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Brown, Lydia Marie, and Lydia Marie Brown. "Biology, Ecology, and Economics of Brown Stink Bug, Euschistus servus (Heteroptera: Pentatomidae), in Desert Cotton Agroecosystems." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/625340.
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Brown stink bug, Euschistus servus (Heteroptera: Pentatomidae), is a recently re-emerged pest of cotton in Arizona. It has been present in southwestern desert-grown cotton since at least the early 1900’s, but dropped from primary pest status in the latter half of the twentieth century. Farmers and pest managers did not perceive it as a primary or economic pest until 2011, when elevated numbers of brown stink bugs were reported in isolated valleys of Arizona and southeastern California. Reports increased and became more widespread in the following years. In response to increased abundance of brown stink bug and corresponding cotton boll injury, research was needed to provide information to cotton farmers. First, pest managers needed information on which factors affect the susceptibility of cotton bolls to stink bug feeding (chapter 1). Young bolls are most vulnerable to stink bug injury, and injury is sustained in the first four days of feeding. In addition, research was needed to determine the effects of currently available brown stink bug chemical controls on the broader integrated pest management system in Arizona cotton (chapter 2). Current chemical control options disrupt natural enemy communities, which results in outbreaks and resurgences of other cotton pests. The negative outcomes and additional costs outweigh the benefits of brown stink bug management.
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Manship, Brendan Anthony David. "The feeding ecology of deposit-feeding holothurians." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318807.
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Drazen, Jeffrey C. "Feeding ecology of Pacific macrourids /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035913.
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Batista, Michela Costa. "Feeding ecology of green lacewings." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/11859.
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Previous issue date: 2016-03-23<br>Fundação de Amparo à Pesquisa do Estado de Minas Gerais<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>Para que os inimigos naturais encontrem as plantas e se estabeleçam em uma área de cultivo para fornecer o serviço de controle biológico, eles precisam ser atraídos para o local, sobreviver, reproduzirem-se e serem capazes de predar as pragas presentes nesse cultivo. Geralmente, a atração de inimigos naturais está direta ou indiretamente ligada às necessidades alimentares. Uma vez atraídos para a área, as fontes de alimento no cultivo e arredores devem ser apropriadas para promover o crescimento e estabelecimento das populações desses inimigos naturais. Nosso objetivo foi entender aspectos chave da ecologia alimentar de crisopídeos, predadores generalistas encontrados naturalmente em agroecossistemas e comumente comercializados como agentes de controle biológico. No Capítulo I, avaliamos a atratividade de espécies de plantas aromáticas a Ceraeochrysa cubana Hagen, uma espécie de crisopídeo com ampla distribuição geográfica e que pode ser encontrada em diversos sistemas de cultivo. Adicionalmente, foram testados os efeitos dessas plantas aromáticas na sobrevivência e performance de larvas e adultos de C. cubana, a fim de elucidar a importância dessas plantas para o estabelecimento de populações de crisopídeos. Constatamos que plantas de Ocimum basilicum (manjericão) sem flores e não infestadas foram atrativas para C. cubana, e que as larvas podem sobreviver em O. basilicum por um período de tempo maior em comparação com as outras espécies de plantas aromáticas avaliadas. Adicionalmente, as flores de O. basilicum proporcionaram uma sobrevivência longa para larvas e adultos de C. cubana, em comparação com o controle negativo (água). Os resultados indicam que a utilização de O. basilicum como um componente de diversificação em áreas agrícolas pode ser benéfico para a atração e manutenção de populações de C. cubana para favorecer o controle biológico. No Capítulo II, foi estudada a amplitude de dieta de Chrysoperla rufilabris Burmeister, uma espécie de crisopídeo comumente usada e comercializada como agente de controle biológico, com 16 espécies de afideos, avaliando-se a qualidade dessas espécies para a sobrevivência e o fitness desse predador generalista. Os resultados mostraram que C rufilabris se alimentou de todas as espécies de afideo oferecidas. No entanto, esse crisopídeo se desenvolveu e produziu ovos apenas quando alimentado por sete das 16 espécies avaliadas, estando a maioria destas espécies agrupadas em um mesmo ramo filogenético. Também foi encontrado um forte sinal filogenético para a sobrevivência, consumo de afídeos e produção de ovos de C. ruleabris, indicando que a maioria das espécies apropriadas a C. ruleabris são filogeneticamente próximas, o que demonstra que essa espécie de crisopídeo é menos generalista do que se havia suposto. Assim, C. ruleabris pode não se beneficiar de uma grande amplitude de presas e isso deve ser levado em consideração no planejamento de estratégias de controle biológico que visem utilizar esse crisopídeo. Conclui-se que o conhecimento sobre a ecologia alimentar de agentes de controle biológico é essencial antes da escolha das espécies a serem liberadas ou atraídas e mantidas em uma área cultivada. Nesse sentido, O. basilicum é uma espécie de planta aromática promissora para atrair e manter populações de crisopídeos no campo. Além da atratividade, é importante considerar a filogenia das presas em estudos de amplitude de dieta de predadores generalistas a fim de se obter melhores resultados em programas de controle biológico.<br>Biological control is a pest management strategy that relies on the action of natural enemies to control the populations of herbivores, minimizing their damage on cultivated areas. For natural enemies to find and establish in a cropping area to provide biological control services they need to be attracted to the area, survive, reproduce, and be capable of preying on the pests present in the crop. Usually, natural enemy attraction is direct or indirectly linked with feeding needs. Once attracted to the area, the food resources in the crop and surroundings must be suitable to promote population growth and establishment of natural enemies populations. Therefore, the aim of this thesis was to understand key aspects of the feeding ecology of green lacewings, generalist predators naturally found in agroecosystems and commonly commercialized as biological control agents. On Chapter I, we assessed the attractiveness of aromatic plant species to Ceraeochrysa cabana Hagen, a lacewing species with a broad geographical range that can be found in several cropping systems. Additionally, we tested the effects of those aromatic plants on survival and performance of larvae and adults of C. cabana, in order to elucidate the importance of such plant species to the establishment of green lacewing populations. We found that non-flowering and uninfested Ocimam basilicam (basil) plants were attractive to C. cabana, and that larvae could survive for a longer period of time in O. basilicam leaves compared to the other aromatic plant species tested. Additionally, O. basilicam flowers promoted a long survival for larvae and adults of C. cabana, compared to the negative control (water). Results indicate that using O. basilicam as a diversification component in cultivated areas may be beneficial to attract and maintain C. cabana populations to support biological control. On chapter II, we studied the diet breadth of Chrysoperla rafilabris Burmeister, a green lacewing commonly used and commercialized as a biological control agent, over 16 aphid species, assessing the quality of those species on survival and fitness of this generalist predator. Results demonstrated that C. rafilabris preyed over all the aphid species, but could develop and produce eggs only in seven species, most of them from the same cluster in a phylogenetic tree. We also found a strong phylogenetic signal for survival, aphid consumption and egg load of C. rafilabris, indicating that most of the species more suitable to C. rufilabris were closely related, which demonstrate that this green lacewing species is less generalist than it was supposed. Thus, C. rufilabris may not benefit from a broad prey range and that has to be taken into consideration when planning biological control strategies using this green lacewing species. In conclusion, knowledge on the feeding ecology of biological control agents is essential before choosing the species to be released or that to be attracted to and to maintain in the cropping system. In this sense, O. basilicum is a promising aromatic plant species to attract and maintain lacewing populations in the field. Additionally to attractiveness, it is important to consider prey phylogeny in the study of generalist predators diet breadth in order to have better results in biological control programs.
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Gökce, M. A. "Reproductive biology and feeding ecology of gurnards." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637060.
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Tub (<I>Trigla lucerna</I>), Red (<I>Aspitrigla cuculus</I>) and Grey (<I>Eutrigla gurnardus</I>) gurnards exhibit a distinct reproductive cycle. The spawning periods of Tub, Red and Grey gurnard occur from March to July, February to August and February to July respectively. The spawning periods of all three species commence at a minimum sea temperature (approximately 8°C) with the onset of increasing daylength and cease with the onset of decreasing daylength. A highly significant correlation was found between absolute fecundity and total weight of all three species. The relative fecundities of the three species are similar, 234-414 per g body weight for Tub, 271-377 per g body weight for Red and 306-551 per g body weight for Grey gurnard. The ovaries of Tub, Red and Grey gurnard can be characterised as asynchronous ovaries. Histological and ultrastructural studies reveal that these three species have similar oocyte development patterns. There was no hiatus or gap observed in the recruitment of oocytes from the PGP into the SGP or between the different oocyte developmental stages. Two types of yolk inclusions are formed: Lipid vesicles which appear in the mid and outer cortex indicate the initiation of the SGP and later migrate to the inner cortex and coalesce into a single lipid mass and protein yolk granules which initially form as small granules in the outer cortex of the cytoplasm. On maturation they fuse into large granules packing the cortical cytoplasm. In all three species Crustaceans and Teleosts are the preferred prey. Red gurnard had the broadest diet, Grey gurnard had the narrowest. The lowest diet overlap was observed between Grey and Red and the highest between Grey and Tub gurnards. This considerable diet overlap occurring between Grey and Tub gurnard may lead to interspecific competition for food.
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Murphy, David. "The feeding ecology of bellbirds at Craigieburn." Thesis, University of Canterbury. Zoology, 1998. http://hdl.handle.net/10092/6975.
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This thesis investigated the feeding ecology of bell birds, Anthornis melanura (Aves: Meliphagidae), at Craigieburn Forest Park to find out what, if any, aspect of the bellbirds' ecology may be limiting the pollination and possibly dispersal of two mistletoe species (peraxilla tetrapetala and Alepis flavida) in the area (shown by Ladley and Kelly, 1995b, 1996; Robertson et al., in press). Two hypotheses were tested to explain why bellbirds may not be making an adequate number of visits to mistletoe plants. The first is that there are non-mistletoe foods which are more energetically valuable to bellbirds than mistletoe fruits and nectar and so make up a larger proportion of the bellbird diet during mistletoe fruiting and flowering seasons. The second is that bellbirds concentrated on mistletoe foods when available but the numbers of bell birds at Craigiebum are too low to allow sufficient pollination and dispersal. To answer these questions, the bellbird diet, the energetic value of their food resources, and bellbird numbers were sampled over a twelve month period.
Direct observation of the bellbird diet showed that they are annual generalists, on invertebrates (annual mean of 54% of bell bird diet, range 22-85%) and honeydew (annual mean of 22% of the bellbird diet, range 2-45%), and seasonal specialists, on mistletoe fruit (mean of 40% of the bellbird diet while available, range 18-60%) and nectar (mean of 39% of the bellbird diet while available, range 27-58%). The energy value of invertebrates dominated the available food energy with an annual mean of 14,255 kJ/ha (range 8,695-22,876 kJ/ha). Honeydew was the only other food source that was available all year with an annual mean energy value of 2,518 kJ/ha (range 1,199-3,283 kJ/ha). Mistletoe fruit and nectar featured prominently in the bellbird diet (18-60%) in the fruiting and flowering season even though their energy values were low with a seasonal mean energy of 2,867 kJ/ha (range 1,467-5,125 kJ/ha) for mistletoe fruit, and 3,658 kJ/ha (range 400-10,050 kJ/ha) for mistletoe nectar. This suggested that mistletoe fruit and nectar could be more valuable to the bellbirds than indicated by the measured energy values (kJ/ha) alone.
One third of the variation in the bellbird diet could be explained by changing energy values of major food resources which suggests that the bellbird diet responds to the energy value of foods. As mistletoe fruit and nectar were preferred foods when in season, and the bellbird index of density was low at Craigieburn when compared to other sites, I concluded that it was the possible low number of bell birds in the area, and not their choice of diet, which was limiting mistletoe pollination, and possibly dispersal
The possible low number of bell birds in the area could have been explained by the population being food limited. The time bellbirds spent foraging (feeding plus locomotion time) was a low percentage of their time budget (mean of 39%, range of 31-60%). This did not change significantly from winter to spring. If the values for late January and February were dropped, because of possible pressures from feeding nestlings, there was a significant decrease in the foraging percentage of the bellbird's time budget from winter to summer. However, when corrected for change in daylength, the hours spent foraging each day were not significantly different between seasons (mean of 4.7 hours foraging and a range of 3.6-5.7 hours) suggesting that bellbirds were not seriously limited by the availability of food. The possible low bellbird density could be a result of introduced vertebrate predators such as stoats which have had a negative impact on the populations of other native birds in New Zealand (pierce, 1993; Elliott, 1996; Elliott et al., 1996; O'Donnell, 1996; Wilson et al., 1998).
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Sawada, Akiko. "Digestion and feeding ecology of Japanese macaques." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/158104.
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Lancaster, Jason. "Identification and Functional Characterization of Sesquiterpene Pheromone Biosynthetic Genes in Stink Bugs (Pentatomidae)." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/96290.
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The stink bugs, (Pentatomidae) harlequin bug (Murgantia histrionica), brown marmorated stink bug (Halyomorpha halys), and southern green stink bug (Nezara viridula) are significant agricultural pests both in the United States and globally. The aggregation or sex pheromones produced by these insects are known to be bisabolene-type sesquiterpenoids; however, the biosynthetic pathways in the formation of these pheromones are unknown. Here we provide evidence that Pentatomidae produce sesquiterpene aggregation pheromones de novo and discuss the evolution of terpene biosynthesis in stink bugs. According to transcriptome analyses, the investigated stink bug species express at least two isoprenyl diphosphate synthases (IDSs), one of which makes (E,E)-farnesyl diphosphate (FPP) as the general precursor in sesquiterpene synthesis, whereas other IDS-type proteins function as terpene synthases (TPSs) generating intermediates in sesquiterpene pheromone formation. The TPS genes are expressed in a sex- and tissue-specific manner. Based on phylogenetic analysis, these IDS-type TPSs arose from trans-IDS progenitors in divergence from bona fide IDS proteins. Compared to microbes and plants, the evolution of TPS function from IDS progenitors in insects appears to have occurred more recently. The discovery of TPS genes in stink bugs provides valuable insight into pentatomid and insect terpene biosynthesis. Moreover, the identified genes may be used in developing alternative management strategies for stink bug pests.<br>PHD
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Nakabayashi, Miyabi. "Feeding ecology of three frugivorous civets in Borneo." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199151.
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Risebrow, A. J. "Specialist and generalist feeding strategies in aphids." Thesis, University of East Anglia, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374295.
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Morrisey, D. J. "Competitive avoidance in marine deposit feeding invertebrates." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332468.
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Duncan, Matthew W. "Determinants of host use in tachinid parasitoids (Diptera: Tachinidae) of stink bugs (Hemiptera: Pentatomidae) in Southwest Ohio." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1495723449203563.
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Wade, Mark Richard. "Behavioural ecology of the Pacific damsel bug, nabis kinbergii reuter (hemiptera: nabidae), in cotton farming systems : towrds 'real' IPM /." St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18042.pdf.
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Pereira, de Felipe Fernanda. "Sexual segregation in spatial and feeding ecology of seabirds." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/668678.
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Sexual Segregation (SS) is a phenomenon that occurs across a wide range of animal species, and that had been broadly categorized in spatial/habitat segregation and social segregation. SS of a given species is often related quantitatively to its Sexual Size Dimorphism (SSD), which frequently drives to sexual differences that can work as a mechanism to avoid competition between individuals of opposite sex. SS has been widely studied among terrestrial birds. The few existing studies on SS involving pelagic seabirds have focused on the breeding period, and the extent of SS in relation to environmental conditions and fisheries and its persistence during the non-breeding period remains poorly understood in this taxa.
In this thesis, we aimed to understand the causes and consequences of SS in spatio-temporal distribution (inferred through geolocation and GPS-tracking data), migratory phenology (inferred through light-level data from geolocators), behaviour (inferred through immersion data from geolocators) and feeding ecology (inferred through Stable Isotope Analysis (SIA)) of three closely-related shearwaters: Scopoli’s, Cory’s and Cape Verde shearwaters (Calonectris diomedea, C. borealis, and C. edwardsii, respectively). To assess and understand potential sex differences within or between breeding (for Scopoli’s shearwater) and non-breeding periods (for the three Calonectris shearwaters), we adopted a multidisciplinary approach combining geolocation, immersion data, GPS-tracking, spatial modelling and SIA.
Our findings pointed out that during the breeding period, females of Scopoli’s shearwater seem to be outcompeted by males and forced to increase their foraging effort, especially under unfavourable conditions. This result suggests unfavourable conditions induced an inter-sexual competition for limiting resources, and males forced females to forage further from the colony. Furthermore, males interacted with fishing vessels to a greater extent, profiting from discards more than females. Otherwise, during the non-breeding period, both sexes of the three Calonectris shearwaters shared the same non-breeding areas, suggesting competitive exclusion does not promote spatial segregation throughout the annual cycle. Sexual differences in the migratory phenology were subtle for the three species, with males consistently returning earlier to breeding colonies, and male Cory’s shearwaters remaining resident in a larger proportion than females, likely due to sex-specific reproductive roles at early stages of the breeding period. For both breeding and non-breeding periods, males consistently feed on higher trophic levels (inferred from higher δ15N) than females, suggesting that sexual differences in diet may persist year-round. For the breeding period, we found an increase of δ15N values correlated with fishing vessel attendance, indicating that sexual differences observed may mostly emerge from differential fishing vessel attendance and consumption of fishery discards between males and females. However, the influence of SSD in bill size in determining differences in diet remains unclear.
Overall, we found consistent differences in foraging movements, migratory phenology, and resource use between sexes, indicating a robust SS during breeding and non-breeding periods in shearwater species. Furthermore, our results indicated that SS in foraging strategies of Scopoli’s shearwater may lead to unbalanced exposure of males and females to bycatch in the North-Western Mediterranean, which could reduce effective population size and compromise the population viability of the species.
This thesis increase our knowledge about SS in Calonectris species, and show that species with slight SSD also present well-marked SS and that intrinsic and extrinsic factors can promote inter-sexual differences throughout the annual cycle. Furthermore, we highlight that SS in distribution and foraging behaviour of Scopoli’s shearwater, and probably in other seabird species, should be taken into consideration when implementing specific conservation plans in the marine environment.<br>La segregación sexual (SS) es un fenómeno habitual en animales, como consecuencia de diferencias entre sexos en la distribución espacio-temporal, el comportamiento o la ecología trófica. En aves marinas, el estudio de la SS se ha centrado principalmente en el período reproductivo. En cambio, su alcance e implicaciones en relación a las condiciones ambientales, así como su ocurrencia fuera del período reproductivo, han sido menos estudiadas. Nuestro objetivo fue comprender las causas y consecuencias de la SS en la distribución, fenología migratoria, comportamiento y ecología trófica de tres especies emparentadas: la pardela cenicienta mediterránea, cenicienta atlántica y de Cabo Verde (Calonectris diomedea, C. borealis y C. edwardsii, respectivamente). Para ello evaluamos las diferencias sexuales en el periodo reproductivo (en la pardela cenicienta mediterránea) y de invernada, y discutimos si dichas diferencias se extienden a lo largo del ciclo anual. Para el periodo reproductivo, nuestros resultados indicaron que las hembras de pardela cenicienta mediterránea son menos competitivas que los machos, viéndose obligadas a incrementar el esfuerzo de búsqueda de alimento, especialmente ante condiciones ambientales desfavorables. Además, los machos fueron más proclives a interaccionar con barcos pesqueros, haciendo mayor uso de descartes, pero exponiéndose a un mayor riesgo de captura accidental, lo que podría comprometer el tamaño efectivo de la población y su viabilidad en el Mediterráneo noroccidental. Fuera del periodo reproductivo, ambos sexos compartieron las zonas de invernada en las tres especies, indicando que la exclusión competitiva no causa, al menos a escala espacial, SS a lo largo del año. Ambos sexos se alimentaron en diferentes niveles tróficos, sugiriendo que la segregación trófica persiste a lo largo del año. Encontramos sutiles diferencias en el calendario migratorio, siendo los machos los primeros en retornar a las colonias, y un mayor porcentaje de machos que de hembras de la pardela cenicienta atlántica no migró, probablemente como estrategia ventajosa de cara a las etapas iniciales del periodo reproductivo. En general, encontramos evidencias de SS en los movimientos de búsqueda de alimento, fenología migratoria y ecología trófica, tanto durante el período reproductivo como en el período de invernada en las tres especies de pardela.
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Granadeiro, Jose Pedro. "Feeding ecology of Cory's shearwater in the Portuguese Atlantic." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241784.
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Kairo, Moses Thairu Kihiu. "Ecology and biocontrol of aphids feeding on cypress trees." Thesis, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268028.
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Mayhew, Peter Watts. "The feeding ecology and behaviour of wigeon (Anas penelope)." Thesis, Connect to e-thesis, 1985. http://theses.gla.ac.uk/635/.
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Schmitt, Joseph Daniel. "Feeding Ecology of Invasive Catfishes in Chesapeake Bay Subestuaries." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/83464.
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Blue Catfish Ictalurus furcatus are native to tributaries of the Mississippi River but are now invasive in several Atlantic slope drainages. This includes subestuaries of the Chesapeake Bay, where their feeding ecology and potential impact on native species was largely unknown. We collected stomach contents from 16,110 Blue Catfish at 698 sites in three large subestuaries of the Chesapeake Bay (James, York, Rappahannock rivers). Cumulative prey curves revealed that sample size was sufficient for diet description, though 1,000 – 1500 stomachs were needed per river. Blue Catfish are opportunistic generalists that feed on a broad array of plant and animal material. Logistic regression models reveal that Blue Catfish undergo significant ontogenetic diet shifts to piscivory at larger sizes (P<0.01) though the lengths at which these shifts occur varies by river system (500 – 900 mm total length; TL). Over 60% of Blue Catfish stomachs contained other invasive species, primarily Hydrilla verticillata and Asian clams Corbicula fluminea. Canonical Correspondence Analysis (CCA) revealed that salinity and season explained the most variation in Blue Catfish diet, while Generalized Additive Models (GAMs) demonstrated that there is considerable spatiotemporal and length-based variation in predation of species of concern. Species of concern include American Shad, American Eel, and river herring, which are imperiled, and blue crab, which support valuable fisheries in Chesapeake Bay. Predation of American Shad, American Eel, and river herring was rare (max predicted occurrence in Blue Catfish diets = 8%), while blue crab was much more common in the diet (max predicted occurrence =28%). Predation of American Shad and river herring peaks in freshwater areas in April, while predation of blue crab peaks in brackish areas in October. Predation of all species of concern is highest for large catfish (500 – 1000 mm TL). Field and laboratory-based estimates of consumption rate revealed that Blue Catfish feed at similar rates as Channel Catfish Ictalurus punctatus, and daily ration is estimated to be 2-5% bodyweight per day during warm temperatures, while peak feeding (maximum daily ration) can approach 10% bodyweight per day. While consumption of imperiled species is rare, Blue Catfish could still have negative impacts on these species due to dense catfish populations.<br>Ph. D.
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Lindsey, Peter Andrew. "The feeding ecology and habitat use of the aardvark (Orycteropus afer)." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-11162006-100552/.
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Buckland, Philip. "The development and implementation of software for palaeoenvironmental and palaeoclimatological research : the Bugs Coleopteran Ecology Package (BugsCEP)." Doctoral thesis, Umeå University, Archaeology and Sami Studies, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1105.
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<p>This thesis documents the development and application of a unique database orientated software package, BugsCEP, for environmental and climatic reconstruction from fossil beetle (Coleoptera) assemblages. The software tools are described, and the incorporated statistical methods discussed and evaluated with respect to both published modern and fossil data, as well as the author’s own investigations.</p><p>BugsCEP consists of a reference database of ecology and distribution data for over 5 800 taxa, and includes temperature tolerance data for 436 species. It also contains abundance and summary data for almost 700 sites - the majority of the known Quaternary fossil coleopteran record of Europe. Sample based dating evidence is stored for a large number of these sites, and the data are supported by a bibliography of over 3 300 sources. Through the use of built in statistical methods, employing a specially developed habitat classification system (Bugs EcoCodes), semi-quantitative environmental reconstructions can be undertaken, and output graphically, to aid in the interpretation of sites. A number of built in searching and reporting functions also increase the efficiency with which analyses can be undertaken, including the facility to list the fossil record of species found by searching the ecology and distribution data. The existing Mutual Climatic Range (MCR) climate reconstruction method is implemented and improved upon in BugsCEP, as BugsMCR, which includes predictive modelling and the output of graphs and climate space maps.</p><p>The evaluation of the software demonstrates good performance when compared to existing interpretations. The standardization method employed in habitat reconstructions, designed to enable the inter-comparison of samples and sites without the interference of differing numbers of species and individuals, also appears to be robust and effective. Quantitative climate reconstructions can be easily undertaken from within the software, as well as an amount of predictive modelling. The use of jackknifing variants as an aid to the interpretation of climate reconstructions is discussed, and suggested as a potential indicator of reliability. The combination of the BugStats statistical system with an enhanced MCR facility could be extremely useful in increasing our understanding of not only past environmental and climate change, but also the biogeography and ecology of insect populations in general.</p><p>BugsCEP is the only available software package integrating modern and fossil coleopteran data, and the included reconstruction and analysis tools provide a powerful resource for research and teaching in palaeo-environmental science. The use of modern reference data also makes the package potentially useful in the study of present day insect faunas, and the effects of climate and environmental change on their distributions. The reconstruction methods could thus be inverted, and used as predictive tools in the study of biodiversity and the implications of sustainable development policies on present day habitats.</p><p>BugsCEP can be downloaded from http://www.bugscep.com</p>
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Buckland, Philip Iain. "The development and implementation of software for palaeoenvironmental and palaeoclimatological research : the Bugs Coleopteran Ecology Package (BugsCEP) /." Umeå : Environmental Archaeology Laboratory, Department of Archaeology and Saami Studies, University of Umeå, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1105.
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Prinsloo, Dominique. "Impacts of African elephant feeding on white rhinoceros foraging opportunities." Thesis, Nelson Mandela University, 2017. http://hdl.handle.net/10948/13768.
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In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.
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Johnson, Rollin Breese. "The feeding strategies of adult male yellow baboons (Papio cynocephalus)." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357762.
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Whitfield, Douglas Philip. "Social organisation and feeding behaviour of wintering turnstone (Arenaria interpres)." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/14660.
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Lindsey, Peter Andrew. "The feeding ecology and habitat use of the aardvark (Orycteropus afer)." Diss., University of Pretoria, 1999. http://hdl.handle.net/2263/29491.
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The seasonal diet, feeding patterns, feeding selection and habitat selectivity of the aardvark were determined during summer and winter at Tussen die Riviere Nature Reserve in the southern Free State. Pitfall trapping, dig sampling and quadrat sampling were used to determine the resource base of three habitats in the summer and winter of 1998. A total of 44 ant species of 5 sub families and 17 genera, and two termite species of two sub families were recorded. Pitfall trapping was the most successful technique, followed by quadrat sampling (51.1%) and finally, dig sampling (48.8%). Abundance and diversity was higher during summer than winter. Monomorium albopilosum was the most abundant species in all habitats in winter, whilst Anoplolepis custodiens was the most abundant in summer. The grassland habitat yielded the highest abundance and diversity, followed by the steep slope and riverine areas. Seasonal diet and foraging patterns were determined through faecal analysis and observation of four habituated aardvarks. The Formicidae were more important than the Isoptera in both seasons. The feeding of the aardvark was highly selective, only 28.8% of the available species having been utilised. Prey selection was found to be most highly correlated with prey size, prey abundance, prey mobility, and prey calorific value. Aardvarks were highly selective in their habitat utilisation. The vast majority of feeds were made in the grassland areas where prey abundance was greatest, compared to negligible numbers of prey in the rocky steep slopes and no prey in the riverine areas due to periodic flooding.<br>Dissertation (MSc (Veterinary Tropical Diseases)--University of Pretoria, 1999.<br>Veterinary Tropical Diseases<br>unrestricted
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Slater, Matthew James. "The sea cucumber Australostichopus mollis: Juvenile feeding ecology and habitat." Thesis, University of Auckland, 2009. http://hdl.handle.net/2292/5833.
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The aspidochirote sea cucumber Australostichopus mollis is a commercially valuable species of research interest as a candidate for aquaculture or polyculture. Understanding juvenile habitat and feeding biology is essential to furthering aquaculture efforts and expanding knowledge of the ecology of the species. Surveying within the Mahurangi Harbour, New Zealand, revealed highly patchy distribution of juvenile A. mollis at one site within an area of high adult density. High juvenile density correlated with sediment qualities favouring epibenthic detritivorous deposit-feeding. Juvenile A. mollis showed no distinct spatial separation from adults and no association with dense macroalgae or preference for shallower depths than adults, as may be expected from studies on other sea cucumber species. Wild caught juveniles displaced to non-juvenile habitats with novel surface sediments showed rapid growth. The results indicate that the highly patchy distribution of juveniles in the harbour is not due to differences in the food quality of sediments but rather other localised effects. Juvenile A. mollis show an ability to exploit a variety of benthic sediment food sources, with growth rates comparable to other cultured species. Juvenile A. mollis exhibited positive selectivity for organic particles both in situ and in the laboratory. Juveniles exhibited an ability to distinguish between different sediment TOM levels, an ability which became limited once TOM exceeded 3%. The results reiterate the specific nutrient recycling role of deposit-feeding sea cucumbers and may help explain the patchy distribution of juvenile sea cucumbers in heterogeneous habitats. In addition the research indicates that diet homogeneity and stability will be important in development of A. mollis artificial diets while a broad range of artificial diet grain sizes will be consumed. Juvenile A. mollis fed a high rate of mussel waste diet over three months exhibited significantly higher specific growth rate (SGR) than those fed natural sediment or algal diets. The results indicate the suitability of mussel waste as a juvenile diet and show that rapid growth can be expected among juvenile sea cucumbers cultured beneath mussel farms provided sea cucumber stocking rates are managed appropriately. Bioavailability of potential artificial diet ingredients was also systematically tested for juvenile A. mollis. Apparent digestibility was moderate for common carbohydrate sources and excellent for a range of artificial protein sources including low-cost protein sources. However, growth on artificial diets was poor and diet performance may need to be improved using fermentation steps or similar before they become viable. Rapid growth and flexible feeding preferences show A. mollis to be well suited to future aquaculture and polyculture.
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Lynch, Patrick D. "Feeding Ecology of Atlantic Menhaden (Brevoortia tyrannus) in Chesapeake Bay." W&M ScholarWorks, 2007. http://www.vims.edu/library/Thesis/Lynch07.pdf.
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Lee, Hoi-ki, and 李凱琪. "The feeding ecology of Littoraria species in Hong Kong mangroves." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31241943.
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Weatherley, N. S. "The feeding ecology of juvenile fish in a lowland river." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354532.
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Procter, R. M. "The feeding ecology of three species of lake-dwelling leeches." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380088.
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Lee, Hoi-ki. "The feeding ecology of Littoraria species in Hong Kong mangroves /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B22956293.
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Staniland, Iain John. "The feeding ecology and behaviour of whiting (Merlangius merlangus L.)." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/34239.
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The development of multispecies fisheries models has led to a need for improved information on the diet composition and consumption rates of fish. This study was an attempt to investigate the feeding ecology of whiting, with an emphasis on how the fishes' behaviour might influence its diet. Analysing the stomach contents of North Sea whiting, found that as whiting increased in size they switched from a crustacean, to a fish dominated diet, and the average size of prey eaten increased. Smaller trawl caught whiting were found to have a higher instance of regurgitation. The whiting appeared to be exploiting one prey species in an area. The majority of fish stomachs sampled at a station contained the same prey type. Studies showed that sandeels were evacuated from the stomachs of whiting at a higher rate than prawns. When fed in combination the evacuation rate of sandeels increased, and the rate of prawns decreased. It was postulated that these evacuation rate changes could be because of stomach packing and/or the prawns' abrasive exoskeleton. Video analysis of whiting feeding on shrimp studied the effects of changing the predator to prey size ratio, stomach fullness and experience. As the predator to prey size ratio increased the handling time decreased, and probability of successfully eating a shrimp increased. As the fish gut filled up the probability of a strike being successful decreased and handling time increased. With increasing experience the hunting sequence of the fish became simplified and the probability of a strike being successful increased. Results from the video analysis were used to develop a stochastic dynamic program of whiting feeding. The program was used to model the optimal prey choices of whiting feeding on two sizes of shrimp. In the model the probability of success was found to be the most important factor in determining the optimal shrimp size. The time spent in handling the shrimp was also found to be important. It was concluded that a more behavioural approach could help in understanding why fish eat what they do and aid investigations into the problems of fish species interactions.
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Zeman, Samantha. "Orientation Behavior and Feeding Ecology of the Scyphomedusa Chrysaora fuscescens." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19212.
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Chrysaora fuscescens is a cnidarian scyphomedusa that occurs in the northern California Current. In this upwelling system, medusae are seasonally abundant, and individuals can ingest 10-60% of the standing stock of vulnerable zooplankton taxa per day. Yet little is known about this medusa's feeding ecology. Using laboratory pseudokreisels, C. fuscescens feeding rates and behavior were quantified in the presence of a controlled flow field. C. fuscescens collected aboard research cruises were dissected, and prey items were counted in order to calculate feeding rates and prey selectivity. In the lab, C. fuscescens feeding rates were not affected by shear flow, and medusa maintained position by swimming counter-current. Field work demonstrates high feeding rates and positive prey selection for nonmotile taxa. For the first time, high clearance rates of ichthyoplankton have been documented. An understanding of jellyfish behavior can help explain jellyfish distributions and trophic impacts in a productive upwelling system.
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Romero, Arias Johanna. "Phylogeny, diversity and feeding ecology in the termite subfamily Apicotermitinae." Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/312782.
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Soils represent an essential habitat for a wide diversity of invertebrates. Among these organisms, termites are considered ecosystem engineers for their impact on nutrient cycling and soil functioning, stemming from their wide feeding habits. For instance, soil/litter-feeding termites are one of the groups that incorporate the most organic matter from the soil. Thus, the high abundance and diversity of this group of termites does not only indicate its ecological success, but also its high value for the ecosystem. TheApicotermitinae subfamily (family Termitidae) is a highly diverse group of soil-feeding termites widespread in Afro- and Neotropical regions. However, due to taxonomic difficulties in soldierless groups and poor sampling of species living deep in the soil, it is also one of the most understudied subfamilies. In this thesis, I addressed phylogenetic, anatomical, and ecological aspects of the Apicotermitinae, with the ultimate goal of explaining their high diversity and ecological success. In the first axis, we investigated the phylogenetic relationships of Apicotermitinae species by using de novo mitochondrial genomes. African taxa with soldiers form several basal branches. We confirmed the monophyly of Asian and neotropical lineages, resulting from two independent dispersal events from tropical Africa, and established the relationships of the main lineages in the subfamily. The relationships among and within some genera remain unresolved, probably revealing an explosive radiation. Some genera appear as polyphyletic, showing the need for further taxonomic revision. In the second axis, we described for the first time in detail the anatomical structures of the gizzard. Thepulvillar belt bears a highly diverse, sclerotized and autofluorescent structures. These structures and the ornamentation patterns remain limited to African species since the Neotropical species do not present such specialized structures. Consequently, these ornamentations are proposed as a new complementary taxonomic tool, which can prove useful in the future revisions of genera with phylogenetic incongruences. In the third axis, we characterized the content of crop-gizzard and inferred the isotopic niche of species. Slight variations in the food content suggested that Apicotermitinae can be considered as a single feeding group, with mineralized soil as a primary source. Variations in the crop-gizzard volume can be related to food-collecting behavior. The neotropical species exhibited the broadest isotopic spaces, indicating flexibility to explore large organic matter humification gradients. The broad overlap of isotopic niches and co-occurrence with other termites suggests that this group could be affected by spatial segregation. Finally, in an evolutionary context, it was inferred that the Neotropical soldierless taxa underwent an explosive radiation during the early-middle Miocene. While the reduction of sclerotized structures in the gizzard is associated with the dispersal towards the Neotropics, the African soldierless species developed a pulvillar armature. All of these results provide an overview of the understanding of Apicotermitinae and open up new perspectives on the evolutionary and functional aspects of associations in favor of diet as an agent of their success.<br>Les sols représentent un habitat essentiel pour une grande diversité d'invertébrés. Parmi ceux-ci, les termitessont considérés comme des ingénieurs de l'écosystème, pour leur impact sur le cycle des nutriments ainsique sur le fonctionnement du sol. Ce rôle écologique majeur est du fait entre autres de la grande diversitéde leur régime alimentaire. Les termites qui se nourrissent de sol et/ou de litière constituent l'un des groupesqui incorpore le plus de matière organique depuis le sol. Ainsi, l'abondance et la diversité élevées de cegroupe de termites indiquent non seulement leur succès écologique, mais aussi leur forte valeur pour lesécosystèmes. La sous-famille des Apicotermitinae (Termitidae) constitue un groupe de termites humivorestrès abondant et diversifié dans les régions afrotropicale et néotropicale. Cette sous-famille est pourtant peuétudiée, du fait des difficultés taxonomiques rencontrées pour les termites sans soldats, mais aussi desdifficultés d’échantillonnage associées aux espèces propres aux sols plus profonds. Le présent travail dethèse se veut être une étude de la diversité des Apicotermitinae selon trois axes, à savoir phylogénétique,anatomique et écologique, dans le but d'expliquer les tenants et aboutissants de la grande diversité desApicotermitinae, ainsi que les raisons de leur succès écologique.Dans le premier axe de la thèse, nous avons étudié les relations phylogénétiques entres les différentesespèces d’Apicotermitinae à l’aide de génome mitochondriaux assemblé de novo. Les taxa africains avecsoldats forment plusieurs branches basales. Nous avons confirmé la monophylie des lignées asiatique etnéotropicale, qui résultent de deux colonisations indépendantes au départ de l'Afrique, et établi les relationsentre les principales lignées de la sous-famille. Les relations, entre ou au sein, de certains genres sont malrésolues et correspondraient à une explosion radiative. Plusieurs genres apparaissent commepolyphylétiques, montrant le besoin d’une révision taxonomique future.Dans la deuxième partie de la thèse, nous avons décrit pour la première fois en détail les différentesstructures anatomiques du gésier. La ceinture pulvillaire porte des structures très diverses, sclérifiées etauto-fluorescentes. Ces ornementations sont proposées comme un nouvel outil taxonomiquecomplémentaire, qui serait utile pour les révisions requises dans les genres problématiques susmentionnés.Ces structures et les motifs d'ornementation restent toutefois limités aux espèces africaines, les espècesnéotropicales ne présentant pas de structures spécialisées.Concernant le troisième axe de la thèse, nous avons caractérisé le contenu du jabot-gésier et estimé la nicheisotopique de différentes espèces. Les légères variations du contenu suggèrent que les Apicotermitinaepartagent sensiblement le même régime alimentaire, en ingérant une quantité importante de sol minéralisé.Les variations du volume du jabot-gésier peuvent être liées au comportement de collecte des aliments. Lesespèces néotropicales montrent une étendue des niches isotopiques plus large, ce qui indique la possibilitéd'exploiter plusieurs niveaux d’humification de la matière organique. Le large chevauchement des nichesisotopiques et la co-occurrence avec d'autres termites suggèrent que les espèces de ce groupe tendraient àse ségréger spatialement.Enfin, dans un contexte évolutif, il a été estimé que le groupe des espèces néotropicales sans soldats a subiune explosion radiative au début du Miocène moyen. Alors que la réduction des structures fortementsclérifiées dans le gésier est associée à la dispersion vers les Néo-tropiques, les espèces africaines sanssoldats ont développé une armature pulvillaire. L'ensemble de ces résultats donne un aperçu de lacompréhension des Apicotermitinae et ouvre de nouvelles perspectives quant à des aspects évolutifs etfonctionnels des associations en faveur du régime alimentaire en tant qu'agent de leur succès.<br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished
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Kaunda, Emmanuel Kamlipe Watson Hawkins. "Feeding ecology of Bathyclarias nyasensis (Siluroidei: Claridae) from Lake Malawi." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1005126.
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In Malawi, fish contribute about 60-80% to the country's animal protein supply. The greater proportion (> 50%) comes from Lake Malawi. Bathyclarias nyasensis and other clariid catfish contribute up to > 20% of the total catches. Catches of Bathyclarias nyasensis in the inshore area of the south-east arm of Lake Malawi are declining and a management plan for the fishery is essentially lacking. There is paucity of biological data that precludes the use of any option to manage the species. The principal aim of the thesis was to define the ecological role B. nyasensis, the most abundant and common of the Bathyclarias species. By examining life history characteristics within a food web context, it was hypothesized that the study would provide an insight into the interrelationships between species, and, hence form the basis for the development of a rational exploitation strategy for the species. The study was undertaken in the south-east arm of Lake Malawi (9° 30'S, 14° 30'S). The principal objectives of the study were to investigate the feeding ecology of B. nyasensis by examining morphological characters and structures associated with feeding, diet of B. nyasensis, food assimilated in the species using carbon (∂¹³C) isotope analysis, daily food consumption rate for B. nyasensis; and to relate the feeding ecology to life history traits such as age, growth, and some aspects of the reproductive biology of B. nyasensis. The suitability of sectioned pectoral spines and sagittal otoliths to age B. nyasensis was assessed. Due to reabsorption of growth zones with increasing spine lumen diameter with fish size, and the relatively low number of spines that could be aged reliably, only otoliths were used. The maximum age for B. nyasensis was estimated at 14 vears. Growth was best was described by the four parameter Schnute mc: lt ={42+(81¹·⁸ - 42¹·⁸)x1-e⁻°·°⁵⁽t⁻¹⁾}¹/¹·⁸ over 1-e⁻⁽⁻°·°⁵⁾⁽¹¹⁾ for female, lt={41+(98¹·² - 41¹·²)x 1-e⁻°·°²⁽t⁻¹⁾}¹/¹·² over 1-e⁻⁽⁻°·°²⁾⁽¹³⁾ and for male fish. Age-at-50% maturity for females and males were estimated at 7 years and 4 years, respectively. Typically, fish grew rapidly in the first year, but slower during subsequent years. Smaller fish were found inshore while larger fish were found in offshore regions. It was hypothesised that the rapid growth in the first year and slower growth later is a consequence of change in diet from high quality and abundant food source to a more dilute food and that this may be associated with a shift in habitat. Morphological characters associated with feeding were used to predict the food and feeding behaviour of B. nyasensis. The size of premaxillary, vomerine, pharyngeal dental and palatine teeth and premaxillary and vomerine tooth plates suggested the capability of B. nyasensis to handle both large and small prey, with a propensity towards smaller prey in composition to C. gariepinus. The molariform teeth on the vomerine tooth plate suggested that molluscs form part of the diet. The relative gut length (1.27±0.24) suggested omnivory, with an ability to switch between planktivory and piscivory. Buccal cavity volume and filtering area changed with fish size at 500-600 mm TL upon which it was hypothesised that the fish diet changed to planktivory at this size. Detailed diet analysis provided information upon which the above hypotheses could be accepted. Percent Index of Relative Importance (%IRI) and a multi-way contingency table analysis based on log-linear models were used to analyse diet data. Results showed that B. nyasensis is omnivorous, but with a distinct ontogenetic dietary shift from piscivory to zooplanktivory at 500 - 600 mm TL. The increased buccal cavity volume at the same fish size therefore, suggests that B. nyasensis is well adapted to filter the dilute zooplankton resource. Increased foraging costs of feeding on zooplankton explained the slower growth of larger fish. The dietary shift was finally corroborated by results of the ∂¹³C isotope analysis. A polynomial equation described the change in carbon ratios with fish size: ∂¹³C = - 33.188 + 0.4997L - 0.0045 (total length)² (r² = 0.598, n = 12, p=0.022). The ontogenetic shift in diet was synchronised with a habitat shift postulated in life history studies. In the inshore region, B. nyasensis were predominantly piscivorous (apex predators), and were zooplanktivorous in the offshore region, thereby forming part of the pelagic food web in the latter region. After examining "bottom-up" and trophic cascade theories, it was postulated that perturbations of the B. nyasensis stock would be discernible both at the top and lower trophic levels. As a piscivore and therefore apex predator, effects of overfishing B. nyasensis in the inshore region could cascade to unpredictable ecological changes in inshore areas and, due to the ontogenetic habitat shift, in the offshore regions. Examples of trophic cascade phenomena are provided. On the basis of the feeding study, it was possible to reconstruct the pelagic food web of Lake Malawi. Apart from the lakefly Chaoborus edulis, B. nyasensis is the other predator that preys heavily on zooplankton in the pelagic zone. Perturbations of the B. nyasensis stock could affect size composition of zooplankton which in tum, could affect production of C. edulis, a resource for the top predators in the food web. The findings of the present study contributed to the ongoing debate of introducing a zooplanktivore into the pelagic zone of Lake Malawi. Proponents for the introductions have argued that zooplankton predation by fish is inferior to that of C. edulis. Introduction of a clupeid zooplankton was proposed as a strategy to boost fish production in the lake. The zooplanktivore would either out-compete or prey on C. edulis to extinction. Opponents to this view argued that zooplankton biomass in the pelagic region was too low to support introductions and that the fish biomass in the pelagic region may have been underestimated. Results from the present study suggest that planktivorous fish (including B. nyasensis) might not be inferior to C. edulis in utilising the zooplankton resource; B. nyasensis is well adapted to utilise the dilute zooplankton resource, and by omitting B. nyasensis from previous studies, overall zooplankton predation by fish may have been underestimated by between 7 - 33%. On the basis of the theoretical migratory life history cycle of B. nyasensis, it is recommended that the current interest in increasing fishing effort in offshore areas should proceed with caution. Ecological changes that may have occurred in the inshore areas due to overfishing have probably not been noticed: as the offshore zone has never been fished. The latter zone may have acted as a stock refuge area. Higher fishing intensity in the offshore areas could lead to serious ecological imbalances and instability. The study has shown that life history characteristics studied in the context of the food web, and in the absence of other fisheries information and/or data, strongly advocates the precautionary principle to managing changes in exploitation patterns.
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Hulea, G. Danut. "Winter feeding ecology of the Red-breasted goose (Branta ruficollis)." Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606314.
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Our knowledge of the Red-breasted goose population has improved considerably over the last 12 years with work carried out in both the breeding and wintering areas. The Romanian and Bulgarian Dobrogea is the main wintering area of the Red-breasted goose. The population size varied considerable during the study period (October 1998 - March 2001) in the wintering area from 41,195 to 88,425. The weather conditions had a strong influence on the number of the geese wintering in the Dobrogea and within the wintering area, the climate conditions influenced their distribution in most years. Geese were spread across the Dobrogea in both inland and coast regions until December. During the coldest period of the winter, in January, the whole population of Red-breasted goose was concentrated on a few lakes located on the Black Sea coast. Some of these major roost sites are protected as reserves. Most frequently, the Red-breasted geese were seen in the Dobrogea in mixed flocks with the White-fronted geese. The geese feed exclusively on crops, mainly on winter wheat but also on barley. In the late autumn in October and November, they preferred newly sown fields where they fed on seeds of winter wheat left on the surface. Later during the winter, the leaves of winter wheat and barley remained the only food available. Geese preferred to feed closer to the roost from December to February but in January, they showed a preference for fields facing east and south. Other landscape variables such as distance to the roads, distance to the villages and slope, were less important. The carrying capacity of the area was calculated and showed that the area cultivated can presently support a larger number of geese. Geese grazing caused losses of yield of on winter wheat causing economic consequences for the farmers. After privatisation, the attitude of farmers towards geese changed. Some guarded their crops, hunted geese or occasionally used poison against geese. Poison was also used more frequently against illegal sheep grazing. This practice is a major concern and affected a number of species. Hunting and farming were the main causes of disturbance during the winter. In Dobrogea, farming activity decreased from November to January. The hunting pressure was constant during the winter and larger at the weekend compared to working days.
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Wilson, Lindsay J. "The diet and feeding ecology of harbour seals around Britain." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6554.
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Since 2000, there has been a marked decline in the number of harbour seals in some regions around Britain; one possible contributing cause is competition for prey with sympatric grey seals. To explore one important aspect of this interaction, in this thesis the diet of harbour seals is estimated using analysis of hard prey remains recovered from faeces and compared with equivalent results for grey seals. To estimate coefficients to account for partial and complete digestion of hard prey remains, 100 whole prey feeding trials were conducted with six harbour seals and 18 prey species. Differences were found among prey species and between harbour and grey seals highlighting the importance of applying predator- and prey-specific digestion correction factors when reconstructing diet. In a comprehensive exploration of the diet of harbour seals around Britain, sandeel and flatfish dominated in the North Sea and large gadoids dominated on the Scottish west coast with seasonal pulses of pelagic prey. Variation in diet was linked to regional and seasonal differences in prey distribution and abundance. Sex-specific variation in harbour seal diet was examined in four regions. The main difference detected was in The Wash, where female diet quality was significantly higher than males in winter, which appeared to be driven by greater consumption of pelagic prey by female seals associated with seasonal energetic requirements of their annual life cycle. Comparison of the diet of harbour and grey seals revealed regional differences in diet composition, diversity and quality between the two species. However, there was no consistent pattern in this variation in relation to regional variation in harbour and grey seals population trajectories and no clear evidence for interspecific competition for prey. Future work should focus on an integrated investigation of prey abundance and distribution, and seal diet and foraging behaviour/distribution.
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Shuttleworth, Craig Michael. "The effect of supplemental feeding on the red squirrel (Sciurus vulgaris)." Thesis, Royal Holloway, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285044.
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Calder, Colin James. "Population performance and feeding ecology of roe deer in farm woodland." Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU075237.
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This thesis investigates and compares the population performance and diet of roe deer (<I>Capreolus capreolus</I>) inhabiting farm woodland and large commercial forestry plantations in North East Scotland, and investigates roe deer use of agricultural fields surrounding farm woodland. Feeding damage by roe deer to cereal fields and conifers was considered, along with the potential of Wolf (<I>Canis lupus</I>), Bear (<I>Ursus arctos</I>), and Lynx (<I>Lynx lynx</I>) odours as roe deer feeding repellents. There was found to be no significant difference in the reproductive performance between farm woodland and forestry plantation habitats. No difference was found between habitats, in the number of ovulations (<I>Corpora lutea</I> present), pregnancy rates (embryos present), and number of kids present per doe. Reproductive performance was found to be related to maternal body weight, and no significant difference was found in either the body weights, or body condition, between habitats. It was concluded that farm woodland and forestry plantation habitats are of similar quality for roe deer, and that new farm woodland is likely to be rapidly colonised by roe deer dispersing from farm woodland or forestry plantation habitats. Rumen and faecal analysis, however, indicated that the diet of roe deer inhabiting farm woodland differed from roe deer inhabiting forestry plantations. The forestry diet was similar to that found by previous British studies, and was characterised by forbs, heaths, and few graminoids. In contrast roe deer occupying farm woodland predominantly ate agricultural cereals, with few forbs and heaths. Cereals were the single most important component of the farm woodland diet, and formed 36.8% over summer, and up to 68.8% over winter, of the volume of the rumen contents. Conifers were eaten in similar proportions in both habitats, contributing up to 4% over the summer, and up to 12% over the winter, of the volume of the rumen contents.
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Hartung, Viktor. "Systematics of Peloridiidae (Insecta: Hemiptera: Coleorrhyncha) - an integrative approach." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19405.
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Einige wenig bekannte Aspekte der Biologie der Peloridiidae (Verhalten, intraspezifische Kommunikation, Wirtspflanzenassoziationen, Feinmorphologie usw.) wurden untersucht. Die gewonnenen Informationen wurden benutzt, um eine phylogenetische Hypothese zu Verhältnissen der Peloridiidae untereinander und zu anderen Hemiptera aufzustellen.
Wirtspflanzen der Peloridiidae wurden in Australien, Chile und Neuseeland systematisch besammelt. Peloridiidae als Familie scheinen keine Präferenz für ein Taxon der Bryophyta zu haben, auch wenn sie eine Affinität zu einigen Gruppen der Moose zeigen. Unterschiedliche Arten und Gattungen der Peloridiidae können sich aber in ihrer Selektivität unterscheiden.
Vibrationssignale von vier Arten der Peloridiidae wurden zum ersten Mal untersucht. Einige Eigenschaften dieser Signale variierten zwischen den Arten: australische und südamerikanische Vertreter waren einander ähnlich, die neuseeländischen unterschieden sich aber von ihnen beiden.
Detaillierte Informationen zu feinen morphologischen Merkmalen der Antennen, Labiumspitze, Tarsen, Integumentaldrüsen usw. in 21 Arten der Peloridiidae und einigen Außengruppen wurden zum ersten Mal präsentiert. Die erarbeiteten Merkmale wurden zur Herstellung einer phylogenetischen Hypothese herangezogen. Die Peloridiidae erwiesen sich da als ein Monophylum, dessen Schwestergruppe die Auchenorrhyncha waren. Dieses Verhältnis wird anhand von Daten aus Literatur und anderen Untersuchungen diskutiert und etwas in Frage gestellt.
Die intrafamiliären Verhältnisse der Peloridiidae sind nach der erarbeiteten phylogenetischen Hypothese denen aus Literatur bekannten ähnlich; der wichtige Unterschied ist die basale Position der Gattung Peloridium. In einer Analyse mit zusätzlichen drei verhaltensökologischen Merkmalen ändert Peloridium aber seine Position, was das Potential der integrativen Ansätze illustriert, aber vorsichtig interpretiert werden muss, da solche Merkmale schwer zu homologisieren sind.<br>Some insufficiently studied aspects of Peloridiidae biology such as behavior, intraspecific communication, host plant preferences and fine morphology were investigated. The newly acquired information was used for production of a phylogenetic hypothesis on Peloridiidae relationships and critical evaluation of the existing ones.
Host plants of Peloridiidae were studied systematically in Australia, Chile and New Zealand. Peloridiidae as a whole were found not to be bound to particular bryophyte taxa, although they regularly occurred in species of Dicranaceae, Hypopterygiaceae, Polytrichaceae and Sphagnaceae. Still, different species and genera could vary in their host plant specificity.
Vibrational signals of four Peloridiidae species were studied for the first time. Features of these signals varied between species, the Australian and South American ones being similar to each other and the New Zealand species different from both of them.
Detailed information on fine morphology of antennae, genae, labium tip, tegminal sculpture, tarsi, abdominal sculpture and integumental glands in 21 Peloridiidae species and some sister groups was presented for the first time. The findings were formalized as a matrix of 93 characters and analyzed phylogenetically with methods of maximum parsimony. A monophyletic Peloridiidae resulted, with significant support of the sister-group relationship to Auchenorrhyncha. This relationship was discussed on the background of other studies and literature data.
The intrafamiliar structure of Peloridiidae in the present study was quite similar to previously published works, with the major exception of the genus Peloridium branching off most basally in the phylogenetic tree. Three additional bioacoustic and behavioral characters, when integrated into the matrix, change the position of Peloridium and demonstrate the potential of integrative approaches, although this result must be treated with care due to complicated homologization of behavioral traits.<br>В данной работе исследуется ряд недостаточно изученных ранее аспектов биологии семейства Peloridiidae: поведение, внутривидовая коммуникация, трофические связи с растениями и тонкие детали морфологии. Полученная информация используется для создания новой филогенетической гипотезы о родственных связях Peloridiidae и для критической оценки существующих гипотез.
Кормовые растения семейства систематически изучены в Австралии, Новой Зеландии и Чили. Peloridiidae в целом, как выяснилось, не привязаны к отдельным таксонам мохообразных, хотя они регулярно встречались на представителях Dicranaceae, Hypopterygiaceae, Polytrichaceae и Sphagnaceae. Однако, трофическая специфичность отдельных родов и видов может сильно различаться.
Впервые изучены вибрационные сигналы четырех видов пелоридиид. Черты сигналов различались внутри семейства: сигналы южноамериканских и австралийских видов были похожи, в то время как новозеландские виды от них отличались.
Впервые представлена подробная информация о морфологии антенн, кончика хоботка, лапок, скульптуры тегменов, брюшка и покровных желез для 21 вида пелоридиид и некоторых внешних групп. Эти находки были организованы в матрицу из 93 признаков и проанализированы филогенетически с помощью методов минимизации изменений. В результате монофилетические Peloridiidae оказались сестринской группой монофилетических Auchenorrhyncha, с неплохим статистическим подтверждением. Эта группировка обсуждается в свете других работ и данных литературы.
Внутренняя структура семейства в настоящей работе оказалась довольно похожей на данные литературы, за важным исключением рода Peloridium, который оказался на самом нижнем ответвлении филогенетического древа. Когда к анализу были привлечены три дополнительных признака (биоакустические и поведенческие), позиция Peloridium изменилась. Этот результат иллюстрирует потенциал интегративных методов, хотя и требует осторожного к себе отношения из-за сложностей гомологизации поведенческих признаков.
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Bennett, Andrew Thomas Deakin. "The ecology of spatial memory in European jays." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302845.
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Thompson, David. "Behavioural ecology and physiology of diving in seals." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367657.
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Crumière, Antonin. "Developmental mechanisms of adaptive phenotypes and associated ecological relevance in the semiaquatic bugs." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN095/document.
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Comprendre comment est générée la diversité biologique est un enjeu majeur de la biologie évolutive. Chaque espèce vit dans un environnement écologique qui lui est propre et dans lequel elle s’est adaptée au cours de l’évolution par les moyens de la sélection naturelle. Chaque espèce est également soumise à la sélection sexuelle contribuant au dimorphisme entre les sexes. Les traits phénotypiques associés au succès évolutif sont formés lors du développement par l’action de gènes qui sont transmis de génération en génération. Ces traits et ces gènes varient d’une espèce à une autre et contribuent directement à la diversité morphologique. La compréhension des interactions entre les mécanismes développementaux et les pressions écologiques permettent de mieux comprendre les processus qui influent sur la diversité morphologique et l’évolution des espèces. Obtenir une vision intégrative est un réel défi et demande de combiner diverses approches. Au cours de ma thèse, j’ai utilisé les insectes semi-aquatiques (Gerromorphes) qui sont un modèle permettant de lier évolution, écologie et développement. En utilisant différentes approches j’ai pu mettre en évidence des gènes impliqués dans le développement de divers traits adaptatifs, l’importance de ces traits dans un contexte écologique et leur impact sur l’évolution du groupe des Gerromorphes. L’ensemble des résultats obtenus améliore notre compréhension de comment sélection naturelle et sélection sexuelle, en agissant sur les mécanismes génétiques, génèrent de la diversité morphologique<br>Understand how biodiversity is generated is a major goal in evolutionary biology. Every species live in a specific ecological habitat where they adapted during evolution by the mean of natural selection. Every species is also under sexual selection that generates dimorphism between the sexes. Adaptive traits contributing to evolutionary success are shaped during development by the action of genes that are transmitted through generations. These traits and genes vary across species and directly contribute to generate morphological diversity. The study of the interactions between developmental genetic mechanisms and selective ecological pressures allow a better understanding of the processes generating morphological diversity and driving the evolution of species. Obtain an integrative view is a challenge and required the combination of different approaches. During my PhD, I used the semiaquatic bugs (Gerromorpha) that are model systems allowing to link evolution, ecology and development. By using various approaches I could highlight genes involved in the development of different adaptive traits, the relevance of these traits in an ecological context and their impact on the evolution of the group of Gerromorpha. Altogether these results improve our understanding of how natural and sexual selection, by acting on genetic mechanisms, generate morphological diversity
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Atiénzar, Navarro Francisco. "Feeding and breeding ecology of three insectivorous birds in Mediterranean ecosystems." Doctoral thesis, Universitat de València, 2009. http://hdl.handle.net/10803/31956.
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Tits (Paridae) are one of the most and better passerines known owing to they are broadly distributed, breeding in different habitats from gardens to forests, and they make use of nest boxes for breeding. Hence, such species are ideal for comparative studies on a large geographical scale. Despite the great amount of information concerned to tits, we still do not really understand life-history strategies of birds living under most ecological conditions.
The present thesis is focused on achieving a better understanding of how birds are adapted to their environment. In particular, to examine the existence and the consequences of food limitation in Mediterranean evergreen habitats, through an adequate knowledge of the constraints affecting both feeding behaviour and breeding success. To achieve the main objectives proposed, studies were conducted in three Mediterranean ecosystems: pine and Holm Oak Quercux iles forests, and an orange grove. This was carried out mainly over Great Tits Parus major, and in certain cases over Crested Tits Lophophanes cristatus and Coal Tits Periparus ater. The specific aims pursued in this thesis are as follows:<br>Los Carboneros son aves insectívoras que pertenecen a la Familia Paridae. Las especies que engloba dicha familia están muy estudiadas, conociéndose bastante sobre su biología. Esto se debe a que están ampliamente distribuidas, reproduciéndose en diferentes tipos de hábitat. Por lo tanto, dichas especies son ideales para estudios comparativos a gran escala geográfica. A pesar de la gran cantidad de información existente, todavía se desconoce las estrategias de vida de las aves bajo determinadas condiciones ecológicas.
La presente tesis pretende alcanzar un mejor entendimiento de cómo las aves están adaptadas a su ambiente. En concreto, se examinó la existencia y las consecuencias de la limitación de alimento en ambientes Mediterráneos perennifolios, sobre el comportamiento trófico y el éxito reproductor. El estudio se llevó a cabo en tres ecosistemas Mediterráneos: bosque de pino y Carrasca Quercus ilex, y en un naranjal. Se utilizó principalmente como especie modelo, el Carbonero Común Parus major, y en menor medida, el Herrerillo Capuchino Lophophanes cristatus y el Carbonero Garrapinos Periparus ater.
En la presente tesis, se ha demostrado que las aves hicieron uso de la temperatura ambiental en tal de ajustarse a las variaciones de la fenología del alimento, haciendo uso de las características de la vegetación para reducir la detección por parte de los depredadores. Las aves también se las arreglaron en relación a factores ambientales e intrínsecos cuando alimentaban a sus pollos, disminuyendo o aumentando su esfuerzo. Han compensado demandas conflictivas, por ejemplo, entre la coloración y la predación del nido. Hembras coloridas evitaron la predación del nido eligiendo lugares camuflados. Además, se ha demostrado cómo se las arreglaron los Herrerillos Capuchinos que se reprodujeron en un ambiente poco usual para la especie (carrascar), mediante la elección de cajas nido rodeadas de pino. Finalmente, las tres especies de aves utilizadas coexisten dentro de un mismo hábitat
alimentándose de presas de distinto tamaño, reproduciéndose en lugares con características de la estructura de la vegetación diferente, o a través de distintos tiempos de reproducción.
Dado que los datos fueron obtenidos mediante el uso de cajas nido, algunos de los resultados obtenidos podrían no ser relevantes o comparativos en aquellos casos en los que se estudie las aves nidificando en agujeros naturales debido a las diferencias, por ejemplo, en la presión por predación.
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Collins, Catherine Matilda. "Aspects of the ecology of two stem feeding willow aphid species." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249673.
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Clarke, Roger Geoffrey. "Aspects of raptor, Falconiformes, feeding ecology : an approach using pellet analysis." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367286.
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Walker, Jonathan S. "Feeding ecology and rarity of frugivorous birds in tropical rain forest." Thesis, Manchester Metropolitan University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400944.
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Lindsay, William Keith. "Feeding ecology and population demography of African elephants in Amboseli, Kenya." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338055.
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Sullivan, Lindsay J. "Feeding ecology of the ctenophore Mnemiopsis leidyi A. Agassiz (Ctenophora, Lobata) /." View online ; access limited to URI, 2007. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3277008.
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Jackson, C. S. "Studies on the ecology of psyllids (Homoptera : Psylloidea) feeding on hawthorn (Crataegus monogyna)." Thesis, Liverpool John Moores University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382503.
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