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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Comparative Morphology of Sensilla Styloconica on the Proboscis of North American Nymphalidae and Other Selected Taxa: Systematic and Ecological Considerations.

Petr, Daniel 12 1900 (has links)
Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to be meaningfully robust due to few available characters. The stylar characters identified in this study should be more useful in future analyses when included with characters from other lines of evidence. The presence of sensilla styloconica in all subfamilies of Nymphalidae, except Danainae, largely supports Ehrlich's (1958) higher classification concept for the family. The presence of less conspicuous sensilla in the Danainae, and other characteristics are presented as further evidence that they should be reconsidered for full family status. Sensilla styloconica in nymphalid butterflies appear to function as extensions that provide greater sensory reach during feeding. The role of these sensilla in liquid uptake, pollen feeding, and host plant selection is discussed.
42

Hong Kong butterfly conservation

Chan, Ching-han, 陳靜嫻 January 2004 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
43

The use of molecular genetics in the formulation of conservation strategies for Lepidoptera

Joyce, Domino Ann January 2001 (has links)
The broad aim of this research, funded by English Nature, was to use genetic techniques to inform conservation strategies and contribute to species action plans for selected Lepidoptera. The three species chosen for the study were the marsh fritillary (Euphydryas aurinia), the high brown fritillary (Argynnis adippe) and the chequered skipper (Carterocephalus palaemon). Allozymes and mitochondrial DNA were used to answer individual questions applicable to each species. All three species seem to have colonised the UK after the last ice-age in one event. Most work took place on E. aurinia forming national and local scale research. Genetic differentiation between populations was fairly high, but it may be that a metapopulation structure ensures local population sizes remain large enough to delay the signs of drift. A. adippe was sampled from two populations; this extremely rare butterfly seems to have lost some genetic diversity, but further samples are required before firm conclusions can be drawn. C. palaemon is being reintroduced into England, and identification of the most genetically appropriate source for a donor population was required, using museum specimens to type the extinct English population. The species seems to have colonised the UK in one post-glacial event, and from a genetic point of view, both northern European and Scotland contain appropriate donor populations. Finally, the ways in which genetics can complement ecological work to aid conservation are discussed.
44

Management effects on butterfly and bumblebee abundance in Swedish semi-natural grasslands

Dahl, Kristoffer January 2015 (has links)
The amount of semi-natural grasslands has decreased in the agricultural landscape and because of this many grassland species are declining. Semi-natural grasslands are dependent on management, but different studies suggest that different management methods are most favorable to species richness and abundance. The aim of this study was to compare the effects of mowing and grazing on butterfly and bumblebee abundance in Swedish semi-natural grasslands. We used data collected through the Swedish environmental monitoring program NILS. We identified 31 comparable meadows and chose 1-10 pastures in the area surrounding each meadow. For six different species groups we calculated the number of individuals found per 100 m. By standardizing the values of the difference between the means for meadows and pastures we were able to compare the effects of the two methods on abundance in each species group. No species group showed a preference for pastures. A significant preference for meadows was found for two butterfly species groups. The four other groups showed a trend to prefer meadows before pastures. According to our study the recommended management method should be mowing, considering protection of butterflies and bumblebees.
45

Responses of grassland birds and butterflies to control of sericea lespedeza with fire and grazing

Ogden, Sarah B. January 1900 (has links)
Master of Science / Division of Biology / David A. Haukos / Sericea lespedeza (Lespedeza cuneata) is an invasive forb that reduces native grass and forb abundance in tall-grass prairie by up to 92%. Controlling invasions is difficult because traditional land management tools used in the Flint Hills, broad spectrum herbicides, spring prescribed fire, and cattle grazing, are ineffective against sericea. Recent research has demonstrated, however, that mid- and late summer prescribed fire and spring fire with early season grazing by steers followed by late season grazing by sheep are effective at reducing sericea whole plant mass, number of seeds produced, and seed mass. Field results were from two separate experiments conducted in tall-grass prairie study sites in the Flint Hills. On a Geary County, Kansas, study site, the utility of 1) spring fire (control), 2) mid-summer fire, and 3) late summer fire on sericea control were compared. On a Woodson County, Kansas, study site, the utility of 1) spring fire with early season steer grazing followed by rest (control) and 2) spring fire with early season steer grazing and late season sheep grazing on sericea control were compared. At the same study sites, I measured responses by the native wildlife community to use of summer fire and sheep grazing, relative to their controls, to manage sericea lespedeza. Specifically, my objectives were to compare grassland songbird density, grassland songbird nest survival, and grassland butterfly species composition and density among treatments at both study sites. I also related patterns in the vegetation community of each treatment for each study site to respective patterns in grassland bird and butterfly communities. Within study sites, density, nest density, and nest success of grassland bird communities responded similarly to treatments and controls, with the exception that densities of Grasshopper Sparrows (Ammodramus savanarrum) were 3.4- and 2.2-fold greater in mid- and late summer fire plots than spring fire plots, respectively, in the Geary County study site. Species compositions of butterfly communities were similar across treatments within experiments, but grassland specialist species comprised only 8.6 and 1.2% of all butterfly observations in the Geary County and Woodson County experiments, respectively. Grassland specialist butterfly species may benefit from summer fire, as their nectar sources were more abundant in Summer Fire plots than Spring Fire plots. Overall, within each experiment, grassland bird and butterfly communities were similar across treatments, suggesting that treatments did not negatively affect grassland songbird and butterfly communities. I additionally demonstrated that Dickcissel (Spiza americana) nest sites contain a lower proportion of sericea than random points, the first evidence that the invasion is detrimental to grassland songbird species. Lacking control, the continued sericea invasion will out compete cumulatively more forb plants resulting in declining quality of grassland bird nesting habitat on the landscape. Controlling sericea lespedeza invasions will allow native forb species to increase in abundance and improve the condition of grasslands for native wildlife and livestock producers. Therefore, I advocate use of summer fire or spring fire with a combination of cattle and sheep grazing to control sericea lespedeza with the long-term goal of tall-grass prairie restoration.
46

Studies on the histopathological effects of bacillus thuringiensis and nosema polyvora on the malpighian tubules of pieris canidia larva.

January 1993 (has links)
Wang Jian Bin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 117-131). / ACKNOWLEDGEMENTS --- p.ii / ABSTRACT --- p.x / Chapter PART I. --- GENERAL INTRODUCTION --- p.4 / Chapter PART II. --- LITERATURE REVIEW --- p.6 / Chapter A. --- The structure and functions of insect Malpighian tubules --- p.6 / Chapter I. --- The excretory system of insects --- p.6 / Chapter 1. --- Morphology of Malpighian tubules --- p.6 / Chapter 2. --- Common types of Malpighian tubule system --- p.7 / Chapter 3. --- Morphology of hindgut --- p.8 / Chapter II. --- Structure of insect Malpighian tubules --- p.9 / Chapter 1. --- General organization of the Malpighian tubules --- p.9 / Chapter 2. --- Structure of the principal cell --- p.10 / Chapter 3. --- The structure of other cell types --- p.14 / Chapter 4. --- The cryptonephridial systems in larvae of Lepidoptera and Coleoptera --- p.16 / Chapter III. --- Functions of insect Malpighian tubules --- p.18 / Chapter 1. --- Mechanism of fluid secretion by Malpighian tubules --- p.18 / Chapter 1.1. --- Ion transport --- p.18 / Chapter 1.2. --- Fluid transport --- p.19 / Chapter 2. --- Active transport of organic compounds by Malpighian tubules --- p.19 / Chapter 2.1. --- Organic anions --- p.19 / Chapter 2.2. --- Organic cations --- p.20 / Chapter 3. --- Resporptive processes in Malpighian tubules --- p.20 / Chapter 3.1. --- KC1 resorption --- p.20 / Chapter 3.2. --- Reabsorption of sugars --- p.21 / Chapter 4. --- The passive permeability of Malpighian tubules --- p.21 / Chapter B. --- The biology and mode of action of Bacillus thuringiensis --- p.23 / Chapter I. --- Introduction --- p.23 / Chapter II. --- Background --- p.23 / Chapter III. --- "Cytology of germination, outgrowth and sporulation" --- p.24 / Chapter IV. --- Bacillus thuringiensis and its toxins --- p.26 / Chapter V. --- Histopathological effects of Bacillus thuringiensis δ-endotoxin on Lepidopterous larva --- p.29 / Chapter VI. --- Mode of action of Bacillus thuringiensis δ-endotoxin --- p.32 / Chapter C. --- The biology and pathological effects of microsporidian protozoa --- p.36 / Chapter I. --- Life cycle of microsporidian protozoa --- p.36 / Chapter II. --- Germination of microsporidian protozoa --- p.37 / Chapter III. --- The fine structure of microsporidian protozoa --- p.38 / Chapter IV. --- Mass production and storage --- p.42 / Chapter V. --- Pathology of microsporidian protozoa --- p.44 / Chapter PART III. --- LIGHT AND ELECTRON MICROSCOPIC STUDIES OF THE MALPIGHIAN TUBULES OF PIERIS CANIDIA LARVA (LEPIDOPTERA) --- p.48 / Summary --- p.48 / Introduction --- p.48 / Materials and methods --- p.49 / Results --- p.50 / Discussion --- p.53 / Chapter PART IV. --- HISTOCHEMICAL STUDIES ON THE PIERIS CANIDIA LARVAL MALPIGHIAN TUBULES --- p.58 / Summary --- p.58 / Introduction --- p.59 / Materials and methods --- p.60 / Results --- p.52 / Discussion --- p.66 / Chapter PART V. --- SEPARATION AND PURIFICATION OF PARASPORAL CRYSTALS OF BACILLUS THURINGIENSIS VAR. KURSTAKI --- p.70 / Summary --- p.70 / Introduction --- p.70 / Materials and methods --- p.74 / Results --- p.77 / Discussion --- p.77 / Chapter PART VI. --- HISTOPATHOLOGICAL EFFECTS OF BACILLUS THURINGIENSIS VAR. KURSTAKI δ-ENDOTOXIN ON THE MALPIGHIAN TUBULES OF PIERIS CANIDIA LARVA --- p.79 / Summary --- p.79 / Introduction --- p.79 / Materials and methods --- p.81 / Results --- p.83 / Discussion --- p.86 / Chapter PART VII. --- THE FINE STRUCTURE OF A MICROSPORIDIAN NOSEMA POLYVORA FROM CABBAGE WHITE PIERIS CANIDIA --- p.92 / Summary --- p.92 / Introduction --- p.92 / Materials and methods --- p.94 / Results --- p.94 / Discussion --- p.97 / Chapter PART VIII. --- HISTOPATHOLOGICAL EFFECTS OF NOSEMA POLYVORA ON THE MALPIGHIAN TUBULES OF PIERIS CANIDIA LARVA --- p.103 / Summary --- p.103 / Introduction --- p.103 / Materials and methods --- p.105 / Results --- p.105 / Discussion --- p.107 / Chapter PART IX. --- GENERAL DISCUSSION --- p.111 / Chapter PART X. --- CONCLUSION AND SUMMARY --- p.115 / REFERENCES --- p.117 / FIGURES AND TABLES --- p.132
47

Mimetismo e reconhecimento específico em borboletas do sul do Brasil

Klein, André Luis January 2015 (has links)
O estudo de adaptações deve levar em conta que a forma das características dos organismos afeta os desempenhos de mais de uma função, sendo, portanto, modificada por mais de uma pressão seletiva. Estas diferentes demandas podem ser conflitantes, como no caso da seleção convergente para mimetismo contra a seleção divergente para o isolamento reprodutivo. As borboletas Heliconius utilizam o padrão de coloração de advertência das asas também para o reconhecimento de parceiros, o que acaba por gerar um conflito de sinais em potencial quando duas ou mais espécies simpátricas compartilham seu padrão. Neste trabalho, as cores das asas de três espécies de Heliconius e de alguns co-mímicos do Sul do Brasil são investigadas através de duas abordagens: uma físico-sensorial, a fim de se caracterizar as diferenças entre cores co-miméticas em termos de discriminabilidade por diferentes tipos de visão, incluindo borboletas e aves; e uma etológica experimental, avaliando a eficácia da coloração das asas como sinal de reconhecimento específico. Uma terceira abordagem procurou caracterizar e comparar a corte das três espécies de Heliconius a fim de se explorar mecanismos adicionais de reconhecimento específico e possíveis relações com a convergência mimética. As análises físico-sensoriais deram suporte à hipótese recente de diferenças crípticas nas cores como um possível sinal privado de comunicação para as Heliconius, mas os testes comportamentais contrariaram esta expectativa, revelando um alto grau de interferência reprodutiva entre co-mímicos, além de um grau moderado entre não mímicos. A análise comparada da corte sugeriu uma influência maior do mimetismo do que da filogenia sobre a semelhança entre padrões comportamentais. Propomos que esta relação se dê indiretamente através da convergência morfológica na forma das asas e no comportamento de voo entre co-mímicos. / The study of adaptation should take into account that the form of characteristics in organisms affects the performance of more than one function, and therefore are modified by more than one selective pressure. These various demands can be conflicting, as in the case of convergent selection for mimicry against divergent selection for reproductive isolation. The Heliconius butterflies use the advertising wing color pattern also for mate recognition, which ultimately generates a potential signal conflict when two or more sympatric species share its pattern. In this work, the wing colors of three species of Heliconius and some co-mimics from Southern Brazil are investigated through two approaches: a physical-sensory, in order to characterize the differences between co-mimetic colors in terms of discriminability by different types of view, including butterflies and birds; and an experimental ethological, evaluating the effectiveness of wing coloration as a specific recognition signal. A third approach aimed to characterize the courtship of the three species of Heliconius in order to explore additional mechanisms of specific recognition and possible relations with mimetic convergence. The physical-sensory analyzes supported the recent hypothesis of cryptic differences in color as a possible private communication signal for Heliconius, but behavioral tests contradicted this expectation, revealing a high degree of reproductive interference between co-mimics, and in addition a moderate degree between non-mimics. The comparative analysis of the courtship suggested a greater influence of mimicry than phylogeny on the similarities between behavioral patterns. We propose that this relationship happens indirectly through morphological convergence in the wings shape and flight behavior between co-mimics.
48

The use of butterflies for conservation evaluation in Hong Kong

Law, Wing-yin, Jennifer., 羅穎賢. January 1998 (has links)
published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy
49

A quantitative study of butterfly assemblages from different biotopes at the Langebaan Peninsula / Phillip Daniël Brummer.

Brummer, Phillip Daniël January 2009 (has links)
Lepidoptera (butterflies and moths) comprises a fairly well-studied invertebrate taxon. The body of knowledge that has been acquired, especially on butterflies, allows for more convincing assessments of the significance of species distributions, for example assessments of rarity and endemism. In spite of their taxonomically well-known status, little is known about the different ranges and limiting factors controlling habitat specificity amongst species at a local scale. Aiming at ensuring more efficient and inclusive conservation planning for new developments and for rehabilitation of disturbed areas this study focused on the identification of species specific and local scale (biotopic) microhabitat attractants. This was done by identifying and classifying locally occurring butterflies in the context of small scale habitat preferences on a spatial and temporal scale taking into account correlations in distributions of butterflies, plants and bio-physical gradients. Results were compared to previous studies to evaluate the use of recorded species as bio-indicators. The methodology entailed the use of twelve 250m fixed belt transects that were sampled in alternating directions across four sites within the West Coast National Park. Seven sampling sessions were set out during four sampling months mainly during the summer of the 2006/07 season. Sampling was conducted through visual observations while walking transects at a constant pace. Distributional variation between species was observed within a relatively small area with limited apparent variation in vegetation, topography and altitude. Pronounced temporal variation and correlation between butterfly species distribution and microhabitats were observed although this is strongly linked to the scale of the study in relation to the species studied. Factors that will affect the choice of microhabitat across time include amongst others: the prevailing sex ratio, temperature and the presence of invasive ants. The influence of plant distribution in predicting butterfly species distribution seemed to be less important. Myrmecophilous butterflies could probably play some role in bio-indication although much more work needs to be done to confirm this. The identification of stepping stone sites with optimum microhabitats during the environmental assessment phase in areas with endangered butterfly species should determine the face of the development and not the other way around. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.
50

A quantitative study of butterfly assemblages from different biotopes at the Langebaan Peninsula / Phillip Daniël Brummer.

Brummer, Phillip Daniël January 2009 (has links)
Lepidoptera (butterflies and moths) comprises a fairly well-studied invertebrate taxon. The body of knowledge that has been acquired, especially on butterflies, allows for more convincing assessments of the significance of species distributions, for example assessments of rarity and endemism. In spite of their taxonomically well-known status, little is known about the different ranges and limiting factors controlling habitat specificity amongst species at a local scale. Aiming at ensuring more efficient and inclusive conservation planning for new developments and for rehabilitation of disturbed areas this study focused on the identification of species specific and local scale (biotopic) microhabitat attractants. This was done by identifying and classifying locally occurring butterflies in the context of small scale habitat preferences on a spatial and temporal scale taking into account correlations in distributions of butterflies, plants and bio-physical gradients. Results were compared to previous studies to evaluate the use of recorded species as bio-indicators. The methodology entailed the use of twelve 250m fixed belt transects that were sampled in alternating directions across four sites within the West Coast National Park. Seven sampling sessions were set out during four sampling months mainly during the summer of the 2006/07 season. Sampling was conducted through visual observations while walking transects at a constant pace. Distributional variation between species was observed within a relatively small area with limited apparent variation in vegetation, topography and altitude. Pronounced temporal variation and correlation between butterfly species distribution and microhabitats were observed although this is strongly linked to the scale of the study in relation to the species studied. Factors that will affect the choice of microhabitat across time include amongst others: the prevailing sex ratio, temperature and the presence of invasive ants. The influence of plant distribution in predicting butterfly species distribution seemed to be less important. Myrmecophilous butterflies could probably play some role in bio-indication although much more work needs to be done to confirm this. The identification of stepping stone sites with optimum microhabitats during the environmental assessment phase in areas with endangered butterfly species should determine the face of the development and not the other way around. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.

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