Tesi: "Life trait history"

1

Larkin, Katelyn. "Effects of polyploidy and reproductive mode on life history trait expression". Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1673.

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Although genomes are perhaps the single most important element of living systems, why they feature such striking variation and how this variation is maintained within and across natural populations remains unclear. One of the most common and important means by which genomic variation is generated is ploidy elevation. While polyploidy has been implicated in the remarkably successful radiations of angiosperms, teleost fish, and amphibians, the phenotypic consequences of changes in ploidy level are poorly understood, especially in animals. I use a large, multi-year common garden experiment to identify potential life history costs and benefits of polyploidy and asexual reproduction, a trait often associated with polyploidy, in Potamopyrgus antipodarum. This snail is well suited for studying ploidy variation and sex because diploid sexuals and triploid and tetraploid asexuals frequently coexist, allowing us to use comparisons of sexuals to asexuals and triploid to tetraploid asexuals to study both the effects of ploidy elevation and sex. I detected a strong negative correlation between growth rate and time to maturity and found that sexual P. antipodarum grew and matured significantly more slowly than the polyploid asexuals. Sexual P. antipodarum were also more likely to die before achieving reproductive maturity than their asexual counterparts. By contrast, there were no apparent life history differences between triploid and tetraploid asexuals, indicating that direct phenotypic benefits of ploidy elevation are unlikely to explain the relatively rapid growth and maturation of asexuals. My results suggest that ploidy elevation does not inevitably confer phenotypic consequences, that reproductive mode influences life history trait expression, and that sexual P. antipodarum persist in many natural populations in spite of substantial life history disadvantages.

2

Barthold, Julia A. "A demographic perspective on trait heritability and sex differences in life history". Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:94f04aac-182f-466b-a267-179d68db398f.

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Biologists have long used demographic approaches to answer questions in ecology and evolution. The utility of these approaches has meant a constant development and refinement of methods. A key milestone has been the development of phenotype structured population models that link ecology and evolution. Moreover, biostatistical research steadily improves methods to coax demographic information from scarce data. In this thesis, I build upon some of the recent advances in the field. My first three studies focus on the consequences of sex differences in life history for population dynamics. Firstly, I test whether males matter for the dynamics of African lion (Panthera leo) populations via a previously unquantified mechanism: the inheritance of phenotype from father to offspring. Secondly, I develop a method to estimate age-specific mortality rates for both sexes in species where one of the sexes disperses around the age of maturity. Thirdly, I apply this method to study variation in mortality between the sexes and between two populations of African lions. After these three chapters, which make contributions to the field of sex-structured population dynamics, I focus on the integration of phenotype structured modelling and quantitative genetics. I illustrate how heritability of a quantitative character that develops with age depends on (i) viability selection, (ii) fertility selection, (iii) the development of the phenotype with age, and (iv) phenotype inheritance from parents to offspring. Our results question the adequacy of quantitative genetics methods to obtain unbiased estimates of heritability for wild populations. This thesis advances our understanding of population development over ecological time scales. This knowledge has applications in conservation and population management, but also contributes to untangling evolutionary processes in wild animals.

3

Cox, Daniel T. C. "Seasonal mass variation as a life history trait in West African savannah birds". Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3581.

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Seasonality influences life history through its effect on the availability of essential resources, with birds timing breeding to occur during peak food availability. Due to density-dependence, investment in breeding is determined largely by the seasonality of food availability, with an increased investment being traded-off against adult survival. A bird's mass acts as an index of a species' foraging environment, because a bird bases its foraging decisions on a trade-off between the risk of predation and the risk of starvation. Under constant predation risk a bird increases its mass as insurance against increased foraging unpredictability. In tropical savannahs day length and temperature remains relatively constant, and there is not a season of increased density-dependent mortality which acts across all species. Thus species have evolved a broad range of life history traits under the same environmental conditions, although how a species experiences seasonality depends largely on its foraging niche. This thesis shows that most savannah species varied their mass across the year, having a reduced mass in the non-breeding season which suggests that foraging remained predictable. Independent of gonad or egg growth they then increased their mass as they started to breed, with the timing of breeding coinciding with peak food availability. Across species in the same foraging niche mass acts as an index of breeding investment, with females increasing their mass more than males. While across species in different foraging niches an increased mass response was associated with higher adult survival, probably because breeding strategy and subsequently adult survival are governed by food limitation. This thesis shows that birds adaptively manage their mass during breeding and that mass is not a result of energetic stress, thus under constant predation risk a bird's mass is a result of foraging predictability as a function of competition for available food and investment in breeding.

4

Armstrong, Jenny. "The genetic architecture of a reproductive life-history trait in a wild passerine". Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/11913/.

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Understanding the capacity for species to respond to changes in their environment and the rate at which they are able to do so is a key topic in evolutionary biology and of increasing importance in wildlife conservation and management. However the mechanisms involved in mediating these responses are poorly understood. Specifically, while reactive responses may be advantageous in the short term persistent directional changes in environmental conditions may require a more profound response in order for organisms to adapt and persist successfully. Here I use data from two long-term studies of the great tit Parus major and apply a range of statistical techniques to dissect the genetic architecture of laying date, a reproductive life-history trait, to discern the extent to which a genetic component of variation contributes to observed phenotypic variation. A heritable component of variation exists in both populations, but specific regions of the genome contributing to trait variation could not be detected by quantitative trait loci mapping (Chapters 2 & 3), genome-wide association (Chapters 2 & 3) or chromosome partitioning (Chapter 4) analyses. These findings are consistent with a highly polygenic basis for variation in laying date, variation maintained by many genes of small effect. Attempts to increase the statistical power by combining two phenotypic datasets to increase overall sample size (Chapter 3) and increasing marker density (Chapter 5) drew similar conclusions, with an absence of genome-wide significant QTL. Despite evidence of a strong association on chromosome 3 (Chapter 5), an overall lack of consistency between analyses and datasets on regions exhibiting the highest associations suggests that power to detect genomic regions, particularly when variation may be determined by many variants of small effect, is low. I conclude that while genetic variation exists, environmental factors and phenotypic plasticity likely account for much of the variation in laying date.

5

Pecoraro, Carlo <1986&gt. "Global Population Genomic Structure and Life History Trait Analysis of Yellowfin Tuna (Thunnus Albacares)". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7537/1/Pecoraro_Carlo_tesi.pdf.

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Yellowfin tuna (Thunnus albacares; YFT) represents one of the most important seafood commodities in the world. The rationale of this Ph.D. project was identified by prioritizing key issues as objectives for contributing to the conservation of YFT and helping to develop a more realistic stock assessment and sustainable management of this species. Specifically, in this work the current mismatch between the biology and/or ecology and the realized management strategies was highlighted, putting particular emphasis on YFT population structure, which is currently characterized by a high degree of uncertainty at both local and global scale. This general pattern was confirmed by the results obtained using a panel of microsatellite loci, which cannot reject the null hypothesis of the existence of only one panmictic population at the global scale. On the contrary, the access to more powerful and cost effective genetic tools would represent the first step for resolving YFT population structure at both global and local scale. After having evaluated the efficiency and usefulness of 2b-RAD genotyping technique for investigating population genetic structure in highly migratory fish species, a panel of 972 SNPs (Single Nucleotide Polymorphisms) was generated. Using this panel, three distinct populations were identified in the Atlantic, Indian and Pacific Oceans. Additionally, it was possible to define a subset of 33 outlier loci putatively under selection to delineate and separate sub-populations within both the Atlantic and the Pacific Oceans (following an east-west division). Finally, it was emphasized for the first time that in the Atlantic Ocean larger YFT females allocate a greater fraction of surplus energy to egg production than smaller ones, improving noticeably the spawning quality. This result sheds light on the important contribution that larger and most experienced spawners have for the YFT productivity.

6

Pecoraro, Carlo <1986&gt. "Global Population Genomic Structure and Life History Trait Analysis of Yellowfin Tuna (Thunnus Albacares)". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7537/.

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Abstract (sommario):

Yellowfin tuna (Thunnus albacares; YFT) represents one of the most important seafood commodities in the world. The rationale of this Ph.D. project was identified by prioritizing key issues as objectives for contributing to the conservation of YFT and helping to develop a more realistic stock assessment and sustainable management of this species. Specifically, in this work the current mismatch between the biology and/or ecology and the realized management strategies was highlighted, putting particular emphasis on YFT population structure, which is currently characterized by a high degree of uncertainty at both local and global scale. This general pattern was confirmed by the results obtained using a panel of microsatellite loci, which cannot reject the null hypothesis of the existence of only one panmictic population at the global scale. On the contrary, the access to more powerful and cost effective genetic tools would represent the first step for resolving YFT population structure at both global and local scale. After having evaluated the efficiency and usefulness of 2b-RAD genotyping technique for investigating population genetic structure in highly migratory fish species, a panel of 972 SNPs (Single Nucleotide Polymorphisms) was generated. Using this panel, three distinct populations were identified in the Atlantic, Indian and Pacific Oceans. Additionally, it was possible to define a subset of 33 outlier loci putatively under selection to delineate and separate sub-populations within both the Atlantic and the Pacific Oceans (following an east-west division). Finally, it was emphasized for the first time that in the Atlantic Ocean larger YFT females allocate a greater fraction of surplus energy to egg production than smaller ones, improving noticeably the spawning quality. This result sheds light on the important contribution that larger and most experienced spawners have for the YFT productivity.

7

Cheynel, Louise. "Age-specific relationships between immunity and life-history traits in a wild mammal". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1273/document.

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Face à la menace des pathogènes présents dans l’environnement, l’immunité représente une fonction cruciale pour la survie des organismes. Cependant, cette fonction représente divers coûts de développement et d’utilisation, et le caractère limité des ressources dans l’environnement impose des compromis d’allocation entre différentes fonctions (immunité, croissance, reproduction). Sur le long-terme, ces choix peuvent avoir de lourdes conséquences sur les probabilités de se reproduire et de survivre à chaque âge. L’objectif de cette thèse a été de décrire les variations avec l’âge du phénotype immunitaire d’un mammifère longévif, le chevreuil (Capreolus capreolus) et de mieux comprendre les compromis régissant l’allocation de ressources entre l’immunité et les autres grandes fonctions de l’organisme. Cette thèse a été menée au sein de deux populations naturelles, permettant de tester l’influence de conditions environnementales contrastées sur ces variations. Nous avons montré qu’une croissance rapide pendant les premiers mois de vie du chevreuil n’imposait pas de coûts en terme de développement du phénotype immunitaire sur la même période (niveaux des traits innés et acquis), ni sur le long-terme. Nous avons aussi montré que le développement de l’immunité des jeunes n’était pas dépendant de l’âge de leur mère, mais était fortement influencé par la condition corporelle de celle-ci. Chez les adultes, nous avons décrit les variations avec l’âge d’une dizaine de traits reflétant l’immunité innée et adaptative. Cela a permis de mettre en évidence de profondes modifications du profil immunitaire aux âges avancés, i.e. une augmentation de la production de marqueurs inflammatoires (haptoglobine, beta-globulines) et une diminution de la réponse adaptative (lymphocytes). L’augmentation parallèle avec l’âge de la charge parasitaire des individus appuie l’idée que le chevreuil est sujet à l’immunosenescence. Enfin, nous avons montré que la longueur des télomères leucocytaires varie avec l’âge. Nous n’avons pas trouvé d’associations entre la longueur des télomères et les proportions de chaque forme leucocytaire (neutrophiles, monocytes, lymphocytes). Cependant, nous avons montré que de forts niveaux de certains marqueurs inflammatoires (beta- et alpha1-globulines) semblent être associés à des télomères courts dans les cellules immunitaires. Ces résultats ouvrent de nombreuses pistes pour une meilleure compréhension des mécanismes physiologiques à la base du vieillissement
Immunity determines an organism’s sensitivity to pathogens and parasites and thus represent a crucial function that affects survival of individuals in the wild. However, this function represents several energy costs for development and use, and in natural conditions, resources are limited. Organisms consequently face energy allocation trade-offs between costly functions such as immunity, growth or reproduction. On the long term, these allocations are supposed to have serious consequences on probability of individuals to reproduce and to survive at each age.The aim of this thesis was to describe age-related variations of immune phenotype in a wild and long-lived mammal, the roe deer (Capreolus capreolus), and to provide a better understanding of energy trade-offs between immune function and other life-history traits. This thesis was conducted in roe deer of both sexes and from two natural populations, which allow to test the influence of sex and contrasting environmental conditions on these variations.We first described that rapid growth did not impair the development of young roe deer immune phenotype (levels of innate and adaptive traits), neither on the short-term (during growth), neither on the long-term (during adulthood). We also proved that immune development of juveniles was not dependent of maternal age, but was strongly influenced by maternal body condition. In adult roe deer, we have described the precise patterns of age-related changes in ten immune traits reflecting both innate and adaptive immunity. It revealed that roe deer are subjected to profound changes in their immune profile with increasing age, i.e. an increase in the production of inflammatory markers (haptoglobin, beta-globulin) and a decrease in the adaptive response (lymphocytes). In the same individuals, the parallel increase with age of parasite load supports the idea that deer are subject to immunosenescence. Finally, we described age-related changes in leukocyte telomere length. We found no associations between telomere length and proportions of each leukocyte form (neutrophils, monocytes, lymphocytes). However, we observed that high levels of some inflammatory markers (beta- and alpha1-globulin) tend to be associated with short telomeres in immune cells. These results open many avenues for a better understanding of the physiological mechanisms underlying aging

8

Orsucci, Marion. "Rôle de la spécialisation à la plante hôte et de l'isolement reproducteur dans la divergence de lépidoptères ravageurs de cultures". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS074/document.

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La spécialisation à différents environnements est un moteur de divergence entre populations et espèces. Les insectes phytophages sont des candidats pertinents pour l’étude de la spéciation par spécialisation écologique, de par leur relation intime à leur plante hôte et à l’occurrence régulière de changements d’hôtes au cours de leur évolution. Cette spéciation écologique nécessite trois composantes : une source de sélection divergente, un isolement reproducteur (pré-ou post-zygotique), et un mécanisme liant les gènes sous sélection et ceux responsable de l’isolement reproducteur. Dans ce cadre, nous avons étudié l’isolement reproducteur et la spécialisation chez deux modèles de lépidoptères polyphages, ravageurs des cultures : (1) la pyrale du maïs, Ostrinia nubilalis, et son espèce sœur, Ostrinia scapulalis, (2) la légionnaire d’automne, Spodoptera frugiperda, dont deux variants sont identifiables, le variant riz (sf-R) et le variant maïs (sf-M). Ces deux modèles montrent des patrons de diversification via la plante hôte : les deux espèces sœurs et les deux variants sont différenciés génétiquement et sont spécialisés sur différentes plantes hôtes (maïs pour O. nubilalis et sf-M ; armoise pour O. scapulalis ; riz pour sf-R). Nous avons étudié les patrons de spécialisation de ces modèles en effectuant des mesures de traits d’histoire de vie à deux moments clés de leur cycle de vie : (1) au stade larvaire, par des expériences de transplantation réciproque, (2) au stade adulte, par des expérience de choix d’oviposition. Ces mesures nous ont permis de mettre en évidence un patron de spécialisation pour les deux espèces de pyrale et pour le variant sf-M au stade adulte et/ou larvaire, alors que les résultats ne montre pas de spécialisation claire pour le variant sf-R de S. frugiperda, du moins sur les plantes testées. Nous avons également recherché des mécanismes de cette spécialisation par une analyse transcriptomique visant à identifier les gènes ou familles de gènes dont l’expression varie en fonction de la plante hôte chez nos deux modèles. Cette étude mécanistique a mis en lumière des fonctions de gènes impliquées dans la détoxification, la digestion et l’immunité qui peuvent expliquer les différences de traits d’histoire de vie que nous avons observés. Enfin, nous avons quantifié différentes barrières (pré- et post-zygotiques) pour estimer le degré de divergence et les facteurs impliqués dans l’isolement reproducteur des entités génétiques étudiées. Nous avons notamment trouvé pour les deux modèles des barrières post-zygotiques précoces avec un pourcentage d’éclosion plus faible dans les croisements interspécifiques. Dans le modèle Ostrinia, nous avons également mis en évidence la présence d’une barrière pré-zygotique en lien avec le bouquet phéromonal émis par les femelles
Specialization in different environments is a driver of divergence between populations and species. Phytophagous insects are interesting candidates to study the speciation process via the ecological specialization, due to the intimate relationship between the insects and their host plant but also the regular occurrence of host changes they experienced during evolution. Ecological speciation requires three important components: a source of divergent selection, a form of reproductive isolation either pre- or post-zygotic, and a mechanism linking the genes under selection to those responsible of the reproductive isolation. In this context, we studied the reproductive isolation and specialization in two models polyphagous lepidopteran pests: (1) the European corn borer, Ostrinia nubilalis, and the closely related species Ostrinia scapulalis, (2) two host races of Spodoptera frugiperda (the fall armyworm), rice strain (sf-R) and corn strain (sf-M). Both models showed a patterns of diversification via the host plant: both species sisters and the two strains are genetically differentiated and are specialized on different host plants (maize for O. nubilalis and sf-M; mugwort for O. scapulalis; rice sf-R). We studied the patterns of specialization of these models by quantification of life history traits in two time points of their life-cycles: (1) in the larval instar, by reciprocal transplant experiments, (2) in the adult, by choice oviposition experiment. These measures highlighted a pattern of specialization at the adult and/or larval instar for both moth species and sf-M. However, the results showed no clear specialization for sf-R of S. frugiperda on the tested plants. We investigated the mechanisms of specialization by RNA-seq in order to identify the genes or the gene families for which variation of their expression depends on the host plant. This mechanistic study revealed genes involved in detoxification, digestion and immunity process that may explain the differences observed in life history traits. Finally, we quantified various barriers (pre- and post-zygotic) to estimate the divergence degree and the causes involved in reproductive isolation of genetic entities studied. In particular, for the two models, we found evidences of post-zygotic barriers with a lower percentage of hatching in the interspecific crosses. In Ostrinia model, we have also demonstrated the presence of pre-zygotic barrier depending of the pheromone blend emitted by the females

9

Rattiste, Kalev. "Life History of the Common Gull (Larus canus) : A Long-Term Individual-Based Study". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis (AUU), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7350.

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10

Orsucci, Marion. "Rôle de la spécialisation à la plante hôte et de l'isolement reproducteur dans la divergence de lépidoptères ravageurs de cultures". Electronic Thesis or Diss., Montpellier, 2015. http://www.theses.fr/2015MONTS074.

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Abstract (sommario):

La spécialisation à différents environnements est un moteur de divergence entre populations et espèces. Les insectes phytophages sont des candidats pertinents pour l’étude de la spéciation par spécialisation écologique, de par leur relation intime à leur plante hôte et à l’occurrence régulière de changements d’hôtes au cours de leur évolution. Cette spéciation écologique nécessite trois composantes : une source de sélection divergente, un isolement reproducteur (pré-ou post-zygotique), et un mécanisme liant les gènes sous sélection et ceux responsable de l’isolement reproducteur. Dans ce cadre, nous avons étudié l’isolement reproducteur et la spécialisation chez deux modèles de lépidoptères polyphages, ravageurs des cultures : (1) la pyrale du maïs, Ostrinia nubilalis, et son espèce sœur, Ostrinia scapulalis, (2) la légionnaire d’automne, Spodoptera frugiperda, dont deux variants sont identifiables, le variant riz (sf-R) et le variant maïs (sf-M). Ces deux modèles montrent des patrons de diversification via la plante hôte : les deux espèces sœurs et les deux variants sont différenciés génétiquement et sont spécialisés sur différentes plantes hôtes (maïs pour O. nubilalis et sf-M ; armoise pour O. scapulalis ; riz pour sf-R). Nous avons étudié les patrons de spécialisation de ces modèles en effectuant des mesures de traits d’histoire de vie à deux moments clés de leur cycle de vie : (1) au stade larvaire, par des expériences de transplantation réciproque, (2) au stade adulte, par des expérience de choix d’oviposition. Ces mesures nous ont permis de mettre en évidence un patron de spécialisation pour les deux espèces de pyrale et pour le variant sf-M au stade adulte et/ou larvaire, alors que les résultats ne montre pas de spécialisation claire pour le variant sf-R de S. frugiperda, du moins sur les plantes testées. Nous avons également recherché des mécanismes de cette spécialisation par une analyse transcriptomique visant à identifier les gènes ou familles de gènes dont l’expression varie en fonction de la plante hôte chez nos deux modèles. Cette étude mécanistique a mis en lumière des fonctions de gènes impliquées dans la détoxification, la digestion et l’immunité qui peuvent expliquer les différences de traits d’histoire de vie que nous avons observés. Enfin, nous avons quantifié différentes barrières (pré- et post-zygotiques) pour estimer le degré de divergence et les facteurs impliqués dans l’isolement reproducteur des entités génétiques étudiées. Nous avons notamment trouvé pour les deux modèles des barrières post-zygotiques précoces avec un pourcentage d’éclosion plus faible dans les croisements interspécifiques. Dans le modèle Ostrinia, nous avons également mis en évidence la présence d’une barrière pré-zygotique en lien avec le bouquet phéromonal émis par les femelles
Specialization in different environments is a driver of divergence between populations and species. Phytophagous insects are interesting candidates to study the speciation process via the ecological specialization, due to the intimate relationship between the insects and their host plant but also the regular occurrence of host changes they experienced during evolution. Ecological speciation requires three important components: a source of divergent selection, a form of reproductive isolation either pre- or post-zygotic, and a mechanism linking the genes under selection to those responsible of the reproductive isolation. In this context, we studied the reproductive isolation and specialization in two models polyphagous lepidopteran pests: (1) the European corn borer, Ostrinia nubilalis, and the closely related species Ostrinia scapulalis, (2) two host races of Spodoptera frugiperda (the fall armyworm), rice strain (sf-R) and corn strain (sf-M). Both models showed a patterns of diversification via the host plant: both species sisters and the two strains are genetically differentiated and are specialized on different host plants (maize for O. nubilalis and sf-M; mugwort for O. scapulalis; rice sf-R). We studied the patterns of specialization of these models by quantification of life history traits in two time points of their life-cycles: (1) in the larval instar, by reciprocal transplant experiments, (2) in the adult, by choice oviposition experiment. These measures highlighted a pattern of specialization at the adult and/or larval instar for both moth species and sf-M. However, the results showed no clear specialization for sf-R of S. frugiperda on the tested plants. We investigated the mechanisms of specialization by RNA-seq in order to identify the genes or the gene families for which variation of their expression depends on the host plant. This mechanistic study revealed genes involved in detoxification, digestion and immunity process that may explain the differences observed in life history traits. Finally, we quantified various barriers (pre- and post-zygotic) to estimate the divergence degree and the causes involved in reproductive isolation of genetic entities studied. In particular, for the two models, we found evidences of post-zygotic barriers with a lower percentage of hatching in the interspecific crosses. In Ostrinia model, we have also demonstrated the presence of pre-zygotic barrier depending of the pheromone blend emitted by the females

11

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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Abstract (sommario):

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.

12

Berger, Vérane. "Senescence and sociality : the example of the alpine marmot (Marmota marmota)". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10257.

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Quels sont les facteurs qui peuvent retarder ou accélérer la sénescence? Les chercheurs tentent d'y apporter des réponses à différents niveaux moléculaires, cellulaires et également au niveau des traits d'histoire de vie. Tl est établi que différents facteurs ont un impact significatif sur les patrons de sénescence tels que le continuum lent-rapide, la sélection sexuelle, ou encore la disponibilité en ressources. De façon surprenante, peu d'intérêt a été porté sur l'influence de la socialité sur les patrons de sénescence. L'objet de cette thèse est de combler cette lacune et d'étudier l'influence de la socialité sur la sénescence grâce à un suivi exceptionnel d'une population de marmottes alpines (Marmota Marmota), mammifère hautement social et longévif. En effet, cette espèce est organisée en groupes familiaux, composés d'un couple dominant reproducteur socialement monogame despotique, et de subordonnés des deux sexes. La marmotte alpine pratique l'élevage coopératif. En effet, les subordonnés mâles participent à l'élevage des jeunes, ils sont aussi appelés helpers. Nous avons mis en évidence une sénescence de la taille de portée à partir de 10 ans et du succès reproducteur vers 8 ans chez les femelles dominantes et une sénescence de survie à partir de 6 ans chez les dominants mâles et femelles. Nous avons montré que le nombre de helpers durant l'année de naissance et durant la vie adulte étaient indépendants et augmentaient additivement le succès reproducteur sur toute la vie et la longévité des femelles dominantes. Nous avons apporté la preuve que les helpers présents l'année de naissance avaient une influence sexe-spécifique sur les patrons de sénescence de survie des dominants. En effet, les mâles nés avec des helpers vieillissaient plus vite et plus tôt que ceux nés sans helpers. Les femelles ayant bénéficié de helpers l'année de naissance présentaient une sénescence tardive et moins intense que celles sans helpers. Également, les helpers présents durant la vie adulte retardait la sénescence des dominants des deux sexes et diminuaient son intensité. Les coûts et bénéfices liés à l'élevage coopératif expliquent en partie la variabilité de la sénescence de survie chez la marmotte alpine. Pour finir, nous nous sommes placés à l'échelle interspécifique et nous avons montré que la socialité chez les mammifères retardait l'âge de début de sénescence
What are factors that can delay or accelerate senescence? Researchers are seeking these factors at molecular, cellular and life history traits level. Recent studies have firmly showed that the slow-fast continuum, sexual selection and food availability are factors shaping variability in senescence patterns. Surprisingly, the influence of sociality on senescence has been less investigated. The aim of this thesis is to fill this gap and to study the influence of sociality on senescence thanks to an extensive dataset spanning 25 years of study on free-ranging Alpine marmots (Marmota Marmota), a long-lived and highly social mammal. Alpine marmots live in family groups typically composed of a dominant pair, of sexually mature and immature (yearling) subordinates, and of pups of the year. Male subordinates help to raise pups, they are also called helpers. We showed in dominant females that litter size declined at 10 years of age and reproductive success at 8 years of age. In both sexes, survival was constant with age until dominants were between 6 and 8 years of age and declined markedly thereafter. We also showed that the number of helpers at birth and during adult life were independent and additively increased female dominant longevity and lifetime reproductive success. Moreover, we provided evidence that the presence of helpers at birth and during adult life strongly influenced survival senescence and that this influence was sex-specific. Indeed, females benefiting from the presence of helpers at birth showed a delayed and less intense senescence while males born with helpers showed a earlier and faster senescence. The presence of helpers during adult life was beneficial for both sexes by delaying senescence and decreasing its intensity. Sociality, more specifically cooperative breeding and its benefits and costs associated, is an important predictor of the diversity of survival senescence in Alpine marmot. Finally, we worked at the interspecific level and showed that sociality in mammals delayed the onset of senescence

13

Quinás, Serra Sónia Raquel. "From taxonomy to multiple-trait bioassessment : the role of Chironomidae in separating naturally poor from disturbed communities". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1138.

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La famille des Chironomidae (Dipteres) présente une large distribution mondiale dans une large gamme d'habitats. Ses représentants ont colonisé presque tous les habitats d'eau douce et on trouve également des Chironomidae dans des environnements terrestres et marins. Cette famille représente ainsi une composante majeure des macroinvertébrés benthiques en termes d'abondance et de richesse. De part leur position trophique, les Chironomidae dominent souvent les communautés non perturbés en termes d'abondance et de biomasse, et représentent plus de 50% des espèces de macroinvertébrés benthiques dans les eaux stagnantes et courantes. Dans les zones profondes des lacs eutrophes et les cours d'eau très impactés par les activités humaines, c'est souvent la seule famille d'insectes aquatiques qui perdure. De ce fait, la famille des Chironomidae comprend un grand nombre de genres et d'espèces présentant des préférences écologiques diversifiées. De plus, la prédominance et la richesse spécifique des Chironomidae en font une source d'énergie très importante pour les prédateurs (vertébrés et invertébrés) et leur confère un rôle majeur dans le flux d'énergie dans les écosystèmes aquatiques. De ce fait, les Chironomidae pourraient avoir un rôle non négligeable dans la mise en place des conditions de référence pour la bioévaluation des rivières et dans la détection des cours d'eau plus et moins impactés, et pourraient fournir une information sur le fonctionnement des écosystèmes aquatiques. Cependant, les Chironomidae sont généralement délaissés dans l'étude de la structure de la communauté des cours d'eau, principalement à cause des difficultés d'identification des stades larvaires aquatiques des espèces. Les approches basées sur les traits fournis par la littérature sont basées sur la théorie de «l'habitat templet» selon laquelle, l'habitat fournit le cadre environnemental sur lequel les espèces forgent des stratégies à travers leur adaptation dans tous les types d'environnements. Conceptuellement, les conditions environnementales représentent des filtres qui, en éliminant les espèces ayant les combinaisons de traits les moins adaptées, participent à la mise en place des communautés. Comme les traits reflètent la performance des organismes dans des conditions environnementales données, l'objectif principal des analyses basées sur les traits est d'acquérir une compréhension plus mécaniste des relations entre les espèces et leur habitat. Dans les deux dernières décennies, la liaison espèces-trait-environnement a été explorée par de nombreux auteurs dans des études où la composition des traits a été analysée individuellement ou combinées en termes de stratégies. Ainsi, l'utilisation des traits dans les approches d'écologie des communautés (écologie fonctionnelle) s'est développée très rapidement, offrant l'avantage d'une relative indépendance des réponses vis-à-vis de la biogéographie des taxons. En d'autres termes, un trait tel que la respiration branchiale se rencontre dans les milieux aquatiques indépendamment de la région biogéographique alors même que l'identité des taxons change de manière importante entre régions [etc…]
Chironomidae (Diptera) have a worldwide distribution, being found over a wide range of habitats. Their larvae thrive in almost every possible freshwater habitat, with representatives also in terrestrial and marine environments, representing a major macroinvertebrate component in terms of abundance and richness. However, Chironomidae are generally neglected in community studies mainly because of difficulties in species larval identification. This compromises also the recognition and use of Chironomidae in trait-based approaches, which promote an indirect measurement of functional integrity in fresh waters. The aim of this thesis was to fill this latter gap by: (1) building a trait database for European Chironomidae at the genus level (Chapter I); (2) evaluating if the developed database at the genus level provides additional information to a commonly used European database developed at the subfamily and tribe level for Chironomidae (Chapter II); (3) testing Chironomidae traits relevance in bioassessment through their ability to discriminate naturally different stream types and segregate least disturbed from disturbed sites (Chapters III and IV); (4) comparing trait information gathered in the new European database (Chapter I) with similar information gathered for North America for the same genus and species, and simultaneously testing for trait variability between continents (Chapter V). In Chapter I the general methodology for the construction of the Chironomidae trait database at the genus level is described. The trait database was developed gathering existing information in literature for 744 species and 178 genera, considering 186 trait categories from 37 traits divided in two major domains: Eltonian - related to organism function and influence over its environments; and Grinnellian - associated to organism requirements and performance in its environments. In Chapter II traits at the genus level (from Chapter I) and the existing ones at the subfamily level (tribe at most; Tachet et al. 2010) are compared. This comparison showed that there are significant differences in trait information gathered at different taxonomic levels, thus questioning the use of the Chironomidae subfamily level in ecological, functional and biomonitoring studies. Subfamilies are very heterogeneous in terms of traits, exposing the evolutionary divergence in each subfamily. The distances between subfamilies given by their traits are also not in agreement with the most accepted phylogenetic subfamily relatedness, indicating a divergence from the traits of a common ancestry. In Chapter III Chironomidae taxonomic composition at the genus level, unlike the subfamily level, allowed the segregation of different stream types: permanent medium elevation, permanent lowland, and south temporary. Different Chironomidae assemblages manifest different trait composition for Eltonian traits (emergence season, maximal body size, overwinter diapause stage, substrate relation), but also morphological traits (body setae, mentum, Lauterborn organs, premandible brush, claws of anterior parapods). Morphological traits seem interesting tools that would avoid the laborious identification of genus that rely on multiple minute structures, enabling the trait assessment through the observation of few Chironomidae structures. In Chapter IV it is tested whether using Chironomidae taxonomic and trait compositions allow the segregation of disturbed sites under multiple anthropogenic stressors (subjected to hydromorphological and physicochemical alterations) from leastdisturbed sites in Mediterranean temporary streams. Traits were analysed individually and also grouped into life-history strategies. Both methods enabled a significant segregation between disturbed and least-disturbed sites. Individual traits that were significantly different between sites were also those that are evolutionarily interrelated and used to define Chironomidae life-history trait strategies [etc]

14

Andreou, Dimitra. "Sphaerothecum destruens : life history traits and host range". Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54976/.

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Sphaerothecum destruens is a multi-host parasite which can infect and cause mortality in a number of fish species including Chinook salmon Oncorhynchus tshawytscha, Atlantic salmon S. salar and the sunbleak Leucaspius delineatus. It has been hypothesised that S. destruens has been introduced to the UK with its invasive hosts L. delineatus and topmouth gudgeon Pseudorasbora parva. As the effects of a novel parasite to naive populations could be detrimental, this thesis aimed to better elucidate the life cycle of S. destruens, its prevalence in wild populations and the susceptibility of cyprinid species. S. destruens was able to infect multiple organs (kidney, liver, gill, gonad and intestine) with similar histopathology between L. delineatus, a cyprinid species, and the histopathology reported for salmonid species. Its spore and zoospore life stages displayed a wide temperature tolerance and zoosporulation occurred at temperatures between 4-30 C. A survey of one UK location detected S. destruens in a wild L. delineatus population. A quantitative polymerase chain reaction was developed in order to quantify S. destruens' infection levels. Reproductive L. delineatus were more susceptible to S. destruens and experienced higher S. destruens prevalence and infection levels. The presence of a second host, P. parva, had no influence on S. destruens' prevalence and infection levels. However, presence of P. parva resulted in significantly lower somatic condition in parasitized female L. delineatus. Exposure to S. destruens through immersion in water containing S. destruens spores revealed that bream Abramis brama and carp Cyprinus carpio were susceptible to S. destruens. A. brama experienced high (53 %) mortalities when exposed to S. destruens whilst C. carpio experienced low (8 %) mortalities. The susceptibility of roach Rutilus rutilus and rudd Scardinius erythrophthalmus could not be excluded and needs to be further investigated.

15

Rougier, Thibaud. "Repositionnement des poissons migrateurs amphihalins européens dans un contexte de changement climatique : une approche exploratoire par modélisation dynamique mécaniste". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0055/document.

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Le changement climatique en cours modifie les conditions environnementales et les espèces doivent s'adapter à ces nouvelles conditions, en restant sur place ou en se déplaçant conduisant alors à de nouvelles distributions. Ce repositionnement revêt deux dimensions principales : (i) l'adaptabilité des espèces aux nouvelles conditions (changement de traits d'histoire de vie) liée à la résilience des populations et (ii) leur capacité à explorer de nouveaux habitats favorables. Cette étude avait pour objectif l’élaboration d’un modèle dynamique mécaniste intégrant ces deux dimensions de manière à pouvoir évaluer, comprendre et prédire les possibilités de repositionnement des poissons migrateurs amphihalins européens face au changement climatique.Pour accomplir leurs cycles de vie, les espèces migratrices amphihalines utilisent nécessairement des écosystèmes dulçaquicoles, estuariens et marins. Ces cycles de vie particuliers leur confèrent un plus grand potentiel de repositionnement que les espèces dulçaquicoles. Une base de données sur les traits de vie de ces espèces intégrant notamment ceux pouvant potentiellement être influencés par le changement climatique et ceux pouvant jouer un rôle dans le potentiel de dispersion des espèces a été construite pour l’ensemble des espèces amphihalines européens. Une méthode d’analyse multicritère hiérarchique a été proposée pour définir un indice basé sur les traits de vies visant à caractériser le potentiel de repositionnement des espèces migratrices amphihalines.Le modèle GR3D (Global Repositioning Dynamics for Diadromous fish Distribution) a ensuite été développé pour étudier de façon dynamique le repositionnement potentiel de ces espèces, à large échelle, dans un contexte scénarisé de changement climatique. Il s’agit d’un modèle de simulation stochastique, individus centré, intégrant les principaux processus de dynamique de population d’un poisson migrateur amphihalin (reproduction, mortalité, croissance, migration de montaison avec dispersion, migration de dévalaison).Un premier cas d’étude exploratoire simulant le repositionnement d’une population virtuelle de grande alose (Alosa alosa) de son bassin versant d’origine à un bassin versant voisin inhabité dans un contexte d’augmentation de la température a permis de réaliser une analyse de sensibilité globale du modèle GR3D à la fois aux paramètres incertains de dynamique de population et aux paramètres reliés à la structure de l’environnement. Il a été mis en évidence une sensibilité particulière du modèle aux paramètres liés à la durée de vie et à la mortalité en mer ainsi qu’à la distance entre les deux bassins versants de l’environnement pour déterminer le succès de colonisation.Enfin, l’utilisation du modèle GR3D sur un cas d’application réel a permis de commencer à évaluer l’évolution de la persistance de la grande alose à l’échelle de son aire de répartition (i.e. la façade atlantique) dans un contexte de changement climatique.Les simulations du modèle GR3D devraient ainsi trouver à terme des applications pour la gestion et la conservation des espèces migratrices amphihalines
The ongoing climate change is modifying the environmental conditions and species have to adapt to these new constraints, either on the same site or migrating in new suitable sites leading to a modification of distribution area. This repositioning has two main dimensions: (i) the species capacity to adapt to the new conditions (modification of life history traits) which is linked to the species resilience and (ii) the species capacity to explore new suitable habitats. The objective of this study was to build a mechanistic model incorporating these two dimensions in order to evaluate, understand and predict the repositioning possibilities of European diadromous fish facing climate change.In their life cycles, diadromous fish species have to use freshwater, estuarine and marine ecosystems. These specific life history strategies represent a great repositioning potential in comparison to freshwater fish species. A database of diadromous fish life history traits, incorporating those that could be influenced by climate change and those that could have an importance in the species repositioning potential, has been built. An Analytic Hierarchy Process has been suggested to develop a composite score based on life traits aiming at assessing the diadromous species repositioning potential.Then, the GR3D model (Global Repositioning Dynamics for Diadromous fish Distribution) has been developed in order to study with a dynamic approach the repositioning potential of diadromous fish, at a large scale, in a context of climate change. This model is a simulation, stochastic and individual-based model incorporating the main population dynamics processes of a diadromous fish (reproduction, mortality, growth, upstream migration with dispersal and downstream migration).A first exploratory application case simulating the repositioning of a virtual allis shad (Alosa alosa) population between two river catchments under a scenario of temperature increase has been carried out and the associated global sensitivity analysis has been performed in order to determine the influence of uncertain population dynamics parameters and of parameters defining the landscape stucture. The results showed that dispersal distance and parameters related to sea lifespan and to survival at sea were crucial to determine the success of colonization.Finally, the use of GR3D in a real application case allowed improving the understanding of allis shad persistence at the scale of its distribution area (i.e. the Atlantic coast) in a context of climate change.Over time, simulation results of GR3D should be relevant and useful in management and conservation of diadromous fish species

16

Penna, Brandy M. "Local adaptation for life-history traits in Silene latifolia". Click here to access thesis, 2006. http://www.georgiasouthern.edu/etd/archive/spring2006/brandy%5Fm%5Fpenna/penna%5Fbrandy%5Fm%5F200601%5Fms.pdf.

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Thesis (M.S.)--Georgia Southern University, 2006.
"A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science" ETD. Includes bibliographical references (p. 42-48) and appendices.

17

Chung, Ming-Tsung. "Functional and life-history traits in deep-sea fishes". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/384568/.

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The deep sea is one of the largest ecosystems on the earth and fishes play an important role of transporting energy and structuring communities in the deep-sea ecosystem. However, the evaluation of functional and life-history traits (behaviours) in deep-sea fishes is challenging and problematic to directly study at sea. Therefore, this research investigates sensory capabilities from functional tissues in deep-sea fishes to identify functional groups and reconstruct vertical migration patterns and ontogenetic metabolic histories of representative species. Visual fields and resolving power, indicated by the ganglion cells density and topography on the retina provide the information of diet preferences, habitats and space usage. Otolith morphology, i.e. the outline, the weight and sensory epithelium areas, displays acoustic and vestibular demands in feeding behaviours. These sensory abilities differ between pelagic- and benthic-foraging species or active and passive feeders, and show that depth exerts a stronger pressure on sensory adaptation in pelagic-foraging species. Pelagic foragers with visual-based hunting respond sensitively to the decrease of light intensity with increasing depth through enhanced visual acuity but are also released from the selective pressure of rapid swimming. Ontogenetic growth, vertical migration and metabolism in four representative deep-water fishes (Alepocephalus bairdii, Antimora rostrata, Coryphaenoides rupestris and Spectrunculus grandis) are reconstructed by the otolith microstructure and stable oxygen and carbon isotopes, respectively. C. rupestris, S. grandis and other passive/benthic foraging fishes, have evolved interspecific consistency in life history traits, with common large-scale ontogenetic vertical migration, transformations of feeding behaviours between life stages and a dramatic decrease of mass-specific metabolism in the early life. In contrast, A.bairdii, A. rostrata and active/pelagic foraging species, develop diverse and inconsistent patterns. This study is first to combine morphological and geochemical data to identify functional and life-history traits, and the diverse datasets greatly aids classification where direct observation is difficult.

18

MacLean, Heidi Joan. "Temperature, Photoperiod, and Life History Traits in Drosophila subobscura". W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539626961.

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Alós, Crespí Josep. "Selection drivers of life-history traits in marine coastal fishes". Doctoral thesis, Universitat de les Illes Balears, 2013. http://hdl.handle.net/10803/123496.

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Humans can induce contemporary evolution through harvesting wild animals. This thesis provides evidence of this process for recreational fishing at surprisingly small geographical scales. Marine fish populations are characterized by high variability in heritable individual life‐history traits which are exposed to biased fishing mortality. The life histories strategies of actual populations, which collectively reduce adult body size, mirror such biased mortality in populations exposed to limited gene flow. Because the relationship between life history and behaviour, it is very likely that fishing also induces adaptive responses in behavioural traits. Due the potential negative effects of fishing selection the productivity and quality of the fishery, this thesis recommend considering the evolutionary impacts of fishing in the management plans of species exploited by the recreational fishing
El humans poden produir evolució contemporània a través de la recol∙lecció de animals salvatges. Aquesta tesis proporciona evidencies d’aquest procés per la pesca recreativa a una sorprenent escala espacial petita. Les poblacions marines de peixos tenen una alta variabilitat individual en caràcters heretables de la història exposada a una mortalitat selectiva per pesca. Les estratègies vitals de les poblacions actuals de peixos costaners, les quals conjuntament produeixin una reducció en la mida del individu, són el reflexa d’aquesta pesca selectiva en poblacions amb baixa connectivitat. Degut a la correlació entre història vital i comportament, la pesca pot induir també respostes adaptatives en cert caràcters comportamentals. Considerant els efectes negatius de la selecció per pesca en la productivitat i la qualitat de les pesqueries, aquesta tesis recomana considerar els possibles efectes evolutius produïts per la pesca en les estratègies de gestió d’espècies explotades per la pesca recreativa.
El hombre puede producir evolución contemporánea por la recolección de animales salvajes. La presente tesis proporciona evidencias de este proceso por la pesca recreativa en una sorprendente escala espacial pequeña. Las poblaciones de peces marinos presentan una alta variabilidad en caracteres heredables de la historia vital expuesta a mortalidad selectiva por pesca. Las estrategias vitales de las poblaciones actuales de los peces costeros, las cuales conjuntamente producen una reducción en el tamaño del individuo, son el reflejo de esta mortalidad selectiva en poblaciones con baja conectividad. Debido a la relación entre historia vital y comportamiento, la pesca puede también inducir cambios adaptativos en ciertos rasgos de comportamiento. Considerando los efectos negativos de la selección por pesca en al productividad y calidad de la pesquería, esta tesis recomienda considerara los posibles efectos evolutivos inducidos por la pesca en la estrategias de gestión de especies explotadas por la pesca recreativa.

20

Ripley, Bonnie J. (Bonnie Jo) 1970. "Life history traits and population processes in marine bivalve molluscs". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47425.

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Davies, Esther K. "Properties of mutations affecting life history traits in Caenorhabditis elegans". Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/13585.

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Life history assays were performed on lines of C. elegans in which spontaneous mutations had been allowed to accumulate for 60 generations (Keightley and Caballero, 1997), using a range of harsh conditions. However, no significant degree of genotype by environment interaction was observed. Under some harsher experimental conditions, estimates of mutation rates increased, but the difference was not significant and these results do not lend support to the theory that differences in estimates of mutational parameters are due to variation in assay conditions. Even harsh conditions may not reveal the effects of all mutations that have accumulated and are deleterious in natural conditions, and the extent to which this may result in underestimation of the mutation rate has been unknown. I have measured the effects of EMS-induced mutations on a series of life history traits in C. elegans, in a situation where the number of mutational events induced has been calibrated from studies of suppressor-induced reversion mutations and forward mutations. None of the assays revealed the effects of more than ~ 10% of the deleterious mutations induced, indicating that standard mutation-accumulation experiments may have dramatically underestimated the rate at which mutations accumulate. Such mutations, although cryptic, may nonetheless be significant for evolutionary biology. Two of the lines were further analysed using an inbred-backcross approach, which provided confirmation that only a very small proportion of the induced mutations could be detected. The joint effects of induced mutations on longevity and productivity were also considered. Mortality curves were observed to flatten with age, and this was more notable among the EMS than control lines. One explanation for this was greater heterogeneity among the EMS lines, although other possible causes are discussed. Overall, bivariate analysis revealed strong, positive correlations between longevity and productivity traits, although one line showed a significant increase in longevity, and a correlated decline in early (but not total) productivity, as predicted by the optimality theory of ageing.

22

Haupt, Meghan. "Life history traits that predispose South African linefishes to overexploitation". Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29748.

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Globally, the status of many fish stocks remains unknown, of which the majority fall under data-limited small-scale fisheries. Management decisions in most of these fisheries are difficult due conflicting objectives and views from fisheries managers and scientists. In South Africa, the traditional boat-based ‘linefishery’ provides such an example of a small-scale, multi-species fishery with a long history. The historical de facto open access nature of this fishery resulted in continuous declines in catches of many linefish species, and in 2000 the fishery was declared to be in a state of emergency. This led to a reduction of up to 70% within the fishery, among other measures, such as introductions of size and bag limits. Assessing the status of linefish species is difficult due to a lack of reliable long-term data for the majority of species. The aims of this study were therefore: (1) to quantify the stock status for all linefish species with available life history and size composition information, (2) compare current and historical stock levels to ascertain if the reduction in effort facilitated any recovery in linefish species and (3) correlate the current stock status estimates to life history traits to identify simple indicators of resilience to exploitation. For this purpose, length frequency data from 1988-1990 and 2008-2010 and biological parameters sourced from literature were used to conduct per-recruit analysis to estimate spawner biomass depletion (SBD) for both time periods. The majority of the 26 species analyzed, (68%) showed improvements in spawner biomass between the two time periods, with 12 species undergoing a change in stock status (i.e. improving from collapsed or overexploited). Specifically, increases in length-at-capture (Lc) as well decreases in fishing mortality (F) facilitated recovery for many species. Asymptotic length (L∞), as well as the ratio between Lc / L∞ and Lc / Lopt (where Lopt is the optimum length) were found to be significantly correlated to spawner biomass depletion. Kruskal Wallis analyses revealed that only movement pattern had a significant relationship to SBD, more specifically, migratory species were significantly more depleted than resident ones. This study identifies simple indicators that, in the absence of conventional stock assessments, provide fisheries managers with a fundamental understanding of a species’ susceptibility to overexploitation – offering another decision making tool for use in data poor fisheries such as the South African linefishery.

23

Borges, Carla Débora Gonçalves. "Interaction of human foraging behaviour and prey life-history traits". Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/774.

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Mestrado em Ecologia, Biodiversidade e Gestão de Ecossistemas
O presente trabalho propõe-se divulgar a pesquisa passada e recente no âmbito das consequências da exploração de recursos costeiros pelo homem na biologia das espécies alvo e na comunidade onde estas estão inseridas. A ênfase das pesquisas aqui apresentadas recai principalmente sobre moluscos bentónicos e lapas em particular, dada a ocorrência de protandria (mudança de sexo de macho para fêmea ao longo do ciclo de vida) em algumas das espécies usadas como recurso alimentar. Questões relacionadas modos de reprodução, hermafroditismo e mudança de sexo no mundo animal são igualmente focadas como introdução aos últimos capítulos da dissertação onde se aborda essas questões mais profundamente. No capítulo final são apresentados trabalhos científicos que retratam a importância das áreas marinhas protegidas na conservação de espécies costeiras. ABSTRACT: The present work aims to bring to public, past and present research in the costal resources exploitation by Man and its consequences upon target species and the surrounding community. Particular attention is given to benthic molluscs and limpets in particular due to the occurrence of protandry (sex change from male to female during the life cycle) in some of the harvested species. The issues related to reproduction mode, hermaphroditism and sex change in animals are presented first as to introduce later chapters where these subjects are deepened. The final chapter presents relevant research of the use marine protected areas to the conservation of coastal species.

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Velasque, Borges Mariana. "Personality, life-history traits and pace of life in the hermit crab Pagurus bernhardus". Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/10223.

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Consistent between-individual differences in behaviour (termed “animal personality”) may be driven by adaptive differences in behavioural and physiological life-history traits. The Pace of Life Syndrome (POLS) hypothesis predicts a suit of correlations between those life-history traits along a fast-slow continuum. Therefore, according to the POLS, individuals that are fast-paced would be bolder, more explorative, show high growth-rates, lower immunity and a higher metabolic rate. A mechanistic link between such traits could also explain variation in cognitive traits, where bold individuals are faster at a given task but pay less attention to external cues and therefore make decisions less accurately. Here, I tested the POLS hypothesis focusing on between and within-individual variance in boldness, metabolic rate (MR), cognitive performance (as decision-making performance) and exploration in the hermit crab Pagurus bernhardus. In addition, I also investigated the potential role of anthropogenic disturbances (constant light exposure) as a driver of between and within-individual variation in boldness. Hermit crabs demonstrated consistent between-individual differences in boldness and exploration, providing evidence for the presence of animal personality. However, variation between individuals in boldness, exploration and cognitive performance were not underpinned by variation in MR. Although there were no between-individual correlations among MR and behaviour, MR did co-vary with within-individual variance in boldness. My results indicate that less predictable hermit crabs, on average, have a higher MR during startle responses compared with those that are relatively consistent in their behaviour. Boldness was positively correlated with exploration rate, indicating that more explorative were also bolder, as well as cognitive performance, as bold individuals had a better performance than shy. Finally, constant light exposure is likely to modify hermit crab personality and physiology. Hermit crabs kept under a constant light regime were less bold and had a higher metabolic rate, than when kept under standard light and dark regime, indicating possible effects light pollution in this species. These results only partially support the POLS hypothesis.

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Lalouette, Auréline. "Place de la plasticité dans la variabilité de la sensibilité toxicologique et des traits d'histoire de vie des populations de Gammarus fossarum exposées à la contamination chronique des cours d'eau par le cadmium". Electronic Thesis or Diss., Lyon 1, 2023. https://n2t.net/ark:/47881/m60865fn.

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Malgré les préoccupations relatives à la contamination de l'environnement, la prise en compte des effets longs termes induits par des expositions chroniques au contaminant des populations sur plusieurs générations demeure limitée dans les études écotoxicologiques et dans le domaine de l'évaluation du risque écologique. De même, dans les milieux naturels, les preuves que l'exposition multigénérationnelle influence la sensibilité des organismes sont encore rares, et les mécanismes doivent encore être élucidés. Ainsi, face au manque de connaissances sur l'importance des effets multigénérationnels de la contamination chimique sur les populations aquatiques, ce projet de thèse interroge le rôle de la plasticité dans la variabilité de la sensibilité et des traits d'histoire de vie chez des populations naturelles de Gammarus fossarum lors d'exposition chronique au cadmium. Pour cela, deux types d'approches ont été mises en œuvre : (1) une approche comparative entre une quinzaine de populations naturellement exposées ou non du fait du contexte géochimique local (exposition évaluée par des mesures de bioaccumulation lors d'encagements in situ), s'appuyant sur des mesures de tolérance et traits d'histoire de vie en sortie de terrain, ou après maintien sur plusieurs mois en eau non contaminée de quelques populations, en incluant la descendance issue de croisements entre géniteurs de différentes populations, et (2) une approche d'exposition multigénérationnelle contrôlée au cadmium (0.3 µg/L) sur 18 mois d'une population de gammares initialement non exposée dans son milieu d'origine. Pour chacune des deux approches, des mesures de la sensibilité au cadmium et des traits d'histoire de vie (taux de croissance, taille, taille à la puberté, taux d'alimentation…) ont été réalisées à différents temps d'exposition ou de déacclimatation. Ces suivis ont démontré (1) une influence marquée des niveaux de contamination naturelle biodisponible sur les niveaux de tolérance et l'histoire de vie des populations, (2) une plasticité marquée de ces caractères individuels et populationnels quand l'exposition cadmique est stoppée, et (3) une transmission non génétique à la descendance de la tolérance en fonction des conditions d'exposition des géniteurs, l'ensemble évoquant l'implication possible de processus épigénétiques dans la modification de la sensibilité. De plus, l'étude de la dynamique d'expression d'une métallothionéine répondant fortement à une exposition cadmique a été réalisée dans deux organes impliqués dans la gestion des métaux chez le gammare (branchies, caeca) ainsi que chez la descendance, ceci au regard des variations de la tolérance cadmique observée entre populations et au cours des expérimentations d'exposition et de déacclimatation. Les résultats ont montré une covariation des niveaux d'expression de la métallothionéine avec la tolérance au Cd et suggèrent un rôle des processus transgénérationnels adaptatifs survenant au cours d'une exposition chronique des populations. Ces résultats soutenant l'hypothèse d'un rôle de l'épigénétique dans la plasticité de la tolérance au Cd observée chez les populations de G. fossarum. Ces travaux de thèse soulignent le rôle important de la plasticité et de la transmission non génétique de la tolérance toxicologique au cours d'une exposition à long terme des populations naturelles à la contamination environnementale et montrent ainsi l'intérêt de mener des études multigénérationnelles chez des espèces environnementales non modèles de laboratoire pour améliorer la compréhension des réponses populationnelles à la contamination
Despite concerns about environmental contamination, the consideration of long-term effects induced by chronic exposure to contaminants in populations over several generations remains limited in ecotoxicological studies and risk assessment. Similarly, in natural environments, evidence that multigenerational exposure influences the sensitivity of organisms is still scarce, and the mechanisms have yet to be elucidated. Given the lack of knowledge about the importance of the multigenerational effects of chemical contamination in aquatic populations, this work aimed to investigate the role of plasticity in the variability of sensitivity and life-history traits in natural populations of Gammarus fossarum during chronic exposure to cadmium. For that, two types of approach were used: (1) a comparative approach between fifteen populations naturally exposed or not due to the local geochemical context (exposure assessed by bioaccumulation biotests by in situ gammarids’ caging), based on measurements of tolerance and life history traits after sampled in the field, or after keeping a few populations in uncontaminated water for several months in the lab (common-garden), including offspring from crosses between genitors from different populations, and (2) a controlled multigenerational exposure to cadmium (0.3 µg/L) over 18 months from a gammarid population that was initially unexposed in its native environment. For both approaches, cadmium sensitivity and life history traits (growth rate, size, size at puberty, feeding rates, etc.) were measured at different times of exposure or de-acclimation. This work demonstrated (1) a strong influence of the levels of bioavailable natural contamination on the tolerance levels and life history of the populations, (2) a plasticity of these individual and population characteristics when cadmium exposure is stopped, and (3) non-genetic transmission of tolerance to the offspring depending on the exposure conditions of the progenitors, all of which suggests the possible involvement of epigenetic processes in the modification of sensitivity. In addition, the dynamics of the expression of a metallothionein that responds strongly to cadmium exposure was studied in two organs involved in metal accumulation or detoxification in gammarids (gills, caeca) and in the offspring, with regard to the variations in cadmium tolerance observed between populations and during exposure and common-garden experiments. The results showed a covariation in metallothionein expression levels with Cd tolerance and suggest a role for adaptive transgenerational processes occurring during chronic exposure of populations. These results support the hypothesis of the role of epigenetics in the plasticity of Cd tolerance observed in G. fossarum populations. Thus, this works underlines the important role of plasticity and non-genetic transmission of toxicological tolerance during long-term exposure of natural populations to environmental contamination and thus demonstrates the value of conducting multigenerational studies in environmental species that are not laboratory models in order to improve our understanding of population responses to contamination

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Starling, Amanda. "Behavioural plasticity of life history traits in the New Zealand avifauna". Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1327.

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The purpose of this research was to determine how predator control influences nest survival and changes in life history strategies of birds. All studies were conducted at two sites: one site had very little mammal control, while the other site is a 'mainland island' in which all introduced mammals were trapped or poisoned. Nest survival rates of introduced and native species were compared between the two sites by locating and monitoring nests of nine species. I found that mammalian predator control increased nest survival rates of both introduced and native species, but the incrase of nest survival was more pronounced in native species. The influence of predator control on the plasticity of life history strategies in introduced and native New Zealand birds was also examined. Some life history strategies (e.g. time spent incubating, frequency of visits to the nest) changed significantly in the area with predator control, while other life history traits (e.g. clutch size) did not vary between areas. I found that both introduced and native New Zealand birds changed a variety of life history traits and that the changes were likely a plastic response to the recent change in predator numbers. As it has been suggested that birds may become less responsive to mammals when predators are controlled, I tested the response of birds to a model of a feral cat. Birds in the predator control area were significantly less likely to recognise the cat model as a potential threat. This suggests the recognition of predators can be rapidly lost from a population. My research confirms that mammal control can increase nest success of native species, but reductions in predator numbers can also change a variety of life history traits and behaviours. As the removal of mammalian predators also appears to make birds less responsive to potential predators, it is important for continued mammalian control once management has begun. Otherwise, any reintroduction of predatory mammals into controlled sites would likely place such bird populations at greater risk as they would have behaviours suited to an environment with lowered nest predation risk.

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Edenbrow, Mathew. "Behavioural phenotypes : associated life-history traits and environmental effects on development". Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3278.

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It is widely documented that non-human organisms express individual differences in behavioural patterns. For example individuals can be categorised as bold or shy and when these individual behavioural differences are consistent through time, they are termed behavioural types (BTs). In recent years research has identified that BTs often correlate across contexts/situations and these correlations are referred to as behavioural syndromes. Behavioural types and syndromes (i.e. personality) have also been implicated as major factors shaping population dynamics and the ability to buffer environmental disturbance. Recent theoretical predictions have proposed that BT variation may be underpinned by life-history strategies; however, these predictions have been little studied to date. Moreover, little research has focused upon environmental influences and the ontogeny of personality. In this thesis I use the Mangrove killifish (Kryptolebias marmoratus), a naturally occurring clonal vertebrate, as a model organism. This species presents a powerful tool providing the ability to replicate within and between isogenic genotypes in a controlled manner. Moreover the natural clonality expressed by this species permits environmental effects upon BT plasticity and BT-life-history interactions to be investigated within a developmental framework. In chapter 2, I present microsatellite genotyping results which show that the founding individuals used to propagate a laboratory population at The University of Exeter represent 20 genetically distinct homozygous genotypes. I additionally address five research questions exploring genotypic, environmental, and developmental effects upon three commonly studied BTs (exploration, boldness and aggression): Firstly; I ask do adult hermaphrodite and secondary males exhibit personality i.e. repeatable BT expression? In chapter 3, I present results showing that both of the sexes express short term personality. Moreover, I show that that genotype is an important factor influencing BTs expressed, regardless of sex, indicating underlying genetic control. Secondly I ask; does genotype level life-history variation underpin personality trait variation during ontogeny? In chapter 4, I show considerable developmental plasticity in behavioural expression between genotypes but not life-history and I find limited behaviour-life-history relationships during development. Thirdly I ask; does the rearing environment influence life-history and behavioural plasticity? In chapter 5, I show that in comparison to a control treatment, the presence of conspecifics during ontogeny results in an average reduction in behavioural scores; however, life-history was unaffected. In addition, I show that development in a low food environment lowered average exploration and growth rate but had no effect on boldness or aggression. Furthermore, fish exposed to a predation risk simulation during ontogeny exhibited similar behavioural scores as the control, yet this treatment generated BTs i.e. personality. My fourth question asks; does the parental rearing environment (utilised in chapter 5) influence behavioural expression in the next generation? In chapter 6, I show that transgeneratonal effects of each parental rearing environment influenced life-history but had a minimal effect upon behaviour in the next generation. Finally I ask; does kin or familiarity influence plasticity in associations and aggression? In chapter 7, I show that genotypes have the ability to discriminate kin and familiars and modulate aggression and association accordingly. These results support the concept that developmental and environmental induced plasticity may be more important than life-history in shaping behaviour. Furthermore, although adults exhibit personality and genotypic effects appear important, genotype interacts with environmental/experiential influences to differentially shape behavioural plasticity during ontogeny. I suggest that theoretical predictions regarding life-history may be insufficient to explain the complexity of animal personality in this species. I discuss these results within developmental and epigenetic frameworks with reference to the ecological significance of these patterns within this species and the animal kingdom as a whole.

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Garcia, Victoria. "Lifetime fitness and changing life history traits in Red-cockaded Woodpeckers". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/71347.

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As environmental change continues and increases, understanding how species will respond to change and how these responses may affect populations will be important for conserving and managing species. Red-cockaded Woodpeckers (Picoides borealis) are well-studied and provide an ideal system in which to examine ecological and evolutionary questions related to life histories because monitoring them accurately is relatively easy, their behavior is well-described and structured. In this study, I examined the following questions using long-term data (1980-2013) from two study sites in North Carolina: 1) what traits contribute most to lifetime fitness, 2) how have traits changed over time and how is climate change influencing life history, and 3) to what extent are traits that contribute to fitness and that are changing over time heritable in this species. I found that a multitude of factors contribute to different aspects of fitness, including: parental age and hatch date affecting survival to year one and probability of attaining breeding status; and lay date, clutch size, age at first reproduction, and variance in clutch size affecting lifetime fitness. I also found that many traits were changing over time including lay date, clutch size, partial brood loss, and survival to year one. These traits were strongly influenced by local climate variables at each study site, but it is not clear that climate has changed over time at the study sites to account for all the observed changes in life history traits. Habitat improvement has also played a role as evidenced by increased fledgling production in terms of raw numbers (without accounting for covariates). I also found that lay date, clutch size, and partial brood loss had low heritabilities after accounting for other random and fixed effects. These results indicate that Red-cockaded Woodpeckers at these two study sites are shifting traits successfully in response to changing conditions, and that these changes are in the direction that increases aspects of fitness. These shifts indicate that individuals are plastic with respect to these traits, but most of the variance in traits was related to external habitat-associated factors rather than additive genetic variance or environmental × genotype interactions.
Ph. D.

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Zimmerman, Kolea. "The Genetics of Life History Traits in the Fungus Neurospora crassa". Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493574.

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The study of life histories is fundamental to understanding why some organisms live for a very short time while others live for a long time, why some produce thousands of offspring while others produce one, or why some need a mate to reproduce while others can do it on their own. The life histories of many animals and plants are well known because we can easily walk into a forest or field and measure them. Fungi, on the other hand, are hard to find and see even though they occur most everywhere in great numbers. In the three chapters of this dissertation, I uncover key aspects of the life history of the genetic model Neurospora crassa, a filamentous fungus. First, I present a novel algorithm for the design of crossing experiments, which test the reproductive abilities of individuals. The algorithm identifies a set of individuals (a “crossing-set”) from a larger pool of potential crossing-sets by maximizing the diversity of traits of interest, for example, maximizing the range of genetic and geographic distances between individuals included in the crossing-set. Second, I use the algorithm to select strains for a mating experiment designed to test for maternal effects—the impact of the mother’s phenotype on the offspring’s phenotype—across sexual reproduction in N. crassa. I measured offspring phenotypes from crosses of all possible pairs of 22 wild-isolated strains. Crosses encompassed reciprocals of 11 mating-type “A” and 11 mating-type “a” strains. After controlling for the genetic and geographic distances between strains in any individual cross, I found strong evidence for maternal control of perithecia (sporocarp) production, as well as maternal effects on spore numbers and spore germination. However, both parents exert equal influence on the percentage of spores that are pigmented, and size of pigmented spores. This experiment is proof of maternal effects in a fungus, an unprecedented discovery. Third, I compared the sexual spore viability data from the maternal effects experiment to asexual spore viability data I gathered for the same strains. I found a striking trade-off between the viabilities of sexual and asexual spores. I used genome-wide polymorphism data to determine the genetic basis of this trade-off and identified 36 single nucleotide polymorphisms (SNPs) significantly associated with both traits. All 36 of the identified SNPs exhibit antagonistic pleiotropy—they have opposing effects on asexual and sexual spore viability. Some of these SNPs occur in well-characterized genes involved in sexual reproduction, asexual reproduction, or both. Using the entire dataset of over 50,000 genome-wide SNPs, I show a negative correlation between effects SNPs on sexual and asexual viability across the entire N. crassa genome. These results suggest that a life history trade-off between asexual and sexual spore viabilities drives a large portion of the genetic variation in the N. crassa genome.
Biology, Organismic and Evolutionary

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Davies, Sarah Katherine. "A metabolomic approach to assessing life-history traits in Caenorhabditis elegans". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9082.

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The proximate causes of ageing and the biological processes that determine lifespan are still unclear. However, many studies using model organisms have led to the identification of genes associated with longevity. While there is a clear link between changes in metabolism and changes in longevity, there has been relatively little ageing-related research that has measured metabolites directly. Metabolic profiling of low molecular weight metabolites (metabolomics) has an advantage over other 'omics' techniques, in that it directly samples the metabolic changes in an organism, and integrates information from changes at the gene, transcript and protein levels, as well as post-translational modification. This thesis demonstrates that metabolic profiling provides a new and useful phenotyping tool for studying ageing in the nematode Caenorhabditis elegans. Using both nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS), I have identified metabolites that are linked with long life. I have carried out the first characterisation of the C. elegans metabolome throughout both development and ageing. Comparing these metabolic changes in wild type worms with those seen in a long-lived mutant aid the understanding of when and how mutant worms acquire their long-lived phenotype. In addition to this, I have examined the effects on metabolism of a commonly used technique in C. elegans ageing research: the inhibition of DNA synthesis to maintain synchronous ageing populations. This provided a way to control for the effects of this technique when used in my work, but also demonstrated that its use may result in artefacts in data. I have also investigated the effect of mutation accumulation on the C. elegans metabolic profile. I have shown that metabolomics provides a way to obtain new phenotypes in this type of study, and novel information about the variation that occurs as a result of spontaneous mutation.

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Sternberg, David. "Life-History Traits and the Functional Diversity of Australian Freshwater Fish". Thesis, Griffith University, 2014. http://hdl.handle.net/10072/367236.

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Australian freshwaters are home to approximately 256 fish species from 36 families, many of which are endemic to the country and considered threatened, vulnerable or rare in the wild. In part this is due to a long history of continental isolation where increasing aridity and flow unpredictability have given rise to a fish fauna characterised by a unique association of life-history traits (i.e. characteristics of an organism that contribute to its fitness or performance, and which allow it to function in the environment) in order to cope with natural variation in environmental seasonality, stability and predictability. My thesis presents an assessment of life- history traits and the functional diversity (the range and value of organismal characteristics) of Australian freshwater fish at multiple spatial scales (i.e. continental, river basin, catchment and population scales), with an emphasis on phylogenetic relationships, environmental determinants and conservation biology.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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DA, COSTA TEIXEIRA ANTONIO. "Life history traits in contrasting environments - intraspecies variation in stress tolerance". Doctoral thesis, Università degli studi di Pavia, 2017. http://hdl.handle.net/11571/1214821.

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Seeds are the next generation of a plant and the transition from seed to seedling is germination that begins with the absorption of water. Germination is controlled by several environmental factors, such as water availability, temperature, light and soil chemistry and the resulting combination of germination requirements is the germination niche, a key aspect of the plant regeneration. The knowledge of such descriptors are of outmost importance in order to select the apropriate species according the location environments in a restotation context. Seed germination characters do not necessarily predict seedling emergence and the timing of plant development, the latter seemingly an ecological function of ‘biology x environment’ and an essential requirement of restoration ecology effort. The effects of temperature, droght stress, exogenous nitrate, seed and soil nitrogen forms content, soil gravimetric water content and seed mucilage quantity in the germination and seedling performance of Plantago albicans, P. coronopus, P. lagopus and P. lanceolata were adressed in the present work. The first aim of this work was test the seed germination and the seedling development in temperature and water stress conditions in order to predict its effects on species in the environment restoration context. Using 30 accessions of P. coronopus, and P. lanceolata in temperature and water stress conditions, experiments showed that P. coronopus germination and normal seedling development physiologic traits differed significantly among the species tested, showing a clear species-specific temperature and minimum water requirement for germination and seedling development. Seed performance refers to the seed germination capacity under various environmental conditions and represents a critical component of the plant life cycle which is of imminent ecological importance. Dormancy is a mechanism by which species can bet, or spread the risk of starting the life cycle by ensuring a degree of non-germination even when conditions are good for germination. Nitrate and light has being described to break seed dormancy in several species but little is known about the interplay between temperature and nitrate in the germination improvement. Our second aim was: 1) evaluate the contribution of temperature regimens and exogenous nitrate to, and its interaction in seed germination improvement; 2) evaluate the effect of the different forms of nitrogen and carbon present in seeds and soils and the contribution of these nutrients to the germination and extrapolate to the ecosystems and 3) evaluate the impact of the exogenous nitrate on the germination cardinal base temperature and thermal time requirement. Using seeds and soil samples of 22 accessions of the four above referred Plantago species, results showed that exogenous nitrate is more effective at constant temperatures, loses effectiveness at supra-optimum temperatures and cooler temperatures and nitrate interaction could interfere positively with the dormancy.

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Marín, Moratalla Miren Nekane. "Reconstructing life history traits from bone histology in extant and fossil ruminants". Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/285623.

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El estudio de las life histories es de vital importancia porque proporciona evidencias sobre las condiciones ecológicas, biodiversidad, demografía, vulnerabilidad y otros muchos aspectos de la biología de las especies. La histología ósea es utilizada como herramienta para reconstruir las life histories de vertebrados, analizando el tejido óseo primario o contando el número de marcas de crecimiento (esqueletocronología). Sin embargo, se ha considerado que los endotermos, al contrario que en ectotermos, muestran un crecimiento óseo no cíclico, invalidando la histología ósea para inferir las life histories de mamíferos. El objetivo general de esta tesis es proporcionar las bases de la histología ósea en mamíferos para inferir estrategias de life history. Los objetivos concretos son: i) analizar la fiabilidad de la esqueletocronología ósea en mamíferos, ii) explorar la asociación entre las características del tejido óseo y el ambiente, fisiología, ontogenia y life history y, iii) reconstruir las características de life history en mamíferos fósiles y actuales para obtener datos sobre la evolución de las life histories y biología de la conservación. Se han analizado 274 láminas transversales de hueso de 225 individuos pertenecientes a lirones actuales (Gliridae) y rumiantes actuales y fósiles (Bovidae, Cervidae, Moschidae y Tragulidae). Se han llevado a cabo tanto análisis cualitativos como cuantitativos. Los análisis cualitativos el tejido óseo primario muestran que, en los estadios tempranos de la ontogenia, los rumiantes forman un tejido fibrolamellar (FLC), mientras que los lirones depositan generalmente un tejido parallel fibered bone (PFB). Cuando son adultos, tanto lirones como rumiantes depositan un hueso lamelar denso (External Fundamental System, EFS). Los resultados también muestran que los Lines of Arrested Growth (LAGs) están presentes de forma universal en los mamíferos analizados. Los LAGs están presentes tanto en el tejido de formación rápido (FLC) así como el tejido de formación lento (EFS). El número de líneas de crecimiento en el hueso concuerda con la edad de los animales, proporcionando la evidencia de la periodicidad anual de los LAGs en estos mamíferos. El fémur es el hueso más conservador para aplicar la esqueletocronología ya que registra el mayor número de LAGs. La remodelación y reabsorción ósea puede eliminar o enmascarar los primeros LAGs depositados durante la ontogenia. Esta investigación muestra que el crecimiento óseo se detiene durante el periodo adverso (pocos recursos), acoplado con la variación fisiológica estacional. Estos resultados apoyan que la parada de crecimiento forma parte de una estrategia termometabólica de conservación energética. Además, este trabajo muestra que las características vasculares y celulares del tejido óseo primario sufre una importante variación ontogenética asociada al descenso de la tasa de crecimiento al acercarse la madurez. La densidad vascular y celular decrece mientras que la proporción de canales longitudinales en relación a los circulares incrementa a lo largo de la ontogenia hasta alcanzar la madurez, lo cual podría estar relacionado con la madurez fisiológica. El cambio más significativo durante la ontogenia ocurre durante la transición entre el FLC o PFB a EFS, lo cual está relacionado con la madurez reproductiva. Este trabajo evidencia que esta transición registra el trade-off entre crecimiento y reproducción en rumiantes. De acuerdo con estos hallazgos, la edad de madurez reproductiva puede determinarse contando el número de ciclos de crecimiento antes del EFS. Los resultados comparando las características histológicas cuantitativas entre bóvidos sugiere que los parámetros vasculares y celulares están relacionados con la masa corporal y el metabolismo. De esta forma, el hueso FLC de grandes bóvidos tiende a mostrar más canales circulares (lo cual estaría reflejando mayores tasas de deposición de hueso perióstico) y menores densidades celulares (lo cual estaría reflejando una menor tasa metabólica específica de masa) que los pequeños.
Bone histology is a widely used tool to reconstruct vertebrate life histories, either by analysing primary bone tissue or by counting the number of growth marks (skeletochronology). However, it has long been considered that endotherms, unlike ectotherms, display a continuous or noncyclical bone growth, disabling bone histology for life history inferences in mammals. The general purpose of the research presented in this PhD Thesis is to challenge this statement, contributing to the foundations of mammalian bone histology as a tool for inferences on life history strategies. A sample of 274 bone cross-sections from 225 individuals belonging to extant dormice (Gliridae) and extant and fossil ruminants (Bovidae, Cervidae, Moschidae and Tragulidae) have been analysed under polarized and transmitted light microscopy. The results show that Lines of Arrested Growth (LAGs) are universally present in both mammalian groups analysed in this work. These growth marks are present throughout both, the fast-growing bone tissue deposited during growing period (fibrolamellar bone, FLC or parallel fibered bone, PFB) as well as the slow-growing dense lamellar tissue deposited during the adulthood (External Fundamental System, EFS). The number of rest lines in cortical bones fits well with chronological age of the animals, providing evidence of the annual periodicity of bone growth marks in these mammals. The femur is clearly the most reliable bone for skeletochronology analyses because it records the greatest number of LAGs. Despite this, bone remodelling and resorption can potentially delete or obscure the earliest ontogenetic record, especially in large ruminants. This research further indicates that bone growth is arrested during the energetically challenging period (low resource supply), coupled with physiological seasonal variation. These findings provide support that growth arrest forms part of a thermometabolic strategy for energy conservation. Moreover, this work shows that vascular and cellular features of primary bone tissue undergo strong ontogenetic variation associated with a decrease on growth rate as maturity approaches in mammals. Specifically, vascular and cellular densities decrease whereas the proportion of longitudinal canals in relation to circular ones increases throughout ontogeny until reach maturity, which may be related to physiological maturity. However, the most significant change along ontogeny occurs during the transition between the main primary tissues, from FLC/PFB to EFS, which is related to reproductive maturity. This work provides evidence that this transition reliable records the trade-off between growth and reproduction in ruminants. According to these findings, the age at reproductive maturity can be determined by counting the number of growth cycles within the fast growing tissue before the EFS. The result of comparing histological quantitative features between bovids suggests that vascular and cellular parameters are related to body mass and metabolism rather than to extrinsic factors, such as climate. Accordingly, the FLC bone of larger bovids tends to show more circular canals canals (which may reflect higher rates of periosteal bone deposition) and lower cellular densities (which may reflect lower mass-specific metabolic rate according to Kleiber’s law) than the smaller ones. Finally, the findings on fossil species provide evidence that bone histology is a valuable tool to explore evolutionary trends in mammalian life histories. Moreover, the results of bone histology to get some life history traits in endangered mammals highlight its usefulness on the field of conservation biology. To conclude, the findings of this work provide evidence that, in mammals, bone growth is mainly regulated by endogenous rates and synchronized with seasonal resource availability. The evidence of cyclical bone growth debunks the classical assumption that homeothermic endotherms grow continuously until they attain maturity, providing a clear support to the usefulness of bone histology to reconstruct life history traits in extinct and extant mammals.

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Varga, S. (Sandra). "Significance of plant gender and mycorrhizal symbiosis in plant life history traits". Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514261398.

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Abstract Most plants grow in association with arbuscular mycorrhizal (AM) fungi in their roots forming the so-called AM symbiosis. AM symbiosis is usually beneficial to the host as it improves plant survival and performance. However, AM symbiosis also entails a cost to the plant in terms of the carbon allocated to the fungus. In sexually dimorphic plants, more than one type of individual can be recognised with regard to their sexual expression or gender. The cost of reproduction in these plants will differ in relation to the relative investment in male versus female function, as the female and the male sexual functions incur different costs. This different cost of reproduction may be translated into differences in other plant functions between the sexes as all functions are connected through trade-offs. Therefore, since sexes differ in resource needs and allocation patterns, and AM mediate resource acquisition and allocation patterns through imposing both costs and benefits to the plant, the sexes of dimorphic plant species may possess, at least theoretically, a different relationship with their AM roots symbionts. In this thesis, I have investigated whether the sexes in sexually dimorphic plant species differ in their mycorrhizal relationship, and if so, in which ways. Several plant life history traits were studied in the dioecious species Antennaria dioica and also in the gynodioecious Geranium sylvaticum using greenhouse, common-garden and field experiments. Resource acquisition, resource allocation, and both plant and fungal benefits from AM symbiosis were considered. Mainly beneficial effects of AM symbiosis were observed in both sexes of the two dimorphic plant species for most of the studied plant life history traits. Overall, both partners benefited from the AM association. However, several sex-specific benefits were detected which were not uniformly present in all experiments for any given trait. Moreover, the responses observed in certain life history traits were dependent on both the AM fungal and plant species involved in the symbiosis. Remarkably, plants gained sex-specific benefits from the same species of AM fungi and the fungal benefit differed depending on the sex of the host plant. In addition, mycorrhizal benefits were lost under certain environmental conditions. To summarise, the results obtained in this study highlight the complexity of AM interactions. My results suggest that the plant-mycorrhizal fungus relationship may differ depending on the sex of the host plant. Through sex-specific effects on survival, growth and reproduction of the hosts, AM fungi may play a role in the evolution of the life histories in the studied species. In addition, sex-specific relationships between plants and their mycorrhizal symbionts may have potential important consequences for the population dynamics of the sexual morphs and the coevolution of the mycorrhizal relationship.

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Harrower, Colin. "Investigating the Relationships Between Life History Traits and Large Scale Macroecological Patterns". Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504375.

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Spiers, Angus A. "Seasonality and life history traits of the Anopheles gambiae complex in Malawi". Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396849.

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37

Birget, Philip Laurent Guillaume. "Evolutionary ecology of parasites : life-history traits, phenotypic plasticity, and reproductive strategies". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28805.

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Adaptive phenotypic plasticity, the ability of a genotype to give rise to different phenotypes in different environments, evolves to allow organisms to fine-tune their life-history traits according to the varying conditions they encounter during their lives. Reproductive investment - the manner in which organisms divide their resources between survival and reproduction - is well studied in evolutionary ecology because it is a key determinant of fitness. However, whilst plasticity in reproductive effort is well understood for free-living multicellular taxa (such as insects, birds, and mammals), the application of evolutionary theory for plasticity and life history strategies to unicellular parasites and pathogens is lacking. In this thesis, I use empirical and theoretical approaches to uncover how differential resource allocation to non-replicating, sexual stages (gametocytes) versus asexually replicating stages can be harnessed by the rodent malaria parasite Plasmodium chabaudi to maximise its fitness across the often very variable conditions it encounters during infections. Differential allocation between those stages is equivalent to the fundamental life-history trade-off between survival and reproduction because gametocytes are responsible for between-host transmission (i.e. reproduction of the infection) whereas asexual parasites mediate host exploitation and within-host survival. A suite of within-host models reveal that malaria parasites could gain considerable fitness benefits in the face of low levels of drug treatment if they reduce their investment into gametocyte production ("reproductive restraint"), thereby assuring the continuity of the infection and capitalising on opportunities for future transmission. In contrast, high levels of drug treatment typically select parasites to commit all of their resources to gametocyte production ("terminal investment"), to escape a host that does not offer much opportunity for future transmission. My experiments reveal that P. chabaudi increases both its reproductive investment and its asexual replication rate in anaemic hosts (i.e. host that have a low density of red blood cells), suggesting that parasites profit from host anaemia and can afford high investment in gametocytes ("affluent investment"). I also uncover plasticity in a number of traits that underpin asexual replication rate, including invasion preference for different ages of red blood cells, but it is plasticity in the number of progeny (merozoites) per infected cell that is the main contributor to asexual replication rate. My experiments also reveal genetic variance in plasticity of the life-history traits investigated, which has profound implications for their evolution. Furthermore, plastic modification of these traits is associated with minimal costs or constraints, so that parasites can rapidly match life-history traits appropriately to the within-host environment. Severe anaemia is one of the deadliest symptoms of malaria, so observing that virulence and infectiousness increases in anaemic hosts has also fundamental clinical implications. Finally, the empirical and theoretical observations of affluent investment, reproductive restraint and terminal investment match theoretical predictions of how organisms should behave in varying environments, confirming P. chabaudi as a useful model system to test life-history theory.

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Beyrend, Delphine. "Life history traits of key brackish copepods from temperate to tropical environments". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10120.

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L’étude de la dynamique de populations du plancton apporte un nouvel aperçu de l’effet du changement du climat sur les milieux aquatiques. Cependant, un besoin réel existe d’une vue d’ensemble de ces effets possible en se basant sur des comparaisons entre les sites à des échelles appropriées. La France et Taïwan sont des pays situés sous des climats contrastés principalement tempéré pour la France et subtropical/tropical pour Taïwan. En France, le copépode saumâtre Eurytemora affinis, connue comme espèce clef en région tempérée, a été le sujet de nombreuses études en laboratoire et sur le terrain. P. annandalei est une espèce dominante de copépode saumâtre mais dans en régions subtropicale/tropical de l’Indopacifique qui n’a pas été bien étudiée malgré son importance écologique et économique. Dans cette thèse, on a étudié l’histoire de vie du copépode P. annandalei particulièrement l’effet de la température et salinité ainsi que d’autres aspects comme la biologie de la reproduction pour comprendre sa dynamique de population en milieu naturel. On a aussi étudié la dynamique de population de copépodes dominants dans deux estuaires contrastés comprenant P. annandalei et E. affinis respectivement dans les estuaires du Danshuei (subtropical) et de la Seine (tempéré). L’étude de l’histoire de vie de P. annandalei a révélé l’importance de la température, salinité et leurs interactions dans sa stratégie de cycle de vie. Il est capable de se développer et reproduire dans une large gamme de température-salinité cependant il montre une meilleure fitness à 25-30°C et à salinité 15. L’étude sur le terrain montre que les dynamiques de populations de copépodes sont influencées par différent facteurs environnementaux dans les deux systèmes comme l’apport en eaux douces dans l’estuaire tempéré de Seine et les typhons dans l’estuaire subtropical du Danshuei. Nos résultats trouveront certainement des intérêts et des applications en dynamique de population des copépodes subtropicaux/tropicaux et dans l’aquaculture ainsi qu’en écologie de systèmes saumâtres principalement subtropicaux dans le contexte de changement global du climat
The study of the plankton population dynamics brings new insights on the effects of the global climate change on aquatic ecosystems. However, there is a real need to have a global overview of these effects through inter-site comparisons at appropriate scales. France and Taiwan are two countries located in contrasting climate regimes, respectively temperate and subtropical/tropical. In France, the temperate brackish copepod Eurytemora affinis which is known as key species has been the subject of numerous laboratory and field studies. P. annandalei which is also a dominant brackish copepod but in subtropical/tropical Indo-Pacific regions found in Taiwan, has not been well studied despite its ecological and economical importance. In this thesis we studied the life history of the copepod P. annandalei particularly the effects of temperature-salinity interactions and other aspects such as the reproductive biology to understand its population dynamics in the field. We also investigate the population dynamics of dominant copepods in two contrasting estuaries including P. annandalei and E. affinis respectively in the subtropical Danshuei Estuary and the temperate Seine Estuary. The main originality of this work was to use similar protocols in laboratory and in the field observations in the two contrasting systems. The life history study of P. annandalei highlighted the importance of temperature and salinity in its life cycle strategy. It is able to develop and reproduce in a wide range of temperature-salinity conditions however it showed better fitness at temperature 25-30°C and salinity 15. The field studies showed that the population dynamics of copepods was driven by different environmental factors in the two contrasting systems such as the river discharge in the temperate Seine Estuary and the typhoons in the subtropical Danshuei Estuary. Finally our result may find some interests and applications in subtropical/tropical copepod population dynamics and in industrial aquaculture as well as in the ecology of subtropical brackish systems within the global climate change context

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Kakehashi, Masayuki. "On the environmental condition and the corresponding patterns of life history traits". 京都大学 (Kyoto University), 1985. http://hdl.handle.net/2433/86355.

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Smith, Samson William. "Effects of Reactive Oxygen Species on Life History Traits of Caenorhabditis elegans". PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/712.

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Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as the cost(s) incurred on one component of fitness (e.g., reproduction) by the increased expression of another fitness-related trait (e.g., longevity). Only recently have researchers begun to investigate the mechanistic bases of life history tradeoffs. A recent proposal is that reactive oxygen species (ROS) have a central role in shaping life history traits and tradeoffs. Research on disparate animal taxa has highlighted strong correlations between oxidative stress resistance and fitness-related life history traits, for example. Here, I use the model organism Caenorhabditis elegans to test several hypotheses concerning the effects of ROS on life history traits and the manifestation of life history tradeoffs. Additionally, I use heat stress and an alternate food source to explore the responses of life history traits to other forms of physiological stress. Relative fitness and other traits related to reproduction were found to be affected in mostly negative ways by increasing oxidative insult. Lifespan was surprisingly unaffected by oxidative stress, but was modified by temperature. In vivo ROS levels as measured by fluorescent microscopy reveal a tradeoff between antioxidant production and reproduction in this species.

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Supp, Sarah R. "Local and Regional Drivers of Biodiversity: From Life-History Traits to System-Level Properties". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1503.

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Biodiversity research aims to understand and predict the occurrence, abundance, and distribution of species and the diversity of species traits, body sizes, and functional roles in a community. Ecologists lack a comprehensive understanding of the interplay between processes driving biodiversity at differing spatiotemporal scales, hindering the ability to predict response to change. A crucial challenge facing ecologists is to incorporate knowledge of the regional dynamics and temporal stability of communities in biodiversity research. This dissertation investigates the role that species traits and system-level properties play in determining biodiversity at local sites and evaluates biodiversity response to change. Local and regional processes may regulate biodiversity via their different influences on core (common, temporally persistent) and transient (rare, temporally intermittent) species. In Chapter 2, we tested the hypothesis that core vs. transient species have fundamentally different life-history traits that are associated with survival strategies targeted at local vs. regional habitat use. Using long-term mark-recapture data from a rodent community, we found that core species generally had high ecological specialization, high survival, low dispersal rates, and low reproductive effort compared to transient species. Life-history trade-offs may correspond to differing roles in maintaining species richness and responses to environmental change. Macroecology describes patterns of biodiversity in communities without respect to species identities or traits. Diversity patterns (i.e., species-abundance distribution-SAD, species-area relationship-SAR, species-time relationship-STR) are well-studied, but drivers of these patterns are poorly understood. In Chapter 3, we tested the hypothesis that local-scale interactions influence the form of SADs, SARs, and STRs using long-term data from annual plant communities. Our results suggest that patterns are directly influenced by system-level properties (species richness, total abundance) and respond indirectly to local-scale processes. In Chapter 4, we analyzed data from a global-span database and found the SAD and species richness generally resilient to environmental change. This work suggests that local processes are important determinants of species composition and abundance and may set an upper limit to species richness, but that regional processes are responsible for maintaining richness and community structure. This insight may partially explain why many biodiversity metrics are often invariant under environmental change scenarios.

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Bezirci, Gizem. "Impacts Of Multistressors On The Survival And Life History Traits Of Daphnia Pulex". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609842/index.pdf.

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As Daphnia have an important role in freshwater food webs, it is important to understand how environmental stressors affect their survival and life history traits. Daphnia pulex were first acutely exposed to a combination of NaCl salinities (0.00-10.0 g/L) and fish-exuded kairomone. The 24 and 48 hour LC50 values were 0.401 and 0.159 g/L in kairomone-absence and 1.962 and 1.007 g/L in kairomone-presence. Hence, survival decreased with increasing salinity, while the kairomone enhanced daphnid resistance to salinity below 2 g/L. During the chronic exposure to salinity (0.00-1.5 g/L) combined with the fish-exuded kairomone, impacts of temperature and food were also investigated. Survival decreased significantly with increased salinity, while the kairomone had a positive impact on survival at intermediate salinity levels, suggesting an antagonistic relationship. Temperature alone had a significant negative impact on survival and its combined effect with salinity and fish kairomone was synergistic. However, the impact of food limitation was insignificant. Life history parameters were affected by both salinity and the fish-exuded kairomone, the combination of which significantly decreased the body length: width ratio. Egg number/individual decreased with salinity and increased in the presence of the fish kairomone. In conclusion, the combined impact of salinity and fish-exuded kairomone significantly affected daphnid survival and life history traits in a non-linear manner, such that fish kairomone enhanced daphnid resistance to intermediate salinity levels. Moreover, the combined effect of salinity, temperature and fish kairomone on daphnid survival was also significant.

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Palacio, Lopez Kattia Paola. "Effects Of Plasticity And Hybridization On Life History Traits In Arabidopsis Thaliana Ecotypes". ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/816.

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Understanding the strategies that plant populations implement to increase evolutionary responsiveness to better survive environmental changes induced by climate change is a critical challenge for ecology and evolutionary studies. This dissertation investigates the role of hybridization, local adaptation, and phenotypic plasticity in plant population responses to environmental change. Specifically, I utilized meta-analysis techniques to investigate the prevalence of local adaptation and phenotypic plasticity as the two main mechanisms used to adapt to heterogeneous environments, and experimentally explored the genetic pathway of plasticity in phenology traits such as bolting time in Arabidopsis thaliana under high temperatures. Furthermore, A. thaliana was used to create artificial hybrids to test if novel trait combinations allow hybrids to outperform their parental source in novel and stressful environments. In the second chapter, I included reciprocal transplant plant studies and found that local adaptation is more common than adaptive plasticity as an evolutionary response to environmental heterogeneity. Although local adaptation was more common, plastic responses have been reported as a mechanism to tolerate increases in global temperature; however, the underlying genetic and developmental mechanisms are only starting to be elucidated. To address this, the third chapter determined whether alternative splicing of the ambient temperature flowering pathway gene FLOWERING LOCUS-M (FLM), and expression of SHORT VEGETATIVE PHASE (SVP), can explain flowering time plasticity in ecotypes of A. thaliana under 18°C and 26°C. Although the expression of SVP and FLM-β tracks reaction norms, I failed to find evidence that alternative FLM splicing plays a role in phenotypic plasticity in intraspecific flowering time variation. Intraspecific hybridization (admixture) disrupts divergent genetic architectures between populations to generate phenotypic novelty and raw material for environmental selection to act upon. In order to understand the effect of this disruption to local adaptation of A. thaliana ecotypes separated along geographic and locally adaptive genetic distances, the fourth chapter used experimentally created F1-hybrids between geographically distant ecotypes, and used single nucleotide polymorphism (SNP) data to estimate (putatively neutral) background and adaptive genetic distances. My results suggest that disruption of locally adaptive genomic loci decreases the performance of offspring between distantly related parents, but that crosses between very closely related parents also reduce performance, suggesting that during admixture selection may have to balance the consequences of disrupting local adaption while also avoiding inbreeding depression. Lastly, I examined the effect of recombination events under limiting and novel growing conditions (i.e. drought, high temperatures, and freezing field over-wintering conditions) in A. thaliana F2-hybrids. I provide empirical data for the effect of limiting growing environment on phenology, growth, and fitness traits on the admixed and parental ecotypes. I found that recombination events generate novel phenotypes. Generally, offspring phenotypic variation increases and shifts from the parental ecotype phenotypes, and in some cases, offspring display transgressive segregation, heterosis, or outbreeding depression. This work provides a novel contribution towards understanding mechanisms that plant implement to deal with rapid environmental changes. Specifically, plastic responses and hybridization events may interplay to maintain and increase genotypic diversity.

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Godwin, Joanne Louise. "Consequences of sexual selection for reproductive and life history traits in Tribolium castaneum". Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/60654/.

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Sexual selection is a widespread evolutionary force that acts on variation between individuals in reproduction, driving the evolution of traits that increase fertilisation success. Although generally well-studied, there are gaps in our understanding of how sexual selection (1) impacts population-level fitness, and (2) shapes trait divergence at the level of the gamete. Here, I investigate these questions using experimentally evolved populations of the promiscuous flour beetle, Tribolium castaneum, which vary only in contrasting strengths of sexual selection across 58+ generations. For population fitness, sexual selection is theorised to act either positively or negatively, depending on its alignment with natural selection, and/or the impact of sexual conflict. I found no evidence for either consistently positive or negative effects of sexual selection history on adult resistance to environmental stresses or intrinsic ageing. However, significant and consistent benefits of strong sexual selection histories were recorded within the ability of individuals to cope with poor nutrition. Furthermore, a history of strong sexual selection improved a population’s ability to invade novel, intra-specific competitor populations across multiple generations, demonstrating superior biotic fitness across life history traits. Overall, these results provide evidence for population fitness benefits of sexual selection. At the gamete level, sperm number is known to be a vital predictor of sperm competition success, however, the influence of sexual selection on the huge diversity in sperm morphology remains unclear. I found that strong sexual selection led to the evolution of greater sperm competitiveness in adult males, and this was associated with increasing sperm length divergence, but no effect on length variance. Finally, a study of sex-specific ageing in this promiscuous species revealed that stark sexual dimorphism in reproductive senescence was associated with sexual dimorphism in intrinsic lifespan, supporting ageing theories and suggesting significant differences in the cost of early reproduction for males and females.

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Njoroge, Joyce Muthoni. "Ivermectin selection and characterization of the life history traits of Heligmosomoides polygyrus (Nematoda)". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23417.

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A stock "parent" (S) strain of the mouse parasite Heligmosomoides polygyrus was exposed to increasing levels of ivermectin at the L4 stage for 15 generations. A Passage line was also developed from the parent strain parallel with the ivermectin selected line to control for the effects of rapid passage of the parasite from host to host during drug selection. A dose titration trial indicated 1.5 fold resistance had developed in the ivermectin selected strain at the 8th generation (IVM-8) both at the L4 and adult stage. A higher dose of drug was required to kill the L4 stage compared to the adults at generation 8. Additional selection pressure for 7 generations (IVM-15) did not change the resistance status of adult worms. The Passage strains (P-8 and P-15) remained susceptible to drug. The life history traits of the parent strain (S), the ivermectin selected (IVM-8 and IVM-15) and the Passage (P-8 and P-15) strains were then compared. Eight generations of selection with ivermectin (IVM-8) resulted in an increase in establishment 8 days post-infection (pi) but decreased egg output and worm burden over 4 months compared with strain S. However these effects were not seen after 15 generations of drug selection. The ivermectin selected strain (IVM-15) had similar establishment, egg production and worm burden as the parent strain (S). Establishment in strain P-8 was intermediate and not different from S or IVM-8 however 15 generations of passage (strain P-15) resulted in higher establishment and more rapid development to adult. This was also reflected in the net egg output and worm burden during the first month of infection. There were no differences in per capita fecundity among the five strains. Environmental pressure exerted by passage of H. polygyrus from host to host rather than ivermectin selection caused shifts in some life history traits of this nematode.

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Tibblin, Petter. "Migratory behaviour and adaptive divergence in life-history traits of pike (Esox lucius)". Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-42995.

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Population divergence shaped by natural selection is central to evolutionary ecology research and has been in focus since Darwin formulated “The origin of species”. Still, the process of adaptive divergence among sympatric populations is poorly understood. In this thesis I studied patterns of adaptive divergence among subpopulations of pike (Esox lucius) that are sympatric in the Baltic Sea but become short-term allopatric during spawning and initial juvenile growth in freshwater streams. I also examined causes and consequences of phenotypic variation among individuals within subpopulations to evaluate the contribution of natural selection to population divergence. I first investigated homing behaviour and population structures of pike to assess the potential for adaptive divergence among sympatric pike that migrate to spawn in different streams. Mark-recapture data suggested that migrating pike displayed homing behaviour and repeatedly returned to the same stream. Analyses of microsatellite data revealed partial reproductive isolation among subpopulations spawning in different streams. These subpopulations, however, were truly sympatric during the life-stage spent in the Baltic Sea. To address whether short-term allopatry has resulted in adaptive divergence among sympatric subpopulations I combined observational, experimental and molecular approaches. Observational data showed that subpopulations differed in morphological and life-history traits and common-garden experiments suggested that differences were, at least in part, genetically based. Moreover, QST-FST comparisons indicated that genetically based phenotypic differences has been driven by divergent selection, and a reciprocal translocation experiment showed that phenotypic variation represented local adaptations to spawning habitats. Finally, longitudinal and cross-sectional comparisons among individuals revealed associations between phenotypes, performance and fitness components. In conclusion, my thesis illustrates how short-term allopatry due to migratory behaviour can result in adaptive divergence among sympatric subpopulations. These findings advance the understanding of evolutionary processes at the finest spatiotemporal scale and illustrate that local adaptations can arise in environments with high connectivity. The results also emphasise that fine spatial scale population structures must be taken into consideration in management and conservation of biodiversity in the Baltic Sea.

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Kruger, L. M. "Effects of increased fire frequency on the life history traits of Protea lorifolia". Thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/26001.

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Fleming, Kelly M. "Functional diversity and life history traits of arbuscular mycorrhizal fungi in disturbed soils". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1191.

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Thesis (M.S.)--West Virginia University, 1999.
Title from document title page. Document formatted into pages; contains viii, 63 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

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Cashmore, Deborah. "Intra-specific variations in the life-history traits of two lacunids (Gastropoda: Prosobranchia)". Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/14636.

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Within life-history trait variations for two herbivorous intertidal lacunids, Lacuna pallidula, a direct developer and Lacuna vincta a planktotroph, were compared and related to their ecology and to marine invertebrate life-history theory. Aspects of life-history theory covered included; reproductive investment, the relationship between egg size and egg fecundity, the Egg-Juvenile-Period (EJP), the implications of egg size for offspring status and maternal effects. Similar patterns of growth and reproductive investment were observed for adult females of both species, although absolute rates of growth and reproduction were differently affected by macroalgal diet. Further, differences in response to the favourability of macroalgal diet were observed for the two species, notably in the manner in which eggs were packaged. Variations in both egg size and egg numbers in spawn masses were observed for the two species, among populations within both species and within Lacuna pallidula populations. For Lacuna pallidula, these variations were shown to be mediated by both maternal macroalgal diet and population source. Maternal diet directly affected the size of hatching offspring but not the size of eggs produced. Consequently, egg size was not a good indicator of hatching size for either species. The EJP was determined for both species for a range of temperatures. Greater variations in the EJP and juvenile size were observed in Lacuna vincta. This was attributed to the ability of the larvae of this species to delay metamorphosis and to display positive growth during the delay phase. Both temperature and microalgal diet were shown to affect patterns of growth and development in Lacuna vincta larvae. Sources of naturally occurring cues for inducing settlement and metamorphosis in Lacuna vincta larvae were investigated to understand further the distribution patterns of this species on macroalgal types. Extension of the work investigated the suitability of various artificial cues for inducing metamorphosis and the effects of larval age and nutritional status of larvae upon latency of response to established inducing cues. Overall, L. pallidula displayed greater variation in traits and was more sensitive to environmental change than L. vincta. This finding is discussed in light of the two species larval strategy.

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Rézouki, Célia. "The influence of lifestyle on demographic responses to climate change : the Alpine marmot as a case study". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1161/document.

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Comprendre la réponse des populations aux variations environnementales est un défi central en écologie et est devenu un enjeu indéniable ces dernières années avec le changement climatique. Dans ce contexte, nous pouvons nous attendre à ce que certaines caractéristiques écologiques propres aux espèces, comme le mode de vie, qui ont évolué en réponse à des contraintes environnementales et qui influencent les traits d'histoire de vie des espèces, puissent façonner la démographie des populations en environnement variable. Pourtant, cette influence du mode de vie sur la réponse démographique des populations demeure encore mal comprise. J'ai essayé de combler cette lacune au cours de ma thèse, principalement par l'analyse d'un jeu de données exceptionnel obtenu grâce à un suivi à long terme d'une population de marmottes alpines (Marmota marmota) dans les Alpes Françaises. La marmotte alpine présente un mode de vie très particulier. Les individus vivent au sein de groupes familiaux de taille variable, généralement composés d'un couple de dominants reproducteurs, de subordonnés et de juvéniles. Ils hibernent durant la moitié de l'année, et pratiquent l'élevage coopératif ; les subordonnés mâles participent activement à la survie des jeunes durant l'hibernation, et sont alors appelés helpers. J'ai d'abord étudié comment le mode de vie de la marmotte (qui allie hibernation et socialité) a influencé les effets des fluctuations météorologiques sur les variations de survie de chaque classe d'âge. Les résultats ont alors révélé une forte diminution de la survie des juvéniles au fil des ans, et cela du fait d'effets interactifs entre facteurs environnementaux (i.e., hivers de plus en plus rudes) et sociaux (i.e., diminution de la présence des helpers). Dans un deuxième temps, j'ai étudié la valeur adaptative de l'élevage coopératif au sein de cette population de marmottes alpines et j'ai pu montrer que les effets bénéfiques de la présence des helpers sur la survie des juvéniles tendaient à disparaître du fait du changement climatique. En conséquence de cela, la population de marmottes alpines semble être actuellement en déclin. Cependant, l'impact du changement climatique semble avoir été en partie limité par une plus grande probabilité d'accéder à la dominance pour les subordonnés au cours des dernières années, ce qui démontre une influence complexe de la socialité sur la réponse de cette espèce. Enfin, j'ai comparé la démographie de la population de marmottes alpines avec celle d'une population de chamois (Rupicapra rupicapra) soumise à des variations météorologiques similaires dans les Alpes. J'ai été en mesure de montrer que le mode de vie et la stratégie de reproduction de ces espèces ont façonné différemment leurs réponses démographiques aux variations environnementales, et ainsi au changement climatique
Understanding populations' response to environmental variation is a central issue of ecology, and has become a compelling goal in the last years due to climate change. In this broad context we could expect some species-specific ecological characteristics known to influence life history traits, such as lifestyle, to shape the demography of populations in variable environments as well as structure between-species differences in response to environmental change. Yet, the influence of species' lifestyle on population demographic responses to environmental variation is still poorly understood. During my PhD, I tried to fill this gap primarily through the analysis of an extensive data set of an Alpine marmot (Marmota marmota) population in the Alps. Alpine marmots present a particular lifestyle. 1ndividuals live in family groups of variable size, typically composed of one dominant breeding pair, of sexually mature and immature subordinates and of pups of the year. Half the year, they hibernate together in burrows and practise cooperative breeding with male subordinates acting as helpers for the pups, increasing their survival probability during hibernation. I first investigated how the marmot's lifestyle (hibernation and sociality) mediated the effects of weather fluctuations on age-specific survival variation. I found that juvenile survival strongly decreased over the years because of inter-related effects of harsher winter weather conditions and social factors (i.e., decrease in helpers' presence). In a second step, I studied the adaptive value of cooperative breeding in this Alpine marmot population, and showed that the positive influence of helpers' presence on juvenile survival was vanishing with climate change. The Alpine marmot population is currently decreasing accordingly. However, in parallel to the latter changes, I found a better access to dominance for subordinate individuals over the years, compensating in part this decrease, and highlighting a complex influence of sociality on marmot response to climate change. Finally, I compared the demography of the Alpine marmot population with that of an Alpine chamois (Rupicapra rupicapra) population, subjected to similar weather conditions in the Alps. I was able to show that the difference in lifestyle and reproductive tactic between these species shaped their demographic responses to environmental variation, providing them with differentresistance to current environmental change

Tesi sul tema "Life trait history"

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