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Jean, Donald. "L'intégration physiologique chez la chicouté, Rubus chamaemorus, et sa contribution au succès reproductif". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ31738.pdf.
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Muller, Karen. "Influence de la plante hôte sur les performances sexuelles des mâles et conséquences sur le potentiel reproductif des femelles phytophages". Thesis, Dijon, 2016. http://www.theses.fr/2016DIJOS021/document.
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L’abondance des insectes phytophages est déterminée par l’influence de facteurs biotiques et abiotiques qui affectent leurs traits d’histoire de vie. Chez les espèces phytophages à reproduction sur capital, la qualité de la plante hôte sur laquelle les individus effectuent leur développement larvaire est un facteur critique affectant le succès reproducteur des adultes. Curieusement, si l’effet de la plante hôte sur le potentiel reproductif des femelles a été largement décrit, il n’a été que peu étudié sur celui des mâles. Par ailleurs, chez les lépidoptères, lors de l’accouplement, la femelle reçoit du mâle un cadeau nuptial sous la forme d’un spermatophore contenant des spermatozoïdes ainsi que des sécrétions produites par les glandes accessoires. Ces sécrétions constituent des bénéfices directs pour la femelle qui pourra les remobiliser pour augmenter sa fécondité. Mon projet de thèse vise à déterminer l’influence de la plante hôte sur les performances reproductives des mâles et d’en évaluer les conséquences sur le potentiel reproductif des femelles et sur l’évolution des stratégies de choix de partenaire chez un papillon ravageur de la vigne, l’Eudémis (Lobesia botrana). Les expériences menées au cours de ces trois années de thèse révèlent que la nutrition larvaire sur différents cépages de vigne module fortement les réserves énergétiques des mâles, affectant leur potentiel reproductif à travers la taille et le contenu des spermatophores qu’ils transfèrent aux femelles pendant l’accouplement. De plus, l’investissement du mâle dans la production de spermatophores décline au cours d’accouplements successifs, les mâles n’étant capables de produire qu’un seul spermatophore riche en nutriments au cours de leur vie. Ces deux facteurs (nutrition larvaire et expérience sexuelle), qui affectent fortement la qualité reproductive des mâles, ont d’importantes conséquences sur le potentiel reproductif de leur partenaire. En effet, les femelles recevant des spermatophores riches en nutriments et en spermatozoïdes ont plus de descendants que celles recevant des spermatophores de moins bonne qualité. Enfin, les femelles semblent capables de discriminer parmi les mâles en se basant sur des critères reflétant leur qualité reproductive, s’accouplant préférentiellement avec ceux leur procurant le plus de bénéfices directs. Ainsi, les résultats de cette thèse confirment l’importance d’intégrer l’effet mâle quand on s’intéresse à l’évolution des populations de phytophages. De plus, identifier les facteurs écologiques modulant les interactions entre les partenaires sexuels chez les espèces menaçant les cultures est crucial pour pouvoir optimiser les programmes de gestion de ces ravageursThe abundance of phytophagous insects is determined by numerous interacting biotic and abiotic factors. In capital-breeding phytophagous insects, larval host plant quality is a key determinant of the adult phenotype and the performance of both males and females. Curiously, if the effect of host plant quality on female reproductive success is well-established, little effort has been conducted to determine this effect on male reproductive success. Moreover, in Lepidoptera, males transfer to females a spermatophore containing sperm and accessory gland products rich in nutrients that could be reinvested into female reproduction. The aim of this thesis was to evaluate how male larval nutrition on different host cultivars affects male reproductive traits which could, in turn, influence female reproductive output and mate choice strategies in an important grapevine pest, the European grapevine moth (Lobesia botrana). During these three years, we found that the host cultivar for the larvae strongly influences the energy reserves of male adult moths, affecting ultimately their reproductive potential through the size and content of spermatophores they transfer to females at mating. Moreover, male investment in the spermatophore declines over consecutives matings, suggesting that spermatophores are energetically expensive to produce in this monandrous capital breeding species. Thus ‘male quality’ depends on both the male larval origin and mating history, and females receiving protein-rich spermatophores at mating have an overall greater reproductive output than females mated with poor quality males producing less nutritionally rich spermatophores. Finally, females are able to discriminate among males and mate more with males having high sperm quality (virgin males or males from certain cultivars or geographical origins) to obtain substantial direct benefits.The results of this thesis confirm the importance of considering the “male effect” when trying to understand the evolution of phytophagous populations. Moreover, identifying the ecological conditions that influence the mating success of male and female in crop-pest species may lead to a better management of these crop pests
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Renoirt, Matthias. "Influence de l’habitat sur l’écologie et la physiologie du crapaud épineux (Bufo spinosus)". Electronic Thesis or Diss., La Rochelle, 2022. http://www.theses.fr/2022LAROS041.
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Un grand nombre d’études ont mis en avant les effets négatifs des pressions anthropiques dans le temps et dans l’espace sur la biodiversité. Parmi ces pressions anthropiques, les activités et l’expansion agricole jouent un rôle principal dans la modification des milieux et dans la perte de biodiversité. De fait, la question de la persistance des espèces animales dans ce type de milieux se pose. C’est dans ce contexte que ma thèse s’axe. Afin d’étudier les réponses des organismes à un milieu dégradé et les contraintes du paysage sur différents traits d’histoire de vie et l’écologie, je travaille spécifiquement sur une espèce d’amphibien occupant des milieux allant de fortement conservés à fortement dégradés. Afin de comparer les populations de crapauds épineux (Bufo spinosus) forestières et les populations agricoles, j’utilise un vaste panel de marqueurs pour examiner (1) la structure génétique des populations (marqueurs microsatellites), (2) l’écologie alimentaire (isotopes stables), (3) la qualité individuelle (télomères, morphologie, traits de développement) et son impact sur la reproduction. De ce fait et au cours de cette thèse, j’ai pu mettre en relation de nombreux facteurs associés aux paysages agricoles qui soulèvent de nombreuses questions quant au maintien des populations de crapauds épineux. Ainsi, nous avons pu montrer un effet significatif des fertilisants sur la signature isotopique en δ15N des populations de B.spinosus. Aussi, nous avons pu souligner que l’environnement agricole reste suffisamment perméable au maintien de la diversité génétique. Cependant, nous avons mis en évidence de nombreuses contraintes de ce milieu sur la reproduction des populations d’amphibiens, que ce soit par la faible (voir l’absence) abondance de femelles sur les sites de reproduction, et/ou directement sur le succès reproducteur et la qualité de la progéniture. Ces résultats suggèrent de possibles effets à long terme sur les populations d’amphibiens et nous suggérons d’approfondir les différentes voies de recherche que nous suggérons tout au long de cette thèse afin de mieux comprendre les mécanismes sous-jacents à ces résultats et de trouver des solutions quant à la pérennité des espèces sauvages qui n’ont d’autres choix que de s’adapterA large number of studies have highlighted the negative effects of anthropogenic pressures intime and space on biodiversity. Among these anthropogenic pressures, agricultural activities and expansion play a major role in the modification of environments and in the loss of biodiversity. Questions whether animal species persist in this type of environment arises. My thesis is based on this context. We aimed at study the responses of organism to a degraded environment and the landscape constraints on life history traits and ecology. My work is focused specifically on an amphibian species persisting in habitat ranging from highly conserved to highly degraded by agricultural activities. In order to compare forest and agricultural populations of model species (Spined toad, Bufo spinosus), I relied on a wide variety of markers to examine (1) population genetic structure (micro-satellite markers), (2) feeding ecology (stable isotope), (3) individual quality (telomeres, morphology, developmental traits) and the impact on reproduction. As a result, I was able to connect many factors associated with agricultural landscapes that raised many questions about the persistence of spined toad populations. We were able to show a significant effect of fertilizers on the δ15N isotopic signature of B.spinosus populations. Moreover, we highlighted that agricultural environment allows genetic diversity between populations. However, using correlative approaches, we pointed out various on strains of this environment on the reproduction of amphibians populations, either through low (or no) abundance of females on breeding sites, and/or directly on reproductive success and offspring quality. These results suggest possible long-term effects on amphibian populations, and we suggest that the various avenues of research we suggested throughout this thesis should be pursued in order to better understand the mechanisms underlying these results and to find solutions for the sustainability of wild species that have no choice but to adapt
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Fortin, Margot. "Influence de la bactérie féminisante Wolbachia sur le comportement de choix du partenaire et la fitness de son hôte Armadillidium vulgare". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2325/document.
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Ce travail de thèse vise à mieux comprendre les mécanismes de choix du partenaire chez l'isopode terrestre Armadillidium vulgare. Cette espèce est infectée par la bactérie intracellulaire Wolbachia, connue pour manipuler la sexualité de ses hôtes. Chez Armadillidium vulgare, Wolbachia entraine une féminisation des mâles génétiques, les transformant en femelles fonctionnelles. L'objectif est donc à la fois de comprendre comment les individus choisissent leurs partenaires sexuels, mais également de connaître l'effet de Wolbachia sur ces mécanismes de choix. Afin de répondre à ces questions, une approche comportementale a été utilisée, afin de comparer l'attractivité et le comportement de différents types de femelles. Les résultats montrent que les mâles sont capables de discriminer finement entres des femelles ayant différents traits d'histoire de vie ou différents degrés d'apparentement. Nous montrons également que cette discrimination est corrélée à des changements d'odeur des femelles en fonction de leur état reproducteur et infectieux. Les conséquences de ces choix ont également été étudiées via des expériences de reproduction, et il apparaît que les préférences des mâles sont liées à des bénéfices en termes de succès reproducteur. Quant aux femelles, un suivi sur le long terme de différentes situations de sex-ratio révèle qu'à la fois les mâles et le fait qu'elles soient infectées par Wolbachia diminuent leur fitness, et notamment leur succès reproducteur, allant même jusqu'à modifier leurs préférences socialesThis work investigates mate choice in the terrestrial isopod Armadillidium vulgare. This species is parasitized with intracellular bacteria Wolbachia, which is known to manipulate the sexuality of its hosts. In Armadillidium vulgare, Wolbachia lead to a feminization of genetic males, transforming them into functional females. The aim of this thesis was both to investigate how individuals choose their mates, and to understand the effect of Wolbachia on such choices. In order to answer these questions, we used a behavioural approach in order to compare the attractiveness and the behaviour of different kinds of females. The results indicate that males are able to accurately discriminate females with different life history traits or different degrees of relatedness. We also show that such discrimination from males toward females is correlated to females odour change, according to both their reproductive and infection status. The consequences of male mate choice were studied through reproduction experiment, and it seems that male’s preferences are linked to benefits in terms of reproductive success. Concerning females, a long-term monitoring in different sex-ratio conditions reveals that both males' presence and Wolbachia infections decrease their fitness, in particular their reproductive success, or even modify their social preferences
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Whelan, Shannon. "The Role of Temperature in Timing of Reproduction and Reproductive Success of Gray Jays, Perisoreus canadensis". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35507.
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Although early reproduction within a breeding season often leads to higher reproductive success in seasonal environments, it is still not well understood how reproductive success can be influenced by climate both indirectly through the timing of breeding or by directly altering parental behaviour. In this thesis, I investigate the role of ambient temperature in reproductive success through its effects on the timing of reproduction and brooding in a population of gray jays, Perisoreus canadensis. In chapter 2, I test whether (i) female gray jays adjust laying date in response to temperature, (ii) individual or environmental characteristics constrain this plasticity, and (iii) laying date influences reproductive success. Females laid earlier in warmer years than in colder years; females partnered with older males laid earlier than females partnered with younger males at colder temperatures, but not at warmer temperatures. Early layers were more likely to rear at least one nestling and have a dominant juvenile survive the summer. These findings suggest that male experience could advance female laying date at cold temperatures and subsequently increase the probability of a positive nesting outcome. Though cold temperatures appear to limit timing of reproduction in gray jays, previous work in this system suggests that cold temperatures could better preserve perishable winter food stores. Thus, in chapter 3, I test whether temperatures during early offspring development interact with timing of reproduction to influence reproductive performance. Colder ambient temperatures during incubation were associated with larger brood sizes than warmer temperatures among late breeders, but temperature did not influence brood size among early layers, indicating that costs of late breeding may be amplified by temperatures that are unfavourable for food storage. This thesis contributes to our understanding of the environmental factors that determine reproductive performance, both through effects on timing of reproduction and after eggs are laid.
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Bründl, Aisha Colleen. "Investissement parental le long d'un gradient altitudinal chez la mésange bleue (Cyanistes caeruleus)". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30265/document.
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Dans cette thèse, j'examine la dynamique de l'investissement parental et la fitness chez la mésange bleue eurasienne (Cyanistes caeruleus) dans les Pyrénées françaises, et j'évalue les différences potentielles dues à un gradient altitudinal qui crée une variation de "dureté" environnementale. J'ai utilisé de données observationnelles et expérimentales, recueillies de plus de 500 nids de mésanges bleues. Les conditions de reproduction sont " plus dures " en cas de températures plus froides et d'une élévation croissante. J'ai trouvé que l'altitude croissante conduit à une diminution du succès de l'éclosion. Néanmoins, la taille des couvées et la mortalité des couvées sont comparables à travers le gradient. Je suggère que les décisions initiales en matière de procréation, telles que le moment et la quantité de progéniture, déterminent fortement le succès d'une tentative de reproduction. Ces résultats ont des implications pour notre compréhension du succès de reproductionIn this thesis, I examine parental investment and fitness in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences due to an altitudinal gradient that creates variation in environmental "harshness". I used observational and experimental data, collected from over 500 blue tit nests. Breeding conditions are "harsher" due to colder temperatures with increasing elevation. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for understanding reproductive success
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Lacoume, Sandrine. "Développement et succès reproducteur des mâles parasitoïdes, Dinarmus basalis, suite à des contraintes environnementales". Tours, 2007. http://www.theses.fr/2007TOUR4009.
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Les mâles doivent préserver leur potentiel de fertilisation en dépit de contraintes environnementales. Le but de cette thèse est de déterminer l’influence de la ressource hôte et d’un choc froid sur la fitness d’un mâle hyménoptère parasitoïde Dinarmus basalis. Nos résultats ont montré qu’un choc froid appliqué sur un mâle adulte n’affecte pas son potentiel de reproduction. A l’inverse ce choc appliqué durant le développement entraîne une réduction du nombre d’individus émergents, sans altérer la durée de développement. Un résultat semblable est obtenu lors d’une contrainte alimentaire. Celle-ci affecte également le phénotype des mâles en réduisant leur taille corporelle et celle de leur tractus génital. Dans les deux cas, nous avons constaté une réduction de la quantité de spermatozoïdes. Les mâles ayant subi un stress durant leur développement sont capables de s’accoupler, mais sont désavantagés lors de compétitions entre mâles et lors d’accouplements répétésMales should protect their sperm stock and fertilization potential. The aim of this thesis is to investigate the effects of different environmental constraints on the reproductive success of males of the hymenoptera parasitoid, Dinarmus basalis. We have chosen a biotic factor (host resource) and an abiotic factor (a cold shock). Our results show that a cold choc on adult males does not affect their reproductive potential. However, a cold shock applied during development reduces males’ emergence but not developmental durations. Similar results are obtained with a dietary constraint applied during male development. This constraint affects also male phenotype by reducing both male and genital tract size. A stress applied during development reduces the quantity of sperm. In single mating, these constraints do not prevent male from mating. However, in repeated mating and male-male competition, constraints applied during development disadvantage males
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Grange, Laura Joanne. "Reproductive success in Antarctic marine invertebrates". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/41355/.
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The nearshore Antarctic marine environment is unique, characterised by low but constant temperatures that contrast with an intense peak in productivity. As a result of this stenothermal environment, energy input has a profound ecological effect. These conditions have developed over several millions of years and have resulted in an animal physiology that is highly stenothermal and sometimes closely coupled with the seasonal food supply, e.g. reproductive periodicity and food storage. Therefore, Antarctic marine animals are likely to be amongst the most vulnerable species worldwide to environmental modifications and can be regarded as highly sensitive barometers for change. Reproductive success is a vital characteristic in species survival and evaluation of change in reproductive condition with time key to identifying vulnerable taxa. Characterising reproductive success with time is a major requirement in predicting species response to change and the early stages of species loss. Some invertebrates are highly abundant in shallow water sites around the Antarctic and form conspicuous members of the Antarctic benthos. Three common echinoderms and one nemertean were sampled from sites adjacent to the British Antarctic Survey’s Rothera Research Station, Adelaide Island, on the West Antarctic Peninsula between 1997-2001. Reproductive patterns were determined by histological analyses of gonad tissue. This study provided further evidence for inter-annual variation in Antarctic gametogenic development, which appeared to be driven to some extent by trophic position and reliance on the seasonal phytoplankton bloom. The largest variation in reproductive condition was demonstrated for the detritivorous brittle star, Ophionotus victoriae. The seasonal tempos of this echinoderm have been attributed in part, to the seasonal sedimentation events common in the high Antarctic. The reproductive patterns in the scavenging starfish, Odontaster validus and the predatory nemertean, Parborlasia corrugatus showed less inter-annual variation. The de-coupling of these invertebrates from the intensely seasonal phytoplankton bloom appeared to partially account for the reproductive trends observed. The lack of inter-annual variation in the reproduction of the filter-feeding sea-cucumber, Heterocucumis steineni, was somewhat counterintuitive, although problems with sample processing probably accounted for the majority of this anomaly. Echinoderms were also collected during the Antarctic summer field seasons in 2003 and 2004. A series of fertilisation success studies were undertaken comparing the adaptations in an Antarctic and an equivalent temperate starfish to achieve optimal numbers of fertilised eggs, and elemental analyses were used to estimate the nutritional and energetic condition of the bodily and reproductive tissues in two Antarctic echinoderms. Fertilisation studies indicated that Antarctic invertebrates require 1-2 orders of magnitude more sperm to ensure optimal fertilisation success. These sperm tended to be long-lived and capable of fertilising eggs 24+ hours after release. The study suggested that synchronous spawning, aggregations and specific pre-spawning behaviour are employed to help counter the deleterious effects of sperm limitation. The Antarctic eggs and sperm were also highly sensitive to even small modifications in temperature and salinity, affecting the number of eggs fertilised. Such stenothermy is of particular relevance if the 1-2ºC rise in global temperature, predicted over the next century, is realised. Biochemical composition of body components of two species of Antarctic echinoderm indicated a significant difference in the composition between the male and female gonad, particularly in the Antarctic brittle star Ophionotus victoriae. The ovaries contained a much larger proportion of lipid compared to the testes, and demonstrated a distinct seasonality in composition. Higher levels of lipid were observed in the ovary during the austral winter coincident with a period of reproductive investment and maturing oocytes in the gonad. O. victoriae exhibited lower amounts of lipid in the late austral spring suggesting the removal of mature oocytes from the ovary through spawning. The seasonality in composition and the high levels of lipid and protein measured in the ophiuroid gut tissue, suggested the gut might play a role in providing material and energy for metabolic function and possibly gametogenesis; higher lipid levels were apparent during the period of seasonal phytodetrital flux. The role of the pyloric ceaca in asteroids as a nutrient storage organ was also evident in the high levels of both protein and lipid observed in this bodily component in the star fish, Odontaster validus.
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Pellerin, Maryline. "Utilisation et sélection de l'habitat chez le chevreuil à différentes échelles spatio-temporelles". Poitiers, 2005. http://www.theses.fr/2005POIT2301.
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Tallents, Lucy A. "Determinants of reproductive success in Ethiopian wolves". Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442999.
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Hardy, Danita Sue 1957. "Reproductive success of round-tailed ground squirrels". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276596.
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I studied round-tailed ground squirrels (Spermophilus tereticaudus) to determine if presence of water or green vegetation significantly increased reproductive success. I compared the number of juveniles produced, body weights, and diets of squirrels during 1981-84 on 2 plots with green vegetation and no free water, on 3 plots with free water and no green vegetation, and 2 control plots. Reproductive success and body weights of adult and juvenile squirrels were significantly higher (P ≥ 0.001) on plots with green vegetation than on either watered or control plots. Body weights of squirrels on plots with water only and control plots were not significantly different (P ≥ 0.05). Adult squirrels without access to green vegetation during winter and spring failed to reproduce even though free water was readily available. Percent of diet overlap, diversity, and evenness of squirrel diets on control and watered plots were not significantly different. Green vegetation appeared to be the limiting factor for round-tailed ground squirrels.
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Pelletier, Luc. "Facteurs affectant le succès reproducteur des bourdons en milieu naturel". Thesis, Université Laval, 2003. http://www.theses.ulaval.ca/2003/21026/21026.pdf.
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Les facteurs limitants le succès reproducteur des colonies de bourdons en milieu naturel sont très peu connus. Grâce au suivi du développement de plus de 200 colonies de huit espèces de bourdons (Bombus impatiens, B. fervidus, B. perplexus, B. terricola, B. bimaculatus, B. ternarius, B. rufocinctus et B. vagans vagans) sur le terrain, j’ai exploré l’effet de la taille de la reine, de la disponibilité en nourriture et de certains parasites sur le succès reproducteur des colonies.
Les plus grandes reines avaient plus de chances de se reproduire et, parmi celles qui y sont parvenues, le nombre de sexués produits était positivement relié à la taille de la reine. Le meilleur succès des plus grandes reines est attribuable, du moins en partie, à la production de plus grosses colonies et, chez certaines espèces, à la capacité à mieux repousser les usurpations de Psithyrus (un sous-genre de bourdons parasites), mais n’est pas relié à la date de nidification ou à l’usurpation par d’autres reines Bombus.
Une expérience où j'ai ajouté de la nourriture dans la moitié des colonies tout au cours de la saison a démontré que la disponibilité en nourriture était aussi un facteur important. Les colonies avec ajout de nourriture sont devenues plus grosses (en nombre d’ouvrières) et ont eu un meilleur succès reproducteur que les colonies témoins, par 51% et 86% respectivement. Toutefois, malgré que l’ajout de nourriture a permis de produire des colonies plus grosses, cela n’a pas permis aux colonies de mieux se défendre contre les macroparasites Psithyrus, Fannia canicularis, Brachicoma devia et Vitula edmandsae.
Le suivi du taux d’activité de butinage de certaines de ces colonies démontre que les colonies nourries ont eu un taux d’activité de butinage par ouvrière 25% plus bas que les colonies témoins. Les ouvrières des colonies dont les réserves en nourriture sont abondantes semblent donc moins butiner sur une base journalière pour réduire les coûts associés à cette activité. Si les ouvrières peuvent en retirer une longévité plus longue, cela fournirait un mécanisme supplémentaire pour expliquer le meilleur succès reproducteur des colonies nourries.Factors that limit the reproductive success of bumblebee field colonies are poorly known. I explored the effect of the queen’s body size, food availability, and some parasites on reproductive success by following the development of more than 200 field colonies of eight species of bumblebees (Bombus impatiens, B. fervidus, B. perplexus, B. terricola, B. bimaculatus, B. ternarius, B. rufocinctus et B. vagans vagans). Larger queens were more likely to reproduce, and, for queens that did so, there was a positive relationship between their body size and the number of sexuals produced. The higher success of larger queens is, at least in part, attributable to the production of larger colonies and, in some species, to the ability to prevent usurpations by Psithyrus (a parasitic subgenus of bumblebees). The higher success of larger queens was not related to the date of nest establishment or to usurpations by other Bombus queens. A field experiment in which I added food to half of the colonies over the entire season showed that food availability was also an important factor. Colonies with increased food supplies reached larger sizes (in number of workers) and had a higher reproductive success than controls, by 51% and 86% respectively. In particular, food supplementation increased the number of males produced and the probability of producing gynes (young queens). However, despite some clear advantages of having larger food supplies such as the build-up of larger worker populations, food supplementation did not appear to help colonies defend themselves against macroparasites because experimental and control colonies experienced similar levels of parasitism by Psithyrus, Fannia canicularis, Brachicoma devia, and Vitula edmandsae. By recording the foraging activity rate in some of these colonies, I showed that food supplementation reduced the foraging activity rate per worker by 25% relative to control colonies. Workers from colonies with abundant food supplies thus appear to forage less on a daily basis to reduce foraging risks and costs. If workers benefit from an increased longevity by reducing their activity, this would provide an additional mechanism to explain the increased reproductive success of colonies with increased food supplies.
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O'Donoghue, Paul. "Reproductive success and effective population size in ungulates". Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528893.
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Banks, M. J. "Population dynamics and lifetime reproductive success of damselflies". Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304819.
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Dickerson, Bobette Ray. "Reproductive success in wild pink salmon, Oncorhynchus gorbuscha /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5337.
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Butcher, Jerrod Anthony. "Minimum patch size thresholds of reproductive success of songbirds". Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2842.
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Payne, Adam Gordon. "Male reproductive success in the beaugregory damselfish, Stegastes leucosticus". Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400343.
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Jones, M. Genevieve W. "Individual variation in reproductive success in the wandering Albatross". Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11500.
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To conserve threatened species it is important to protect the productive individuals, and so I aimed to identify factors accounting for individual-level variation in long-term reproductive success. I examined current breeding characteristics that might explain past reproductive performance amongst experienced breeders.
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Kieckbusch, Jens. "How do natural killer cells contribute to reproductive success?" Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708449.
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McLean, Jennifer Elizabeth. "Reproductive success of hatchery and wild steelhead, Oncorhynchus mykiss /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5327.
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Inoue, Eiji. "Male reproductive success and kin structure in primate societies". 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136839.
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Orr, Harold Allen. "Social Factors Affecting Male Reproductive Success in Nasonia vitripennis". W&M ScholarWorks, 1985. https://scholarworks.wm.edu/etd/1539625295.
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Royle, Nicholas John. "Reproductive decisions in the lesser black-backed gull Larus fuscus and their effects on reproductive success". Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4688/.
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The effect of several fundamental reproductive 'decisions' upon reproductive success were examined over a three year period at a large, inland gullery in the Pennines. Variations in reproductive parameters in relation to timing of breeding and reproductive success were compared among years. Determinants of the degree of hatching asynchrony were identified. Eggs from two years were taken for yolk lipid analysis, using gas chromatography. Variation in micronutrient content of eggs within clutches and between years was assessed in relation to egg size and yolk size, in order to examine resource allocation decisions of individuals. Timing of breeding of individuals was experimentally manipulated through the exchange of whole clutches of eggs between early and late laying birds, whilst controlling for variation in clutch size and egg-size, in order to assess whether the seasonal decrease in reproductive success was best explained by a decrease in food supply or differences in quality among parents. I experimentally manipulated the within-brood mass hierarchy of gulls, whilst controlling for variation in both chick quality and parental quality, in order to assess the effect of hatching asynchrony per se on chick growth and survival, and whether parents optimized the degree of hatching asynchrony with respect to the prevailing food supply. Brood size was experimentally reduced in order to assess the costs and benefits of the production of supernumary young. This was acheived by comparison of chick growth, feather development and chick survival of unmanipulated three-chick broods with broods where either the a-chick or the c- chick had been removed. I present a general discussion of the results within the context of life-history theory and a model for the evolution of hatching asynchrony in the lesser black-backed gull.
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Patterson, Michael E. "Piping plover breeding biology and reproductive success on Assateague Island". Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43276.
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I studied the piping plover on Assateague Island during the 1986 and 1987 breeding seasons. In 1987, I estimated the population to be 69 pairs. During both years, plovers nested on only a few portions of the island. I think that this pattern of nesting was determined by the distribution of three types of foraging habitats: bayside mud and sand flats, saltwater pools formed by storm tides, and a drawn down waterfowl impoundment. Reproductive rates were lower than two recent estimates of the level necessary to maintain a stable population. The primary problem was poor nest success and the leading cause of nest loss was nest predation by red foxes (Vulpes vulpes) and raccoons (Procyon Iotor). I was not able to identify factors responsible for chick mortality, but my data show a relationship between chick survival and foraging habitat. Broods feeding on bayside foraging areas had a much higher survival rate than broods which did not have access to these areas. Management efforts should focus on reducing nest predation. Recent experiments have indicated that predator exclosures constructed around individual nests can be used to reduce nest predation. These exclosures should be tested on Assateague. Future research efforts should focus on the role of foraging habitat in breeding site selection and the relationship between chick survival and the type of foraging used.Master of Science
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Lagrange, Paméla. "Déterminants de la survie et de la dispersion de reproduction par une approche Capture-Marquage-Recapture chez l’Hirondelle bicolore au Québec". Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6855.
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Résumé : En Amérique du Nord, la superficie des monocultures utilisatrices d’intrants tels que des fertilisants et des pesticides couvre aujourd’hui 85 % des surfaces agricoles et autant de pâturages ont disparus en 50 ans afin de répondre aux besoins de l’Homme. Ces changements d’usage des terres ont profondément transformé le paysage et altéré la biodiversité des agro-écosystèmes. Parmi les espèces d’oiseaux champêtres, les insectivores aériens tels l’Hirondelle bicolore, Tachycineta bicolor, ici étudiée, présentent un fort taux de déclin des effectifs, reflétant probablement une dégradation des agro-écosystèmes. Les mécanismes biologiques à l’origine de ce déclin sont encore méconnus ainsi que les patrons de dispersion chez les passereaux migrateurs. Le présent travail vise à étudier les effets environnementaux sur les traits individuels (survie et succès reproducteur) et la dispersion de reproduction (probabilité de disperser et taux d’occupation des sites de reproduction) chez l’Hirondelle bicolore. Pour ce faire, 2200 reproducteurs et 8000 oisillons ont été bagués entre 2004 et 2013 et suivis en reproduction pendant 10 ans sur une aire d’étude au Sud du Québec, laquelle est composée de 40 sites et couvre une mosaïque de paysages agricoles hétérogènes. Le développement d’un nouveau modèle de capture-marquage-recapture, flexible d’utilisation, a permis de réduire les biais d’estimation des probabilités de survie et de dispersion de l’espèce. Cette approche a permis de tester l’effet de plusieurs variables en lien avec la qualité de l’habitat, l’information publique et les caractéristiques individuelles sur la variabilité des paramètres de dispersion, de survie et de succès reproducteur au niveau individuel. Les milieux cultivés intensivement associés à la présence du Moineau domestique, Passer domesticus, un compétiteur pour les cavités de reproduction, diminuaient au maximum de 19 % la survie des mâles. Les femelles étaient quant à elles affectées par le coût de la reproduction, qui était d’autant plus grand en milieu intensif qu’il y avait une présence de moineaux et une disponibilité moindre en ressources alimentaires. Pour autant, la décision de disperser n’était pas affectée par les conditions environnementales que ce soit par la présence de compétiteurs ou la qualité du milieu, et ne dépassait pas les 4 % chez les mâles. Les femelles dispersant jusqu’à 14 fois plus s’appuyaient sur leur expérience personnelle pour décider de disperser. Un échec de reproduction augmentait jusqu’à 7 fois la probabilité de disperser et pour la première fois chez une espèce à courte durée de vie, nous avons montré que la probabilité de disperser était augmentée l’année suivant une première dispersion. Ces patrons de dispersion étaient stables dans le temps. La dispersion semblait donc être un processus coûteux, comparé à la fidélité au site, qui apparaissait comme un phénotype minoritaire dans la population. Elle répondait à des conditions défavorables de reproduction. Enfin, ce travail montre l’utilisation de l’information publique dans la décision de s’établir sur un site généralement fortement dense et productif en jeunes l’année précédente et ce, une fois que la décision de disperser est amorcée. La présence de moineaux et la forte proportion de cultures intensives dans un rayon proche participaient également à ll‘évitement des sites lors de l’établissement. D’après ces résultats, le milieu intensif contribuerait au déclin de l’Hirondelle bicolore.Abstract : In North America, monoculture areas using high inputs of fertilizers and pesticides cover 85 % of agricultural lands, and as many pastures disappeared in the past 20 years to satisfy human food needs. These land-use changes have deeply transformed landscapes and altered the biodiversity of agro-ecosystems. Among farmland birds, aerial insectivores such as Tree Swallow, Tachycineta bicolor, studied here show a high rate of decline in their abundance, partly reflecting the degradation of agro-ecosystems where they breed. Biological mechanisms leading to the decline and dispersal patterns in migratory passerines are still poorly known. The present work quantifies the environmental effects on Tree Swallow individual traits (survival, reproductive success) and breeding dispersal (probability to disperse and occupation rates of breeding sites). Between 2004 and 2013, 2200 breeders and 8000 chicks were ringed and monitored during 10 breeding seasons on a study area composed of 40 sites and covering a mosaic of heterogeneous agricultural landscapes in southern Québec. The development of a new, flexible capture-mark-recapture model has reduced estimate bias of survival and dispersal probabilities of Tree Swallows. This approach allowed to assess the effect of several variables linked to habitat quality, public information and individual characteristics on dispersal, survival and reproductive success parameters of individuals. Within intensively cultivated landscapes associated to the presence of a nest site competitor, the House sparrow, Passer domesticus, male survival is up to 19 % lower. Females were affected by the cost of reproduction, especially in intensive landscapes where House sparrows and found and where food resources and nest site appear limited. Dispersal probability was not affected by environmental conditions either through the presence of House sparrows or habitat quality, and was restricted to 4 % in males. Females, which dispersed up to 14 times more than males, based their decision on their personal experience. Breeding failure increased up to 7 times the probability to disperse and for the first time in a short-lived species, I show that dispersal likelihood increased if the individual had dispersed in the previous year. These dispersal patterns were stable in time. Dispersal appeared as a costly process compared to site fidelity and was a minority phenotype in the population. It appeared an answer to unfavorable condition for reproduction. Finally, this work shows the use of public information (partners density, fledglings productivity the previous year) on the decision to settle on a site and this, after the dispersal decision had been initiated. The presence of House sparrows and the proportion of intensive areas near nest boxes were used as information to select a breeding site. Based on these findings, agricultural intensification likely plays a role in the decline of Tree swallow populations.
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Gauthey, Zoé. "Effet de l’environnement sur l’évolution de la sélection sexuelle chez la truite commune (Salmo trutta)". Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3049/document.
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La sélection sexuelle est une composante de la sélection naturelle qui génère des différences de succès reproducteur entre les individus par le filtre de la reproduction, et influence donc la transmission intergénérationnelle des gènes. Dans le cadre de cette thèse, l’effet de la variabilité de l’environnement hydraulique sur la sélection sexuelle chez la truite commune a été étudié à différentes échelles : intra- et inter-populationnelle. Des méthodes nouvelles permettant de mieux appréhender l’investissement reproducteur, ainsi que de décomposer l’effet des traits sur la fitness des individus en fonction des différentes étapes de la sélection sexuelle, ont été mises au point. Les expériences réalisées en milieux naturel et semi-naturel indiquent que la variabilité environnementale n’affecte pas le choix d’habitat de reproduction par les femelles, mais peut affecter l’investissement reproducteur dans la compétition par exemple, ainsi que les flux de gènes entre des populations génétiquement distinctes. Ces résultats permettent une première projection de l’évolution de la sélection sexuelle dans le contexte du changement climatique qui prédit l’augmentation de la variabilité hydrologique en zone tempéréeAs a component of natural selection, sexual selection produces variation in reproductive success throughout the reproductive period, and therefore impacts genes transmission between generations. During this PhD, the effect of variation in hydraulic environment on sexual selection in brown trout was investigated at both within and between populations scales. New approaches to improve estimation of reproductive investment, as well as models to decompose the effect of traits on individual fitness at each stage of sexual selection, were developed. Experiments in natural and semi-natural environments indicate that environmental variation does not impact reproduction habitat choice by females, but it can modify reproductive investment in some populations, as well as it can control gene flow between genetically distinct populations. These results help to understand the evolution of sexual selection in the broad context of increasing stochastic variations of river systems hydrology as predicted by climate change models in temperate areas
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Logie, John W. "Population ecology and lifetime reproductive success of dippers Cinclus cinclus". Thesis, University of Stirling, 1998. http://hdl.handle.net/1893/26684.
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Acidified catchments are known to hold significantly reduced dipper Cinclus cinclus populations throughout the year relative to circum-neutral rivers, although the processes leading to these declines remain unclear. This study considered the population ecology of dippers within the circumneutral River Devon catchment, Central Scotland, and focused primarily on determining the factors influencing survival, breeding probabilities and reproductive success. It aimed to examine the role of spatial variation in 'habitat quality' on the population (and meta-population) dynamics of dippers, based on measures of seasonal and lifetime reproductive success, and the balance between survival and reproduction; in particular, to assess if the reduced reproductive success of dippers on acid rivers is likely to lead to population declines. Within the Devon catchment, approximately 81% of all adults survived from spring (March/April) to autumn (September/October), with 65% of these birds surviving from autumn to the following breeding season. Overall, these estimates predicted annual adult survival rates of c.53%, with no significant differences between years. Population density had no detectable effect on adult mortality rates, although juvenile over-winter survival was significantly lower than the adult rate at between 40 and 58%, and negatively related to the total size of the autumn population. There was no evidence of sex differences in juvenile over-winter survival, or any significant influence of weather or river flows on the rates for adults or juveniles. The local post-fledging survival of females was significantly lower than for males, however, apparently reflecting sex differences in post-natal dispersal. On average, less than 6.5% of all eggs laid, or 10.4-14.5% of male and 6.3-9.2% of female fledglings raised within the Devon catchment survived locally to breeding age. Juvenile, although not adult, recapture rates in spring were significantly lower than for birds known to have bred previously and negatively related to spring river flows. This suggested that with recapture dependent on a breeding attempt that was successful at least until laying, either more first year birds failed during the initial stages of nesting or that full breeding was not achieved at age one. The birds fledging the most young, both within a season and over a lifetime, all bred at 'prime' lowland sites characterised by wide, shallow rivers of intermediate gradient, although with less than 10% of all birds attempting to raise a second brood each year, no significant habitat differences were identified in any component of reproductive output measured until fledging. River width, altitude and gradient were all significantly inter-correlated and related to laying date, however, and post-fledging survival was significantly reduced for late fledged young. On average, lowland birds laid earlier than upland breeders, and were significantly more likely to produce autumn 'recruits' due to the enhanced post-fledging survival prospects of their young. This suggested that broad measures of river structure can provide a biologically appropriate classification of habitat quality. The size of the breeding population of dippers within the Devon catchment appeared to be related to the availability of critical resources, most likely food, roost sites and ultimately breeding territories through density-dependent changes in over-winter mortality and recruitment. The relative importance of resource abundance and recruitment levels in determining autumn population densities on acid streams still remained unclear, although reference to published relationships between acidity and reproductive success suggested that with adult survival at the rate estimated for the Devon catchment, many dipper populations are unlikely to produce sufficient recruits to match all adult losses, and may only persist with continued immigration from more productive (circumneutral) catchments elsewhere.
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Jones, Kelly C. "Reproductive biology and nest success of cerulean warblers in Indiana". Virtual Press, 2006. http://liblink.bsu.edu/uhtbin/catkey/1339151.
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Within the Pleasant Run Unit of the Hoosier National Forest, Morgan-Monroe State Forest, and Yellowwood State Forest in Indiana, a total of 45 Cerulean Warbler territories were mapped during 2004 and 2005. We sampled vegetative characteristics of the Cerulean Warbler territories and 45 random plots in southern Indiana, as part of a description of Cerulean Warbler habitat usage in this part of their breeding range. Cerulean Warbler song-perch trees were larger and taller than surrounding trees within territories. In addition, certain species were selected as song-perch trees, whereas others were avoided. Territories were characterized by fewer mid-sized trees (11.6-14.9 m tall), and a higher mean canopy height. In addition to tree size, tree species may play an important role in territory site selection of Cerulean Warblers in southern Indiana. Relative abundance, reproductive success, territory sizes, and observations of nest material thievery are also reported.Department of Biology
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Convey, Peter. "Influences on mating behaviour and reproductive success in the Odonata". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330166.
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Gichuki, Nathaniel Ndegwa. "Factors affecting the reproductive success of the Grey Crowned Crane". Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318098.
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Jiang, Sanjie. "CMV infection affects bumblebee pollination behaviour and plant reproductive success". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275637.
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Viruses can affect plant-insect interactions by altering emission of plant volatile organic compounds (VOCs). Previous work in the lab suggested that VOCs emitted by tomato (Solanum lycopersicum) plants infected with cucumber mosaic virus (CMV) were more attractive to bumblebees (Bombus terrestris) in free choice assays. I extended this work using Arabidopsis thaliana mutants with lesions in genes encoding factors in RNA silencing. In conditioning assays, I confirmed that plant VOC emission is controlled in part by the microRNA regulatory pathway. I used gas chromatography coupled to mass spectrometry and principal component analysis to confirm that CMV infection caused changes in VOC emission by tomato. VOCs collected from non-flowering mock-inoculated and CMV-infected plants were qualitatively distinct from each other. CMV-infected plants also released greater quantities of VOCs than mock-inoculated plants. CMV appears to be both ‘turning up the volume’ of plant volatile emission, whilst ‘tuning’ volatile blend composition so as to diminish levels of a repellant signal. These data are likely to explain how bumblebees can discriminate between VOCs emitted by mock-inoculated and CMV-infected plants. To determine if CMV infection of tomato plants affects plant reproductive success, I carried out a series of bumblebee pollination experiments. Bumblebees pollinate tomato by ‘buzzing’ (sonicating) the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. First, I established that CMV-infected tomato plants produced fruits with a lower seed yield than mock-inoculated plants. When single bumblebees were allowed to buzz-pollinate flowers in a small flying arena, the fruit that developed from buzz-pollinated flowers on virus infected plants had significantly more seeds than fruit from non-visited flowers. Subsequent experiments were performed in a large flying arena. Bumblebees consistently spent longer foraging on the mock-inoculated tomato plants but seed yield was increased by bumblebee pollination in both mock-inoculated as well as virus-infected tomato plants. However, although buzz-pollination significantly enhanced seed yield from CMV-infected plants compared to fruit from non-buzz-pollinated flowers, the yield was higher in buzz-pollinated fruits from mock-inoculated plants. Similar experiments were carried out utilizing a transgenic line of tomato that constitutively expresses the green fluorescent protein in order to estimate the level of cross-pollination from either CMV-infected plants to mock-inoculated plants or vice versa. More pollen from virus-infected plants was transferred to mock-inoculated plants than the reciprocal cross. However, some caution is needed in the interpretation of the larger scale experiments because the tomato plants were affected by a fungal infection. I investigated if the defensive plant hormone salicylic acid (SA) affects bee-perceivable VOC emission. Exogenous SA treatment renders non-flowering tomato plants more attractive to bumblebees in free choice experiments in which bees could only perceive VOCs, but bumblebees spent less time visiting SA-treated flowering tomato plants in the glasshouse (when the bumblebees were allowed unimpeded access to the flowers). Taken together, these data provide evidence that virus infection can affect host-pollinator interactions. Speculatively, CMV infection may change the fitness of susceptible plants via changes in production of pollinator-attractive VOCs and this may affect the balance of resistant or susceptible plants within the host population.
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Piggott, April. "REPRODUCTIVE SUCCESS IN HATCHERY-PRODUCED EASTERN OYSTER, CRASSOSTREA VIRGINICA (GMELIN)". VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3503.
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The eastern oyster (Crassostrea virginica Gmelin 1791) has great ecological and economic importance but populations have declined, especially in Chesapeake Bay, to historically low numbers. Hatcheries strive to produce oysters with beneficial characteristics for supplementation and commercial purposes, both natural and stimulated mass spawning. Unequal contribution of parents in mass spawnings potentially can lead to high levels of inbreeding and a loss of beneficial characteristics in offspring. In this study, we determined microsatellite genotypes for parents (n^parents =24, 49, and 77 parents) and progeny (n=96 each) of three hatchery-produced families and used the data for parental assignment. We observed the presence of more than two alleles per locus for some offspring, yet because genetic analysis software only allows for a maximum of two alleles per locus, we chose the two alleles with the strongest signals. For the three parent “populations,” 71% of alleles had frequencies of <0.05 and observed heterozygosities were lower than expected by an average factor of 0.27. Inbreeding within the various parent populations was similar across the three families ranging from F^IS 0.26–0.43. In all three families, the offspring exhibited greater levels of genetic diversity and lower inbreeding levels than the parents (F^IS 0.14–0.21), and in some cases offspring exhibited alleles that were not present in the parents. Variance in the number of offspring produced per parent was observed for all families and in general, <10% of potential parents (generally 2-5 females and 1-3 males) produced >10% of the offspring. Reproductive success for spawning parents, N^b, determined by three methods, ranged from 0.07 to 0.27. As the number of parents per family increased, a higher proportion of parents failed to produce offspring. Across all three families, the average effective number of breeders was N^b = 7.1 and the level of reproductive success was inversely proportional to the number of potential parents. This finding implies that to maintain high levels of diversity and beneficial characteristics in the offspring (and to avoid the chance of unintentional inbreeding), hatcheries should perform more spawnings with fewer parents.
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Steinhart, Geoffrey B. "Exploring factors affecting smallmouth bass nest success and reproductive behavior". Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1079982955.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains p.; also includes graphics. Includes abstract and vita. Co-advisors: Elizabeth A. Marschall and Roy A. Stein, Dept. of Evolution, Ecology, and Organismal Biology. Includes bibliographical references.
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Lane, Sarah Marie. "The role of cuticular hydrocarbons in determining male reproductive success". Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/20078.
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Cuticular hydrocarbons (CHCs) are found on the outer cuticle of all terrestrial arthropods. Although their primary function is in desiccation prevention, these compounds have also been shown to play a variety of roles in insect chemical communication, from species and sex recognition to providing cues of dominance and attractiveness. However, despite growing evidence of their versatility as cues, our knowledge of how CHCs are used in mating interactions is limited to Drosophila and field crickets. In this thesis I investigate the roles CHCs play in interactions at each stage of the mating process in the broad-horned flour beetle Gnatocerus cornutus. I assess the relative importance of CHCs in influencing male reproductive success and examine the complex interplay between different episodes of selection and the mechanisms of sexual selection acting on males. I use a combination of behavioural assays, experimental manipulations and gas chromatography. First, I identify the role of CHCs as cues of sperm competition risk and intensity, demonstrating how the presence of male-derived CHCs on the cuticles of virgin females elicits males to adjust their pre- and post-copulatory investment (chapter 2), by providing information on the state of their competitive environment. I then go on to look at the stability of CHCs as cues of sperm competition over time, finding that they are highly sensitive to environmental degradation (chapter 3) and do not persist in the habitat substrate of this species. Next, I investigate how male CHCs determine fighting and mating success. By estimating and comparing the strength and form of sexual selection imposed by male-male competition and female mate choice, I show that male CHCs are subject to strong antagonistic sexual selection (chapter 4). By experimentally manipulating male CHC profile, I then attempt to verify the selection gradients estimated for female choice 3 (chapter 5). However, my experimental manipulation fails to verify the importance of male CHCs for female mate choice. Finally, I explore the role of same-sex sexual behaviour (SSB) in determining male reproductive success (chapter 6). I find evidence to suggest that SSB may in fact be a form of aggression in its own right, and demonstrate that SSB and fighting may provide equivalent means for males to overcome female choice and secure a mating advantage. My results indicate that CHCs play key roles as chemical cues throughout the mating process and significantly impact male reproductive success. My thesis reveals the intricate nature of the relationships between mechanisms of sexual selection, alongside highlighting the need to consider both the social and physical environment when investigating the importance of chemical cues. I discuss the implications of these results for the evolution of male CHCs and how my findings can be used to further our knowledge of this field.
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Panagakis, Andrea. "Le succès reproducteur au début de la vie, la longévité et le succès reproducteur tardif chez la femelle de la chèvre de montagne". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26943.
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La théorie biodémographique liée à l’âge prédit un compromis entre l'allocation reproductrice au début de la vie et la reproduction tardive, la survie, ou ces deux composantes de la valeur adaptative à la fois. Actuellement, la notion de compromis a été démontrée par plusieurs études en milieu naturel. Par contre, l’effet des conditions environnementales et de la qualité des individus a rarement été étudié. Grâce aux données longitudinales récoltées dans la population de chèvres de montagne (Oreamnos americanus) de Caw Ridge, Alberta, nous avons pu examiner l'influence de l'âge à la première reproduction (APR) et du succès reproducteur au début de la vie (SRD) sur la longévité et sur le succès reproducteur tardif, en tenant compte des conditions environnementales natales et de la qualité des individus. Contrairement à nos prédictions, nous n'avons pas détecté la présence d’un compromis entre l'allocation reproductrice au début de la vie et la performance tardive dans cette population. Au contraire, l'APR et le SRD avaient des effets directs et faiblement positifs sur le succès reproducteur tardif. La densité de population à la naissance d'une femelle a fortement réduit le succès reproducteur tardif de manière directe. Elle l'affectait également de manière indirecte par son effet sur l'APR et le SRD. La densité était le seul facteur déterminant de la longévité, par un effet direct et fortement négatif. Tel que démontré dans des études précédentes sur la même population, les femelles de bonne qualité avaient un SRD élevé par rapport aux femelles de mauvaise qualité. Ces résultats fournissent une vision intégrée des compromis au début et à la fin de la vie, en soulignant l'importance de tenir compte des conditions environnementales, qui pourraient engendrer des implications à long terme sur la dynamique des populations.The life-history theories of aging, which describe the mechanisms underlying age-related physiological declines, predict lifetime trade-offs between early reproductive allocation and latelife survival, reproduction, or both components of fitness. Recent studies in wild populations have found evidence for these early-late life trade-offs, but rarely across multiple traits while exploring the additional effects of variation in environmental conditions and individual quality. Benefiting from 27 years of longitudinal data from monitoring adult female mountain goats (Oreamnos americanus) at Caw Ridge, Alberta, we investigated the influence of age at first reproduction (AFR) and early reproductive success (ERS) on longevity and late reproductive success, while accounting for the influence of natal environmental conditions and individual quality. Contrary to our predictions, we did not find evidence for early-late life trade-offs in this population. AFR and ERS instead had positive but weak direct effects on late reproductive success. Population density in the year of a female's birth strongly reduced late reproductive success both directly and indirectly through AFR and ERS. The sole determinant of female longevity was the direct, negative effect of density. As predicted by previous studies in this population, high-quality females had a higher ERS compared to low-quality females. The results of this investigation provide an integrated picture of early-late life trade-offs, underscoring the importance of accounting for environmental conditions due to their potentially strong implications for population dynamics.
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Rooney, Jennifer. "Male reproductive investment in two fireflies, Photinus ignitus and Ellychnia corrusca : effects on male and female reproductive success /". Thesis, Connect to Dissertations & Theses @ Tufts University, 2000.
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Thesis (Ph.D.)--Tufts University, 2000.Adviser: Sara M. Lewis. Submitted to the Dept. of Biology. Includes bibliographical references (leaves 100-107). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Lagrange, Paméla. "Déterminants de la survie et de la dispersion de reproduction par une approche capture-marquage-recapture chez l'Hirondelle bicolore au Québec". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS077/document.
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En Amérique du Nord, la superficie des monocultures utilisatrices d'intrants tels que des fertilisants et des pesticides couvre aujourd'hui 85% des surfaces agricoles et autant de pâturages ont disparu en 20 ans afin de répondre aux besoins de l'homme. Ces changements d'usage des terres ont profondément transformé le paysage et altéré la biodiversité des agro-écosystèmes. Parmi les espèces d'oiseaux champêtres, les insectivores aériens tel l'Hirondelle bicolore, Tachycineta bicolor, ici étudiée, présente un fort taux de déclin des effectifs, reflétant probablement une dégradation des agro-écosystèmes. Les mécanismes biologiques à l'origine de ce déclin sont encore méconnus ainsi que les patrons de dispersion chez les passereaux migrateurs. Le présent travail vise à étudier les effets environnementaux sur les traits individuels (survie et succès reproducteur) et la dispersion de reproduction (probabilité de disperser et taux d'occupation des sites de reproduction) chez l'Hirondelle bicolore. Pour ce faire, 2200 reproducteurs et 8000 oisillons ont été bagués entre 2004 et 2013 et suivis en reproduction pendant 10 ans sur une aire d'étude au Sud du Québec, laquelle est composée de 40 sites et couvre une mosaïque de paysages agricoles hétérogènes. Le développement d'un nouveau modèle de capture-marquage-recapture, flexible d'utilisation, a permis de réduire les biais d'estimation des probabilités de survie et de dispersion de l'espèce. Cette approche a permis de tester l'effet de plusieurs variables en lien avec la qualité de l'habitat, l'information publique et les caractéristiques individuelles sur la variabilité des paramètres de dispersion, de survie et de succès reproducteur au niveau individuel. Les milieux cultivés intensivement associés à la présence du Moineau domestique, Passer domesticus, un compétiteur pour les cavités de reproduction, diminuent jusqu'à 19% la survie des mâles. Les femelles sont quant à elles affectées par le coût de la reproduction, qui est d'autant plus grand en milieu intensif qu'il y a présence de moineaux et une disponibilité moindre en ressources alimentaires. Pour autant, la décision de disperser n'est pas affectée par les conditions environnementales que ce soit par la présence de compétiteurs ou la qualité du milieu, et ne dépasse pas les 4% chez les mâles. Les femelles dispersant jusqu'à 14 fois plus s'appuient sur leur expérience personnelle pour décider de disperser. Un échec de reproduction augmente jusqu'à 7 fois la probabilité de disperser et pour la première fois chez une espèce à courte durée de vie, nous montrons que la probabilité de disperser est augmentée l'année suivant une première dispersion. Ces patrons de dispersion sont stables dans le temps. La dispersion apparait donc comme un processus coûteux, comparé à la fidélité au site, qui apparaît comme un phénotype minoritaire dans la population. Elle répond à des conditions défavorables de reproduction. Enfin, ce travail montre l'utilisation de l'information publique (densité en partenaires, productivité en jeunes l'année précédente) dans la décision de s'établir sur un site et ce, une fois que la décision de disperser est amorcée. La présence de moineaux et la proportion de cultures intensives dans un rayon proche participent également à la sélection d'un site. D'après mes résultats, le milieu intensif contribuerait au déclin de l'Hirondelle bicoloreIn North America, monoculture areas using high inputs of fertilizers and pesticides cover 85% of agricultural lands, and as many pastures disappeared in the past 20 years to satisfy human food needs. These land-use changes have deeply transformed landscapes and altered the biodiversity of agro-ecosystems. Among farmland birds, aerial insectivores such as Tree swallow, Tachycineta bicolor, studied here show a high rate of decline in their abundance, partly reflecting the degradation of agro-ecosystems where they breed. Biological mechanisms leading to the decline and dispersal patterns in migratory passerines are still poorly known. The present work quantifies the environmental effects on Tree swallow individual traits (survival, reproductive success) and breeding dispersal (probability to disperse and occupation rates of breeding sites). Between 2004 and 2013, 2200 breeders and 8000 chicks were ringed and monitored during 10 breeding seasons on a study area composed of 40 sites and covering a mosaic of heterogeneous agricultural landscapes in southern Québec. The development of a new, flexible capture-mark-recapture model has reduced estimate bias of survival and dispersal probabilities of Tree swallows. This approach allowed to assess the effect of several variables linked to habitat quality, public information and individual characteristics on dispersal, survival and reproductive success parameters of individuals. Within intensively cultivated landscapes associated to the presence of a nest site competitor, the House sparrow, Passer domesticus, male survival is up to 19% lower. Females are affected by the cost of reproduction, especially in intensive landscapes where House sparrows and found and where food resources and nest site appear limited. Dispersal probability is not affected by environmental conditions either through the presence of House sparrows or habitat quality, and is restricted to 4% in males. Females, which disperse up to 14 times more than males, base their decision on their personal experience. Breeding failure increases up to 7 times the probability to disperse and for the first time in a short-lived species, I show that dispersal likelihood increases if the individual has dispersed in the previous year. These dispersal patterns are stable in time. Dispersal appears as a costly process compared to site fidelity and is a minority phenotype in the population. It appears an answer to unfavorable condition for reproduction. Finally, this work shows the use of public information (partners density, fledglings productivity the previous year) on the decision to settle on a site and this, after the dispersal decision has been initiated. The presence of House sparrows and the proportion of intensive areas near nestboxes are used as information to select a breeding site. Based on my findings, agricultural intensification likely plays a role in the decline of Tree swallow populations
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Celis, Patricia. "Reproductive success and male traits in the spotless starling, Sturnus unicolor". Thesis, St Andrews, 2009. http://hdl.handle.net/10023/722.
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Lord, Alexa. "Environmental Components of Reproductive Success in the Blue tit, Parus caeruleus". Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486417.
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Previous work has shown that reproductive success in the blue tit (Parus caeruleus) is largely environmentally determined. In this thesis I explore the roles of human disturbance. habitat quality and parental quality as environmental components of reproductiv~ success. measured in terms of lay date. clutch size, number of offspring fledged and body condition of offspring. I start by quantifying the effects of human disturbance on vocal defence behaviour and reproductive success. -My results show. that blue tits increase their investment in vocal oefence as their chicks age. and quickly become habituated to human disturbance. I found no evidence that reproductive success was significantly related to human disturbance or investment in vocal defence. I then investigate the relative effects of habitat quality and parental quality at the territory level on reproductive success. The prevalence of oaks. the preferred host of the primary food source for breeding blue tits. within estimated territories is measured and relationships with reproductive success explored.. The number of oaks within a blue tit territory is positively associated with reproductive success. leading to advancement of lay date. increased clutch size and greater fledging success. Body condition of offspring. however. is not related to habitat quality. but instead is positively associated with the body condition of both the male and female parents. The mechanism.behind .these relationships are then further examined using data on the phenology of individual oaks in a breeding territory. I found that -oak phenology is a significant determinant of chick condition and survival and that. where blue tits mis-time their reproduction relative the phenology of the oaks. fecundity is reduced. Lastly. I discuss the implications-of my findings in the context of environmental change. and identify..possible directions for future research.
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Rakitin, Ana. "Body size and reproductive success in Atlantic cod, Gadus morhua L". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0007/NQ43270.pdf.
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Rise, Marlies. "The role of prezygotic events in the reproductive success of conifers". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ62525.pdf.
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Durocher-Granger, Léna. "The effects of phenotypic plasticity on reproductive success of Trichogramma euproctidis". Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104821.
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The body size of parasitoids varies with the amount of resources contained in a single host and this phenotypic plasticity applies to their reproductive traits. The impact of this phenotypic plasticity on the reproductive success of the egg parasitoid Trichogramma euproctidis in context of competition has been investigated. This species has been chosen for this study because different aspects of the reproductive strategies of both males and females are well known.Phenotypic plasticity in reproductive traits was observed in T. euproctidis. Results show that sperm size, and oocyte volume and number increased with body size. An index of maternal investment was calculated to determine how the effort invested in reproduction by females varies with body size and suggests that larger females invested more resources in reproduction. The plasticity in reproductive traits in T. euproctidis was a consequence of an environmental constraint of food availability, suggesting that resources acquisition during larval stage is a determinant factor of fitness. In context of sperm competition, smaller sperm were able to fertilize eggs earlier in an oviposition sequence but that advantage was apparent only when small sperm were in numerical inferiority which indicates that smaller sperm can compensate by being more competitive. Oocyte volume did not influence the outcome of the larval competition, but the clutch of the second-ovipositing female was advantaged, suggesting an ovicidal behavior from the second female.Les parasitoïdes démontrent une variation dans leurs tailles corporelles lorsqu'ils sont contraints par la quantité de ressources contenue dans l'hôte. La plasticité phénotypique des caractères reproducteurs du parasitoïde des œufs Trichogramma euproctidis ainsi que son impact sur le succès de reproduction en contexte de compétition ont été étudiés. Cette espèce a été choisie pour cette étude parce que différents aspects des stratégies de reproduction des mâles et des femelles sont bien connus.Une plasticité phénotypique des caractères reproducteurs a été observée pour T. euproctidis. Les résultats ont montré que la longueur des spermatozoïdes, et le volume et le nombre d'oocytes augmentent avec la taille corporelle. Un indice d'investissement maternel a été calculé pour déterminer l'effort investi en reproduction en lien avec la taille corporelle des femelles et suggère que les femelles de grandes tailles investissent plus de ressources en reproduction. Dans cette étude, la plasticité des caractères reproducteurs chez T. euproctidis est une conséquence d'une contrainte environnementale de disponibilité de la nourriture, suggérant que l'acquisition des ressources pendant le stade larvaire est un facteur déterminant de la valeur adaptative.En contexte de compétition spermatique, les petits spermatozoïdes ont fertilisé les œufs plus tôt dans la vie des femelles que les longs spermatozoïdes, mais seulement lorsque les petits spermatozoïdes étaient en infériorité numérique indiquant qu'ils peuvent compenser en étant plus compétitifs. Le volume des oocytes n'a pas influencé les résultats de la compétition larvaire, cependant la progéniture de la deuxième femelle qui pond a été avantagée sur la première, suggérant un comportement d'ovicide de la deuxième femelle.
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Woodroffe, Rosemary Brigitte. "Factors affecting reproductive success in the European badger, Meles meles L". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316891.
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Arundell, Katherine Louise. "Sex and success : factors influencing survival and reproduction in amphipod crustaceans". Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.634200.
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In this thesis I use four amphipod host-parasite systems to investigate factors influencing survival, behaviour and reproduction. In Chapter 2, I identify a newly observed trophically-transmitted parasite, Podocotyle atomon, and assess its impact on the survival and reproduction of its intermediate host Gammarus zaddachi. I observed high prevalence in the field, but found an overall low impact of infection on behaviour and reproductive success, in contrast to similar host: parasite systems. In Chapter 3, I investigate the significance of the carotenoid colouration of the acanthocephalan Pomphorhynchus laevis, infecting Gammarus pulex, in trophic parasite transmission. My results regarding the role of the colouration in transmission proved inconclusive; however, I show th,at the three-spined stickleback Gasterosteus aculateus utilises both visual and olfactory cues to detect amphipod prey. In Chapter 4, I assess the impact of predator cues and infection by vertically transmitted microsporidian parasites on brooding success and brood-care behaviour in two species of amphipod. I found no effect of parasite infection on brooding; however, predator cues were found to influence the characteristic ventilation behaviours of Crangonyx pseudogracilis, suggesting that observed levels of brood-care are a trade-off between maximising ventilation of embryos and minimising predation risk. In Chapter 5, I investigate the relationships between fluctuating asymmetry (FA), parasite infection and fecundity in two gamma rid host: parasite systems. I found no relationship between FA and egg or sperm numbers; however parasite infection by both horizontally and vertically transmitted parasites was associated with increased levels of FA. Finally, in Chapter 6, I investigate the scope for ejaculate tailoring in response to risk and intensity of sperm competition in Gammarus duebeni. I report a decrease in sperm numbers and length in response to increased numbers of rivals and suggest that gammarid investment in mate-guarding negates the risk of sperm competition for this species.
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Rose, Karen Elizabeth. "Factors affecting lifetime reproductive success in red deer stags (Cervus elaphus)". Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388484.
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Lautenbach, Joseph Mark. "Lesser prairie-chicken reproductive success, habitat selection, and response to trees". Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18810.
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Master of ScienceDepartment of Biology
David A. Haukos
The lesser prairie-chicken (Tympanuchus pallidicinctus) is a species of prairie grouse native to the southwest Great Plains. Population declines and threats to populations of lesser prairie-chickens led U.S. Fish and Wildlife Service to list the species as “threatened” under the protection of the Endangered Species Act in May 2014. Lesser prairie-chickens are found within three distinct ecoregions of Kansas and Colorado and portions of the species’ range are affected by tree encroachment into grasslands. The effect of trees on lesser prairie-chickens is poorly understood. I evaluated habitat selection and reproductive success and across the northern portion of the species’ range. I captured female lesser prairie-chickens within the three different ecoregions in Kansas and Colorado to track nest and brood survival and measure nest and brood habitat. My findings show that there are regional and annual variations in nest and brood survival. Mean nest survival during 2013 and 2014 was estimated to be 0.388 (95% CI = 0.343 – 0.433) for a 35-day exposure period. Brood survival during 2013 and 2014 was estimated to be 0.316 (95% CI = 0.184 – 0.457) for 56 days. Chick survival was the lowest during the first week of life and is probably a limiting factor for population growth. Chick and brood survival decreased as Julian hatch date increased. Across the northern portion of the species’ range, females consistently select visual obstruction between 2-3 dm. Vegetation at the nest changes between regions and years to reflect environmental and regional conditions. Broods consistently selected habitats with greater percent cover of forbs than was expected at random across all study sites. Broods also selected against areas of bare ground. The threshold of lesser prairie-chicken use was 2 trees/ha throughout the year. No nests were located within areas with greater densities. Lesser prairie-chickens had a greater probability of use at greater distances from trees and at lower tree densities. To provide adequate nesting habitat managers should provide 2-3 dm of visual obstruction. Providing forb cover with visual obstruction between 2.5-5 dm near nesting habitat should provide adequate habitat for broods. Removing trees in core habitats and expand removal efforts outward should expand potential habitat for lesser prairie-chickens.
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O'Malley, Sean L. C. "Mating behaviour and reproductive success in the reed bunting Mmberiza schoeniclus". Thesis, University of Leicester, 1993. http://hdl.handle.net/2381/34185.
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The reproductive behaviour and success of a number of male reed buntings were studied at Rutland Water (Leicestershire) during the the breeding seasons of 1988, 1989 and 1990. A major constraint on reproductive success was the level of nest predation. Only 42% of nests survived to fledging, representing 41.5% of males' territories. The annual mean productivity for each male was estimated to be 0.77 offspring surviving to the following season. With these large constraints on male reproductive success, extra-pair paternity is seen as potentially highly advantageous to males. Females are constrained in their mate choice indicating a potential advantage in seeking sires from surrounding males of higher quality than their mate. Rates of extra-pair paternity as derived from DNA fingerprinting were found to be high: 50% of chicks and 69% of broods. Approximately one-third of males were responsible for 51 cases of extra-pair paternity. However, 70% of males lost some paternity in their nests to other males with no correlation between levels of extra-pair and within-pair paternity. Copulations were observed to be frequent (estimated to be 4.06 per day) during the prelay period and continued through to the day of the third egg. A large between male variation in copulation rates was observed, with a diurnal peak immediately following the laying of an egg. Observed extra-pair copulations were rare (4.39%) with a significant disparity compared to extra-pair paternity levels, indicating that females may seek furtive extra-pair copulations. Mate guarding as measured by time spent less than 10 m from the female, flights orientated towards the female and vigilance were observed to peak during the prelay period. These behaviours declined dramatically on the day of the first egg, indicating that peak fertility probably occurs prior to egg laying. No increase in mate guarding activity was observed to occur in response to an increased neighbour density, whilst neighbour status did not influence guarding. A diurnal pattern in guarding was recorded for vigilance and all three behaviours showed significant between male variation. Territorial intrusions were mainly by neighbours; they peaked significantly during the prelay period and were responded to by an attack from the defending male. The seeking of extra-pair copulations was observed as excursions into neighbouring territories, followed by an attack from the territory holder. Excursions occurred primarily when males were not mate guarding, during egg laying and incubation, and were significantly directed towards territories with nests in the prelay stage. Song was found not to function as a mate guarding behaviour, with a significant decline in output during the prelay period. Song output increased significantly in the presence of a neighbour with a "fertile" female, supporting the hypothesis that song functions as a measure of male quality to fertile females Song of unpaired males was significantly different from that of paired males and is hypothesised to function in territorial maintenance (and to indicate male status), whereas the more complex song of paired individuals also functions to display male quality to their partners. An analysis of the relationship between behaviour and reproductive success when analysed indicated that males which guarded most were more subject to losing paternity. Acquisition of extra-pair paternity was found to be significantly enhanced through increased song output and excursions. Song output was also recorded as significantly increasing total reproductive success, indicating that females may choose males on the basis of their song to obtain furtive extra-pair copulations.
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Shortlidge, Erin Elizabeth. "Testing the Ecological and Physiological Factors Influencing Reproductive Success in Mosses". PDXScholar, 2014. http://pdxscholar.library.pdx.edu/open_access_etds/1951.
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As non-vascular, early land plants with an aquatic ancestry, mosses do not regulate internal water conditions separate from that of their environment and as a result, evolved mechanisms to survive in a terrestrial world out of water. Yet, there is a widely accepted dogma that moss reproductive success is solely dependent on rainfall events carrying swimming, bi-flagellate sperm across the landscape to reproductively mature and receptive female mosses--but this classic view of moss reproduction may be too simplistic. In this dissertation I test the assumptions of reproductive limitation in mosses and present novel findings in a basal, yet understudied terrestrial plant mating system.
I find evidence of environmental desiccation tolerance in moss sperm, thus offering the potential for stress-tolerant gametes on the landscape possibly suited for various transport vectors, reminiscent of a pollen grain. To investigate the broad evolutionary implications of this newfound complexity in moss sexual reproduction, I tested classic tenets of plant-pollinator theory on the ancient mosses and their ubiquitous microarthropod inhabitants. Experimental results show that mosses and microarthropods are engaged in a "pollination-like" syndrome guided by sex-specific volatile cues that differentially affect microarthropod behavior. These data indicate an existing complex mutualistic relationship and provides new evidence of sexually dimorphic investment by male and female mosses into reproductive success. Further, these data put forth the idea that female mosses challenge an inherent mate limitation by investing into reproductive assurance via maintaining a relationship with microarthropods.
Experimental work further confirms a role for invertebrates in moss reproductive success and tests mutualism theory through ongoing experiments. Such experiments include an assessment of moss genetic diversity, paternity, and male fitness traits as it relates to mosses with or without the presence of microarthropods, thereby testing for fitness benefits gained by mosses possibly engaged in a transport mutualism with microarthropods.
I further tested mutualism, community ecology and moss sexual reproduction concepts in extreme geothermal moss populations living at the edges of inhabitable Earth, and results show that even geothermal moss canopies are diverse and host differential and abundant life. In a first field test of mutualism I found that although extreme heat stress may constrain sexual reproduction in mosses, a correlation between within-population moss genetic diversity and microarthropod abundances exists. To further examine mosses in extreme environments, and how these environments may constrain sexual reproductive success, I evaluated the effects of simulated warming on Antarctic moss physiology and reproductive biology. Data indicates that simulated warming relieves mosses of physiological stress, and results in a greater investment into primary productivity and sexual reproduction. These data support the hypothesis that with less stress, sexual reproduction is increased. Mosses are an ideal system by which to understand organisms that exist in environments ranging from the mesic to the extreme, in the laboratory and the field and even in the classroom, where the small functioning ecosystem of mosses can be used for discovery-based biology education as described in the Mosscosms curriculum.
This work contributes significantly to the field of bryophyte and plant biology by revealing novel insights into the biotic and abiotic drivers of sexual reproduction in mosses.
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Kilduff, Ian Andrew. "Mate choice and reproductive success in the speckled bushcricket, Leptophyes punctatissima". Thesis, Open University, 2000. http://oro.open.ac.uk/54186/.
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Leptophyes punctatissima is unusual in that both sexes call. The male calls, the female replies and the male performs phonotaxis to the stationary female. Consequently mate choice could occur at either of two stages: first, during the interchange of calls and second, on the basis of proximate criteria once the male has approached. There is no evidence that females choose their mates on the basis of calling behaviour or call characteristics, though males that call more may achieve more matings. There is no evidence that body asymmetry has any effect on mating success for either sex. Males on a protein-supplemented diet do not produce larger spermatophores than males whose diet is not supplemented, but they do mate more often, possibly as a result of female choice but more likely because diet affects the rate at which males can produce spermatophores. Unsupplemented females mate more often than supplemented females, possibly as a result of male male choice or because they are seeking matings so that they can supplement their diet with spermatophores. Males give larger spermatophores to unsupplemented females. Larger males produce larger spermatophores. They also mate more often than smaller males, possibly as a consequence of female choice, success in male-male contests, or because larger males have larger energy reserves and can produce spermatophores more quickly. Larger females mate more often than smaller females but only when their diet was supplemented. Females lay more eggs the more times they mate. Females lay heavier eggs after their first mating than they do in later batches, and unsupplemented females lay more eggs after their first mating than supplemented females do, but otherwise female size, diet or level of asymmetry has no effect on the size or weight of eggs, or the number of eggs laid. The total weight of spermatophores females receive does not affect any measure of female reproductive success: neither fecundity, egg size or egg weight is affected by the weight of spermatophores females consume, irrespective of the diet the females were maintained on. Diet, size or number of matings does not affect female longevity.
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Perkins, Jordan Carol. "Reproductive Success and Evaluation of Management Strategies for Least Terns in Maine". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/PerkinsJC2004.pdf.
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