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Greeff, Michael. "Costs and benefits of sexual reproduction." kostenfrei, 2007. http://e-collection.ethbib.ethz.ch/view/eth:29704.
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Chapman, Tracey. "Costs of reproduction in female Drosophila melanogaster." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/13364.
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The experiments presented in this thesis investigated the mechanisms of costs of reproduction in female Drosophila melanogaster. There was no evidence to support the existence of seminal feeding, as remating was not more beneficial for females when they were nutritionally stressed. Continual exposure to males did not lead to an increase in female reproductivy success, suggesting that females were not maximising their reproductive output by frequent rematings. Females that remated often suffered a cost of mating, as a decrease in lifespan and reproductive success. The results also suggested that nutrition itself did not affect remating frequency, and that either the rate of egg-laying or the number of sperm in store accounted for differences in remating probability. Females exposed to males that could not transfer sperm also suffered a cost of mating, suggesting that sperm was not costly; so the cost of mating is probably due to mating itself or the transfer of disease, parasites or accessory fluid. One of the accessory fluid sub-components, the sex peptide (SP), has previously been shown to cause an increase in fecundity and a decrease in female sexual receptivity following transfer at mating; it was therefore a candidate for contributing to a cost of receiving accessory fluid. However, whilst the injection of male accessory gland extract into females significantly reduced female lifespan and lifetime reproductive success, there was no evidence to suggest that the SP contributed to this cost. Several experiments explored the possibility of a correlation between the rate of sterile egg-laying and SP-usage in virgin females, as would be predicted if there were receptors for the SP on the ovary, or some other site controlling oviposition rate. There was no evidence to suggest that this was the case. The correlation between the rate of fertile egg-laying and receptivity previously reported for mated females may therefore be an effect of sperm-depletion rates or some other consequence of mating and not of egg-laying per se.
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Tempest, Louisa-Jayne. "Parasites and the costs of reproduction in Soay sheep." Thesis, University of Stirling, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720356.
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Proaktor, Gil. "Costs of reproduction invertebrates : an ecological and evolutionary approach." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444064.
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Prowse, Nicholas Brian. "The evolution of life histories in Drosophila melanogaster : costs of reproduction and responses to artificial selection on age at reproduction." Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266207.
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Archer, Catharine Ruth. "Food, sex and death : costs of reproduction and the mechanistic basis of ageing." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3568.
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Ageing is the progressive decline in physiological performance with age, which is almost universal amongst multicellular organisms. While understanding ageing is an important aim in biological research, our current understanding of how and why we age is incomplete. In this thesis, I examine how sexual selection affects the evolution and mechanistic basis of ageing. I then explore how diet affects lifespan and reproduction in either sex. Finally, I test the hypotheses that oxidative stress, which occurs when cellular levels of Reactive Oxygen Species exceed circulating antioxidant defences causes ageing (i.e. the free radical theory of ageing) and/or constrains life-history strategies. To ask these questions, I employ quantitative genetics in decorated crickets Gryllodes sigillatus to examine the genetic co(variance) of ageing, lifespan, reproductive effort, oxidative damage and antioxidant protection. In the Australian field cricket, Teleogryllus commodus, I apply the geometric framework of nutrition to examine how lifespan, reproductive effort, oxidative damage and antioxidant capacity respond to dietary manipulation. In G. sigillatus, I found that sexual selection caused divergent strategies of age-dependent reproductive effort across the sexes and that this, in turn, promoted different rates of ageing in males and females. I found a trade-off between early reproductive effort and ageing rate in both sexes, although this trade-off was more pronounced in females (Chapter 3). I then explored the mechanistic basis of these sex-specific life-history strategies and, in support of the free radical theory of ageing, I found that oxidative damage was greatest in the shortest lived sex (females) and was negatively genetically correlated with lifespan. Additionally, oxidative damage was a cost of female reproductive effort that accelerated ageing, showing that oxidative stress may mediate sex-specific life-history strategies in decorated crickets (Chapter 4). If sexual selection affects reproduction and lifespan it should promote sex-specific life-history responses to dietary manipulation. In Australian black field crickets Teleogryllus commodus, I found that males and females have distinct dietary optima for lifespan and reproductive effort and that diet mediated a trade-off between these traits. I found that mating affected responses to dietary manipulation and caused sexual dimorphism in dietary intake under choice (Chapter 5). However, oxidative stress did not explain these life-history responses to dietary manipulation across the sexes (Chapter 6): although oxidative damage was greatest in the shortest lived sex (i.e. females), diets that extended lifespan did not reduce oxidative damage. My thesis illustrates the importance of considering sexual selection when considering the evolution and mechanistic basis of ageing. It offers equivocal support for the free radical theory of ageing but shows that oxidative stress may help underpin sex-specific life-history strategies. However, my results highlight that unravelling the relationship between oxidative stress and life-history strategies across the sexes will be a very difficult task.
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Blount, Jonathan David. "Carotenoids and the costs of reproduction : studies on the lesser black-backed gull." Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394825.
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Ibler, Benjamin [Verfasser]. "Costs of reproduction : a demographical approach to examine life-history trade-offs / Benjamin Ibler." Greifswald : Universitätsbibliothek Greifswald, 2017. http://d-nb.info/1141825023/34.
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Coste, Christophe. "The costs of reproduction in evolutionary demography : an application of Multitrait Population Projection Matrix models." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC259/document.
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Les coûts de la reproduction sont un compromis biologique (trade-off ) fondamental en théorie des histoires de vie. Par ce compromis, le succès, pour un organisme, d’un évènement de reproduction réduit sa survie et sa fertilité futures. Pour les écologues, ce trade-off correspond principalement à un compromis physiologique résultant d’un processus d’allocation ayant lieu à chaque instant et au niveau de chaque individu. Au contraire, en démographie évolutive, il est envisagé comme un trade-off génétique découlant du polymorphisme génotypique d’un gène pléiotropique agissant de manière antagoniste sur la reproduction aux jeunes âges et la fitness aux âges élevés. L’étude des mécanismes des coûts de la reproduction, physiologiques et génétiques, de leur possible cohabitation et de leur effets relatifs, croisés et conjoints est le sujet de cette thèse. Un examen attentif de la définition originelle des coûts de la reproduction par Williams (1966), nous permet de construire un modèle théorique des coûts physiologiques intégrant leurs aspects mécaniques et évolutifs. Cette construction nous permet d’induire l’intensité des coûts de la reproduction selon la position d’un organisme sur trois continuums d’histoire de vie: "slow-fast", "income-capital breeders" et "quantity-quality".A partir de la décomposition, par Stearns (1989b), de l’architecture des contraintes d’histoire de vie en trois parties – le niveau génotypique, la structure intermédiaire et le niveau phénotypique – nous étendons notre modèle conceptuel pour y intégrer à la fois des trade-offs physiologiques et génétiques. Cela nous permet d’inférer les effets de l’environnement, de sa variance et de la stochasticité individuelle sur la détectabilité de chaque famille de coûts. La différence entre coûts physiologiques et génétiques se retrouve également dans leur modélisation mathématique. Il est donc nécessaire de développer de nouveaux modèles permettant d’incorporer coûts physiologiques et génétiques. Nous proposons ensuite une méthode vectorielle de construction d’un tel type de modèle, que nous appelons Matrice de Projection de Population Multitrait (MPPM). Ce dernier peut implémenter chaque type de coût en l’intégrant dans la matrice en tant que trait. Nous étendons ensuite aux MPPMs les techniques d’analyse de sensibilité, standards en démographie évolutive, des modèles à un trait aux MPPMs. Surtout, nous décrivons un nouvel outil d’analyse, pertinent en théorie des histoires de vie et en démographie évolutive: la Trait Level Analysis. Elle consiste à comparer des modèles qui partagent les mêmes propriétés asymptotiques. Ceci est rendu possible par le repliement d’une MPPM selon certains traits, une opération qui réduit le nombre de traits du modèle en moyennant ses transitions selon les abondances ergodiques relatives. Ainsi, la Trait Level Analysis permet de mesurer l’importance évolutive des coûts de la reproduction en comparant des modèles implémentant ces coûts, avec des versions ergodiquement équivalentes de ces modèles mais repliées selon les traits supportant les compromis. Nous utilisons des méthodes, classiques et nouvelles, de calculs des moments de la fitness – gradient de sélection, variance du succès reproducteur, variance environnementale – que nous appliquons aux modèles avec coûts et sans coûts afin de mesurer leurs effets démographiques et évolutifs. Nous présentons les effets conjoints des coûts physiologiques et génétiques sur la distribution par âge des taux vitaux d’une population. Nous montrons également comment les coûts physiologiques influencent les deux composants de la sélection efficace, en aplatissant le gradient de sélection d’un côté et en accroissant la taille efficace de la population de l’autre. Enfin, nous démontrons comment l’effet tampon des coûts sur les variances environnementales et démographiques améliore la résilience d’une population soumise aux coûts physiologiques de la reproductionCosts of reproduction are pervasive in life history theory. Through this constraint, the reproductive effort of an organism at a given time negatively affects its later survival and fertility. For life historians, they correspond mostly to a physiological trade-off that stems from an allocative process, occurring at each time-step, at the level of the individual. For evolutionary demographers, they are essentially about genetic trade-offs, arising from a genetic variance in a pleiotropic gene acting antagonistically on early-age and late-age fitness components. The study, from an evolutionary demographic standpoint, of these mechanisms and of the relative, cross and joint effects of physiological and genetic costs, is the aim of this thesis. The close examination of Williams (1966)’s original definition of the physiological costs of reproduction led us to produce a theoretical design of their apparatus that accounts for both their mechanistic and evolutionary mechanisms. This design allowed us to make predictions with regards to the strength of costs of reproduction for various positions of organisms on three life-history spectra: slow-fast, income-capital breeders and quality-quantity. From Stearns (1989b)’s tryptic architecture of life history trade-offs –that divides their structure into the genotypic level, the intermediate structure and the phenotypic level – we devised a general framework, which models the possible cohabitation of both physiological and genetic costs. From this, we inferred differing detectability patterns of both types of costs according to the environmental conditions, their variance and individual stochasticity. We could also establish that both costs buffer environmental variations, but with varying time windows of effect. Their dissimilarity emerges also from the differences between mathematical projection models specific to each cost. A new family of evolutionary models is therefore required to implement both physiological and genetic trade-offs. We then describe the vector-based construction method for such a model which we call Multitrait Population Projection Matrix (MPPM) and which allows incorporating both types of costs by embedding them as traits into the matrix. We extend the classical sensitivity analysis techniques of evolutionary demography to MPPMs. Most importantly, we present a new analysis tool for both life history and evolutionary demography: the Trait Level Analysis. It consists in comparing pairs of models that share the same asymptotic properties. Such ergodic equivalent matrices are produced by folding, an operation that consists in reducing the number of traits of a multi-trait model, by averaging transitions for the traits folded upon, whilst still preserving the asymptotic flows. The Trait Level Analysis therefore allows, for example, to measure the evolutionary importance of costs of reproduction by comparing models incorporating them with folded versions of these models from which the costs are absent. Using classical and new methods to compute fitness moments – selection gradient, variance in reproductive success, environmental variance - in models with and without the costs, we can show their effects on various demographic and evolutionary measures. We reveal, in this way, the combined effects of genetic and physiological costs on the vital rates of an age-structured population. We also demonstrate how physiological costs affect both components of effective selection, as they flatten the slope of selection gradients and increase the effective size of a population. Finally, we show how their buffering of environmental and demographic variance confer greater resilience to populations experiencing physiological costs of reproduction
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Andersson, Måns S. "Physiological trade-offs in reproduction and condition dependence of a secondary sexual trait." Doctoral thesis, Uppsala University, Department of Evolutionary Biology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1407.
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This thesis examines parental condition, how it is traded off against reproduction and how it is displayed in a secondary sexual trait. The studies were performed on nest-box breeding collared flycatchers Ficedula albicollis on the island of Gotland, in the Baltic Sea. Early breeding and high fitness were found to be associated with high levels of glycosylated haemoglobin possibly governed by migratory exertion and infectious disease. In order to test if immune function is expressed in secondary sexual traits and how it is traded off against reproductive effort a series of experiments were performed, in which birds were challenged with an antigen, via a vaccine containing neutralised paramyxovirus. The forehead patch of the male collared flycatcher serves as a badge of status and is under sexual selection. Good condition, as reflected in strong immune response and low levels of blood parasites was found to be associated with bigger patch size. Patch size was also found to vary in size within the same breeding season in a pattern predictable from immune response data. Immune response, in itself, was found to be costly in terms of reduced survival, confirming that trade-offs involving suppression of immune response may increase fitness. Mating effort was found to be traded off against immune function and moult. Experimental brood size manipulations revealed a trade-off females between number of offspring and immune function. Thus I suggest a set of parameters useful for condition estimation. I also show that immune response is costly and, second, that pathogen resistance probably plays an important role in the shaping of secondary sexual traits and life-history decisions.
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Webber, Simone Leigh. "The role of food availability in determining the energetic and life history costs of reproduction in short-lived birds." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3784/.
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Food availability strongly affects avian breeding success. Conflicting results from food supplementation studies have obscured the role of food availability in shaping the life history trajectories of birds. With the popularity of providing food for wild birds increasing, the effects of this resource for breeding birds need to be clarified. In this study Blue Tits (\(Cyanistes\) \(caeruleus\)) and Great Tits (\(Parus\) \(major\)) were provided with supplementary food to investigate whether food availability reduced the costs of breeding for adults, and affected life history traits. Food supplementation with peanut cake disrupted the timing of Great Tit breeding and reduced fecundity. There was no effect of food supplementation on Great Tit adult or juvenile survival, except in 2010 when females traded off fecundity against future survival. Blue Tit fecundity was largely unaffected by food supplementation, but the provision of mealworms improved adult female survival. Food supplementation reduced female Daily Energy Expenditure (DEE) for both species during egg laying and for Great Tits feeding nestlings, revealing unexpectedly complex life history strategies. Through the integration of physiological techniques and life history frameworks we can understand the interaction between organisms and their environment and the effects of anthropogenic actions such as food supplementation of birds.
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Capelli, Mathilde. "Décrypter l’irrégularité de production des fruitiers tropicaux via l’analyse des coûts de la reproduction : le cas du manguier (Mangifera indica L.)." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT079/document.
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Le manguier (Mangifera indica L.), cinquième production fruitière mondiale, est une espèce à production irrégulière. L’irrégularité de production a des retombées économiques marquées pour tous les acteurs de la filière fruitière. Il apparait donc important de mieux comprendre les mécanismes qui déclenchent et entretiennent ce phénomène d’irrégularité de production. Le premier objectif de cette thèse est d’apporter un regard nouveau sur l’irrégularité de production du manguier en mobilisant le concept des coûts de la reproduction. Cette étude est effectuée à plusieurs échelles spatiales, unité de croissance (UC), branche charpentière, arbre, et de manière dynamique sur quatre cultivars. Les résultats montrent un effet négatif, ou coût, de la reproduction sur la croissance végétative au cycle suivant, avec des comportements contrastés des cultivars en lien avec leur irrégularité de production. En particulier, un effort reproducteur important diminue la probabilité de débourrement végétatif des UCs porteuses. Le second objectif est d’étudier, chez deux cultivars et à l’échelle de l’UC, les modifications anatomiques et hydrauliques liées à la croissance du fruit, et des mécanismes trophiques et hormonaux contribuant à cet effet négatif de la reproduction sur le débourrement végétatif. Les résultats montrent que la reproduction entraîne une différenciation du cambium de l’UC porteuse principalement en phloème. Les inflorescences et les fruits diffusent de l’auxine qui inhibe le démarrage végétatif des UCs reproductrices. Les fruits en croissance mobilisent les réserves en amidon de l’UC porteuse. Les faibles teneurs en amidon de ces UCs pendant et après la récolte contribuent à réduire leur probabilité de débourrement végétatif, et/ou à le retarder lorsqu’il a lieu. Les résultats diffèrent entre les deux cultivars, et l’implication de ces mécanismes dans l’irrégularité de production est discutée. Nos résultats permettent de mieux comprendre les facteurs qui entretiennent l’irrégularité ou l’alternance de production de différents cultivars de manguiers. De façon appliquée, ils suggèrent que des techniques de taille adaptées à chaque cultivar et nature d’UC pourraient permettre d’obtenir une production plus régulière chaque annéeThe mango tree (Mangifera indica), the fifth fruit crop production in the world, is characterized by an irregular bearing pattern. Irregular bearing is responsible for economic difficulties for producers and for all actors along the fruit industry chain. A better understanding of mechanisms which trigger and maintain irregular bearing is therefore necessary. The first objective of this study is to provide a new perspective on irregular bearing of the mango tree using a concept developed in ecology and evolutionary biology, the costs of reproduction. The experiment was carried out dynamically at several spatial scales, growth unit (GU), scaffold branch, tree, and on four cultivars. Results show a negative effect, or cost, of reproduction on vegetative growth during the following cycle, with cultivar-specific behaviors related to their bearing pattern. In particular, an important reproductive effort reduces the probability of vegetative burst of the bearing GUs. The second objective is to study, for two cultivars and at the GU scale, the anatomical changes of the bearing axis during fruit growth, and hormonal and trophic mechanisms involved in the negative effects of reproduction on vegetative bud outgrowth. Results show that reproduction leads to cambium differentiation mainly in phloem, favoring nutrients and water supply to the fruit. Inflorescences and growing fruits release auxin, contributing to vegetative bud burst inhibition on fruiting GUs. Growing fruits mobilize starch reserves of bearing GUs. Their low starch content at and after harvest contributes to decrease their probability of vegetative burst, and/or delay it when it occurs. The results reveal a strong cultivar effect, and the involvement of these mechanisms in irregular bearing is discussed. Our results allow to better understand the factors maintaining irregular or alternate bearing of different mango cultivars. From a practical perspective, they suggest that pruning techniques adapted to each cultivar and GU fate may contribute to more regular production each year
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Séguret, Alice Caroline [Verfasser], Robert J. [Gutachter] Paxton, Thomas [Gutachter] Flatt, and Karen [Gutachter] Kapheim. "Ageing and the costs of reproduction : insights from Euglossa viridissima, an orchid bee on the cusp of sociality / Alice Caroline Séguret ; Gutachter: Robert J. Paxton, Thomas Flatt, Karen Kapheim." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2021. http://d-nb.info/123768577X/34.
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McDonald, Paul, and Paul McDonald@latrobe edu au. "Reproductive success, dimorphism and sex allocation in the brown falcon Falco berigora." The Australian National University. Faculty of Science, 2003. http://thesis.anu.edu.au./public/adt-ANU20041111.100436.
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This project describes various aspects of the breeding ecology and behaviour of the brown falcon Falco berigora, a common but poorly study Australian raptor. In particular it examines (a) the main influences on reproductive success; (b) tests predictions of theories proposed to explain the evolution and maintenance of sexual size dimorphism (RSD; females the larger sex) in raptors; and (c) investigates sex allocation patterns in the light of current sex ratio and parental investment theory. The study was conducted between July 1999 and June 2002 approximately 35 km southwest of Melbourne, at the Western Treatment Plant (WTP), Werribee (38°0S 144°34E) and surrounds, a total area of approximately 150 km2.¶
· In all plumage and bare part colouration of 160 free-flying falcons was described. The majority of variation in these characters could be attributed to distinct age and/or sex differences as opposed to previously described colour morphs.¶
· Nestling chronology and development is described and formulae based on wing length derived for determining nestling age. An accurate field-based test for determining nestling sex at banding age is also presented.¶
· Strong sex role differentiation was apparent during breeding; typical of falcons females performed most parental duties whilst males predominantly hunted for their brood and partner. Based on observations of marked individuals, both sexes of brown falcons aggressively defended mutual territories throughout the year, with just 10% of each sex changing territories during the entire study period. Males performed territorial displays more frequently than females, the latter rarely displaying alone.¶
· The diet of the population as a whole was very broad, but within pairs both sexes predominantly specialised on either lagomorphs, small ground prey (e.g. house mice Mus musculus), small birds, large birds or reptiles, according to availability.¶
· Reproductive parameters such as clutch size and the duration of parental care were constant across all years, however marked annual differences in brood size and the proportion of pairs breeding were evident.¶
· Age was an important influence upon reproductive success and survival, with immature birds inferior to adults in both areas. However, interannual differences were by far the most influential factor on breeding success and female survival. Heavy rain downpours were implicated as the main determinant of reproductive success and adult female mortality in a population largely devoid of predation or human interference.¶
· Female-female competition for territorial vacancies was intense; larger adult females were more likely to be recruited and once breeding fledged more offspring. In contrast, male recruitment and breeding success was unrelated to either body size or condition indices, although smaller immature males were more likely to survive to the next breeding season. This directional selection is consistent only with the predictions of the intrasexual competition hypothesis.¶
· Despite marked RSD (males c. 75% of female body mass), throughout the nestling phase female nestlings did not require greater quantities of food than their male siblings. However, female parents fed their last-hatched sons but not daughters, resulting in the complete mortality of all last-hatched female offspring in focal nests. Given last-hatched nestlings suffered markedly reduced growth rates and female, but not male, body size is important in determining recruitment patterns, the biased allocation amongst last-hatched offspring is likely to reflect differing benefits associated with investing in small members of each sex, consistent with broad-scale Trivers-Willard effects. Recruitment patterns support this, with surviving last-hatched females, in contrast to males, unable to gain recruitment into the breeding population upon their return to the study site.¶
Thus selection appears to act at the nestling, immature and adult stages to maintain RSD in the focal population. Larger females were favoured in the nestling phase, at recruitment and once breeding had greater reproductive success. In contrast, selection favoured a reduction or maintenance of immature male size as smaller birds had a greater chance of survival in the year following recruitment than their larger counterparts; thereafter male size was unimportant. Together, this directional selection favouring increased female competitive ability is consistent only with the predictions of the intrasexual competition hypothesis, which appears the most probable in explaining the maintenance and perhaps evolution of RSD in raptors.
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Hurskainen, S. (Sonja). "The roles of individual demographic history and environmental conditions in the performance and conservation of northern orchids." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526220888.
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Abstract A population growth rate is the sum of all individuals’ reproduction and survival, which in turn depend on many external and internal factors, e.g. weather and individual reproductive history. In plants, for example, previous reproduction can deplete an individual’s resources, resulting in trade-offs between demographic functions. To understand these demographic processes, it is necessary to follow populations for many years. Such long-term studies are especially crucial for endangered species, as they can reveal the causes of population declines and provide information that is directly applicable for the management. In my thesis, I applied this approach to the study of rare orchids. Specifically, I analyzed long-term orchid monitoring data from two countries, Finland and Estonia, to assess the external and internal factors that affect the performance of these long-lived plants, which reproduce both sexually (via seeds) and vegetatively (via new ramets). My research reveals that plant performance depends on both the demographic history and the environment of a plant. For example, although Finnish and Estonian populations of the lady’s slipper orchid, Cypripedium calceolus, differed in direction and statistical significance of their responses to environmental factors, the two most-influential weather variables in both cases were spring snow depth and the temperature of the previous summer. However, the influence of weather on both flowering and vegetative growth was dwarfed by the effect of plants’ own demographic histories: there was a trade-off between current and future reproduction which created asynchronous two-year cycles in reproduction and growth. Furthermore, in all three studied orchid species — the lady’s slipper orchid (C. calceolus), the fairy’s slipper orchid (Calypso bulbosa), and the dark-red helleborine (Epipactis atrorubens) — the probability of dormancy (a state in which the plant spends a year or more underground) and the demographic costs this state incurred with respect to size or future reproduction depended on a plant’s size and whether it flowered prior to dormancy. In other words, dormancy had both absolute and relative costs in large, but not in small, individuals. Finally, I show here that environmental alteration via selective tree removal can be used as a management method to increase orchid reproduction via both seeds and rametsTiivistelmä Populaation kasvunopeus riippuu siitä, kuinka monta yksilöä populaatioon syntyy ja kuinka monta yksilöä kuolee. Yksilöiden lisääntyvyyteen ja elossa säilyvyyteen puolestaan vaikuttavat monet ulkoiset ja sisäiset tekijät, kuten sää ja yksilön oma lisääntymishistoria. Kasvilla on rajallinen määrä resursseja, joten sen pitää tehdä kompromisseja eri elintoimintojen, esimerkiksi kasvun ja lisääntymisen, välillä. Klonaaliset kasvit voivat myös lisääntyä usealla tavalla: joko suvullisesti siemenistä tai kasvullisesti tuottamalla uusia versoja. Demografisten prosessien tutkimisessa pitkäaikaiset seuranta-aineistot ovat välttämättömiä. Pitkäaikaisseurannat voivat myös paljastaa uhanalaisen lajin populaation taantumisen syyt ja näistä seurannoista saatua tietoa voidaan soveltaa harvinaisten lajien, esimerkiksi kämmeköiden, suojelutoimien suunnittelussa. Tässä väitöskirjassa analysoin aineistoa kämmeköiden pitkäaikaisseurannoista Suomesta ja Virosta. Tavoitteenani oli arvioida ulkoisten ja sisäisten tekijöiden merkitystä pitkäikäisten kasvien menestykselle. Tulokset osoittavat, että kasvin menestys riippuu sekä yksilön omasta demografisesta historiasta että sen ympäristöstä. Eri säätekijöiden vaikutus tikankontin (Cypripedium calceolus) kasvuun ja kukkimiseen vaihteli Suomen ja Viron välillä, mutta lumen syvyys ja edellisen kasvukauden lämpötila nousivat merkittävimmiksi tekijöiksi molemmissa maissa. Tikankontin kasvu ja kukinta riippuivat kuitenkin säätä enemmän kasvin omasta demografisesta historiasta. Runsas lisääntyminen edeltävällä kasvukaudella vähensi lisääntymistä tulevalla kasvukaudella, mikä johti kaksivuotiseen jaksottaisuuteen tikankontin lisääntymisessä ja kasvussa. Tutkiessani dormanssia (lepotila, jossa kasvi ei tuota maanpäällistä versoa) kolmella kämmekkälajilla, tikankontilla, neidonkengällä (Calypso bulbosa) ja tummaneidonvaipalla (Epipactis atrorubens), havaitsin lisäksi, että todennäköisyys siirtyä dormanssiin riippui kasvin koosta. Myöskin tämän lepotilan aiheuttamat kustannukset olivat riippuvaisia kasvin aikaisemmasta tilasta. Isoilla kasveilla dormanssilla oli sekä suoria kustannuksia että kustannuksia suhteessa versomiseen. Pienillä kasveilla näitä kustannuksia ei ollut. Osoitan väitöskirjassani myös, että maltillisella puunpoistolla voidaan lisätä tikankonttipopulaatioiden siementuottoa ja versotiheyttä
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Sendecka, Joanna. "Age, Longevity and Life-History Trade-Offs in the Collared Flycatcher (Ficedula albicollis)." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7787.
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Cheatsazan, Hamed. "Asymptomatic interaction with the fatal amphibian pathogen, Batrachochytrium dendrobatidis : costs, environmental drivers, the outcome and the risk of chytridiomycosis for the palmate newt (Lissotriton helveticus)." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2350/.
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L'objectif général de cette thèse est l'étude des coûts, des facteurs environnementaux, ainsi que de l'impact sur la reproduction de la chytridiomycose asymptomatique pour le triton palmé, Lissotriton helveticus. Premièrement, nous avons testé l'impact de l'infection asymptomatique par Batrachochytrium dendrobatidis (Bd) sur les tritons aquatiques : la condition, et l'expression des caractères sexuels. Nous avons ensuite étudié l'impact de l'infection sur la reproduction, le développement et la survie des larves et également examiné l'impact de l'environnement sur les coûts sub-létaux et la résistance de l'hôte à l'infection. Nos résultats montrent que des populations n'ayant jamais été exposées à la maladie et infectées par Bd subissent des coûts sub-létaux qui nuisent à leur reproduction et à leur survie. Cependant, les tritons qui ont déjà été exposés à Bd sont trouvés à être tolérants à l'infection et peuvent servir comme réservoir du pathogèneThe objective of this thesis was to study the costs, environmental drivers, and the outcome of asymptomatic chytridiomycosis for the palmate newt, Lissotriton helveticus. After reviewing related scientific literature we tested for the impact of subclinical Batrachochytrium dendrobatidis (Bd) infection on condition and sexual traits. We studied the impact of asymptomatic Bd infection on newts' reproductive output, the development and survival of larvae and also considered the impact of environment on sub-lethal costs and host resistance against infection. Finally, the costs and the impact of the infection on a population with a recent, natural Bd exposure were investigated. Collectively, our results show that newts are incurred by sub-lethal costs which impair host's reproduction and survival. Newts that have already been exposed to Bd are found to be tolerant to the infection and can serve as infection reservoir
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Martins, Thais Lima Fernandes. "The cost of reproduction of swifts." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314908.
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Tagg, Nikki. "The ecological cost of sexual reproduction." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400475.
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Tufton, Toby J. "The cost of reproduction in Callosobruchus maculatus." Thesis, University of Sheffield, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700952.
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Georgiev, Alexander. "Energetic Costs of Reproductive Effort in Male Chimpanzees." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10262.
Full textAbstract:
Male reproductive success in many mammals depends on their ability to allocate sufficient energetic resources to mating competition. Such costs are particularly pronounced in species with high levels of sexual body dimorphism, intense polygyny and distinct breeding seasons. I tested the hypothesis that male reproductive effort incurs significant energetic costs in wild chimpanzees (Pan troglodytes), a species with moderate sexual dimorphism, promiscuous mating and lack of breeding seasonality. My field studies combined behavioral observations on male chimpanzee behavior with non-invasive sampling of urinary C-peptide (UCP). UCP is a biomarker of insulin production that indexes individual energy balance. This dissertation contributes to the understanding of UCP as an energy assay by (1) validating the application of UCP for assessing dietary quality in bonobos (Pan paniscus) at Kokolopori, DRC and (2) providing a detailed assessment of diurnal variation in UCP levels in relation to short-term changes in food intake in chimpanzees at Kanyawara, Kibale NP, Uganda. I used UCP measurements in conjunction with full-day focal observations of male chimpanzees to assess the energetic costs of male-male competition for status and mating opportunities. Data on feeding time and rates of aggression suggested that males experience a reduction in energy intake and an increase in energy expenditure when highly attractive parous females were in estrus. UCP data supported these conclusions because males had lower UCP levels on mating days, and rates of aggression were negatively associated with UCP levels. Mean daily party size was also associated with low UCP levels, controlling for the presence of estrous females. Habitat-wide availability of preferred fruits was positively associated with male rates of aggression suggesting that energy availability mediates male investment towards energetically costly competitive behaviors. Contrary to expectations males who were most successful in obtaining copulations (high-ranking males) did not suffer higher energetic costs than lower-ranking males during periods of mating competition. Costs or reproductive effort include both direct competition for matings and long-term competition over social status. Maintenance of social rank over long periods appears to be particularly important in this slow-reproducing, long-lived and nonseasonally breeding primate.Human Evolutionary Biology
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Jones, Allystair. "Generality of the Terminal Investment Hypothesis: Effects of Extrinsic Mortality and Resource Availability on Age-Related Reproductive Investment." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5710.
Full textAbstract:
A central question in life history theory is, what combination of traits and behaviors will lead to the highest reproductive success throughout a lifetime. The trade-off between current and future reproduction is central to the lifetime reproductive success of an organism. If there is a cost to reproduction, then allocation of energy to current reproduction will come at a cost to future reproduction. We expect young individuals to favor future reproduction over current reproduction and that balance shifts to current reproduction as they age (i.e. terminal investment hypothesis). However, how this transition from an emphasis on future reproduction to emphasis on current reproduction changes throughout a lifetime should depend on environmental factors like mortality and resource availability. We test for the generality of terminal investment across three species of poecilliid fishes in a range of environments. We found evidence of terminal investment in all three species in both high and low mortality environments and high and low resource availability environments. In general, high mortality or high resource availability tended to result in a decreased slope of the relationship between reproductive allocation and body size. Terminal investment appears to be general, even though there was an effect of high mortality and resource availability, it was not sufficient to completely preclude terminal investment.
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Graham, Jessica Lynn. "Reproductive Timing in a Changing World: Understanding Mechanisms and Costs Associated With Reproductive Timing Decisions." Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/27478.
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Organisms in temperate zones time reproduction to occur when conditions are optimal for raising offspring. However, individuals of many taxa vary in precise timing of breeding. The mechanisms underlying the existing variation are not well understood, particularly in females. I hypothesized that individual variation in daily (i.e., circadian) rhythms, which are highly conserved across taxa, are related to variation in reproductive timing. By measuring activity onset in two species of songbirds, we found that females beginning their day earlier also breed earlier. I further asked if sex-steroid hormones were related to onset of daily activity in free-living individuals. My results show that maximal levels of estradiol are correlated with onset of activity in free-living females. This suggests that circadian rhythms may influence much of the variation seen in timing of breeding and individual physiology influences circadian behavior. In addition to mechanisms underlying reproductive timing, I also investigated potential selective pressures that could act on timing decisions. Early breeding females often produce more and larger offspring, however, most of the population breeds later than this optimum, suggesting there are costs associated with early reproduction. To determine if early breeding females are better able to handle an additional energetic challenge, I injected incubating females with a mild antigen and monitored nest survival in early and late breeders. The immune challenge caused a significant increase in nest failure compared to controls and success did not differ between early and late breeders. Next, using a long-term dataset I asked whether females who breed early experience accelerated rates of aging via telomere loss. I found that early breeding females experience higher telomere attrition compared to females breeding later. Annual change in telomere length was not related to reproductive output, but females experiencing cooler temperatures during egg laying and incubation (i.e., laying earlier in the season) had higher telomere attrition. With telomere loss and length being important determinants of lifespan and longevity, higher telomere attrition in early breeders may be linked with reduced overwinter survival. A better understanding of mechanisms and costs will help determine how populations will adjust to, or suffer from, a changing climate.NSF; ND EPSCoR; Sigma Xi; Mountain Lake Biological Station; Department of Biological Sciences; Environmental and Conservation Sciences Program; American Ornithologists Union; Wilson Ornithological Society
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Lourdais, Olivier. "Coûts de la reproduction, gestion des ressources et fréquence des épisodes reproducteurs chez la vipère aspic (Vipera aspis)." Poitiers, 2002. http://www.theses.fr/2002POIT2303.
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Le nombre d'épisodes reproducteurs au cours de l'existence d'un organisme constitue un trait d'histoire de vie majeur. On distingue ainsi des espèces semélipares (une seule reproduction et la mort de l'organisme), et d'autre itéropares (reproductions répétées). La vipère aspic occupe une position intermédiaire avec une faible fréquence de reproduction (tous les 2-4 ans) et une tendance marquée vers la seméliparité. Chez cette espèce, des contraintes énergétiques et écologiques de la reproduction (coûts) sont d'amplitude élevées et indépendantes de la fécondité. Nos travaux suggèrent l'existence d'une relation directe entre la fréquence des reproduction et les contraintes reproductrices et soutiennent donc l'hypothèse de Bull et Shine (1979). Notre idée originale repose sur une connexion du modèle de Bull et Shine avec les stratégies d'acquisition et d'allocation de l'énergie et notamment le stockage de réserves corporelles. Nos résultats supportent largement l'existence d'une relation évolutive entre les coûts indépendants de la fécondité, les systèmes à faible fréquences de reproductions et les stratégies de capitalisation de l'énergie ("Capital-breeding"). Cette étude apporte des éléments de réponses pertinents sur les conditions d'émergence des systèmes de reproduction "extrêmes" et sur la transition évolutive vers la seméliparitéThe number of reproductive episodes is a major life history trait. A classical distinction is made between semelparous (one reproductive event during the lifetime of the individual) and iteroparous organisms (repeated reproductive events). The aspic viper occupies an intermediate position while showing a low frequency of reproductions (one every 2-4 years) and a marked tendency toward semelparity. In this species the ecological and energetic constraints of reproduction are high and independent of reproductive effort and litter size. Our results indicate a close relationship between those reproductive constraints and reproductive frequency and thereby, support the Bull and Shine (1979) hypothesis. The original idea we developed relies on a connection between Bull and Shine's model and the strategy of energy acquisition and allocation. Our work points out a clear connection between fecundity-independent costs of reproduction, low frequency of reproduction and capital breeding systems. This study brings original informations about the condition favouring the emergence of "extreme" reproductive strategies and the evolutionary transition toward semelparity
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Федорович, І. В. "Організаційно-економічне забезпечення процесу відтворення лінійної частини магістральних газопроводів." Thesis, Івано-Франківський національний технічний університет нафти і газу, 2011. http://elar.nung.edu.ua/handle/123456789/1941.
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Дисертаційна робота присвячена розвитку теоретичних положень формування та функціонування процесу відтворення ЛЧ МГ на газотранспортних підприємствах. У роботі розвинуто теоретичні положення щодо сутності поняття «відтворення», досліджено вплив чинників на процесвідтворення ЛЧ МГ та виникнення відмов та аварій на газопроводах, удосконалено методичний підхід щодо оцінювання готовності ЛЧ МГ до транспортування природного газу.
Розроблено методичний підхід до розрахунку фінансових втрат, які несуть газотранспортні підприємства в результаті виникнення аварійних ситуацій на газопроводах.
Запропоновано алгоритм оптимізації процесу планування капітальних ремонтів на газопроводах.
Оцінено ефективність застосування інноваційно-модифікованого протикорозійного покриття для захисту газопроводів.
Реструктуризовано функції управління процесом відтворення ЛЧ МГ на рівні управлінь магістральних газопроводів.The thesis is dedicated to the development of theoretical principles of formation and operation of reproduction process of linear part of main gas pipelines at gas-transport enterprises. Theoretical principles as for the essence of the concept of “reproduction” are evolved? The influence of factors on the process of reproduction of linear part of main gas pipelines, and appearance of refusals and breakdowns at gas pipelines is studied, technical approach to estimating availability of linear part of main gas pipelines for transporting natural gas is improved. Technical approach to calculation of financial losses at gas-transport enterprises as a result of appearance of breakdown situations at gas pipelines is worked out. Algorithm of optimization of the process of planning overhauls at gas pipelines is propounded. Functions of managing the reproduction of line part of main gas pipelines at the level of main gas pipelines administrations are restructured.
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Hadley, Gillian Louise. "Recruitment Probabilities and Reproductive Costs for Weddell Seals in Erebus Bay, Antarctica." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/hadley/HadleyG0506.pdf.
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The study of life history traits such as age at first reproduction and the evaluation of recruitment probabilities and reproductive costs allow insight regarding the diverse factors and mechanisms shaping reproductive strategies. We investigated these mechanisms using a 26-year mark-resight dataset for Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica. Mean age at first reproduction was 7.62 years of age (SD=1.71), but varied from four to 14 suggesting the presence of important heterogeneity in quality among females. Survival rate was maximized for offspring of age-14 mothers (φ=0.70 [SÊ=0.08]), whereas recruitment probability was highest for pups born to youngest-breeding mothers. For example, probability of recruitment at age 7 was an average of 43% lower for seals born to age-14 mothers than for seals born to age-6 mothers. These results suggest the influence of countervailing selection (where favored genotypes for reproductive success are generally those that are selected against as juveniles). Sea-ice extent affected annual recruitment rates, likely due to cascading effects of oceanographic conditions on marine primary productivity and fluctuations in food availability for female Weddell seals. Results from the reproductive cost analysis strongly supported the presence of reproductive costs to survival (φ was 0.91 for breeders versus 0.94 for nonbreeders). Costs to fecundity were present for first-time breeders (mean probability of breeding the next year was 0.20 lower for first-time breeders than for experienced breeders). Females that delayed breeding until later in life experienced highest reproductive costs to fecundity, possibly due to their inferiority relative to other individuals in the population, again suggesting the influence of heterogeneity in individual quality. From these analyses we have gained insight into 1) the extent of within-population variation in important life-history characteristics for a long-lived species, and 2) the sources of this variation and potential linkages with environmental variables. Keys to future research will be 1) explaining variation in individual quality with random effects models or by using mass as an indicator variable, and 2) more detailed exploration of appropriate climate and sea-ice indices to elucidate linkages between this top trophic level predator and variation in the Antarctic marine environment.
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Foucart, Thomas. "L'évolution de l'oviparité à la viviparité chez les reptiles : approche éco-physiologique de l'équilibre des coûts et bénéfices chez une espèce à reproduction bimodale (Zootoca vivipara)." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S125/document.
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Dans son Historia Animalium en 343 av. J.C., Aristote proposait déjà deux critères qui continuent d’être les bases fondamentales de notre compréhension de la diversité des modes de reproduction : l’origine des nutriments des embryons (lécitotrophie vs. matrotrophie) et le mode de parition (oviparité vs. viviparité). Depuis plusieurs décennies la compréhension de la transition évolutive vers la viviparité a attiré un intérêt scientifique considérable. En effet les analyses phylogénétiques récentes reconnaissent une évolution indépendante de la viviparité dans plus de 150 lignées de vertébrés dont au moins 115 concernent uniquement le taxon des reptiles squamates actuels (lézards, serpents et amphisbènes). Les lignées présentant une transition évolutive de l’oviparité à la viviparité chez les squamates se retrouvent généralement associées aux climats froids, mais pas uniquement. Les explications proposées pour ce patron reposent sur le contrôle comportemental de la température de développement chez les femelles gestantes, offrant ainsi des températures plus favorables que celles des sites de ponte situés sous la surface du sol. Durant cette thèse doctorale nous avons étudié une espèce à reproduction bimodale (Zootoca vivipara) chez qui coexistent des populations ovipares et vivipares disjointes. Ce contexte nous a permis de comparer les modes reproducteurs en minimisant les biais phylogénétiques. Nous avons pu mettre en évidence et quantifier différents coûts « potentiels » de la reproduction (énergétique, contrainte volumique, phénotype des nouveau-nés) et certains bénéfices (phénologie et performance des nouveau-nés) associés à la régulation maternelle du développement. Nos résultats nous amènent à discuter des différentes pressions de sélection s’exerçant sur la durée de rétention des embryons, dont les directions seraient opposées et/ou dont l’intensité serait variable au cours du développement embryonnaire. Dans ce schéma, la viviparité ne devrait être favorisée que dans des contextes plus contraignants et où les bénéfices thermiques compensent les coûts de prolongation de la rétention. Ce contexte sélectif aurait abouti chez les squamates à l’existence de deux modalités reproductives avec entre elles une instabilité évolutive des états intermédiairesIn his Historia Animalium in 343 B.C., Aristotle proposed two fundamental distinguishing criteria for reproductive diversity: the source of nutrients for embryonic development (lecitotrophy vs. matrotrophy) and partuition mode (oviparity vs. viviparity). Understanding the evolutionary transition to viviparity attracted considerable scientific interest over the past few decades. Phylogenetic analyses indicate that viviparity has originated independently in more than 150 vertebrate lineages, including in a minimum of 115 clades of extant squamate reptiles (lizards, snakes and amphisbaenians). Transitions from oviparity to viviparity in squamate reptiles seem closely related to cold climates, but not exclusively. Explanations for this pattern are based on the fact that pregnant females can behaviouraly thermoregulate and thus offer more suitable developmental temperatures than those available in nests under the soil surface. During this PhD thesis we studied a reproductively bi-modal species (Zootoca vivipara) in which non-overlapping oviparous and viviparous populations exist. This context allowed us to compare oviparous and viviparous reproductive modes while minimizing phylogenetic biases. We identified and quantified potential reproductive costs (energy, volume constraints, offspring phenotype) and also benefits (phenology and offspring performances) associated with maternal thermoregulation. Our results provide support for multiple selective pressures on embryo retention, with variable intensities and opposite directions depending on embryonic developmental stage. In this scheme, viviparity should be selected in constraining environments where thermal advantages exceed the costs of increased retention. This context may explain the dichotomy observed in squamate reproductive modes and the evolutionary instability of intermediate stages
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Germain, Marion. "The links between dispersal and individual fitness : correlation or causality ? : exploring mechanisms using correlative and experimental approaches in a passerine bird species, the collared flycatcher." Doctoral thesis, Uppsala universitet, Zooekologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-254731.
Full textAbstract:
Dispersal is commonly defined as the movement of an individual from its natal orprevious breeding site to a new breeding site. Because dispersal involves movements ofindividuals and genes among populations, it is recognized as a key life history trait withstrong effects on many ecological and evolutionary processes such as populationdynamics and genetics but also species spatial distribution or response to brutalenvironmental variations induced by human activities. Yet, the consequences of dispersalin terms of individual fitness remain poorly understood despite their crucial importance inthe understanding of the evolution of dispersal. The aim of this PhD is to get betterinsights in the fitness consequences of dispersal using both correlative and experimentalapproaches at different scales, i.e. annual and lifetime scales, in a wild patchy populationof migratory passerine bird, the collared flycatcher (Ficedula albicollis). Using a long-termdata set encompasses more than 20 years of data, differences between dispersing andphilopatric individuals were demonstrated both at a lifetime and annual scale. The resultsshowed strong phenotypic- and condition-dependent effects of dispersal and highlightthat the balance between the costs and benefits of dispersal is likely to be the result ofsubtle interactions between environmental factors and individuals’ phenotype. Moreover,the forced dispersal experiment demonstrated that dispersal might entail costs link tosettlement in a new habitat, which only some individuals may overcome. Nevertheless,the absence of difference in major fitness related decisions after settlement suggests thatdispersal is mostly adaptive for individuals overcome such costs.Key words: dispersal, fitness, collared flycatcher, dispersal costs and benefits,experimental approach, correlative approach, passerine.Joint PhD Uppsala, Lyon
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Stoeckel, James A. "Herbicides, Reservoirs, and Daphnia Reproduction: Is There a Cost to Male Production?" Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1186153732.
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com, Christinelamont@hotmail, and Christine Lamont. "Sex Allocation and Reproductive Costs in a Gull with a Long Breeding Season." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050617.102950.
Full textAbstract:
The Silver Gull is a small gull (265 - 450g), which exhibits sexual dimorphism, with males larger than females. It has a protracted laying period of about 8 months over the winter on Penguin Island in Western Australia. The Silver Gull was studied on Penguin Island from 2000 to 2002. Completed clutches were removed from breeding pairs to induce repeat laying in order to determine the effect of increased reproductive effort on maternal body condition, egg production ability, offspring sex ratio and chick rearing capacity.
Increased egg production had no significant effect on maternal body condition as measured by condition index, derived from mass divided by a measure of skeletal size. The seasonal period, divided into thirty-day intervals, had a significant impact on female condition index, with a decline in condition toward the end of the breeding season. While male condition also appeared to decline at the end of the season, this pattern was not significant.
The initiation of laying varied between the three years of the study. The earliest occurred in 2000, which also experienced earlier rainfall than the later two years. Egg size and mass decreased throughout the breeding season although the number of eggs in a clutch did not decline. The size and mass of the eggs was significantly affected by the laying history of the parents, although this effect was dependent on the year in which the eggs were produced.
The minimum interval required by Silver Gulls to replace a lost clutch is about 14 days. This interval increased from the start of the breeding season, but then declined toward the end, as summer was approaching. Laying interval increased significantly as the number of clutches produced by the parents also increased, up to 4 clutches in total. As more clutches were produced past this point, the laying interval became shorter.
The probability of a replacement clutch being produced after clutch removal, declined as the clutch number increased and as the season progressed. Individuals that laid clutches with a larger mean mass were more likely to lay a replacement clutch. Increasing reproductive output caused a decline in the proportion of clutches that were replaced after clutch removal. The proportion of clutches that were replaced also varied between the years with the highest rates of replacement seen in 2000 which was also the year that experienced the earliest start in laying. The size of the original clutch in terms of its mean mass and volume was related to the size of the replacement clutch, but this relationship varied according to the timing of laying.
During 2000 and 2001 male offspring predominated in the first two clutches produced by Silver Gulls. Further clutches that were produced demonstrated a sex ratio skewed toward females, the smaller sex in this species. Offspring sex ratio was close to equality in 2002 with very little effect caused by increased egg production. There was no effect of year, season or the laying history of the parents on hatching success. Growth rate in chicks was influenced by the year in which the chick hatched, the period during the season in which the chicks hatched, its sex and the laying history of the parents. The relationship between chick growth and the laying history, however, was complex with no consistent pattern emerging in terms of the performance of chicks from each treatment group. While the chicks from control groups generally grew faster than the chicks from manipulated parents, those individuals that were laid or raised by manipulated parents that had laid at least three clutches in total also performed well.
Using the two main measures of reproductive success in the current study, egg production and chick rearing, those birds that were induced to lay multiple replacement clutches, were able to maintain a high level of condition and reproductive success. It is proposed that in the Silver Gull, only those individuals with a high level of condition continue to lay replacement clutches. If the female is unable to produce well provisioned eggs with a high chance of success, the breeding attempt is abandoned. Despite no loss of condition detected in female Silver Gulls with increasing clutch number, there was a significant shift in the offspring sex ratio toward females, indicating that strategies were in place to cope with the increased reproductive effort incurred as a consequence of repeat laying. Protracted laying in this species allows replacement of lost clutches only after maternal condition has been regained after laying.
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Lamont, Christine. "Sex allocation and reproductive costs in a gull with a long breeding season." Lamont, Christine (2004) Sex allocation and reproductive costs in a gull with a long breeding season. PhD thesis, Murdoch University, 2004. http://researchrepository.murdoch.edu.au/143/.
Full textAbstract:
The Silver Gull is a small gull (265 - 450g), which exhibits sexual dimorphism, with males larger than females. It has a protracted laying period of about 8 months over the winter on Penguin Island in Western Australia. The Silver Gull was studied on Penguin Island from 2000 to 2002. Completed clutches were removed from breeding pairs to induce repeat laying in order to determine the effect of increased reproductive effort on maternal body condition, egg production ability, offspring sex ratio and chick rearing capacity.
Increased egg production had no significant effect on maternal body condition as measured by condition index, derived from mass divided by a measure of skeletal size. The seasonal period, divided into thirty-day intervals, had a significant impact on female condition index, with a decline in condition toward the end of the breeding season. While male condition also appeared to decline at the end of the season, this pattern was not significant.
The initiation of laying varied between the three years of the study. The earliest occurred in 2000, which also experienced earlier rainfall than the later two years. Egg size and mass decreased throughout the breeding season although the number of eggs in a clutch did not decline. The size and mass of the eggs was significantly affected by the laying history of the parents, although this effect was dependent on the year in which the eggs were produced.
The minimum interval required by Silver Gulls to replace a lost clutch is about 14 days. This interval increased from the start of the breeding season, but then declined toward the end, as summer was approaching. Laying interval increased significantly as the number of clutches produced by the parents also increased, up to 4 clutches in total. As more clutches were produced past this point, the laying interval became shorter.
The probability of a replacement clutch being produced after clutch removal, declined as the clutch number increased and as the season progressed. Individuals that laid clutches with a larger mean mass were more likely to lay a replacement clutch. Increasing reproductive output caused a decline in the proportion of clutches that were replaced after clutch removal. The proportion of clutches that were replaced also varied between the years with the highest rates of replacement seen in 2000 which was also the year that experienced the earliest start in laying. The size of the original clutch in terms of its mean mass and volume was related to the size of the replacement clutch, but this relationship varied according to the timing of laying.
During 2000 and 2001 male offspring predominated in the first two clutches produced by Silver Gulls. Further clutches that were produced demonstrated a sex ratio skewed toward females, the smaller sex in this species. Offspring sex ratio was close to equality in 2002 with very little effect caused by increased egg production. There was no effect of year, season or the laying history of the parents on hatching success. Growth rate in chicks was influenced by the year in which the chick hatched, the period during the season in which the chicks hatched, its sex and the laying history of the parents. The relationship between chick growth and the laying history, however, was complex with no consistent pattern emerging in terms of the performance of chicks from each treatment group. While the chicks from control groups generally grew faster than the chicks from manipulated parents, those individuals that were laid or raised by manipulated parents that had laid at least three clutches in total also performed well.
Using the two main measures of reproductive success in the current study, egg production and chick rearing, those birds that were induced to lay multiple replacement clutches, were able to maintain a high level of condition and reproductive success. It is proposed that in the Silver Gull, only those individuals with a high level of condition continue to lay replacement clutches. If the female is unable to produce well provisioned eggs with a high chance of success, the breeding attempt is abandoned. Despite no loss of condition detected in female Silver Gulls with increasing clutch number, there was a significant shift in the offspring sex ratio toward females, indicating that strategies were in place to cope with the increased reproductive effort incurred as a consequence of repeat laying. Protracted laying in this species allows replacement of lost clutches only after maternal condition has been regained after laying.
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Lamont, Christine Rae. "Sex allocation and reproductive costs in a gull with a long breeding season." Thesis, Lamont, Christine Rae (2004) Sex allocation and reproductive costs in a gull with a long breeding season. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/143/.
Full textAbstract:
The Silver Gull is a small gull (265 - 450g), which exhibits sexual dimorphism, with males larger than females. It has a protracted laying period of about 8 months over the winter on Penguin Island in Western Australia. The Silver Gull was studied on Penguin Island from 2000 to 2002. Completed clutches were removed from breeding pairs to induce repeat laying in order to determine the effect of increased reproductive effort on maternal body condition, egg production ability, offspring sex ratio and chick rearing capacity.
Increased egg production had no significant effect on maternal body condition as measured by condition index, derived from mass divided by a measure of skeletal size. The seasonal period, divided into thirty-day intervals, had a significant impact on female condition index, with a decline in condition toward the end of the breeding season. While male condition also appeared to decline at the end of the season, this pattern was not significant.
The initiation of laying varied between the three years of the study. The earliest occurred in 2000, which also experienced earlier rainfall than the later two years. Egg size and mass decreased throughout the breeding season although the number of eggs in a clutch did not decline. The size and mass of the eggs was significantly affected by the laying history of the parents, although this effect was dependent on the year in which the eggs were produced.
The minimum interval required by Silver Gulls to replace a lost clutch is about 14 days. This interval increased from the start of the breeding season, but then declined toward the end, as summer was approaching. Laying interval increased significantly as the number of clutches produced by the parents also increased, up to 4 clutches in total. As more clutches were produced past this point, the laying interval became shorter.
The probability of a replacement clutch being produced after clutch removal, declined as the clutch number increased and as the season progressed. Individuals that laid clutches with a larger mean mass were more likely to lay a replacement clutch. Increasing reproductive output caused a decline in the proportion of clutches that were replaced after clutch removal. The proportion of clutches that were replaced also varied between the years with the highest rates of replacement seen in 2000 which was also the year that experienced the earliest start in laying. The size of the original clutch in terms of its mean mass and volume was related to the size of the replacement clutch, but this relationship varied according to the timing of laying.
During 2000 and 2001 male offspring predominated in the first two clutches produced by Silver Gulls. Further clutches that were produced demonstrated a sex ratio skewed toward females, the smaller sex in this species. Offspring sex ratio was close to equality in 2002 with very little effect caused by increased egg production. There was no effect of year, season or the laying history of the parents on hatching success. Growth rate in chicks was influenced by the year in which the chick hatched, the period during the season in which the chicks hatched, its sex and the laying history of the parents. The relationship between chick growth and the laying history, however, was complex with no consistent pattern emerging in terms of the performance of chicks from each treatment group. While the chicks from control groups generally grew faster than the chicks from manipulated parents, those individuals that were laid or raised by manipulated parents that had laid at least three clutches in total also performed well.
Using the two main measures of reproductive success in the current study, egg production and chick rearing, those birds that were induced to lay multiple replacement clutches, were able to maintain a high level of condition and reproductive success. It is proposed that in the Silver Gull, only those individuals with a high level of condition continue to lay replacement clutches. If the female is unable to produce well provisioned eggs with a high chance of success, the breeding attempt is abandoned. Despite no loss of condition detected in female Silver Gulls with increasing clutch number, there was a significant shift in the offspring sex ratio toward females, indicating that strategies were in place to cope with the increased reproductive effort incurred as a consequence of repeat laying. Protracted laying in this species allows replacement of lost clutches only after maternal condition has been regained after laying.
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Lamont, Christine Rae. "Sex allocation and reproductive costs in a gull with a long breeding season /." Access via Murdoch University Digital Theses Project, 2004. https://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050617.102950.
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Morin, Audrée. "Coûts de la reproduction chez les femelles de chamois des Alpes (Rupicapra rupicapra)." Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6593.
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Les coûts de la reproduction sont un élément fondamental de la théorie biodémographique, qui étudie l'évolution des stratégies d'histoire de vie. Puisque l'énergie est limitée, la quantité qui est allouée à une composante de la reproduction sera détournée des autres fonctions, entraînant des compromis entre la reproduction actuelle, la reproduction future, la survie et la croissance. Ce mémoire vise à évaluer les coûts énergétiques de la reproduction et les coûts de la reproduction sur le succès reproducteur futur en relation avec l'âge chez les femelles de chamois des Alpes ( Rupicapra rupicapra ). Pour ce faire, j'ai suivi des chamois marqués individuellement dans le Parco Naturale delle Alpi Marittime (Italie) entre 2007 et 2012. J'ai capturé et pesé 107 femelles et suivi leur succès reproducteur par les associations entre mère et jeune et le comportement d'allaitement. J'ai utilisé une nouvelle approche analytique basée sur les tests de permutations pour contrôler pour l'hétérogénéité individuelle, qui modifie souvent les estimations des coûts de la reproduction en introduisant des corrélations positives entre les traits d'histoire de vie. Le succès reproducteur était fortement associé à l'âge. Les femelles de 4 à 7 ans avaient le taux de reproduction le plus élevé (71%) et la sénescence reproductrice commençait plus tôt que chez d'autres espèces d'ongulés (8 ans). Les femelles chamois semblent avoir une tactique différente de la majorité des ongulés avec une fécondité relativement faible et une survie des jeunes au sevrage très élevée et stable. Les femelles adultes alternaient davantage entre succès et échec reproducteur que dans un patron aléatoire, ce qui suggère des coûts de la reproduction sur la reproduction suivante. Pour les vieilles femelles, le succès reproducteur était très hétérogène, suggérant de la variabilité dans l'âge de début de la sénescence. Elles ne montraient aucun coût sur la reproduction suivante et étaient plus lourdes que les femelles adultes, suggérant de la restreinte reproductrice en fin de vie. Au printemps, les femelles allaitantes pesaient 1.21 kg (5%) de moins que les non-reproductrices et la masse demeurait stable pendant tout l'été, indiquant des coûts énergétiques de la gestation et du début de l'allaitement. Nos résultats suggèrent que la tactique de reproduction et les coûts de la reproduction changent de façon importante en fonction de l'âge des individus chez cette espèce. En quantifiant séparément les effets de l'hétérogénéité individuelle et des coûts de la reproduction, mon projet de maîtrise a permis de mettre en évidence que l'hétérogénéité individuelle peut changer au cours de la vie d'un individu. Cela souligne l'importance de tenir compte de cette potentielle modification dans les études sur les coûts de la reproduction.
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MYERS, TERRY LELAND. "REPRODUCTIVE CHARACTERISTICS OF AMERICAN COOTS (FULICA AMERICANA) IN NORTHERN ARIZONA." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184086.
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I studied coots nesting at semipermanent and seasonal wetlands near Flagstaff, Arizona. Coot nests in bulrush (at the semipermanent wetland) were spaced closer together than nests in spikerush (at seasonal and semipermanent wetlands). Nests were much more successful in bulrush at the semipermanent wetland than in spikerush at seasonal wetlands. Coots nesting in bulrush laid larger eggs than coots nesting in spikerush. However, coots nesting in spikerush at seasonal wetlands laid larger clutches than coots nesting in bulrush at the semipermanent wetland. Better nesting success was related to better vegetative concealment of the nest from crows and ravens. Smaller territories and larger eggs among nests in bulrush were related to better food resources in the vicinity of the nest as indicated by a greater abundance and diversity of emerging aquatic insects. Clutches with more eggs, however, did not correspond to nest sites associated with more abundant aquatic insects. I suggest that clutch size might have been influenced by some aspect of nutrients stored prior to egg-laying which were not necessarily gained from resources on the territory. In general, in areas where nests were more closely spaced (e.g., bulrush) clutches contained fewer eggs than in areas where nests were spaced further apart (e.g., spikerush at seasonal wetlands) indicating the amount of energy expended by the female on the defense of territories might also affect clutch size.
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Lopez-Casas, Eugenia. "Social and biological reproduction of lower-income groups on the Meseta Central in Costa Rica." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6648/.
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This thesis examines the social and biological reproduction of households in the sectores populares, ie low income groups, both rural and urban, in the Meseta Central, yields specific outcomes at household level: the social formation based, originally, on smallholder coffee also depends on unusually successful domestic labour. Only multidisciplinary team work could adequately evaluate reproduction at the household level and establish the crucial role of the household in the wider economic system, as well as the role of women in maintaining diverse forms of subordination. The standard of living of the groups studied was estimated from the nutritional status of the children as a basic indicator of wellbeing; explanations of this status were sought in multivariate analysis of biological, economic, and social factors. Unexpectedly, the explanatory power of such variables such as income proved weak, the explanation appearing rather to lie with the less quantifiable social factors which rendered domestic labour more or less effective. Surveys and analysis, 1981-1984, sought to establish household survival strategies; diversified household enterprise proved of great importance in a survival constantly endangered by the insecurity of temporary, part-time and seasonal work so familiar in the Costa Rican economy as a whole. The household itself, as a flexible social organisation, seems one of the best resources for livelihood in the sectores populares, along with the ‘peasant' tradition of unpaid female and child labour. Proletarianisation remains incomplete. The economic categories of traditional Marxism prove inadequate to explain the gender subordination which characterises male female relations in countries of markedly uneven development, such as Costa Rica.
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Meyers, Peter J. "Variation in Resource Utilization and Cost of Reproduction for Two Burying Beetle Species." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5761.
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The cost of reproduction hypothesis suggests that allocation into current reproduction constrains future reproduction. How organisms accrue reproductive costs may differ between species and with varying levels of resource quality. Burying beetles are model organisms for testing for the cost of reproduction because of their unique natural history; beetles utilize small vertebrate carcasses for reproduction and they and their offspring feed exclusively on these discrete resources. Burying beetles also can utilize a large range of carcass sizes for reproduction. We tested for the cost of reproduction in two species of burying beetles, Nicrophorus marginatus and Nicrophorus guttula found in Central Utah by breeding beetles on a range of carcass sizes (5g, 10g, 20g, 30g, 40g, and 50g carcasses). We also used a manipulation experiment to force beetles into over-allocating energy into reproduction to assess reproductive costs. For both species, reproduction was costly, with beetles suffering reduced lifespan and reduced lifetime fecundity with increased resource quality. Both species also showed clear signs of senescence, having reduced brood size and lower efficiency as individuals aged. Females did not show indications of terminal investment in terms of female mass change, unlike the previously studied Nicrophorus orbicollis, which gained less mass after each reproductive attempt as it aged. Nicrophorus marginatus consistently outperformed N. guttula in terms of total number of offspring produced for all carcass sizes. Nicrophorus guttula populations may continue to persist with N. marginatus by exploiting a less desirable but more abundant resource.
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Smith, Hilary April. "Evolution of Reproduction and Stress Tolerance in Brachionid Rotifers." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/52145.
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Stress can be a driving force for new evolutionary changes leading to local adaptation, or may be responded to with pre-existing, ancestral tolerance mechanisms. Using brachionid rotifers (microzooplankton) as a study system, I demonstrate roles of both conserved physiological mechanisms (heat shock protein induction) and rapid evolution of traits in response to ecologically relevant stressors such as temperature and hydroperiod. Rapid evolution of higher levels of sex and dormancy in cultures mimicking temporary waters represents an eco-evolutionary dynamic, with trait evolution feeding back into effects on ecology (i.e., reduced population growth). I also reveal that prolonged culture in a benign laboratory environment leads to evolution of increased lifespan and fecundity, perhaps due to reduction of extrinsic mortality factors. Potential mechanisms (e.g., hormonal signals) are suggested that may control evolvability of facets of the stress response. Due to prior studies suggesting a role of progesterone signaling in rotifer sex and dormancy, the membrane associated progesterone receptor is assayed as a candidate gene that could show positive selection indicating rapid divergence. Despite some sequence variation that may contribute to functional differences among species, results indicate this hormone receptor is under purifying selection. Detailed analyses of multiple stress responses and their evolution as performed here will be imperative to understanding current patterns of local adaptation and trait-environment correlations. Such research also is key to predicting persistence of species upon introduction to novel habitats and exposure to new stressors (e.g., warming due to climate change). Perhaps one of the most intriguing results of this dissertation is the rapid, adaptive change in levels of sex and dormancy in a metazoan through new mutations or re-arrangements of the genetic material. This suggests species may be able to rapidly evolve tolerance of new stressors, even if standing genetic variation does not currently encompass the suite of alleles necessary for survival.
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Laidlaw, Clinton T. "Latitudinal Variation in Lifetime Survival and Reproduction in a Burying Beetle." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5733.
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Temperature variation experienced across a latitudinal range is tied to changes in lifespan and life history across multiple taxa. Two patterns of adaptation to latitudinal temperature variation have been documented – counter-gradient (or co-gradient) variation, and local adaptation. To determine how natural selection has shaped life history variation in a burying beetle, Nicrophorus orbicollis, we quantified lifetime patterns of reproduction in two populations that represent the geographic and temperature extremes occupied by the species. Lifetime reproduction was quantified at two temperatures that represented conditions typical for each population. Burying beetles from different extremes of their geographic range show considerable variation in lifetime survival and reproduction at different temperatures. Patterns are generally consistent with the local adaptation hypothesis. However, at the higher temperature both populations have lower and equal numbers of offspring over a lifetime. High temperatures may create a constraint on offspring production because of the increased cost of maintaining the food source against bacterial decomposition. This temperature constraint on reproductive success may partially explain the absence of burying beetles from tropical environments, and may predict reductions in latitudinal range as global climate change proceeds.
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Nyame, Hallex Berry. "A child at any cost : A study on how the issue about assisted reproduction for single people is being interpreted by the Swedish media." Thesis, Södertörns högskola, Institutionen för kommunikation, medier och it, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-16883.
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March 13th 2012 the Swedish social Committee brings up a proposal that assisted reproduction should be legalize for single women in Sweden. The suggestion was quickly forwarded to the parliament for a decision making. Although majority of the Swedish parties (the alliances) are positive about this proposal, there are also a few who are strongly against the proposal, for example the Christian Democratic Party. The purpose of this study has been to investigate how the two Swedish newspapers Dagens Nyheter and Svenska Dagbladet has written about the issue on legalizing assisted reproduction for single women in Sweden. To help me come to my results and conclusion on this study I decided to use the quantitative content analysis and the qualitative text analysis method. I have specifically chosen to concentrate on how these two newspapers have chosen to present this issue and what angles do Dagens Nyheter and Svenska Dagbladet uses to present this issue to their readers. After my qualitative text analysis, I came to the conclusion that this issue didn’t get the attention that it deserves from both of the newspapers. Since the issue is about babies, women and their bodies, I expected the newspapers to write about this issue as a gender issue, but that was not the case. Instead it was twisted around by the press and made into a political fight between the Christian Democrat party that is against the proposal and the alliances that is positive to the proposal. In all the articles I had chosen to analyze, I as a reader was met by the voices of different politicians that had strong opinions about legalizing assisted reproduction for single women. The opinion of ordinary people didn’t seem to matter to any of the journalist and neither was the opinion of women, because I realized that neither of these groups were found in the articles. Even more interesting was the fact that the voices of the politicians were all dominated by men. In conclusion looking at the issue on legalizing assisted reproduction for single women, one would supposed that the issue is going to be based on subjects about babies, hospitals, women and their bodies. Instead the issue was made into a political fight and dominated by male voices and opinions.
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Bleu, Josefa. "Etude expérimentale et intégrative des coûts et bénéfices de la viviparité chez le lézard vivipare." Paris 6, 2011. http://www.theses.fr/2011PA066452.
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Ce travail s’intéresse à l’évolution de la viviparité, mode de reproduction qui consiste à mettre au monde directement des jeunes vivants, et de l’oviparité, mode de reproduction qui consiste à pondre des œufs. J’ai utilisé le lézard vivipare comme espèce modèle car c’est une des rares espèces au sein de laquelle on observe des femelles vivipares et ovipares. Mon étude repose sur des approches expérimentales, comparatives et corrélatives pour étudier les coûts et bénéfices de la viviparité. Tout d’abord, j’ai montré que l’investissement dans la reproduction est contraint par la condition passée de la femelle et les conditions environnementales présentes. Cependant, le mode de reproduction vivipare ne semble pas permettre des ajustements post-ovulatoires (pendant la gestation) de cet investissement reproducteur. Selon le contexte, la gestation est associée à certains coûts, ayant des effets sur le système immunitaire, sur le comportement de thermorégulation, sur l’endurance, et sur la perte de poids des femelles ; mais la gestation n’a pas d’effet sur la survie après la mise bas. Par ailleurs, la viviparité a aussi certains avantages. Par exemple, une comparaison intra-spécifique a montré que les coûts de la reproduction sont plus importants pour les femelles ovipares que les vivipares avant la gestation. Finalement, il existe aussi des effets maternels pendant la gestation. Afin de mettre en évidence les facteurs à l’origine de ces effets maternels, j’ai développé une approche expérimentale qui repose sur l’incubation in vitro d’embryons de lézards vivipares. Les résultats préliminaires sont prometteurs étant donné que ce processus permet d’obtenir des jeunes vivants.
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Hillegass, Melissa Ann. "SEX-BIASED PARASITISM AND THE REPRODUCTIVE COSTS OF PARASITES IN A SOCIAL AFRICAN GROUND SQUIRREL." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2205.
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Vertebrate males frequently carry higher numbers of parasites than females. This bias in parasite loads could be a consequence of sexual selection. Grouping species are also assumed to be afflicted with larger numbers of parasites than solitary animals and associated costs of this parasitism could vary with group size or structure. I examined sex-biased parasitism and the influence of group size on parasite loads in Cape ground squirrels (Xerus inauris), a highly social species that occurs in the arid regions of southern Africa. Males carried three times as many ectoparasites as females, but females harbored nearly three times more endoparasites than males. Amount of time spent (per hour) autogrooming was similar between males and females, but amount time spent allogrooming by adult female was over eleven times that of adult males. Longer allogrooming of group members could be decreasing the numbers of ectoparasites of group members and ultimately the group. Males infrequently give or receive allogrooming and travel in very large home ranges, potentially increasing their exposure to ectoparasites. However, movement throughout a large home range may result in males foraging in areas with lower densities of fecal pellets, which could explain the lower endoparasite loads observed in males. When I considered the age class of group members, female age classes were similarly parasitized but male age classes were not. Sub-adult males carried similar ectoparasite loads to adult males and similar endoparasite loads to adult females. This result is of particular interest because sub-adult males are becoming scrotal but typically remain in the group until adulthood. Sexual selection does appear to influence parasite loads in this species, and parasite removal or avoidance potentially mitigates individual parasite loads and their associated costs. Parasites can be detrimental to the health, longevity, and reproduction of their hosts, but these costs are rarely quantified. I removed ectoparasites and endoparasites from Cape ground squirrels for three months and evaluated changes in female body mass, reproduction, burrow use, and grooming in response to parasite removal. Female body mass did not increase with parasite removal, but reproductive success (per capita offspring raised to emergence) increased nearly four-fold, while allogrooming by treated females decreased. Since breeding is highest in the late winter dry season when fewer resources are available, the impact of parasites may be highest during this season. Lactation and gestation are the most physiological stressful processes that females undergo, and the dramatic increase in reproductive success in treated females suggests that these females are able to allocate more resources to reproduction than females afflicted with parasites. These results suggest that studies investigating reproduction and fecundity must consider the vulnerability of the host to parasite infection and the potential impact on reproductive success.M.S.
Department of Biology
Sciences
Biology MS
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Gélin, Uriel. "Stratégies de reproduction des femelles du kangourou géant (Macropus giganteus)." Thèse, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/87.
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Résumé : La reproduction entraîne des dépenses énergétiques importantes chez les femelles mammifères. Ces dépenses sont supposées diminuer l'énergie disponible pour d'autres traits positivement corrélés à l'aptitude phénotypique et augmenter les besoins d'alimentation. Toutefois, des différences individuelles dans la capacité d'acquisition et d'allocation peuvent masquer l'impact négatif de l'effort reproducteur. La manipulation expérimentale de l'effort reproducteur et le contrôle statistique des effets individuels sont deux approches puissantes et complémentaires mises en œuvre dans le cadre de mon étude afin de contrôler pour l'hétérogénéité individuelle. Elles ont permis de montrer clairement un coût de la reproduction chez le kangourou gris de l'Est (Macropus giganteus). Dans un premier temps, nous avons trouvé que le coût de la reproduction affectait le montant d'énergie alloué à certaines fonctions somatiques (CHAPITRE I). L'effort reproducteur diminuait le gain de masse et la croissance des jambes pour des intervalles de capture supérieurs à deux ans. Chez les femelles non manipulées, un effet négatif sur le gain de masse était aussi observable pour un intervalle inférieur à 3 ans. À l'échelle de deux événements successifs de reproduction, le gain de masse et dans une moindre mesure la croissance des bras, mais non des jambes diminuaient avec un effort reproducteur plus important à la précédente reproduction. Ensuite, nous avons démontré qu'il y avait un coût de la reproduction en terme de futur succès reproducteur (CHAPITRE II). Les individus dont l'effort reproducteur avait été diminué expérimentalement produisaient davantage de jeunes qui survivaient au stade 'LPY', âgés approximativement de 7 mois, que les femelles contrôles. Ils diminuaient également davantage leur taux de reproduction en allongeant l'intervalle entre les naissances, mais la survie au sevrage n'était pas affectée. Le CHAPITRE III montre que les femelles adaptaient leur comportement alimentaire en fonction de leur statut reproducteur. En comparaison avec les individus manipulés ou ayant perdu leur jeune, les femelles allaitantes augmentaient leur temps passé à s'alimenter durant la journée, l'intensité de leurs bouchées et de leur mastication sans impliquer de compromis avec la vigilance. Nous avons aussi découvert que la survie au sevrage du jeune précédent menait à une augmentation du taux de bouchées pour l'année en cours.
Les CHAPITRES I et II ont mis en évidence l'effet non négligeable des différences individuelles sur la détection des coûts de la reproduction. En effet, en l'absence de manipulation expérimentale ou de contrôle statistique, aucun compromis n'était détecté autant en terme de croissance que de prochaine reproduction. Au contraire, des corrélations positives entre l'effort reproducteur et les autres traits ont été trouvées. Le CHAPITRE I suggérait notamment que cette variabilité du succès reproducteur était liée à l'hétérogénéité individuelle dans le gain de masse maternelle qui augmentait la survie du jeune. Dans le CHAPITRE II, une corrélation positive entre les probabilités d'avoir un 'LPY' lors de deux événements successifs de reproduction suggérait que certaines femelles étaient capables de mener à bien ou non leur reproduction, mais cela indépendamment de l'effort reproducteur précédent. Enfin dans le dernier CHAPITRE (III), l'effet aléatoire était significatif dans l'analyse de différents comportements d'alimentation, ce qui pourrait être lié aux différences de gain de masse des femelles présentées dans le CHAPITRE I.
Certaines contraintes individuelles affectant le coût de la reproduction ont été identifiées. La masse et la condition corporelle augmentaient le succès reproducteur et diminuaient l'intervalle entre deux naissances successives (CHAPITRES I et II), mais contrairement à de précédentes études le comportement d'alimentation des femelles n'était pas affecté par leur masse (CHAPITRE III). L'âge des individus avait également une influence. Les jeunes femelles croissaient davantage, avaient aussi une prise alimentaire plus importante et subissaient un coût de reproduction supérieur. Ce dernier se traduisait par un taux d'échec plus élevé à la reproduction suivante si les jeunes femelles avaient eu un jeune l'année précédente (CHAPITRES I, II et III).
Des contraintes environnementales fortes influençaient la reproduction des femelles. La croissance, le succès reproducteur, l'intervalle entre les naissances et les comportements d'alimentation variaient suivant le site et l'année d'étude. Le site du Promontory et l'année 2011 apparaissaient particulièrement limitants. En effet en 2011, le gain de masse et le succès reproducteur ont diminué et l'intervalle de naissance et la prise de nourriture pour les femelles allaitantes ont augmenté (CHAPITRE I,II et III).
Nous cherchions également à mettre au jour une allocation différentielle des mères suivant le sexe de leur jeune. Si le coût supérieur d'avoir un mâle par rapport à une femelle était évident quant aux taux de bouchées (CHAPITRE III), il s'est avéré plus difficile à détecter sur d'autres traits. À Anglesea, les jeunes mères avaient moins de probabilité d'avoir un jeune qui atteigne le stade 'LPY' après avoir eu un fils qu'une fille (CHAPITRE II). Toutefois, des résultats contraires à nos attentes ont été trouvés, du moins au premier abord, sur la croissance et le succès reproducteur subséquent. Ainsi, les femelles qui avaient eu une fille perdaient davantage de masse (CHAPITRE I) et avaient généralement une probabilité moindre de produire un jeune qui atteigne le stade 'LPY' ou qui soit sevré par la suite (CHAPITRE II). En revanche, l'intervalle de naissance n'était pas différent suivant le sexe du jeune alors qu'il était fortement affecté par le coût de la reproduction démontré grâce à la manipulation, invoquant une autre explication qu'un coût supérieur des filles par rapport aux fils. En effet, les femelles qui étaient en mauvaise condition corporelle gagnaient de la masse quand elles produisaient une fille, mais pas un fils (CHAPITRE I). De surcroît, les jeunes mères avaient moins de chances de sevrer un jeune à l'événement de reproduction suivant si elles avaient eu un fils plutôt qu'une fille, et le succès reproducteur des mères des fils n'était plus différent de celui des mères des filles dans les années plus difficiles (CHAPITRE II). Enfin, les mères des fils augmentaient la quantité de nourriture ingérée si elles avaient sevré un jeune l'année précédente, mais les mères des filles la diminuaient. Ces différents résultats suggéraient fortement qu'un ajustement du sexe-ratio était utilisé quand les ressources individuelles ou environnementales contraignaient davantage la reproduction.
En conclusion, pour limiter le décalage entre les besoins énergétiques et la disponibilité en nourriture, les femelles chez le kangourou gris de l'Est pourraient modifier l'allocation de leurs ressources à la reproduction en reportant la prochaine mise bas et en produisant un jeune du sexe le moins coûteux en accord avec les contraintes individuelles et environnementales. Ces résultats soulignent l'importance d'études avec un suivi individuel sur plusieurs années afin de pouvoir comprendre la variabilité des stratégies de reproduction et leurs conséquences sur la dynamique des populations. // Abstract : Reproduction in living beings, particularly in female mammals that produce milk, is costly, potentially involving trade-offs with life-history traits if resources are limited and an increase in foraging effort. Individual differences may, however, hide the negative effects of this cost on life-history traits. I used two powerful and complementary approaches, to deal with individual heterogeneity: experimental manipulation of reproductive effort and statistical control of individual effect. Using both approaches, I investigated the effect of presence, size and sex of young on growth, subsequent reproduction and individual foraging behaviours of females. I used data of tagged free-ranging eastern grey kangaroos (Macropus giganteus) collected over six years at five study sites in Victoria, Australia. There was a clear cost of reproduction. Reproductive effort decreased mass gain and limb growth for inter-capture intervals greater than two years. Over two successive reproductive events, mass gain and arm growth were reduced but leg growth was independent of reproductive effort (CHAPTER II).In addition, survival to Large Pouch Young ('LPY') stage, about 7 months of age, was higher and birth rate lower in manipulated compared to control females but survival to weaning was not affected (CHAPTER III). CHAPTER IV shows that lactating females cope with current reproductive costs by increasing ivtime spent foraging as well as bite and chewing rates without decreasing vigilance comparedto non lactating ones. Bite rate was also greater for females that weaned a young at the previous reproductive event. My study supports reproductive cost hypothesis while showing substantial individual differences. To limit mismatch between energetic needs and resource availability, females of eastern grey kangaroo could modify resource allocation to reproduction by delaying birth date of subsequent young and producing the less costly sex according to individual and environmental constrains. My thesis shows the importance of experimental approach and individual monitoring over multiple years to understand the diversity of reproductive strategies and their consequences in evolutionary ecology and population dynamic.
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Nguyen, Quynh Anh. "Economic evaluation of adolescent reproductive health education interventions in Chilinh, Vietnam." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/79547/1/Quynh%20Anh_Nguyen_Thesis.pdf.
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This research was an economic analysis of two novel health education interventions compared to existing practice for reproductive health among young people in northern Vietnam. The research showed that implementing an educational intervention including school-based and health facility-based components was cost effective for males and females. The findings will assist decision makers in efficient allocation of scarce resources for adolescent health promotion in Vietnam and similar socio-economic contexts in Asia.
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Dahirel, Maxime. "Déterminants individuels et environnementaux de la dispersion chez une espèce hermaphrodite, l'escargot Cornu aspersum." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S068/document.
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Les comportements de dispersion, c'est-À-Dire les mouvements conduisant à des flux de gènes dans l'espace, jouent un rôle majeur dans de nombreux processus écologiques et évolutifs. Les Gastéropodes terrestres sont des hermaphrodites simultanés dont le mouvement est extrêmement coûteux, une combinaison de traits très intéressante pour étudier les liens entre dispersion et autres traits d'histoire de vie. Dans le cadre de cette thèse, nous avons étudié (i) les relations complexes entre dispersion, croissance, reproduction mâle et femelle chez le petit-Gris Cornu aspersum, un escargot anthropophile, (ii) comment la dispersion et le comportement exploratoire de cette espèce varient en fonction de la compétition ressentie et de l'hétérogénéité environnementale, (iii) comment la propension à disperser coévolue avec d'autres traits à l'échelle interspécifique. Cornu aspersum passe par une phase subadulte mâle de durée variable avant de devenir adulte et hermaphrodite. Le comportement de dispersion s'exprime principalement pendant cette phase subadulte, et sa diminution chez les adultes est liée à l'accroissement de l'investissement dans la fonction femelle. Cette espèce disperse de façon très densité-Dépendante : les individus quittent les sites à haute densité et s'installent dans ceux peu peuplés, une stratégie qui facilite la colonisation et la persistance en environnements instables. La propension à explorer augmente en environnements urbains fragmentés, malgré les coûts plus élevés du mouvement. Au niveau interspécifique, dispersion et généralisme sont liés, ce qui rend les espèces spécialistes doublement vulnérables, mais facilite le succès des généralistes en milieux hétérogènes. Cette combinaison de traits a probablement joué un rôle majeur dans la colonisation de nombreux milieux anthropisés par cette espèce à travers le mondeDispersal behaviours, i.e. movements leading to gene flow in space, play a key role in many ecological and evolutionary processes. Terrestrial gastropods are simultaneous hermaphrodites and have an extremely high cost of locomotion, a seldom studied combination of traits which makes them very valuable to investigate the links between dispersal and other life-History traits. During this project, we investigated (i) the complex relationships and trade-Offs between dispersal behaviour, growth, male and female reproduction in the anthropophilous brown garden snail Cornu aspersum, (ii) how its dispersal and exploration vary as a function of competition and environmental heterogeneity, (iii) how dispersal ability coevolved with other traits at the interspecific level. This snail presents a male-Biased subadult phase of varying duration before reaching adulthood and hermaphroditism. Dispersal behavior was mostly expressed during this subadult stage, and its decrease in adults was linked to investment in the female function. Brown garden snail dispersal is highly density-Dependant: snails leave crowded sites and settle readily in low-Density patches, a strategy that facilitates colonization and persistence in spatio-Temporally variable environments. Their movement propensity increases in urban, fragmented habitats, despite the higher costs of movement. At the interspecific level, dispersal and ecological generalism are linked in a dispersal syndrome, which makes specialist species doubly vulnerable, but increases success odds of generalists in heterogeneous landscapes . This combination of traits is likely to have played a major role in the successful worldwide colonization of many anthropogenic landscapes by this species
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Pook, Christopher James. "The bioenergetic cost of metal resistance and its consequences for reproduction in the harbour ragworm, Nereis diversicolor." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/107058.
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The population of harbour ragworms, Nereis diversicolor, inhabiting the upper reaches of Restronguet Creek in the Fal Ria, UK, are known to be resistant to the acute, toxic effects of copper, zinc and cadmium. This research aimed to establish whether metabolic and reproductive performance costs were associated with the resistance phenomenon and what the biochemical mechanisms of resistance were, by comparing animals from the Creek with two comparable study sites in the South West of England: Froe Creek and the Teign estuary. There was a significant metabolic cost, measured as a reduction in Scope for Growth, associated with the resistance phenomenon. As no differences in energy intake or uptake were found between resistant and non-resistant animals it was concluded that this cost was covered by demand-side regulation of energetics. A reduction in the amount of biochemical energy reserves in the form of lipids and sugars was also observed in resistant animals suggesting that resource allocation had been shifted away from this endpoint and towards maintenance and activity. The perturbed metabolism and physiology of resistant N. diversicolor is shown to have detrimental consequences for their life-history. Sexually mature, resistant females were significantly smaller than non-resistant ones, indicating that they had either matured at a younger age or grown more slowly. Both total fecundity and mass-specific fecundity were significantly reduced in resistant females, likely as a direct result of the metabolic costs of resistance reducing the resources available to fuel gametogenesis. No differences were found in the energetic reserves stocked within each gamete by resistant and non-resistant animals, suggesting that this trait is heavily selected for. Synthesis of reduced glutathione [GSH] in resistant animals’ tissues appeared to be elevated. Glutathione peroxidase activity was also increased, likely to remediate the effects of Reactive Chemical Species [RCS] that result from the inevitably incomplete binding of intracellular metals. As GSH functions in metal detoxification to covalently binding metals entering resistant animals’ cells, preventing their involvement in toxic interactions and their catalysis of the production of RCS, it is proposed that together there two phenomena comprise the fundamental mechanism of resistance to metal toxicity. Ultimately, this research revealed a hierarchy of health and reproductive performance across the three study populations, with significant associations evident between measured biological endpoints and the degree of metal contamination, illustrating the consequences of anthropogenic pollution for the biology of wild animals.
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G??lin, Uriel. "Strat??gies de reproduction des femelles du kangourou g??ant (Macropus giganteus)." Thèse, Universit?? de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/87.
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R??sum?? : La reproduction entra??ne des d??penses ??nerg??tiques importantes chez les femelles mammif??res. Ces d??penses sont suppos??es diminuer l'??nergie disponible pour d'autres traits positivement corr??l??s ?? l'aptitude ph??notypique et augmenter les besoins d'alimentation. Toutefois, des diff??rences individuelles dans la capacit?? d'acquisition et d'allocation peuvent masquer l'impact n??gatif de l'effort reproducteur. La manipulation exp??rimentale de l'effort reproducteur et le contr??le statistique des effets individuels sont deux approches puissantes et compl??mentaires mises en ??uvre dans le cadre de mon ??tude afin de contr??ler pour l'h??t??rog??n??it?? individuelle. Elles ont permis de montrer clairement un co??t de la reproduction chez le kangourou gris de l'Est (Macropus giganteus). Dans un premier temps, nous avons trouv?? que le co??t de la reproduction affectait le montant d'??nergie allou?? ?? certaines fonctions somatiques (CHAPITRE I). L'effort reproducteur diminuait le gain de masse et la croissance des jambes pour des intervalles de capture sup??rieurs ?? deux ans. Chez les femelles non manipul??es, un effet n??gatif sur le gain de masse ??tait aussi observable pour un intervalle inf??rieur ?? 3 ans. ?? l'??chelle de deux ??v??nements successifs de reproduction, le gain de masse et dans une moindre mesure la croissance des bras, mais non des jambes diminuaient avec un effort reproducteur plus important ?? la pr??c??dente reproduction. Ensuite, nous avons d??montr?? qu'il y avait un co??t de la reproduction en terme de futur succ??s reproducteur (CHAPITRE II). Les individus dont l'effort reproducteur avait ??t?? diminu?? exp??rimentalement produisaient davantage de jeunes qui survivaient au stade 'LPY', ??g??s approximativement de 7 mois, que les femelles contr??les. Ils diminuaient ??galement davantage leur taux de reproduction en allongeant l'intervalle entre les naissances, mais la survie au sevrage n'??tait pas affect??e. Le CHAPITRE III montre que les femelles adaptaient leur comportement alimentaire en fonction de leur statut reproducteur. En comparaison avec les individus manipul??s ou ayant perdu leur jeune, les femelles allaitantes augmentaient leur temps pass?? ?? s'alimenter durant la journ??e, l'intensit?? de leurs bouch??es et de leur mastication sans impliquer de compromis avec la vigilance. Nous avons aussi d??couvert que la survie au sevrage du jeune pr??c??dent menait ?? une augmentation du taux de bouch??es pour l'ann??e en cours.
Les CHAPITRES I et II ont mis en ??vidence l'effet non n??gligeable des diff??rences individuelles sur la d??tection des co??ts de la reproduction. En effet, en l'absence de manipulation exp??rimentale ou de contr??le statistique, aucun compromis n'??tait d??tect?? autant en terme de croissance que de prochaine reproduction. Au contraire, des corr??lations positives entre l'effort reproducteur et les autres traits ont ??t?? trouv??es. Le CHAPITRE I sugg??rait notamment que cette variabilit?? du succ??s reproducteur ??tait li??e ?? l'h??t??rog??n??it?? individuelle dans le gain de masse maternelle qui augmentait la survie du jeune. Dans le CHAPITRE II, une corr??lation positive entre les probabilit??s d'avoir un 'LPY' lors de deux ??v??nements successifs de reproduction sugg??rait que certaines femelles ??taient capables de mener ?? bien ou non leur reproduction, mais cela ind??pendamment de l'effort reproducteur pr??c??dent. Enfin dans le dernier CHAPITRE (III), l'effet al??atoire ??tait significatif dans l'analyse de diff??rents comportements d'alimentation, ce qui pourrait ??tre li?? aux diff??rences de gain de masse des femelles pr??sent??es dans le CHAPITRE I.
Certaines contraintes individuelles affectant le co??t de la reproduction ont ??t?? identifi??es. La masse et la condition corporelle augmentaient le succ??s reproducteur et diminuaient l'intervalle entre deux naissances successives (CHAPITRES I et II), mais contrairement ?? de pr??c??dentes ??tudes le comportement d'alimentation des femelles n'??tait pas affect?? par leur masse (CHAPITRE III). L'??ge des individus avait ??galement une influence. Les jeunes femelles croissaient davantage, avaient aussi une prise alimentaire plus importante et subissaient un co??t de reproduction sup??rieur. Ce dernier se traduisait par un taux d'??chec plus ??lev?? ?? la reproduction suivante si les jeunes femelles avaient eu un jeune l'ann??e pr??c??dente (CHAPITRES I, II et III).
Des contraintes environnementales fortes influen??aient la reproduction des femelles. La croissance, le succ??s reproducteur, l'intervalle entre les naissances et les comportements d'alimentation variaient suivant le site et l'ann??e d'??tude. Le site du Promontory et l'ann??e 2011 apparaissaient particuli??rement limitants. En effet en 2011, le gain de masse et le succ??s reproducteur ont diminu?? et l'intervalle de naissance et la prise de nourriture pour les femelles allaitantes ont augment?? (CHAPITRE I,II et III).
Nous cherchions ??galement ?? mettre au jour une allocation diff??rentielle des m??res suivant le sexe de leur jeune. Si le co??t sup??rieur d'avoir un m??le par rapport ?? une femelle ??tait ??vident quant aux taux de bouch??es (CHAPITRE III), il s'est av??r?? plus difficile ?? d??tecter sur d'autres traits. ?? Anglesea, les jeunes m??res avaient moins de probabilit?? d'avoir un jeune qui atteigne le stade 'LPY' apr??s avoir eu un fils qu'une fille (CHAPITRE II). Toutefois, des r??sultats contraires ?? nos attentes ont ??t?? trouv??s, du moins au premier abord, sur la croissance et le succ??s reproducteur subs??quent. Ainsi, les femelles qui avaient eu une fille perdaient davantage de masse (CHAPITRE I) et avaient g??n??ralement une probabilit?? moindre de produire un jeune qui atteigne le stade 'LPY' ou qui soit sevr?? par la suite (CHAPITRE II). En revanche, l'intervalle de naissance n'??tait pas diff??rent suivant le sexe du jeune alors qu'il ??tait fortement affect?? par le co??t de la reproduction d??montr?? gr??ce ?? la manipulation, invoquant une autre explication qu'un co??t sup??rieur des filles par rapport aux fils. En effet, les femelles qui ??taient en mauvaise condition corporelle gagnaient de la masse quand elles produisaient une fille, mais pas un fils (CHAPITRE I). De surcro??t, les jeunes m??res avaient moins de chances de sevrer un jeune ?? l'??v??nement de reproduction suivant si elles avaient eu un fils plut??t qu'une fille, et le succ??s reproducteur des m??res des fils n'??tait plus diff??rent de celui des m??res des filles dans les ann??es plus difficiles (CHAPITRE II). Enfin, les m??res des fils augmentaient la quantit?? de nourriture ing??r??e si elles avaient sevr?? un jeune l'ann??e pr??c??dente, mais les m??res des filles la diminuaient. Ces diff??rents r??sultats sugg??raient fortement qu'un ajustement du sexe-ratio ??tait utilis?? quand les ressources individuelles ou environnementales contraignaient davantage la reproduction.
En conclusion, pour limiter le d??calage entre les besoins ??nerg??tiques et la disponibilit?? en nourriture, les femelles chez le kangourou gris de l'Est pourraient modifier l'allocation de leurs ressources ?? la reproduction en reportant la prochaine mise bas et en produisant un jeune du sexe le moins co??teux en accord avec les contraintes individuelles et environnementales. Ces r??sultats soulignent l'importance d'??tudes avec un suivi individuel sur plusieurs ann??es afin de pouvoir comprendre la variabilit?? des strat??gies de reproduction et leurs cons??quences sur la dynamique des populations. // Abstract : Reproduction in living beings, particularly in female mammals that produce milk, is costly, potentially involving trade-offs with life-history traits if resources are limited and an increase in foraging effort. Individual differences may, however, hide the negative effects of this cost on life-history traits. I used two powerful and complementary approaches, to deal with individual heterogeneity: experimental manipulation of reproductive effort and statistical control of individual effect. Using both approaches, I investigated the effect of presence, size and sex of young on growth, subsequent reproduction and individual foraging behaviours of females. I used data of tagged free-ranging eastern grey kangaroos (Macropus giganteus) collected over six years at five study sites in Victoria, Australia. There was a clear cost of reproduction. Reproductive effort decreased mass gain and limb growth for inter-capture intervals greater than two years. Over two successive reproductive events, mass gain and arm growth were reduced but leg growth was independent of reproductive effort (CHAPTER II).In addition, survival to Large Pouch Young ('LPY') stage, about 7 months of age, was higher and birth rate lower in manipulated compared to control females but survival to weaning was not affected (CHAPTER III). CHAPTER IV shows that lactating females cope with current reproductive costs by increasing ivtime spent foraging as well as bite and chewing rates without decreasing vigilance comparedto non lactating ones. Bite rate was also greater for females that weaned a young at the previous reproductive event. My study supports reproductive cost hypothesis while showing substantial individual differences. To limit mismatch between energetic needs and resource availability, females of eastern grey kangaroo could modify resource allocation to reproduction by delaying birth date of subsequent young and producing the less costly sex according to individual and environmental constrains. My thesis shows the importance of experimental approach and individual monitoring over multiple years to understand the diversity of reproductive strategies and their consequences in evolutionary ecology and population dynamic.
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Fuentes, Belgrave Laura. "L'autonomie reproductive au Costa Rica et au Nicaragua : un talon d’Achille dans le processus de laïcisation." Paris, EHESS, 2012. http://www.theses.fr/2012EHES0008.
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Comment expliquer le maintien des restrictions à l’autonomie reproductive des femmes qui prévaut au Costa Rica et au Nicaragua ? Pour répondre à cette question qui demeure plus que jamais d’actualité, cette thèse interroge les conséquences de l'influence de l'Église catholique sur l’établissement des frontières symboliques à l’intérieur desquelles se sont construits les États-nations costariciens et nicaraguayens. Le maintien, jusqu’à aujourd’hui, de l’affinité élective entre les autorités politiques et religieuses a nui aux tentatives de laïcisation de ces pays : à chaque seuil de laïcisation franchi a succédé un seuil de confessionnalisation qui a pris très largement pour enjeu les droits des femmes. Si ces droits sont finalement passés du contrôle religieux au contrôle étatique, le processus de sécularisation reste inachevé, empêchant l’avènement d’un statut de la femme reconnue dans sa liberté à disposer d’elle-même. Les États s’emparent de la morale chrétienne pour confisquer son corps, même si le Nicaragua est devenu laïc tandis que le Costa Rica demeure confessionnel. Cette situation de non-droit est renforcée par l’apparition et le développement rapide des Églises évangéliques qui viennent soutenir l'Église catholique sur le terrain politique grâce à la participation électorale des partis pentecôtistes. Ces communautés religieuses par ailleurs concurrentes trouvent un terrain d’entente autour de la défense du « droit à la vie du non-né » et face à l’émergence des droits sexuels et reproductifs. Elles s’allient pour lutter contre l’accès à l’avortement thérapeutique, à la pilule du lendemain et à la fertilisation in vitro. Cette alliance porte ses fruits : l’avortement thérapeutique est interdit au Nicaragua tandis que la pilule du lendemain et la fertilisation in vitro sont condamnées au Costa Rica. Le populisme, la juridicisation du politique et la resacralisation de « l’ordre naturel » dans les lois, transforment le non-né en sujet de droit, au détriment des droits acquis par les femmes. La laïcité est considérée comme une valeur minoritaire. Elle menace l’identité de la communauté de citoyens et remet en question le ciment chrétien des imaginaires nationauxHow to explain the continued restrictions on women's reproductive autonomy which prevails in Costa Rica and Nicaragua? To answer this question, which remains more than ever, this thesis interrogates the consequences of the influence of the Catholic Church on the establishment of symbolic boundaries inside of which were built the Nations-States of Costa Rica and Nicaragua. The maintenance until today of the elective affinity between political and religious authorities has hampered attempts to secularization of these countries: each crossed threshold of secularization was succeeded by a threshold of confessionalization which has taken issue extensively for women's rights. If these rights are ultimately passed from religious control to state control, the secularization process remains incomplete, preventing the emergence of a recognized status of women's freedom to dispose of themselves. States take possession of Christian morality to confiscate their body, even if Nicaragua became secular while Costa Rica remains confessional. This lawlessness is reinforced by the appearance and rapid growth of Evangelical Churches that are supporting the Catholic Church in the political arena with the electoral participation of Pentecostals parties. These religious communities find a common goal about the defense of the "right to life of the unborn" with the emergence of sexual and reproductive rights. They join forces to fight against the access to therapeutic abortion, morning-after pill and in vitro fertilization. This alliance is bearing fruit: therapeutic abortion in Nicaragua is prohibited while the morning-after pill and in vitro fertilization are condemned in Costa Rica
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Corewyn, Lisa Cheryl. "Social and reproductive strategies of male mantled howlers (Alouatta palliata) at La Pacifica, Costa Rica." Thesis, The University of Texas at San Antonio, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3594560.
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This dissertation examines the competitive and cooperative strategies of male mantled howlers (Alouatta palliata) living within a fragmented habitat at La Pacifica (LP), Costa Rica. Mantled howlers exhibit considerable intraspecific variation in their social behavior, and there remains much to learn regarding the nature of their sociality and the proximate mechanisms that underlie it, particularly among males living in multimale groups. In contrast to males at other mantled howler study sites, males at LP had higher rates of within-group agonism, and exhibited clear dominance hierarchies. Both groups inhabited a fragmented forest, which may exert greater pressure to compete for both food and reproductive resources than mantled howler males living in more intact forests. However, data from this dissertation also suggest that males may adjust competitive relationships as forest fragment characteristics within the same population vary. The group inhabiting the larger forest fragment experienced higher intergroup competition but lower intragroup competition than the group inhabiting the smaller fragment, allowing higher-ranking males to be more tolerant of subordinates accessing key resources, including females, in order to cooperate in group defense. Despite clear hierarchies, males at LP nevertheless form both preferred and avoided associations with specific males, which suggest that cooperative relationships among males have adaptive value. Neither rank nor age emerged as clear drivers shaping competitive and cooperative relationships. Collectively, these results suggest that male mantled howlers show considerable flexibility in their social relationships that are likely dependent on a complexity of ecological, social, and demographic factors.
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Wood, Matthew James. "Parasites, reproductive costs and sexual selection : studies of the European blackbird Turdus merula and the great tit Parsus major." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340166.
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