the ecological but also the evolutionary aspects of species’ response to changes. This integrative approach is likely to improve our predictions on species’ population dynamic in a changing environment. I focus on a community of butterflies in Sweden (Vanessa cardui, Polygonia c-album, Aglais urticae, Aglais io, Araschnia levana) that feeds on the stinging nettle (Urtica dioica). The available knowledge on the biology of these species and their short life cycles, which allow investigations of their response to changes on a short-time scale, make them a good system to study. Among three of these species, I showed great differences in organisms’ response to variation in food nutrient content. This is a potentially important finding considering the increased use of chemical fertilizers. These differences are to a large extent explained by differences among species in their degree of host plant specialization and voltinism (paper II). Thus, life history traits determine the response of species to environmental changes, but are themselves likely to evolve in response to such changes. Climate change, for instance, may alter the phenological synchrony between plant-feeding insects and their host plants, making it necessary for the insects to evolve their host plant range in order to ensure the availability of resources during larval development (paper I & III). The biology of a species, including biotic interactions, helps to explain the observed shift in a species’ distribution and environmental niche that result from climate change. I have shown that the recent establishment of A. levana in southern Sweden has modified the niche of the resident species, A. urticae and A. io (Paper IV). Niche partitioning in this community is likely mediated by parasite-driven apparent competition.
Mänsklig påverkan på klimat och markanvändning har orsakat en dramatisk förlust av biologisk mångfald. Effekten av dessa förändringar på lokal och regional nivå är dock komplex, och kräver integrativa strategier för att kunna förstå och förutsäga förändringar, på individ-, art- och samhällsnivå. Experimentella studier har utforskat arters plastiska och evolutionära respons till främst abiotiska förändringar, och observationsdata har använts för att modellera skiften i fenologi och utbredning som en konsekvens av klimatförändringar. Trots detta är det fortfarande mycket kvar att förstå för att kunna förutsäga hur miljöförändringar ska påverka arters respons på olika rumsliga och tidsliga skalor. Denna avhandling undersöker i vilken utsträckning arters specifika livshistoria och artinteraktioner kan förklara deras ekologiska och evolutionära respons på miljöförändringar. För att angripa detta har jag fokuserat på ett samhälle av fjärilar i Sverige (Vanessa cardui, Polygonia c-album, Aglais urticae, Aglais io, Araschnia levana) som alla lever på brännässla (Urtica dioica). Den tillgängliga kunskapen om dessa arters biologi samt deras korta livscykler gör det möjligt att undersöka deras svar på förändringar över korta tidsskalor, vilket gör dem till ett lämpligt studiesystem. Huvudslutsatsen från denna avhandling är att för att beskriva hur en art svarar på en förändring måste man ta hänsyn till variation i livshistorieegenskaper och artinteraktioner. Till exempel har den ökade användningen av kemiska gödningsmedel förändrat näringstillgången även i naturliga ekosystem, vilket gynnar växtarter som är kapabla att växa under höga näringsnivåer, som brännässla. Variation i växternas näringsinnehåll kommer i sin tur att påverka herbivorerna som äter av dem, och artikel II visar att skillnader mellan fjärilsarter i hur de svarar på variation i näringstillgång till stor del beror på specialiseringsgrad och voltinism (antal generationer per år). Livshistorieegenskaper avgör således hur arter kommer att svara på förändringar i klimat och markanvändning, men sådana miljöförändringar påverkar i sin tur också evolution av livshistorieegenskaperna (artikel I & III). Slutligen, förändringar i utbredning som ett resultat av klimatförändring kommer även att påverka den lokala sammansättningen av interagerande arter (resurser, predatorer, konkurrenter). Ett exempel på detta är hur den relativt nyliga koloniseringen av södra Sverige av A. levana har förändrat nischerna hos de inhemska arterna A. urticae och A. io (artikel IV).
Le réchauffement climatique et les changements d’occupation des terres d'origine anthropique provoquent une forte érosion de la biodiversité. Pour comprendre cette érosion, et prédire les transformations futures de la biodiversité, il nous faut mieux connaitre la réponse des espèces à ces changements, aux différentes échelles spatiales et temporelles. Grâce à des outils de modélisation statistique, des corrélations entre les paramètres physiques de l’environnement et la distribution des espèces à grande échelle spatiale ont été observées. Mais ceci ne suffit pas à caractériser finement la réponse d’une espèce donnée, car celle-ci dépend des caractéristiques biologiques propres de l’espèce. Cette thèse se propose donc d’associer les connaissances sur la biologie des espèces obtenues par des expériences en laboratoire à des études de modélisation. Ceci permettra (i) d’identifier des traits d’histoire de vie et les relations biotiques qui influencent le potentiel adaptatif des espèces, et donc expliquent d’éventuelles différences de répartition, et (ii) d’envisager, au-delà des aspects écologiques, la composante évolutive de cette réponse. Une telle approche intégrative est susceptible d’améliorer nos prédictions sur la dynamique des espèces dans un environnement changeant. Le système d’étude de cette thèse est une communauté de papillons en Suède (Vanessa cardui, Polygonia c-album, Aglais urticae, Aglais io, Araschnia levana), se nourrissant de l'ortie (Urtica dioica). La biologie de ces espèces est bien connue et leur cycle de vie rapide permet d’étudier leur réponse aux changements à une échelle de temps court. Chez trois de ces espèces, j’ai mis en évidence des réponses très différentes à une augmentation de la teneur en nutriments de leur nourriture, conséquence attendue de l’utilisation accrue d’engrais chimiques. Ces différences sont dans une large mesure expliquée par la gamme de plantes hôtes utilisées et le voltinisme (article II). Ces traits d'histoire de vie déterminent donc la réponse des espèces aux changements, mais sont eux-mêmes susceptibles d’évoluer. Par exemple, le réchauffement climatique modifie la synchronie entre les insectes herbivores et leurs plantes hôtes et pousse à l’évolution du régime alimentaire des papillons afin que la présence de ressources soit assurée durant le développement des larves (articles I & III). Les connaissances sur la biologie des espèces, y compris leurs interactions biotiques, permettent de comprendre les variations de leur distribution spatiale et de leur niche environnementale. Ainsi, l’établissement récent d’A. levana dans le sud de la Suède, suite au réchauffement, a modifié les niches des espèces résidentes, A. urticae et A. io (article IV).

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 4: Manuscript.

Ekoklim

The genetic diversity in modern species is strongly affected by contemporary gene flow between populations, which in turn is governed by individual dispersal capacities and barriers in the landscape. However, current patterns of variation have also been shaped by movement over longer time-scales, such as the successive shifts in species distributions that have occurred during past climate changes. This thesis is focused on cold-adapted species, and one parameter that has greatly influenced their current genetic diversity is how they coped with climate warming at the last glacial/interglacial transition, ca 11.7 thousand years ago. I examined this in three different small herbivore taxa; true lemmings (Lemmus), ptarmigan (Lagopus) and hares (Lepus), whose modern distributions stretch from the exposed tundra to the subarctic moorlands and taiga. In the first paper, I investigated contemporary genetic structure in the cyclic Norwegian lemming (Lemmus lemmus) and proposed that mass movements during peak years act as pulses of gene flow between mountain areas, which homogenise the gene pool over surprisingly vast geographic distances. However, when I used ancient DNA to analyse the lemmings’ ability for long-term directional movement, I found that the Ice Age populations that inhabited the former midlatitude European tundra-steppe appear to have been incapable of shifting their distribution northwards following post-glacial climate warming. Instead, the results suggest that the endemic Norwegian lemming descends from an isolated population that survived the last glacial maximum in situ in a restricted ice free refugium. In contrast to the glacial lemmings, as well the majority of previously studied mammals, the ptarmigan (L. lagopus and L. muta) and hare (L. timidus) analyses revealed a long-term genetic continuity in Europe, where the midlatitude populations were able to keep pace with the rapidly changing climate at the last glacial/interglacial transition, enabling them to shift their ranges to northern and high-alpine regions. These different outcomes might be explained by ptarmigans’ flight capability that allows a less restricted dispersal across fragmented landscapes, and that the generalist nature of mountain hares makes them less vulnerable to habitat alterations. Species distribution modelling, however, indicated that continued climate warming will make some isolated regions unsuitable in the future, thereby forcing populations to adapt the new environmental conditions in order to avoid local extinctions.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.

It is known that artificial light at night has a role in disrupting many birds’ routines when it comes to timing of dawn song. However, studies show various results on which species that are affected, how much and on what latitude. Birds at northern latitudes is experiencing longer and brighter natural nights during the breeding season as the spring is progressing, compared to birds living in areas more south. The bright nights might affect how the birds respond to the artificial light at night. This study's aim was to investigate how different species of songbirds in Linköping (58°N), Sweden, time their dawn song during breeding season, depending on presence or absence of artificial light at night coming from street lamps. The results show that early singing species are more affected than late singing species. The common blackbird for example, advanced its song because of artificial light, up to over an hour on average. Late singing birds was also affected by the urban lights, though not as strongly as the early singing species. Also shown was that the temperature and the amount of cloudiness, did not affect the difference in timing of dawn song between the locations. Future studies should focus on collecting data from more northern latitudes. The effect the advanced timing of dawn song, both regarding the birds on an individual scale and also regarding the ecosystems in total,should also be investigated further.

In this study I attempt to develop a rationale for the role of student writing in advancing learning in Zoology. To this end, I use the informed and insightful voices of five academics from the University of Cape Town's Department of Zoology to present a picture of the goals of the discipline, how they view the role that student writing plays in advan~ing these goals, a sense of the tensions they face in dealing with student diversity, and the promise and challenges of innovative approaches. My interest in how staff view student writing stems from a belief that staff make use of student writing in different ways, depending on their assumptions about writing. I explore these assumptions by means of interviews with members of staff, in which I ask about how they understand the pursuit of science, the qualities a scientist needs to develop, the best ways to develop these qualities in students, and the part that student writing plays in this development. What emerges in this study is the understanding that the kinds of writing we ask students to do reflect the forms of educational practice that we sustain. On the one hand, certain forms of writing may support forms of transmission pedagogy that are viewed as being at odds with progressive science education. On the other hand, if we are to develop alternative teaching approaches which are in keeping with contemporary views of science and learning, then we need to develop new genres of student writing that give expression to these goals and methods. The study concludes with suggested avenues into curriculum review that would operationalise the insights developed by this study.

This thesis associates the cultural elevation of discourse articulating physiologically-centred conceptions of self in mid-nineteenth-century Britain with a shift in power relations. I contend that the proliferation of zoologically- and neurologically-oriented texts, themselves embodying politics of natural truth, constituted a condition of possibility for the emergence of what I portray as a 'technicalization' of power. The articulation of organically determined notions of subjectivity are associated with the constitution of a technical ideal of knowledge production. Further, technical assemblages upon which physiological conceptions of self relied are shown to have helped constitute modes of resistance to discourse concerned with the organic determination of mind and life. Technical entities played an active role in the constitution of organic subjectivities, and organic subjectivities in turn participated in the constitution of technical modes of being. The historical narrative represents the formation of two related disciplines, zoology and psychology, as contingent upon the relative status of different kinds of epistemic equipment. In a natural philosophic context pervaded by uncertainty regarding the relation of matter to spirit, claims that could be made regarding nature were circumscribed by what 'gentlemanly' equals could agree to have 'witnessed.' Gentlemen appealed to differing forms of epistemic equipment in attempts to constitute zoology and psychology as disciplines. The relative success of such appeals was determined not only by the political valency of the claims themselves, but also by the conditions constituted by the types of equipment used to make them. The thesis then goes on to highlight ways in which the disciplined consideration of body and mind as entities determined by nature constituted conditions of possibility for the articulation of tool- and technique-centred subjectivities. The epistemic tools and representational claims appealed to as proof that the self is inherently organic (have) paradoxically participate(d) in the constitution of modes of being that extend the self into the realm of the technical. By the late nineteenth century, the capacities of cognition and replication are beginning to be attributed to the combination of technical and organic entities.

Thesis (Ph. D.)--University of Oregon, 2002.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 246-250). Also available for download via the World Wide Web; free to University of Oregon users.

Due to increasing habitat loss, human-lion conflict, poaching and other reasons, African lion (Panthera leo) populations have suffered a drastic decline. The African Lion and Environmental Research Trust (ALERT) is working to stop this pattern and is the first organization with an ex-situ conservation project for lions. Before releasing lions raised by captive-bred adults, they must first be ensured to behave properly to make sure they have the highest chance of survival. One challenge in the wild is encountering and competition with unknown conspecifics. By conducting playback of unfamiliar lion roars, the behaviours of lions under this ex-situ reintroduction program were tested and compared with observations from earlier studies of wild lions. Social interactions were also collected and a social network analysis was done to give information about the social structure in the pride. This in turn was compared with boldness scores, calculated from behavioural responses in the playback experiments. Lastly, I searched for associations between age and sex with both boldness and social interactions.   The studied pride consisted of 12 lions. The lions were more vigilant when a playback consisted of numerous lions vocalizing, but playing more than three lions seemed to make them loose interest, suggesting either habituation or false information. One adult female and the alpha-male were most bold, followed by five sub-adults. Boldness did not vary according to sex or age differences, but the social network analysis showed that some social interactions were more dominated by one sex or age group. These behaviours were in agreement with comparisons of wild prides.   This study showed that captive-bred lions have developed natural social behaviours. Based on the behavioural responses observed by the captive-origin lions to the playbacks of unfamiliar lions, it is unclear whether these lions would appropriately respond when encountered with unfamiliar conspecifics in the wild post-release.

The taxonomy of the taxa in the Prinia atrogularis-khasiana-superciliaris complex has changed several times in recent history. To this day, different world bird lists classify this complex as 1–3 species. These classifications are based mainly on morphological comparisons of museum specimens. No study has analysed the songs and genetics of this complex. This thesis focuses on the integrative taxonomy of this complex by analysing and comparing their song and mitochondrial cytochrome b (cytb) gene. Seventeen different variables from in total 172 individual songs were measured and analysed. A linear discriminant analysis showed a clear separation in song between atrogularis, khasiana and the superciliaris group (latter including the taxa superciliaris, erythropleura, klossi, dysancrita and waterstradti). The mitochondrial cytb phylogenetic tree produced using Bayesian inference suggested that atrogularis and khasiana split from superciliaris around 4.9 million years ago (mya), with atrogularis and khasiana splitting from each other around 3.4 mya. Based on the combined results of the song and cytb analysis I propose to recognise three species: Black-throated Prinia Prinia atrogularis, Rufous-crowned Prinia P. khasiana and Hill Prinia P. superciliaris. The study also showed some support for classifying klossi as a separate species, but acquisition of additional information is needed to verify this.

Between 1815 and 1840, decades of unprecedented social and political upheaval, the life sciences in Britain were transformed. What for centuries had been a single subject, natural history, fragmented into a set of related but distinct scientific disciplines, defined by their objects of investigation. This study focuses on one of them, zoology, and the ways in which its emerging, transitional practices and methodologies, prompted by the vast increase in empirical information, the emergence of new institutions, development of new audiences, and increasing colonial expansion, were codified and disseminated in some of the most stunning images ever created of life on earth. At the heart of this process was quinarianism, a now almost forgotten system of ordering the natural world which originated in the long-running and acrimonious ‘Species Debate’, the single most important issue in early-nineteenth century biology. Far from being a historical and scientific irrelevance, quinarianism was crucial to the institutional and methodological development of zoology in Britain. As developed by a small, politically-diverse group of zoologists centred upon the Linnean and Zoological Societies of London, it fused natural theology and continental Idealism in a powerful synthesis which, for twenty years, defined zoology as a British, imperial science, providing the institutional framework which made possible the great advances of the 1860s and 1870s. At a time when widespread unrest, calls for political reform, and imported European materialism seemed to threaten the stability of British society, the quinarian vision of a stable, divinely-ordained world was mobilised to both establish zoology as a discipline and promote a ‘safe’, hierarchical social order. Ornithology was one of the first biological disciplines to emerge from the broader natural history, and it was here that quinarianism made the greatest impact. It was also the most visual and ornithological works, from relatively cheap editions to the vast expensive folios of John Gould were copiously illustrated by well-known artists and engravers. These illustrated works have long been neglected as a historical resource, their images regarded as secondary to text as a source of scientific knowledge and often regarded purely on aesthetic grounds. To fully understand the genesis and appeal of quinarianism, it is crucial to consider these images not simply as art objects, but as sources of scientific authority within their wider context. Deploying an interdisciplinary methodology, and building upon recent studies by Lorraine Daston, Peter Galison, and Jonathan Smith, it is demonstrated here that, created through the manipulation of the visual conventions of natural history, images such as Gould’s were central to the epistemological and extrascientific agendas of early nineteenth-century zoologists, and crucial to our understanding of a formative, transitional period in British science that has long been shrouded in obscurity.

Animals in captivity can be deprived of performing some of their natural behaviours. Using enrichments may allow them to express a larger part of species-specific behaviour repertoire and with a better frequency distribution. This study focuses on three species of the family Herpestidae which live in captivity at Bioparc Valencia (Spain). The project aims to study the effect of environmental enrichment on the behaviour of meerkats, banded mongooses and dwarf mongooses in human care. To achieve this goal two different types of enrichmentswere tested: (1) a food enrichment with several variations and (2) an olfactory enrichment with the presentation of two new odours. The food enrichment aimed to increase foraging behaviour and the olfactory enrichment aimed to test if captive animals behave differently in the presence of a predator’s odour compared to a non-predator’s odour. Results revealed that foraging can increase up to 16% implementing enrichments and that success depends on the presence and quantity of food. On the other hand, animals did not seem to behave differently in the presence of both odours. The frequencies of behaviours and time spent interacting did not differ between these olfactory enrichments. I conclude that implementing enrichment programmes may ensure better welfare for captive animals.

Osämja mellan människan och rovdjuren har funnits sedan vi slutade jaga och började bruka jorden och bedriva lantbruk. En av de absolut viktigaste faktorerna som bestämmer vart en art förekommer, hur stark en stam är och hur den förändras över tiden, är predation. I svensk historia har både rådjurs (Capreolus capreolus) och rödräven (Vulpes vulpes) båda populationer varit nära nationell utrotning. Syftet med uppsatsen är att ta reda på om räven har någon påverkan på rådjurspopulationen. Detta görs genom att analysera avskjutningsstatistik från viltdata.nu i tre olika län med liknande klimat och innehåller samma arter av predatorer. Analysen gjordes med korrelationsanalys. Dock var det inget utav resultaten som visade någon signifikans. Dessa olika resultat i de olika län tyder på att det finns andra faktorer än räven som påverkar rådjurspopulationen.
A conflict between humans and predators has existed since man stopped hunting and started with agriculture instead. We know today that one of the most important factors influencing the distribution and abundance of a species is predation. Over the last two? centuries, both the roe deer (Capreolus capreolus) population and the red fox (Vulpes vulpes) population have been very close to extinction in Sweden. The purpose of this study was to determine if the red fox population affects the roe deer population. This was done by analyzing hunting statistics from viltdata.nu in three different regions with similar climate and with the same type of carnivores. The analysis was performed using correlation analysis. None of the relationships between roe deer and the fox in the three different areas was significant. This indicates that there are factors other than predation by fox that influence the deer population.

Thesis (MSc)--University of Stellenbosch, 2005.
ENGLISH ABSTRACT: Physiological diversity in insects was investigated in terms of gas exchange patterns and metabolic rate. Since the majority of hypotheses that propose to explain the occurrence of Discontinuous Gas Exchange Cycles (DGCs) are adaptive, the possibility of adaptation was explored in two ways. First, since repeatability is one of the three prerequisites for natural selection, and rarely tested in insects, the repeatability of gas exchange characteristics and metabolic rate were tested in a Perisphaeria sp. cockroach. Four major gas exchange patterns were recognized and these patterns were found to be extremely variable within this species. However, repeatability was still generally high for the majority of the gas exchange characteristics and metabolic rate. Moreover, between individual variability generally accounted for a large proportion of the variance, supporting the repeatability findings. Therefore, both metabolic rate and gas exchange patterns might indeed be adaptive traits in this Perisphaeria sp. cockroach. Second, the distribution of the three gas exchange patterns (DGCs, cyclic and continuous) across the insect phylogeny was investigated. Data were extracted from the literature and gas exchange patterns for eight insect orders, representing mainly the endopterygotes, were measured. Using standard respirometry techniques, data for a total of ten additional orders were added, which represented both apterygote orders, six exopterygote orders and two endopterygote orders that were previously uninvestigated. In addition, four of the five adaptive hypotheses were tested by investigating the occurrence of DGCs in winged or wingless insects, subterranean and non-subterranean insects, and insects from mesic and xeric environments. Results indicate that DGC has evolved at least five times in the insects and that the cyclic gas exchange pattern is likely to be basal. No support was found for the chthonic, hybrid and oxidative damage hypotheses, while DGCs were associated with xeric environments. This analysis provides some support for the hygric hypothesis. In addition the prediction of the fractal network model for metabolic scaling which states that both intra- and interspecific scaling coefficients should be identical and equal to 0.75, was tested. Three species of polymorphic worker ants were used to determine the intraspecific scaling coefficient. Data from the literature were added to provide metabolic rate information on 42 species of the Formicidae. The interspecific scaling coefficient was determined in several ways: the traditional method (Ordinary Least Squares regression models), with the two respirometry techniques analyzed separately or in combination (e.g. open and closed system), and using phylogenetic independent contrasts with the same sets of data. Intraspecific coefficients were significantly different from 0.75. The slope of the interspecific regression obtained using Ordinary Least Squares regression models was not significantly different from 0.75. However, when phylogenetic relatedness was accounted for the slope differed significantly from 0.75. Therefore, the fractal network model was not supported by these findings, since slope values are not equal and also not statistically equivalent to 0.75. Overall, variability of both metabolic rate and gas exchange patterns in insects is higher than generally suggested by the literature. These findings provide much scope for future work.
AFRIKAANSE OPSOMMING: Hier word die fisiologiese diversiteit van insekte ondersoek in terme van hul gaswisselings patrone asook hul metaboliese tempo. Die oorgrote meerderheid van die hipoteses wat voorgestel is om die onstaan en bestaan van Diskontinue Gaswisseling in insekte te verklaar, is op ‘n evolusionêre grondslag gebaseer. Vir hierdie rede word die moontlikheid van Diskontinue Gaswisseling as ‘n aanpassing op twee maniere ondersoek. Herhaalbaarheid is een van die voorvereistes van aanpassing (in terme van evolusie) en dit is tot dusver slegs ‘n paar keer in insekte getoets is. Daarom word die herhaalbaarheid van die gaswisselings komponente, asook die metaboliese tempo hier in ‘n Perisphaeria sp. kokkerot ondersoek. Vier hoof gaswisselings patrone is geidentifiseer en die bevinding was dat die patrone geweldig kan varieer binne hierdie spesie. Ten spyte hiervan was die herhaalbaarheid steeds hoog vir die oorgrote meerderheid van die gaswisselings komponente asook vir die metaboliese tempo. Verder het die variasie tussen individue tot ‘n groot proporsie van die totale variasie bygedra, wat die betekenisvolheid van die hoë herhaalbaarheid beklemtoon. Dus, beide metaboliese tempo sowel as gaswisselings komponente kan moontlik as ‘n aanpassing beskou word in hierdie kokkerot. Tweedens, die verspreiding van die drie gaswisselings patrone (Diskontinue Gaswisseling, siklies en kontinu) in die insekte is ondersoek. Gaswisselings patrone vir agt van die dertig insek ordes is vanuit die literatuur verkry, alhoewel dit meestal verteenwoordigend van die Endopterygota is. Data vir tien additionele ordes wat nog nooit voorheen ondersoek is nie is bygevoeg, insluitende beide die ordes van Apterygota en ses ordes van die Exopterygota, asook twee ordes van die Endopterygota. Verder is vier van die vyf hipoteses met betrekking tot aanpassing ondersoek deur die teenwoordigheid van Diskontinue Gaswisseling in gevleuelde en ongevleuelde insekte, ondergrondse en bogrondse insekte, asook insekte van gematigde en droeë omgewings te ondersoek. Resultate dui aan dat Diskontinue Gaswisseling ten minste vyf keer onafhanklik in insekte onstaan het en dat die sikliese patroon heel moontlik basaal is. Die resultate bied geen ondersteuning vir die hipoteses wat gegrond is op gaswisseling in ondergrondse omgewing of oksidasie beskerming nie. Daar is wel ondersteuning vir die hipotese aangaande die rol van water verlies in die onstaan en onderhoud van Diskontinue Gaswisseling. Additioneel is daar ondersoek ingestel na die verwagting wat deur die fraktale netwerk model vir metaboliese glyskale gestel word, wat lui dat beide die binne- sowel as tussen-spesies koëffisiënte identies aan mekaar en gelyk aan 0.75 sal wees. Drie polimorfiese mier spesies is gebruik om die binne-spesies koëffisiënt te bepaal. Data vanuit die literatuur is hier bygevoeg en sodoende was informasie vir 42 mier spesies van die Formicidae beskikbaar. Verskillende metodes is gebruik om die tussen-spesies koëffisiënt te bepaal: die tradisionele metode (sg. “OLS”-regressie), met die twee tegnieke om metaboliese tempo te bepaal (bv. oop en geslote sisteem metodes) apart asook saam, en deur gebruik te maak van filogeneties onafhanklike vergelykings vir dieselfde datastelle. Die binne-spesies koëffisiënte was almal betekenisvol verskillend van 0.75. Die tussen-spesies regressie waar gebruik gemaak is van ‘n “OLS”-regressie model was nie betekensivol verskillend van 0.75 nie. Met filogenetiese verwantskappe egter in ag geneem, het die koëffisiënt wel betekenisvol verskil van 0.75. Dus word die fraktale netwerk model nie ondersteun deur hierdie studie nie, aangesien die koëffisiënte nie indenties aan mekaar is nie, en ook statisties verskil van 0.75. In die algemeen is die variasie in metaboliese tempo sowel as gaswisselings patrone aansienlik hoër as wat afgelei kan word uit die literatuur. Hierdie bevindinge stel ‘n basis vir heelwat verdere werk in die toekoms.

Variability in annual recruitment for many fishes is correlated with survival during the larval phase. Yellow perch in Lake Michigan have experienced sustained recruitment failure since 1990 and this has been blamed on low larval survival. Direct examination of factors important to larval yellow perch survival in Lake Michigan is complicated by the large size of the lake (52,000 km2) and the short length of the pelagic larval period (30-40 days). Individual-based modeling is a valuable indirect method for assessing the importance of multiple factors to larval survival. I used an individual-based modeling approach combined with field data collection to test four hypotheses regarding factors limiting survival of larval yellow perch in Lake Michigan. I tested whether larval survival is limited by prey community composition, size-selective predation, advection of larvae into offshore habitat or an interaction of these factors. I sampled larval and zooplankton abundance in Lake Michigan along a transect from 1 ? 32 km from shore in 2000 and 2001. I conducted laboratory experiments to quantify larval vulnerability to predation by three typical predators as a function of both predator and prey size. I also conducted laboratory experiments to quantify larval selectivity for different zooplankton prey as a function of larval size and prey community composition. I used the results of these experiments to develop an individual-based model specifically to describe growth and survival of larval yellow perch. Field data suggest that larval yellow perch are being transported from the nearshore to the offshore zone of Lake Michigan, but the timing of this transport varies between years. Model simulations in which the offshore prey community and the timing of larval advection were both varied suggested that larval survival will be highest in years when advection occurs within two weeks of peak hatch, allowing larvae to exploit offshore prey resources early during ontogeny. The model predicts that larvae will make foraging decisions based on prey availability as well as innate preference and they will change their diet if they are exposed to different prey communities. Model simulations also demonstrated that predation currently may not be an important factor for survival of larval yellow perch in Lake Michigan. This result is because alewife is the only fish abundant in Lake Michigan known to eat larval yellow perch. Experimental results suggest that alewife feeding rate on larval yellow perch is a positive function of larval density; yellow perch densities are currently too low to induce significant predation by alewife. Predation appears to be more important in smaller systems where larval densities are higher and larvae are exposed to other predator species. Larval survival in Lake Michigan appears to be primarily limited by an interaction of prey community composition and the timing during the larval period of offshore advection. Both factors vary between years and a good year-class is predicted when the offshore prey community is rich in cyclopoid copepods and larvae are advected offshore early. Early access to cyclopoid copepods results in an earlier transition from feeding on rotifers to feeding on copepods, which is predicted to increase larval growth and decrease mortality. These results suggest that survival of larval yellow perch in Lake Michigan is affected more by density-independent factors such as physical transport and prey community composition; Lake Michigan more closely resembles a marine environment than a typical lake with respect to larval recruitment processes. The unique aspects of larval yellow perch dynamics in Lake Michigan must be considered when applying lessons learned from analysis of larval yellow perch in other lakes to understanding survival of larval yellow perch in a large meso-oceanic system like Lake Michigan.

The striped mullet, Mugil cephalus, has supported a commercial fishery in North Carolina since the 1800s and today ranks in the top ten of commercially valuable fin- fisheries in the state worth over a million dollars annually. The species is a direct link between lower and higher trophic levels and thus serves an important role in the food web. Despite striped mullet?s biological and economic importance, basic life history data from North Carolina are limited and the stock status is unknown. Objectives of this study were to describe striped mullet growth, reproductive seasonality, size and age at maturity, and fecundity. Monthly samples of striped mullet were collected using both fishery independent and dependent sampling strategies throughout North Carolina. Sagittae otoliths were removed and sectioned for age and growth analyses. Gonads were fixed and histologically prepared for maturity indices and fecundity estimation. Length was highly variable within age classes. Regional growth differences within North Carolina were found as fish collected from the southern sampling regions were smaller at age and lived longer than fish from the northern regions. Growth models suggest growth rates in North Carolina were greater than other areas in the species? range. Based on the presence of recently post-spawned fish and gonadal development, striped mullet spawn between late September and December. The collection of a hydrated female less than 1 km from an inlet, coupled with the presence of post-ovulatory follicles from fish sampled within the estuary, provided evidence for near-shore spawning. Males matured at a smaller length (L50) than females, 283 mm and 324 mm fork length, respectively. Fecundity correlated well with fork length (r2=0.88) and body weight (r2=0.91), and ranged from 1193 to 2535 eggs per gram of eviscerated body weight. This study provides the first life history assessment of striped mullet reproduction and growth from North Carolina and shows differences in growth, maturity, spawning location, reproductive seasonality, and fecundity compared to other areas in the species? range.

As top predators, sharks have an important role in marine ecosystems in relation to populations of fish and invertebrates at lower trophic levels. Fishery management plans stress the need for an ecosystem approach, but few quantitative data on the foraging ecology of sharks have been published. Results from a literature review found that shark species close in taxonomic relation have high diet overlap. Stomach contents and catch data of early life stages of Atlantic sharpnose (Rhizoprionodon terraenovae), blacktip (Carcharhinus limbatus), finetooth (Carcharhinus isodon), and spinner sharks (Carcharhinus brevipinna) taken from fishery independent surveys in Apalachicola Bay, Florida, April-October 1999-2002 were examined to test for resource competition. All species are capable of taking teleost prey from birth, though Atlantic sharpnose and blacktip sharks show an ontogenetic shift in diet. Young-of-the-year Atlantic Sharpnose sharks feed mainly on shrimp, juveniles on sciaenids, and adults on clupeids. Young-of-the-year blacktip sharks feed mainly on sciaenids, whereas juveniles feed on clupeids. The primary prey of young-of-the-year and juvenile finetooth and spinner sharks is menhaden. Seven of ten size-selectivity tests showed neutral selection. Atlantic sharpnose and finetooth sharks consume relatively small-sized prey (over 60% <20% of their length) compared to teleost piscivores while blacktip sharks consume relatively larger prey (58% >20% of their length). Regardless of maturity state and species, diet overlap is high for species-life stage combinations that are similar in size; however, species-life stages did not show significant overlap in habitat use. One possible interpretation is that prey categories shared by similar-sized species are not limiting, but competition may exist for available habitat resources. More intensive monitoring is needed to fully understand temporal and spatial habitat use patterns among these early life stages. Quantifying the links among these sharks and the links between these sharks and resource species are critical for ecosystem modeling and a key step to a broader approach in fisheries management.

Eight Xenopus laevis claudin genes, Xcla1, Xcla4B, Xcla5, Xcla6, Xcla12, Xcla16, Xcla18 and Xcla19, were cloned and sequenced. Their normal mRNA expression was determined from cleavage stage to tadpole stage by whole mount in situ hybridization. The protein expression of Xcla5 was detected at the neural stage by whole mount immunostaining. Overexpression of Xcla5 by injection of synthetic mRNA into embryos caused morphological defects similar to those in embryos exposed to Bisphenol A (BPA). Altered patterns of claudin gene expression in the presence of BPA can be correlated with these developmental defects. The results suggest that claudins may play an important role in neural crest cell migration, epithelial-mesenchymal transition and ultimately organogenesis during embryonic development.

We used a system capable of simulating avian census conditions when birds are detected aurally to evaluate environmental effects on the detection process. We were interested in quantifying the effects of observers, species, and background noise on detection probability and maximum detection distance in two habitats (mixed pine/hardwood forest and deciduous forest) and two leaf conditions (leaves on and leaves off). We found significant effects of background noise, habitat, and leaf conditions on maximum detection distance. Maximum detection distance decreased on average by 36.61 m +- 5.44 with the addition of background noise, 29.52 m +- 6.25 with leaves on trees, and 35.68 m +- 5.58 between mixed pine/hardwood forest and deciduous forest. Average estimated detection probabilities varied greatly by factor combination and species, but in general they decreased with the addition of background noise, under leaf-on conditions, and in deciduous forest sites compared to mixed pine/hardwood sites. Average detection probabilities at 100 m ranged from 0 to 1 among species and under different environmental conditions. Average detection probability estimates never exceeded 0.19 for the Black-and-white Warbler (Mniotilta varia) at 100 m in deciduous forest. We found that a relative hearing index explained a maximum of 37% of the variation in observer detection probabilities. Interacting factors differed among species and were therefore difficult to predict. Environmental conditions can impart substantial bias in auditory point count data. We suggest estimating detection probability directly and incorporating this estimate in abundance estimates.

In the year 2000, a reported 460 turtles were removed from North Carolina for commercial use. In 2002, the reported take of turtles soared to a staggering 23,311 turtles. A continuation of this trend could severely deplete the turtle populations of North Carolina in a short time. Therefore a moratorium on commercial turtle harvesting was instituted by the North Carolina General Assembly on July 1, 2003, effective until the NC Wildlife Resources Commission could determine rules and regulations for harvesting. It is crucial to know the level of harvest that populations can sustain, and, if a population is harvestable, which age groups are most sensitive to harvest. Regulations on reporting and validation of numbers, identifications, sizes, and sex of turtles will be crucial. I conducted a mark-recapture survey of freshwater turtles in six eastern Piedmont ponds: three of which had been harvested and three of which had no record of harvest. I tested for differences in sex ratios, size and age distributions, and population densities between the harvested and unharvested populations of Yellow-bellied Sliders (Trachemys scripta). Although no significant differences were found between the two types of populations, the amount of variance in the results does not allow any clear conclusions to be drawn. Severe weather impacts on habitat may have influenced sampling results. More research is required to determine the true effects turtle harvesting has on populations, including extensive stage-based simulation modeling and determination of metapopulations.

The spermatheca of the acridid Orthoptera Schistocerca americana and Dissosteira carolina both consist of a ductus seminalis and a receptaculum seminis that ends in two blind sacs called the apical and preapical diverticula. The diverticula of acridid grasshoppers show high morphological variation that might imply functional differences. A microscopic examination of the structure of the spermatheca surface of both species found the presence of numerous gland ductules, but a lack of acanthae typical of many acridids. A histological study of macromolecules in the spermatheca of mated females found large carbohydrate and protein secretions present in all chambers. The secretion was not present in virgin S. americana but was present in virgin D. carolina. These secretions are likely glycoproteins either secreted by female gland ductules or contributed from males. Lipids were limited to small droplets contained within epithelial cells lining the walls of the spermatheca of both mated and virgin females. Histological sections of the spermatheca were utilized to track the course of sperm bundles in the chambers at various intervals following copulation initiation. In S. americana sperm bundles are found primarily in the diverticula and appear to be degraded in the apical diverticulum. In D. carolina sperm bundles are seen in all chambers of the spermatheca except the ductus seminalis and maintain a constant distribution an hour into copulation. Implications of this study are discussed in relation to the function of acridid spermatheca and sperm organization.

After partial denervation of mature muscle, the remaining motoneurons grow terminal sprouts, which reinnervate denervated muscle fibers. In neonatal rat soleus muscle however, not only do the remaining motoneurons fail to reinnervate nearby muscle fibers, but they also display clear morphological and physiological evidence of terminal disruption. My ultimate aim is to attain a better understanding of this disruption by performing repeated in vivo observations of individually identified terminals in transgenic mice expressing fluorescent proteins in their motoneurons. For technical reasons, these in vivo imaging studies would ideally be conducted on CFP mouse sternomastoid (SM) muscle. I therefore tested whether neonatal partial denervation of CFP mouse SM muscle also causes terminal disruption. Two to five days after neonatal partial denervation, I fluorescently labeled nerve terminals and acetylcholine receptors (AChRs) to assess the effect on terminal morphology. Terminal disruption after partial denervation did not occur as extensively in CFP mouse SM muscle (a fast-twitch muscle) as it did in rat soleus muscle (a slow-twitch muscle). This relative absence of terminal disruption in CFP mouse SM suggested that the extent/occurrence of terminal disruption after neonatal partial denervation could depend on either the species being studied or muscle fiber type. To distinguish between these possibilities, I investigated terminal disruption after partial denervation of rat SM muscle. In both soleus and sternomastoid muscles of rats, neonatal partial denervation resulted in disruption of about half of the terminals, whereas in SM muscles from CFP mice only 8% of terminals showed evidence of disruption. Therefore, it appears that the nature of terminal disruption that takes place after partial denervation of neonatal muscles is not related to muscle fiber type but may be species-specific.

A series of static toxicity tests were conducted to determine the tolerance of yellow perch to ammonia and nitrite on larvae, juvenile and adult fish. Toxicity tests on adults were conducted at 18, 22, and 25 C. The tests on larvae showed highly varible results and were ultimately inconclusive. The 96h LC50 for ammonia and nitrite to juveniles were 0.77 mg/L as NH3-N and 78.24 mg/l as NO2-N, respectively. Adult and juvenile yellow perch had similiar tolerance levels. lc50 values for ammonia and nitrite varied with temperature and were 0.64 mg/l as NH3-N and 65.8 mg/l as NO2-N, respectively at 22 C. Lower water temeprature reduced the toxicity of ammonia and nitrite to yellow perch adults significantly. At 18 C, the LC50 values and nitrite were 59% higher (1.02 mg/l as NH3-N) and 34% higher (88.5 mg/l as NO2-N), respectively than the values at 22 C.

Natural mortality has always been a challenging quantity to estimate in harvested populations. The most common approaches to estimation include a regression model based on life history parameters and more recently tag-return models. In recent years, Bayesian methods have been increasingly implemented in ecological models due to their ability to handle increased model complexity and auxiliary datasets. In this dissertation, I explore the implementation of Bayesian methods to analyze tag-return data focusing on natural mortality. Chapter 1 is focused on the addition of two components to the tag-return model framework: random effects and auxiliary data. Auxiliary information on the instantaneous rate of natural mortality is provided through Hoenig's equation relating lifespan to natural mortality, and also implemented through a hierarchical prior. A simulation study validates the performance of the model while an analysis of the classic Cayuga Lake trout dataset demonstrates its use. Chapter 2 adds a change-point allowing for the estimation of two levels of natural mortality and the timing of the discrete-time shift in mortality. Analysis is focused on a Chesapeake Bay striped bass tagging dataset of fish tagged at six years of age and older from 1991-2002. Results show the ability to account for shift in timing. Contrasting with Jiang et al.'s study on the same striped bass dataset, the timing of the change-point was different between the two studies, likely because the Jiang study assumed a fixed tag-reporting probability of 0.43 whereas estimates seem to indicate it may be closer to 0.3. Chapter 3 introduces a change-point allowing for a shift in the tag-reporting probability while assuming a constant natural mortality rate. High reward tags are included in a subset of the data time-series to improve estimation. A factorial simulation design was used to investigate the model performance with different reporting rate and high reward tag scenarios. In general, the model performed very well with little bias except in the case of no high-reward tags. The model performed surprisingly well in a six year study. The results suggest the importance of high reporting rates and/ or auxiliary data sources such as high reward tags.

The movement of individuals is one of the fundamental components of contemporary ecological problems such as metapopulation theory, epidemic models, competitive coexistence, and invasion dynamics. Advection-diffusion models, sometimes with a reaction term, have been usefully applied to such problems. For this dissertation, I broadened this approach by seeking to understand the effects of certain biotic and abiotic factors on movement ecology, and asking how to incorporate flexible behavioral responses into classical advection-diffusion models. I asked how resources, competitive environment, and habitat structure, interacting with body size or not, affect the movement behaviors of two coexisting invasive snails (Melanoides tuberculata and Tarebia granifera), and whether including the behavioral response to these factors improves advection-diffusion models of movement. I also made natural history observations regarding the snail system to provide a biological context for my empirical work. To address these questions, I conducted replicated experiments and observational studies, extended advection-diffusion models, and arbitrated among candidate models using AIC (Akaike?s Information Criterion) model selection. Specific studies included (1) behavioral response to phenotypic and resource heterogeneities, and their interaction, (2) behavioral response to intraspecific and interspecific competition, and (3) behavioral response to spatially uniform versus spatially heterogeneous environments. In summary, this dissertation provides insights into modeling movement behaviors, using two coexisting invasive snails as the model system. I advocate for a behaviorally informed modeling framework that integrates sentient responses of individuals in terms of movement, improving our ability to accurately model ecological processes that depend on movement ecology.

Seed dispersal mutualisms are important ecological interactions that can shape plant communities by influencing species distributions, community composition, and the regeneration of populations following a disturbance. Considering the fundamental role seed dispersal mutualisms play in many plant communities, it is important to understand, both generally and for individual seed dispersal mutualisms, what determines when animal partners successfully disperse seeds and when they do not. Myrmecochory, the dispersal of seeds by ants, is the most common form of zoochory in Western Australia. Myrmecochore plant diversity is richest in the Kwongan sandplains of the south-west, where ant-dispersed species can make up as much as 36% of the plant community. Here, I studied the determinants of seed dispersal rates to understand local variation in myrmecochorous seed dispersal rates. At a series of 30 sites, we sampled the ant and plant communities, measured aspects of the community structure (vegetation height, openness, topography, soil), measured seed removal rates and observed ant-seed interactions. The most significant factor that governed seed removal rates was the presence of the ant species Rhytidoponera violacea. Additionally, during seed dispersal observation trials, R. violacea removed 95% of all seeds taken. To better understand the fate of Acacia blakelyi seeds dispersed by R. violacea, we simulated variable seed burial depths and elaiosome removal by ants, followed by a bushfire to stimulate germination. Seed burial depth had a significant effect on seedling emergence, with the proportion of emerged seedlings declining with burial depth. The effect of depth was due to the strength of a fire-cue (heat) declining with depth. Seed burial depth also had a fitness cost, with a greater proportion of ârobustâ seedlings emerging from seeds buried closer to the surface. Seeds buried too deep to receive fire-cues remained dormant, adding to a long-lived soil seed bank.

Claudin-5 is an important member of the claudin gene family. The expression of claudin-5 in the heart of Xenopus laevis was determined by whole mount in situ hybridization. RNA over expression and knock down experiments demonstrated that claudin-5 is critical for heart development. Meanwhile, claudin-5 down regulated bone morphogenetic protein 4 (BMP4) expression in early stage through upregulating chordin (chd). In addition, other pathways such as estrogen hormone and transforming growth factor-β (TGF-β) may also affect claudin-5 activity. The results show that claudin-5 plays an important role in heart development and is involved in a complex pathway of gene regulation. The mRNA expression of claudin-12, another member of claudin protein family was also determined from cleavage stage to tadpole stage by whole mount in situ hybridization.

The common dolphin (Coryphaena hippurus) supports economically important fisheries along the east coast of the United States. In recent years, landings of dolphin from the United States Atlantic have increased dramatically. For example, recreational landings in the US South Atlantic Bight have increased from 162,000 dolphin in the 1960s to over 1.3 million dolphin in recent years. The last age and growth study of North Carolina dolphin was conducted in the early 1960s. It is hypothesized that life history parameters may have changed due to increased exploitation. Age, growth and reproduction were studied on dolphin (n=802; size range=89 to 1451 mm FL) collected between May 2002 and May 2004 from commercial and recreational catches in North Carolina. Annual increments from scales (n=541) and daily increments from sagittal otoliths (n=126) were examined; estimated von Bertalanffy parameters were L∞ = 1299 mm FL and k = 1.08 yr ^-1. The maximum age observed was 3 years. No major change in length at age has occurred since the early 1960s. Daily growth increments for age-0 dolphin reduced much of the variability in length-at-age values for age-0 dolphin and provided an average growth rate of 3.78 mm/day in the first six months, which is extremely fast for a teleost fish. Growth of North Carolina dolphin is similar to that found in Florida and the Mediterranean, but differs from observed growth in the Caribbean and Gulf of Mexico. Age at 50% maturity was around 4 months for female dolphin and 6 months for male dolphin. Monthly length-adjusted gonadal weights suggest that peak spawning occurs from April through July off North Carolina; back-calculated hatch dates from age-0 dolphin along with prior studies on the east coast of Florida suggest that dolphin spawning occurs year round with highest levels from January through June. This study provides an updated and improved (year-round sampling and otolith daily ages) age-length function for dolphin caught off the coast of North Carolina using both scale annuli and daily growth increments and provides some of the first comprehensive data on North Carolina dolphin reproduction. The life history of dolphin, including fast growth and early maturity, allows for high levels of exploitation.

The mechanism of sperm transfer and sperm organization inside the spermatheca was investigated in two grasshoppers, (Scudder) and (DeGeer). The spermathecae were examined histologically from females whose copulations were interrupted at various prescribed intervals, either during their first or subsequent mating. Sperm organization inside the spermatheca from 24 to 120 hours after copulation had terminated was also investigated in . Scanning and transmission electron microscopy were used to investigate the distribution and morphology of small hair-like structures inside the spermathecae.

In both species sperm were first observed inside the spermatheca approximately 30 minutes after the initiation of copulation. The majority of sperm transferred into the spermatheca were in the form of sperm bundles, or spermatodesmes. In the rate at which sperm bundles were transferred appeared to decrease after 13 hours into copulation (average mating duration in the laboratory was 28 hours). In the rate of sperm transfer remained constant throughout copulation (average mating duration in the laboratory was 1.3 hours). The occurrence of both an abundance of individual sperm and sperm bundles was observed only in females of who had mated previously and had a second copulation of less than 9 hours in duration and in females of that had a second copulation less than 45 minutes in duration. As mating continued, fewer and fewer individual sperm were observed, and by 15 hours into copulation in only sperm bundles were observed inside the spermatheca. Therefore, it appears that the majority of the individual sperm in the above copulations are from prior matings, while most of the sperm bundles are from the last copulation. The interrupted matings of previously mated females indicate that at least some sperm bundles remain inside the spermatheca while individual sperm were removed by some mechanism, possibly sperm flushing by an excess of seminal fluid provided by the mating male.

In some sperm bundles remained intact for at least 7 days after the termination of copulation. The sperm bundles must disassociate into individual sperm prior to fertilizing the female's eggs, and therefore it may be the female that provides the mechanism or chemical stimulus to initiate sperm bundle disassociation prior to oviposition or prior to a second mating or both.

The results of this investigation suggest sperm competition, perhaps mediated by female choice, as a primary reason for lengthy copulations in . Male weight in has been documented to play a significant role in female choice and mating duration, whereas in , other factors such as nutrient transfer may play a significant role in female choice and mating duration. In , males may also act as mechanical plugs by remaining in copula for an extended time after a sufficient amount of sperm has been transferred, or males may be participating in the process of sperm removal by transferring an excess of seminal fluid to "flush-out" any sperm present from previous matings.

ABSTRACTWEEKS, KENDRICK COLLINS. The foraging and nesting ecology of Black-throated Blue Warbler () in the southern Appalachians. Chair of Advisory Committee: Theodore R. Simons.Some species of Neotropical-Nearctic migrant birds have been showing declines in populations for the past thirty years. Black-throated Blue Warbler ( in the southern Appalachians. This research documents the foraging and nesting habitat use and nest fate of these two species primarily in cove forests at elevations of 2800-3200 ft. Two cove forests were delineated: acidic cove hardwood and rich cove hardwood. I conducted foraging observations randomly while searching for nests. I also collected structural and floristic vegetation data to relate foraging, nest-site selection, and nest fate to habitat..There was no difference in nest success for either species between forest types. Both species readily utilized rhododendron as a nesting substrate but was lowest for nests initiated mid-season (0.9472 ± 0.009 and 0.9519 ± 0.012, respectively) as opposed to early (0.9664 ± 0.008 and 0.9652 ± 0.009, respectively) or late (0.9708 ± 0.006 and 0.9862 ± 0.006, respectively) in the season.Both species selected nest sites with high cover of low shrubs and small disturbances. However, nests in rhododendron (t = 3.58, df = 56, p < 0.05) and over all (t = 6.89, df = 122, p < 0.001). Nest fate was dependent on cover 1 m above the nest for both species. These results highlight the subtle differences in the ecology of similar species that may allow for species coexistence. Additionally, small changes in management can potentially affect similar species differently. High nest success of in the southern Appalachians indicates that these forests may indeed be source populations. Future research should be directed towards mortality during other times in these species' annual cycle.

We assessed the utility of developing predictive models of species distribution within a large contiguous forest based solely on GIS (Geographic Information Systems) data. We conducted more than 7000 point count surveys of breeding birds at approximately 4000 locations throughout Great Smoky Mountains National Park (GSMNP). We combined these empirical data with habitat, topographic, and location variables to develop logistic regression models for 20 breeding bird species. The mean of observed points correctly classified for evaluation data was 74.3% with a range of 67.4% to 83.1%. Mean improvement in model classification rates with the addition of a trend surface was 0.9% with a range of ?0.4% to 2.0%. We also assessed the importance of controlling for differences in species detectability in different vegetation types. Comparisons of models based on unlimited radius plot data with models based on fixed width plot data that minimized detectability differences between vegetation types showed classification rates dropped an average of 0.9% with a range of -3.8% to 3.7% for fixed width plots. In the eastern U.S., invasion of hemlock wooly adelgid (Homoptera: Adelgidae: Adelges tsugae) is transforming species composition of native forests by causing extensive mortality in eastern hemlock (Tsuga canadensis) populations. We assessed the potential effects of hemlock loss in GSMNP by evaluating current hemlock distribution and abundance patterns and identifying environmental correlates of hemlock presence. We investigated potential effects of hemlock mortality on the park's avifauna by identifying bird species associated with hemlock. Our results indicate hemlock is widespread in all vegetation strata at low and mid elevations and is the second most common tree species in the park. Hemlock presence is significantly associated with elevation, total relative moisture index, disturbance history, vegetation type, and bedrock geology. Sixteen of 30 common breeding bird species showed significant correlations with hemlock presence. Hemlock loss will favor increased abundance of avian species associated with early successional and disturbed habitats and reduced abundance of avian species associated with late successional forests.We compared breeding bird community structure and composition in old growth and mature second growth (65-100 years old) forests in the southern Appalachians using paired point count. We found few differences in the two communities. Comparisons of relative abundance based on counts of individual bird species showed two species were significantly more abundant on old growth sites and one species was significantly more abundant on second growth sites. After incorporating differential detectability into relative abundance estimates, we found that 4 breeding bird species were significantly more abundant in old growth sites compared to second growth sites and that no breeding bird species was significantly more abundant in second growth sites. These results highlight the importance of incorporating detectability measures into sampling and analytic methods. Analysis of vegetation samples for the paired sites showed significant differences between old growth and second growth sites. Old growth sites had significantly more large trees for classes > 50 cm diameter at breast height. Vegetation composition comparisons showed old growth sites had significantly more late successional species and significantly fewer species associated with early successional forests. Nonetheless, measures of species richness, relative abundance, and number of standing snags did not differ between old growth and second growth sites. Breeding bird composition similarities between old growth and second growth sites in this study may not be typical of more fragmented landscapes because large remaining patches of old growth forest adjacent to second growth sites may ameliorate differences between the

Juvenile largemouth bass C annually. Water level increase could be used to stimulate largemouth bass spawning in systems where water temperature is suitable. CPUE of age-1 largemouth bass was positively correlated with water levels of the previous year and negatively correlated with water level fluctuations. The effect of these hydrological variables on largemouth bass recruitment appeared to be exponential rather than linear. Age-1 largemouth bass comprise the majority of the fishable stock in Lucchetti Reservoir, and the stock is typically below carrying capacity. Thus, the potential exists to adopt a water level management plan during the spawning period of largemouth bass to ensure successful largemouth bass recruitment into the next year?s fishable stock.

Corridors have been shown to serve as movement conduits for a wide variety of species, though their effects on interspecific interactions have been largely unstudied. I designed a replicated experiment to investigate corridor-mediated prey responses to predators in a network of open habitat patches surrounded by a matrix of planted pine forest. I used mark-recapture studies and foraging trays to monitor the movements and behaviors of several small mammal species. The presence of predators was artificially manipulated in half of my replicates by applying bobcat urine to specific patches. I then compared the movements of small mammals and changes in foraging activity in the treated and untreated replicates, and tested how corridors affected behaviors and population sizes. I found significant differences in foraging activity between patches treated with predator urine and patches to which they were connected, whereas I found no differences in foraging activity in unconnected patches adjacent to treated patches. Movements detected by mark-recapture were too infrequent for analysis, but were proportionally consistent with previous results showing corridor effects on movement. There were no significant differences in small mammal abundances between connected and unconnected patches. These results suggest that corridors do facilitate movement between habitat patches and prey will preferentially use corridors to forage in patches with reduced predation risk. However, the corridors in this study had no apparent affect on long-term displacement of small mammals.

Amphipods are found in large numbers from the top elevation at the Nature Institute (TNI) in Madison County, IL to lower areas of the stream that flow into the Mississippi River. Amphipod success depends greatly on their ability to survive dynamic streams with changing flow and physical conditions. It would be thought that by the end of spring rains, all aquatic organisms would be washed downstream. After observations of persistence of amphipods at the highest reaches of a small fishless stream that experiences relatively severe flooding, the present study sought to determine if a relationship existed between stream elevation and microhabitat type with respect to amphipod abundance. Do certain microhabitats serve as systematically better refuges in flooding streams? This study also sought to determine if there was a relationship between amphipod size and stream elevation. Do larger or smaller amphipods persists better at different stream elevations? Two surveys were conducted in July 2015 with sampling at 8 different elevation zones which included 5 microhabitats. One survey was conducted in August 2015 at 10 different elevation zones (8 of which were repeat areas from July), with samples taken from various elevations along the stream from 5 microhabitats. A total of 2,616 amphipods (Gammarus pseudolimnaeus) were collected over the two-month time period, collected, counted and body length measured. Results did not show a relationship between amphipod body length and stream elevation, nor was there a relationship between amphipod abundance and stream elevation.

Frogs exhibit a range of locomotor behaviors, which can be broadly grouped based upon limb movement patterns. Asynchronous behaviors are those that involve alternating limb movements and include crawling, climbing, burrowing, and asynchronous (trot) swimming. Synchronous behaviors are those that involve simultaneous limb movements and include jumping, lunge feeding, and synchronous (frog-kick) swimming. The degree of handedness (preferential limb use) in motor responses is thought to reflect functional lateralization of the brain, an indicator of neural complexity. Handedness has been examined across a range of anuran taxa and has been hypothesized to be related to a species’ preferred locomotor mode, with greater handedness predicted in species that make more extensive use of asynchronous locomotion. In contrast, it has been hypothesized that anuran handedness varies phylogenetically, with ambidexterity being the ancestral condition and handedness being derived. To date, research in this area has focused primarily on derived taxa and relatively little is known about basal taxa. The basal-most anuran family Leiopelmatidae is the sister group to all other frogs (Lalagobatrachia), and represents an excellent test of these competing hypotheses. Moreover, leiopelmatids rely exclusively on asynchronous swimming and likely exceed all other anuran taxa in their reliance on alternating limb movements during locomotion. We tested these competing hypotheses by examining handedness in two behaviors, righting response and trot-swimming, in the leiopelmatid Rocky Mountain Tailed Frog, Ascaphus montanus. Tailed Frogs showed no evidence of handedness despite the prevalence of asynchronous locomotion in their behavioral repertoire. The absence of handedness in a highly asynchronous basal anuran taxon, suggests that this phenomenon was not characteristic of the earliest frogs, but rather appeared later in the evolutionary history of the group.

Bibliography : pages 178-202.
Combined laboratory and field studies were employed to examine the feeding ecology of sardine Sardinops sagax in order to evaluate conflicting hypotheses regarding the trophic position of clupeoids in upwelling ecosystems, and to compare the trophodynamics of sardine with those of the co-occurring anchovy Engraulis capensis. Carbon and nitrogen budget models constructed using data from these studies were used to quantify the effect of particular food environments upon sardine growth. Sardinops sagax is primarily a filter-feeder, with food particles <1230μm total length eliciting a filtering response while larger particles elicit particulate-feeding at low concentrations and filter-feeding at high concentrations. This species is able to retain cells as small as 13μm, feeds at near-maximum efficiency when filterfeeding, and displays size-selectivity during particulate-feeding. Significant linear relationships between respiration rate and swimming speed obtained for sardine demonstrate that filter-feeding is the most energetically cheap feeding mode. Although omnivorous, sardine absorbs carbon and nitrogen more efficiently from zooplankton than from phytoplankton. Gastric evacuation follows an exponential pattern in sardine, and is influenced by food type; phytoplankton is evacuated faster than zooplankton. Feeding periodicity in sardine is size dependent; small fish show a feeding peak at, or around, sunset whereas larger fish appear to feed continuously. Estimates of daily ration range between 0.99 to 7.58% wet body mass.d-¹, depending on fish size and food type. Sardine stomach contents are numerically dominated by small particles, principally dinoflagellate phytoplankton, but the majority of the sardine's dietary carbon is derived from zooplankton, principally small calanoid and cyclopoid copepods. The budget models indicate that sardine is capable of positive growth under most of the trophic conditions it is likely to encounter in the southern Benguela upwelling system. The classical hypothesis that the high abundance of clupeoids in upwelling ecosystems results from their phytophagy is rejected; like anchovy, sardine are primarily zoophagous. However, these two species are trophodynamically distinct and show resource partitioning on the basis of prey size; sardine consume small zooplankton whilst anchovy consume large zooplankton. This difference is likely to contribute to regime shifts observed between these two species.

The prickleback family Stichaeidae, as currently recognized, is a diverse group of small (<30 cm TL) eel- or blenny-like marine fishes distributed in intertidal, subtidal, and continental slope waters of the North Pacific, Arctic, and North Atlantic oceans. Stichaeidae is one of nine families within the Cottiformes suborder Zoarcoidei and includes six subfamilies, 38 genera, and about 80 species. However, there are questions regarding the monophyly of the family and its position within Zoarcoidei, due in part to a lack of fundamental descriptive anatomical data for the family. The first chapter of my dissertation describes the osteology of Xiphister, a genus of Stichaeidae that includes two species, X. atropurpureus and X. mucosus, found in intertidal and subtidal waters from southern Alaska to southern California. I describe and illustrate their skeletal anatomy, clarify aspects of their anatomy discussed by previous researchers, and describe for the first time elements such as the hyoid and gill arches, scales, and the development of their lateral line canals. These data establish a foundation for the further anatomical and systematic studies of Stichaeidae, and Zoarcoidei generally. Some members of Stichaeidae, including both species of Xiphister , have multiple lateral line canals on their trunk, which is a feature found in only 15 families of teleostean fishes. In the second chapter of my dissertation, the structure and ontogeny of lateral line canals of both species of Xiphister were studied using cleared & stained specimens and histology. Both species have seven cephalic canals and three paired canals on the trunk located on the dorsolateral, mediolateral, and ventrolateral body surfaces. The ventrolateral canal also includes a short loop across the ventral surface of the abdomen. The trunk canals and four short branches of the infraorbitals that extend across the cheek are supported by small ossified rings. The trunk canals develop asynchronously and separately from the development of scales, suggesting that the ossified rings that support the canals are not modified scales. Results from histology show that neuromasts, the sensory components of the mechanosensory system, are found only in the cephalic, dorsolateral, and mediolateral canals; the ventrolateral canal and its loop lack neuromasts. The evolution and functional role of multiple trunk lateral line canals is discussed. The third chapter of my dissertation examines the phylogenetic systematics of Stichaeidae using 106 morphological characters and 60 terminal taxa, including 30 genera of Stichaeidae, representatives from all eight other families of Zoarcoidei, and additional outgroup taxa. The suborder Zoarcoidei was recovered as a monophyletic group sister to Cottoidei within the order Cottiformes. Within Zoarcoidei, however, the family Stichaeidae was not recovered as a monophyletic family. Only two of the six subfamilies within Stichaeidae, Lumpeninae and Neozoarcinae, were recovered as monophyletic. The high level of homoplasy in the remaining four stichaeid subfamilies, and the inclusion of zoarcoid families nested within Stichaeidae, suggests that the current classification of Stichaeidae does not accurately reflect the evolutionary history of Zoarcoidei.

Includes abstract.
Includes bibliographical references (p. 146-168).
This study investigates whether anthropogenic changes in the Cape Peninsula, South Africa, have affected gastrointestinal parasite infections in a free-living population of chacma baboons (Papio ursinus). Data on parasite diversity and prevalence were obtained from 616 faecal samples collected from over 350 individuals in eight troops (six from the Cape Peninsula, one from Pringle Bay, and one from Wildcliff Nature Reserve) between July 2006 and August 2007.

Includes bibliography.
This study investigated the potential usefulness of aerial seabirds as indicators of the distribution of peculiar oceanic biotopes and prey populations in the African sector of the Southern ocean. The hypothesis examined was that the distribution and abundance of seabirds are non-random and predictable with respect to the availability of prey at the sea-surface. The distribution of seabirds was correlated with prey density, in cases where the appropriate information was available. More often than not, however, data on prey distributions were unavailable, so that seabird distribution was correlated with the abiotic indicators of hydrodynamic processes which order the distribution of potential prey. The distribution of seabirds was determined by means of shipboard observations. The trophic structure of seabird assemblages was assessed according to the diversity, biomass and abundance of 35 seabird species according to four principal diet-classes. The ecological structure of seabird populations was defined in terms of relationships between the trophic structure of seabird assemblages and Southern Ocean oceanography, meteorology and biogeography. The predictability of seabird distribution and abundance with respect to environmental variation was assessed using linear and nonlinear regression procedures. A deterministic model was developed in which analytical techniques are standardized and which can be applied to other ocean areas. There are predictable associations between the trophic structure of seabird assemblages and the structure of the surface of the sea. Assemblages of putative prey feature squid and fish in low latitudes, and plankton predominate in higher latitudes. The ecological structure of seabird populations reflects this trend on a macro-scale level. On a meso-scale level, the abundance of seabirds by diet-class correlates with the relative abundance of putative prey. Moreover, seabird abundance and biomass correlate positively with abiotic indicators of frontal zones and sea-surface mixing, where prey diversity and abundance are greatest. Regressions of seabird abundance with sea-surface temperature explain important aspects of the variation in the ecological structure of selected seabird populations. This study showed that it may be possible to track the distribution of prey stocks through concurrent observations of seabirds and hydrography. Consequently, the descriptive model developed in this study contributes towards the objective of circumventing the need for direct sampling of prey stocks. The predictability of seabird distribution and abundance previously obtained has been surpassed by the results of this study through progressive reduction of the spatio-temporal scale of data collection and analysis, and by treating biotic-abiotic relationships with non-linear regression models where appropriate. The study concludes that sufficient advances have been made to justify further research into the use of selected species of aerial seabirds as indicators of prey distribution and abundance at sea.

Bibliography: leaves [148]-164.
This field study set out to identify the key ecological factors influencing the population dynamics of the Namaqua Sandgrouse Pterocles namaqua, through an investigation of diet and the nutritional demands during different stages of the annual cycle, the timing of breeding seasons and movements in relation to patterns of rainfall-dependent food availability, breeding success and the factors limiting productivity. In addition, the nesting habits and success of 11 coexisting arid-zone bird species were examined to test a variety of hypotheses regarding the relationship between nest-predation rate and nest site, nest density, predator-avoidance behaviour, stage of the nesting cycle and season, and degree of residency. Furthermore, the importance of rainfall as a breeding stimulus and its effects on clutch size were investigated for several species. The Namaqua Sandgrouse is an obligate granivore at all times, feeding on the seeds of annual plants, primarily of the family Fabaceae. Even while breeding, energy is the first-limiting nutrient in the foods of adults. Growing chicks have a proportionally greater protein demand, and are more dependent than adults on protein-rich legume seeds to satisfy first-limiting amino acid requirements. The chick growth phase was identified as the most nutritionally demanding stage in the annual cycle. The breeding season was found to be unexpectedly variable, and not consistently correlated with periods of peak food availability.

Includes bibliographical references.
In the past decade African penguin (Spheniscus demersus) populations have experienced declining population sizes of > 60% in some instances. This has primarily been attributed to shifting prey availability and competition with regional purse-seine fisheries; however, possible novel threats exacerbated by diminishing population sizes and increased stress, may also be important contributors to the regional persistence of the species. These threats include the impacts of arthropod-borne blood parasites on the health of penguin populations. While parasitism of wild penguins has been poorly studied, susceptibility to infection with blood protozoa is well established in a wide range of penguin species held in captivity. This thesis assesses the prevalence of blood parasites in wild African penguins throughout the greater Agulhas-Benguela ecosystem. Using PCR-based techniques, 317 individuals were screened for the presence of known haemoparasite species of Plasmodium, Haemoproteus and Babesia across 12 breeding colonies. Babesia infection was confirmed for 60% of wild birds sampled, but methods used did not indicate infection with either Haemoproteus or Plasmodium species. Generalised linear modelling of ecological and life history parameters suggests that Babesia prevalence is primarily driven by a colony’s distance from the mainland, decreasing significantly as distance from the mainland increases. Captive birds held at the SANCOBB rehabilitation facility in Cape Town present with both Plasmodium and Babesia species, providing the positive controls for the study. The relative scarcity of Plasmodium and Haemoproteus infection in the wild may be the result of an absence of suitable vectors and/or high post mortality in the host. Alternatively, the sensitivity of the method used requires further investigation as Plasmodium infection has been confirmed previously in penguin populations using PCR-based approaches. This study provides the first baseline estimate of blood parasitism in African penguins across their breeding range, and raises the need for further research and monitoring. The results suggest that high Babesia prevalence in African penguins may be related to (1) an ecological system of chronicexposure to infection reservoirs, such as the co-occurring cormorant and gannet populations and (2) increasing anthropogenic impacts, especially in mainland colonies. Data on blood parasitism in co-occurring seabird species is required to fully elucidate their role in Babesia infection dynamics in the region. To improve understanding and facilitate timely detection of changes in blood parasite exposure, standardised methodologies are advocated to better inform the conservation management of this iconic species.

Bibliography: p. 436-482.
Eight new species of digenea were found in a survey of Aulacomya ater, Choromytilus meridiana/is, Perna perna and Mytilus galloprovincialis. Metacercaria notobucephala sp. nov., a bucephalid from Choromytilus has locality-specific prevalences ranging from 0.23% to 4.46%. It is a severe reproductive stress and reduces the sperm count by a factor of 1000. Metacercaria notobucephala also causes Choromytilus to lose ninhydrin positive substances. The gymnophallid Metacercaria perchorupis sp. nov. occurs in 90.7% to 100% of Choroinytilus and in 74.83% of Perna. Metacercaria A sp. nov., a renicolid, occurs in 78.86'yo to 90.33% of Choromytilus and 44.74% of Perna. Metacercaria B sp. nov., a lepocreadid, infects from 18.3% to 43.17% of Choromytilus and 3.51% of Perna. The combined effect of these three digenea causes 10% of the variation in emersion survival time of male Choromytilus (P = 0.02). Longer surviving mussels had fewer cysts; this suggests that these parasites constitute a somatic stress. Metacercaria columbinesis sp. nov., a zoogonid, was found in 28.6% of Mytilus. The fellodistomid Metacercaria maculatopsis sp. nov. occurred in 0.4% of Choromytilus. The gymnophallid, Metacercaria ater sp. nov. was found in 0.125% of Aulacomya. A rapid technique of semi-permanent staining and fixing with acetic orcein was developed to aid the description of these worms. Juvenile pycnogonids, Nymphonella sp., were found in 0.15% to 7.5%. ofChoromytilus. Nemerteans, nematodes, copepods, polychaetes and other minor symbionts are quantified in these mussels. Mastigocoleus sp., a shell boring cyanophyte, colonises Mytilus with prevalences from 1% to 94% and can reduce shell strength by 43%. The relationship between stress (amount of alga on the shell) and strain (degree of damage) is demonstrated: 61.8% of variation in damage is attributable to the extent of infection (P = 0.001). Stress is defined as an agent that reduces the fitness of the organism. The degree of reduction is termed strain. Fitness is an ontological statement about the organism. Schemes are proposed for rendering these concepts operational. Individual and ecosystem concepts of stress are not homologous and therefore cannot be substantively integrated. In contrast, psychological and physiological stress are deemed integrable: a scheme for this is proposed. Physical (salinity), chemical (ammonia & phenol) and biological agents (scavenging whelks) are shown to be substantively integrable as stresses since they all inhibit shell gaping and byssus production. Mussels demonstrate clear and appropriate closure responses when in the presence of salinity, ammonia levels and Burnupena: all agents that are likely to be of historical selective significance. In contrast, phenol, an unfamiliar agent, elicits an inconsistent response. It is hypothesised that this difference may help distinguish natural stresses from synthetic pollutants. As predicted, the valve opening dynamics of heat stressed mussels were qualitatively and invariably different from those of non-lethal voluntary movements. Dying dynamics have increasing velocity; voluntary dynamics show maximum velocity initially. Analysis of stimuli effects, often interpreted as eustresses, show that assays covering distal as well as proximal effects and those that tend towards whole body integrations are more likely to detect the agent as deleterious. Thus any notion of positive deflections or eustress must be treated with great caution and subject to longer term tests and with more complete integrations if it is to be accepted.

Bibliography: p. 147-160.
Protective gillnets (shark nets) have been successful in reducing the frequency of shark attacks on the coast of KwaZulu-Natal (KZN), South Africa. This is achieved primarily through a reduction in numbers of large sharks. The nets also take a by-catch of dolphins, sea turtles, batoids and teleosts.Catch rates of most shark species declined initially but have shown no trend since the mid-1970s. Turtle and teleost stocks do not appear to be threatened by net mortalities, but there is concern about the sustainability of catches of the humpback dolphin. Certain batoids may have declined despite a high release rate. A published contention that shark netting has resulted in a proliferation of small sharks through reduced predation is re-examined and considered to be exaggerated. Reduced predation on dolphins, as a result of shark netting, is estimated. Considerably less fishing effort is applied in the shark control programs of New South Wales and Queensland, Australia, than in that of KZN. On the basis of a comparison of factors such as the nearshore physical environments and trends in shark catch and catch rate, it is concluded that the number of nets used in KZN could be reduced. To test whether a 70 cm mesh would continue to capture potentially dangerous sharks, while at the same time reducing by-catch, a gamma distribution model was used to determine length-specific selectivities in 50.8 cm and 70 cm mesh nets respectively. A reduction in relative selectivity from 81 to 25 for a shark of 1.6 m PCL would result from an increase in mesh size from 50.8 to 70 cm. Despite a probable reduction in catch of dolphins .and certain other by-catch species, the introduction of the larger mesh would constitute an unacceptable reduction in levels of bather safety. Baited lines, or drumlines, were tested as possible alternatives to gillnets. They demonstrated greater species selectivity for sharks, including a higher catch of two of the target species, Carcharhinus leucas and Galeocerdo cuvier, and also a reduced by-catch of nonshark animals. The probability of the bait being scavenged, or a shark being caught, was modelled in relation to a number of physical factors. Although there were insufficient data for a quantitative comparison of catch rates between nets and drumlines, the results indicated that an optimal solution may be to deploy a combination of nets, using the existing 50.8 cm mesh, and drumlines, using 14/0 shark hooks.

Includes bibliographical references.
The Diep River estuary is a small, urban estuary situated in the suburbs of Cape Town and has been subjected to long-term modifications and abuse that far exceeds that of most other estuaries around South Africa. Activities in the Diep River catchment, together with the intensive urban development in the areas adjacent to the estuary, have resulted in massive changes in biodiversity, altered flow and salinity regimes; causing a marked deterioration in water quality and a frightening increase in non-indigenous species introductions. Several studies have been undertaken at the Diep River estuary, however, they are out-dated and many changes have occurred within the last few decades. The aim of this study was to provide an up-to-date list of the fauna residing within the Diep River estuary, as well as to provide a synthesis of all the major physical, hydrological and faunistic changes that have occurred within and around the estuary, dating back to the late 1800s, whereas faunistic changes are described using information provided by several earlier surveys dating back to the early 1950s. Infauna, epifauna and salinity were taken at designated stations along Milnerton Lagoon. Prawn (Callichirus kraussi) counts were also made in order to determine current abundance and distribution. Results showed a substantial decline in sand prawn abundance with the estimated standing stock calculated at just over 12 million. Fauna collected were generally poor in abundance and were mainly limited to euryhaline, detritus feeders. Earlier surveys conducted in the 1950s recorded at least 49 infauna and epifauna species residing within Milnerton Lagoon, whereas in 1974, only 23 species were found. Similarly, 24 species were recorded in this study. The European shore hopper (Orchestiagammarella) was recorded as a new introduction within the system. Only five fish species were recorded in the summer period, including the highly invasive mosquito fish (Gambusiaaffinis), which was found in relatively high abundance within the lagoon. A regular monitoring of the infauna and epifauna populations for this system needs to be established, in order to obtain a clear picture of the faunistic distribution and changes occurring within this highly dynamic environment. Additionally, serious management protocols need to be established in order to prevent the further degradation of this important system.

Although scallops have a high economic value, they have yet to be commercially harvested or farmed in South Africa. Of the 29 Pectinid species recorded on the southern African coastline, Pecten sulcicostatus is the only species considered suitable for aquaculture, due to its large size. An investigation of the suitability of P. sulcicostatus for farming in South Africa forms the basis of this study. The successful cultivation of P. sulcicostatus will depend on successful rearing from fertilized egg to market size, and achieving a growth rate comparable to that of other commercial scallop species. This study aimed to examine the reproductive life cycle, in order to establish whether this species can be artificially conditioned to produce ripe gametes throughout the year and to investigate the various stages of cultivation, in order to determine whether this species is viable for farming. This thesis therefore describes the reproductive cycle of P. sulcicostatus and also reports on the first assessment of broodstock conditioning, larval rearing and the grow-out of spat. The reproductive study was undertaken by monthly collection of scallops in their natural habitat in False Bay from August 2004 - October 2005 and again from August 2010 - August 2011. The reproductive cycle was assessed by means of both gonadosomatic index (GSI) and qualitative and quantitative histological investigation. Environmental parameters were also monitored to determine any linkage to the reproductive cycle. The reproductive cycle was seasonal, with a peak spawning period in winter. A resting period appeared absent, as individuals started producing new gametes immediately after spawning, indicating a possible lack of synchronicity.

The southern African echiuran fauna currently comprises two families, four genera and eighteen species. The taxonomic positions of three other species, one of Ochetostoma and two of Thalassema, remain to be resolved. Of the recorded species, three are new to science and a further five are new records for the southern African region. This survey reveals that there are ten species of Ochetostoma, four of Thalassema and three of Anelassorhynchus. The family Echiuridae contains a single genus, Echiurus and in southern Africa, E. antarcticus is the only species recorded to date. Full descriptions of the new species and those formerly inadequately described are given. The diagnoses of some others are modified and, where necessary, additional notes added. Keys for the identification of families, genera and species are provided and the taxonomic characters are evaluated and discussed. The zoogeographic distribution of the southern African species is mapped and an attempt has been made to analyse the recorded species on the basis of faunistic provinces. The phylogenetic position of the Echiura in the system of the animal kingdom is discussed. The lack of any form of segmentation of the mesodermal bands during embryonic developnent seems to justify their status as a separate phylum. The biomechanics of burrowing, locomotion and trunk irrigatory movements of Ochetostoma caudex are described and compared with the activities of some other animals with unsegmented coelomic cavities. Pressure changes within the coelom have been measured with the use of electronic recording techniques and the results interpreted in relation to direct visual observation. The anatomy of the reproductive system and the process of gametogenesis in O. caudex have been investigated with light and electron microscopes. Some observations on aspects of breeding behaviour and spawning are also included.

The history of the Department of Zoology & Entomology at Rhodes University is traced from its origin with a single staff member, through the era of permanent heads of department to the present day staff. Significant achievements and developments in teaching and research are highlighted, and some anecdotal material is included.

碩士
中國醫藥學院
中國藥學系
82
Tetraodonidae was first described in Kai-Pao Pen-Tsao at Sung Dynasty,and was used as analgestic,for antigoat,hemorrhoid andarasite.There were about 36 species of Monacanthidae iniwan, all of these species were almost toxic fish. Intraperitoneal administration of TTX(Tetrodotoxin)(1-7ug/kg) produced dose- dependent decrease in colonic temperature inats. Daily injection of TTX(5 ug/kg,i.p.) for 4 days,it did not attenuated the TTX-induced hypothermia.TTX also decreased theyperthermia produced by LPS(lipopolysaccharide) for 60 mins. Direct administration of small amount(0.003 ug/ul or 0.005 ug/ul) of TTX into the rat''s hypothalamus also producedame amount of hypothermia. The TTX-induced hypothermia was not affected by depletion ofrain serotonin produced by 5,7-DHT(5,7- dihydroxytryptamine) orCPA(p-chloro-phenylalanine) and 6-OHDA(6- hydroxydopamine). The TTX-induced hypothermia was due to decreased metabolismnd increased heat loss( or skin vasodilation). In vivo voltammetrical measurement also revealed that TTXdministration enhanced the 5-HT and dopamine release in thepothalamus of rat brain. These results suggest that TTX may act through theonoaminergic mechanism in the brain to influence the effect ofpothermia.