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Oakes, E. J. "Comparative and experimental studies of sexual selection in birds." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339051.
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Winquist, Steven Todd. "A comparative analysis of two secondary sexual characters in birds." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26184.
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This thesis investigates the evolution of two secondary sexual characters in birds, large male body size and exaggerated male tail length. To determine whether the elaboration of these two characters is associated with two correlates of sexual selection intensity, mating system and parental care, I collected and examined morphological information for 1,990 species and natural history data for 745 species. Comparative studies should account for the problem of related species sharing similarities through common descent, so here I investigate associations with contrast scores that measure the variation radiating from unique ancestral nodes in a phylogeny. I show that greater polygyny correlates strongly with increasing male size but only slightly with longer male tail length, and that lesser paternal care correlates strongly with both traits. These results indicate that the evolution of increased male body size and exaggerated male tail length in birds is substantially influenced by the intensity of sexual selection.
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Collins, Sarah Amanda. "Some factors affecting female mate preference." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305998.
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Roberts, Mark Lyndon. "The effects of the endocrine system on immunocompetence and sexual selection in birds." Thesis, University of Exeter, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425495.
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Rowe, L. V. "The role of natural and sexual selection in the evolution of tail ornaments." Thesis, University of Stirling, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311655.
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Nadeau, Nicola Jacqueline. "The evolutionary genetics of sexually selected plumage colour traits in the galliform birds." Thesis, University of Cambridge, 2007. https://www.repository.cam.ac.uk/handle/1810/243353.
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Extravagant male plumage traits in birds are a classic example of sexual selection. However we know very little about the units that selection is acting upon, the genes themselves – what are they and how are they influenced by sexual selection? In this study I focused on in the evolution and genetics of colouration the galliform birds. Several novel loci were used to create a well resolved phylogeny of this group. This was then used to investigate and reconstruct the evolution of sexual plumage dichromatism. Four pigmentation genes were sequenced in an array of galliform species. A measure of the rate of evolutionary change (dN/dS) at these loci was then compared between lineages with different strengths of sexual selection, using sexual dichromatism as the main index of sexual selection. I found evidence for sexual selection acting at the MC1R locus, in the form of a robust correlation between dN/dS and sexual plumage dichromatism that was not found at any of the other loci. I then went on to investigate the evolution and population genetics of MC1R in the grouse, focusing on the strongly dichromatic black grouse and the relatively monochromatic red grouse. I found some evidence for an adaptive change at this locus between these species. Finally I used a candidate gene approach to investigate the role of several genes in avian pigmentation using the Japanese quail (Coturnix japonica) as a model system. I found evidence that the avian agouti gene is involved in dorso-ventral pigmentation patterning and a regulatory mutation at this locus that produces a yellow phenotype. In addition point mutations at MC1R and TYRP1 were found to be responsible for producing pigmentation variants. I then compared the expression of several of these candidate genes in male and female common pheasants (Phasianus colchicus) and found lower TYRP1 expression in males. Knowledge of the genetic basis of secondary sexual traits and the action of sexual selection at this level could have important implications for our understanding of the process of sexual selection as a whole.
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Maia, Villar de Queiroz Rafael. "The Development and Evolution of Iridescent Colors in Birds." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1407503755.
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John, Jeremy Leighton. "The spleen, parasites and sexual selection in birds : a comparative study of disease resistance evolution." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308603.
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Greenwood, Hamilton. "Sexual selection and delayed plumage maturation in the sub-adult male cohort of the red-winged blackbird (Agelaius phoeniceus)." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72067.
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The variable plumage characteristics of the sub-adult male cohort of the red-winged blackbird (Agelaius phoeniceus) are described. At one extreme of the plumage variation, there are a group of sub-adult males that are indistinguishable from the adult males. These birds can only be correctly aged by cloacal examination for the bursa of Fabricius in the autumn. At the other extreme, approximately 4% of the population are near perfect female-mimics. A simple scoring system based on the interspersion of dark feathers in the epaulet is presented, which permits classification of the sub-adult males into 1 of 6 plumage classes. These epaulet classes are significantly correlated with other traits of the plumage.Age when entering the prebasic molt, and the physical condition of the sub-adult male may influence the development of the varied plumage characteristics.
The distribution of the plumage characteristics of a population of sub-adult males collected at a major blackbird roost in the province of Quebec is described for birds captured in the fall and spring. The spring plumage characteristics are more variable than the fall, a phenomenon which is not consistent with plumage wear as has been previously reported, but which may be related to a prealternate molt which the birds undergo. The prealternate molt is prevalent in some but not all of the contour feather tracts, and is restricted to females and the sub-adult male cohorts.
An age- and sex-specific spring migration of red-winged blackbirds is examined. Adult males arrive to the spring roosts first, followed by yearling males and then females. A similar pattern of dispersal to the breeding territories is described. Within the subadult male cohort, the birds with the most adult-male like plumage traits arrive at the vernal roosts first.
The characteristics of the prealternate molt and differential spring migration are discussed in relation to the pressures of sexual selection on the respective age and sex cohorts.
The adaptive significance of variable sub-adult male plumages and delayed plumage maturation in passerines is evaluated. Several competing hypotheses have been advanced to describe the phenomenon of delayed plumage maturation. These hypotheses are reviewed, and a test is proposed which unequivocally differentiates between the various alternatives. (Abstract shortened with permission of author.)
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Sheard, Catherine. "The role of social and ecological processes on phenotypic evolution in birds." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:65fbf687-4201-4c2b-9ceb-4d780e926b8c.
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The broad concept of 'biodiversity' can be roughly separated into two related components: trait diversity and species richness. Despite the fact that one or both of these types of biodiversity underlie much of ecology, evolution, and conservation, however, it remains largely unknown how traits and speciation dynamics can interact, particularly at a large scale. My thesis uses modern phylogenetic comparative methods and a new global database of avian morphological traits to quantify and predict the drivers of biodiversity across the world's birds, focusing particularly on the relative roles of ecological and social traits to understanding broad evolutionary patterns. In Chapter 2 I present a survey of avian functional traits, focusing on eight measurements of the beaks, wings, tails, and tarsi of 42,334 individuals representing 10,023 extant and recently extinct species. The global trait distribution of avian communities is consistent with a competition-based model of community assembly, and I find no evidence of environmental filtering at the biome level. The traits exhibited within avian orders tend to become more dissimilar as species richness increases, with the notable exception of the Passeriformes, an order containing around 60% of the total avian species richness but occupying a region of morphospace expected of a clade two orders of magnitude smaller. The Passeriformes also possess remarkable vocal morphology and behavior, and thus I spend the next three chapters of this thesis focused on the role of social processes in avian evolution. In Chapter 3, I use detailed morphological and vocal trait data from the suboscine family Furnariidae to demonstrate that social traits evolve faster and with less regularity than ecological traits. I then in Chapter 4 examine the social and ecological drivers of female song in birds, a widespread trait whose persistence challenges traditional sexual selection theory. I find that the separate drivers of male and female song can be explained by social selection theory, a framework which encompasses all social interactions above and beyond competition for mating opportunities. In Chapter 5 I apply this concept of social selection to macroevolutionary studies, using sex-specific song behaviors to separately investigate the roles of social and sexual selection on speciation and extinction rates. I demonstrate that lineages with male-only song (sexual selection) diversify faster than lineages with both male and female song (social selection). This result suggests that social selection theory may inform the controversial relationship between sexual selection and diversification. Finally, in Chapter 6 I look at the role of dispersal in modulating these speciation and extinction rates. Using data from the wing morphologies of 26,043 individuals from 6,028 species, I test the 'intermediate dispersal hypothesis', hitherto only examined at small scales, across the order Passeriformes, revealing that the highest rates of diversification are indeed found in lineages with an intermediate capacity for flight. When birds that defend year-round territories are considered separately from non-territorial birds, however, the intermediate dispersal hypothesis only holds for territorial birds, demonstrating the importance of considering the ecological context of traits in macroevolutionary studies. Together, my results present evidence that both social and ecological processes facilitate the generation and maintenance of biodiversity in birds.
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Schwartz, Brian A. "Sex-specific investment in incubation and the reproductive biology of two tropical antbird." [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-05072008-151032/unrestricted/MSc_Thesis_Brian_A._Schwartz2008.docx.
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Wood, Matthew James. "Parasites, reproductive costs and sexual selection : studies of the European blackbird Turdus merula and the great tit Parsus major." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340166.
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McKeown, Jennifer J. "Modelling the evolution of sexual behaviour." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21823.
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This thesis presents two studies where natural and sexual selection have interacted to evolve sexual behaviours. The thesis uses mathematical modelling to understand how these forces have caused each behaviour to evolve. This is useful because the results allow for reflection on the potential role of sexual selection in adaptation of these species to a changing environment. The first study is of early male arrival to spring breeding grounds in migratory avian species, this is termed protandry. The study explores the main hypotheses for avian protandry and then tests the susceptibility of each hypothesis to changing environment. The second study is of convenience polyandry in species where there is conflict over mating rate. Females have multiple strategies to avoid harassive males but strategies vary in cost and success rate; she must balance her strategy use to minimise her fitness depreciation. The study identifies the main factors that cause convenience polyandry to evolve and paves the way for future studies to investigate if sexual selection over resistance strategy provides these species a future advantage in adaptation to a changing environment.
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Gluckman, Thanh-Lan. "The mechanisms underlying convergent evolution in the plumage patterns of birds." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/247220.
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Convergent evolution is a central theme in biology. Birds are an ideal system to examine the mechanisms underlying convergent evolution. Although bird patterning is diverse, within-feather patterns have repeatedly converged on the same four types: mottled patterns, scales, bars and spots. Other avian patterns occur, e.g. stripes, but are rare. In my thesis I examine the four main mechanisms underlying convergent evolution in plumage patterns: evolutionary genetics, evolutionary development, natural selection for signaling and camouflage. Japanese quail (Coturnix japonica) is a model system in developmental biology. Examining the developmental basis of pattern formation using molecular techniques, the dorsal patterning of embryonic quail is likely due to activation of the melanocortin-1 receptor, which is a highly conserved pathway in vertebrates. I examined whether a reaction-diffusion based theoretical model of pattern formation may predict developmental constraint in two groups that have different lifestyles and spectacular patterns: waterfowl (Anseriformes) and gamebirds (Galliformes). Tracing the evolutionary trajectory of pattern evolution with Bayesian comparative modeling there was evidence for developmental constraint in pattern evolution. Adaptive explanations may also result in convergence. Cuckoo-hawk mimicry has been demonstrated in the common cuckoo (Cuculus canorus) and the Eurasian sparrowhawk (Accipiter nisus), but may be prevalent in Old World cuckoos. Randomly selecting a parasitic cuckoo from each genera of Old World cuckoos and <8 sympatric raptors, I quantified their barred patterns using digital image analysis and found that parasitism can explain convergent evolution in the patterns of parasitic cuckoos and raptors. Patterns may have evolved due to ecological selection. Examining the patterns of 80% of all avian species worldwide, I found that habitat does not predict patterning, and that all four patterns are found in all habitats. These results demonstrate that the mechanisms of convergent evolution are diverse, and that development and natural selection have contributed to pattern evolution.
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Lees, John. "Seasonal adaptations in the energetics and biomechanics of locomotion in the Svalbard rock ptarmigan (Lagopus muta hyperborea)." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/seasonal-adaptations-in-the-energetics-and-biomechanics-of-locomotion-in-the-svalbard-rock-ptarmigan-lagopus-muta-hyperborea(867ab906-4d06-4500-a4dc-ac6d27bc1965).html.
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One of the most striking things about many animals is that they can be defined by the ways in which they move. Moving costs metabolic energy and is a significant contributor to the daily energy balance of organisms and therefore fitness. Balancing energy needs is critically important to species inhabiting areas of limited resources. The metabolic cost of locomotion is influenced by physiological, morphological and behavioural factors that vary across species. The influence of these factors within species is less well understood. The objective of my PhD is to elucidate the potential for variation in locomotor performance, in particular the energy consumed and the biomechanics of locomotion within a species, in response to differences in season, sex, age and the nature of the terrain. The Svalbard ptarmigan (Lagopus muta hyperborea) is the only year-round avian resident of the Arctic archipelago of Svalbard. Svalbard is characterized by extreme photoperiodic and climatic conditions, with 24 hours of daylight in summer and continuous darkness in winter, when ice makes food unpredictable. As a result, ptarmigan annually gain significant fat stores, as much as doubling their body mass in winter. The consequences of such large gains in mass upon the metabolic cost and biomechanics of terrestrial locomotion are yet to be quantified. The Svalbard ptarmigan represents a unique opportunity to gain insight into avian adaptations.Using respirometry, I present evidence that winter birds are able to carry their fat stores at no metabolic cost. Using kinematic and force plate data, I show that acquiring fat results in reduced locomotor performance in terms of speed and take-off ability. As well as exhibiting phenotypic variation, male and female Svalbard ptarmigan are behaviourally very different. I present evidence that these behavioural differences are reflected in the metabolic cost of locomotion. In particular, males are both more efficient and faster than female birds during both summer and winter. I suggest that this results from sexual selection upon male locomotor performance. Furthermore, I present data demonstrating that sub-adult males experiencing their first winter possess the same metabolic and speed capabilities of adults. These data may indicate that selection for improved male locomotor performance may act upon sub-adult birds. Regardless of season, age or sex, Svalbard ptarmigan must locomote on a predominantly sloping terrain. The influence of inclines upon the metabolic cost of locomotion in birds is poorly understood. I provide evidence that at the same degree of incline, the cost of lifting 1 kg by 1 vertical metre is similar regardless of season and is therefore dictated by increased positive work. However, this cost varies according to the degree of incline and may be influenced by gait.The principal findings of the 5 first author papers presented are that behavioural, physiological and morphological variation within a species can have significant impacts upon the metabolic cost of locomotion and other aspects of locomotor performance. The potential for intraspecific differences should therefore be taken into account in future research regarding the patterns of energy expenditure in animals.
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Cardoso, Gonçalo Canelas. "Evolução de características sexuais secundárias no género Serinus (aves, Fringillidae) : canto e coloração." Doctoral thesis, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 2005. http://hdl.handle.net/10400.12/1620.
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Tese de Doutoramento em Biologia, especialidade de Ecologia, apresentada à Faculdade de Ciências e Tecnologia, Universidade de CoimbraEstudámos a dinâmica evolutiva e aspectos selectivos das duas características sexuais secundárias mais proeminentes em passeriformes – canto e coloração – por meio de experimentação no serino (Serinus serinus) e de análises comparativas no género Serinus. A velocidade e frequência aguda das canções de serino são extremas quando comparadas com as restantes espécies do género, o que sugere evolução por selecção sexual. Em experiências comportamentais, fêmeas de serino manifestaram preferência por canções agudas; canções rápidas, pelo contrário, inibiram as respostas das fêmeas. Os machos de serino não discriminaram quanto à frequência das canções, mas foram inibidos por canções rápidas. Estes resultados sugerem pressões selectivas distintas: a evolução da frequência de canto é compatível com um processo de selecção inter-sexual, e a velocidade das canções parece ser um sinal agonístico, passível portanto de selecção intra-sexual. Documentamos um padrão de diversificação evolutiva intensa do canto no género Serinus, que se sobrepõe a constrangimentos vocais importantes. A evolução do canto neste género foi apenas parcialmente acompanhada por adaptação vocal às características das canções nas diferentes espécies. Tal deve-se, pelo menos em parte, ao facto de várias espécies evoluírem características de complexidade silábica em relação às quais detectámos custos de produção vocal fortes. Diferentes sintaxes de canto correlacionam-se com aspectos distintos de desempenho vocal, o que sugere formas de selecção indirecta sobre a sintaxe. A coloração apresenta um padrão de evolução intensa em ambos os sexos de Serinus spp., como é típico de características sexualmente seleccionadas. Mostramos que a coloração conspícua em fêmeas evoluiu sobretudo por constrangimento sexual, pelo que advertimos contra a inferência de causalidade evolutiva a partir do valor adaptativo presente de ornamentos femininos. Os principais eixos de complexidade do canto e elaboração da coloração estão fortemente correlacionados entre as espécies de Serinus, e tendem a variar com aspectos do habitat que indicam maior intensidade de selecção sexual, sugerindo que selecção sexual é o processo selectivo mais determinante na sua evolução.
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Cooney, Christopher Richard. "Global patterns and processes in avian diversification." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:cf2dcbf2-892f-48e3-97b2-70a25d2a20fd.
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The natural world consists of a vast array of forms, some more plentiful than others, yet our understanding of the processes responsible the production of biological diversity remains surprisingly limited. Here I combine novel datasets with powerful phylogenetic modeling techniques and computer simulations to test the effects of both biotic and abiotic factors on the dynamics of species radiations and the evolution of organism traits in birds. In the first part of this thesis, I develop our understanding of the importance of abiotic factors for diversification by showing that in the early stages of lineage diversification at least, rapid adaptation to novel climatic conditions is likely to represent a prominent driver of avian diversification. In the second part I concentrate on the role of biotic factors, in particular that of sexual selection. I show that not only is sexual selection associated with accelerated rates of speciation and secondary sympatry—as well as faster rates of net diversification across the entire avian tree of life—but also that across-species variation in rates of phenotypic evolution is best understood with reference to the focus and intensity of sexual selection. Finally, given that the relative importance of such processes appears to vary predictably across latitudes, in the final part of the thesis I argue that latitudinal differences in the speciation process offers a potentially powerful explanation for conflicting viewpoints regarding the contribution of speciation to high tropical diversity. Overall, this work provides fresh insight into the processes governing broad-scale patterns in biodiversity.
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Kimball, Scott Allen. "Mating System Dynamics in Passerine Birds." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1242317441.
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Fargevieille, Amélie. "Sélection sexuelle et évolution des ornements femelles : une étude de la coloration du plumage femelle utilisant des analyses comparatives et des jeux de données à long terme issus de populations de mésange bleue (Cyanistes caeruleus)." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT127/document.
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Les traits ornementaux sont classiquement vus comme un attribut des mâles chez les espèces animales. Cette vision est liée à un rôle considéré historiquement comme très asymétrique des sexes, avec les mâles qui entrent en compétition (sélection intra-sexuelle) pour attirer les femelles qui choisissent (sélection intersexuelle) le meilleur partenaire. Cette idée fut développée en liaison avec l’asymétrie dans la production des gamètes mâles et femelles. Les femelles, qui produisent un nombre réduit de gamètes de grosse taille, maximisent la chance de survie de leurs descendants en investissant plus dans les soins parentaux ; elles deviennent ainsi le sexe limitant et choisissent les mâles qui entrent donc en compétition pour avoir accès à la reproduction. Tout trait ornemental qui augmente le succès d’appariement sera donc avantageux pour les mâles conduisant à des traits sexuels secondaires plus développés chez ce sexe. Si les traits ornementaux sont fréquents chez les mâles, il existe également de nombreux exemples chez les femelles, notamment chez les espèces socialement monogames à soins biparentaux. C’est seulement récemment que les biologistes évolutifs ont cherché à tester les processus expliquant l’apparition et le maintien des ornements femelles. Si le rôle de la corrélation génétique dans cette évolution est incontestable, et que la sélection sociale est aussi majeure, plusieurs études empiriques ont montré un choix mâle pour les ornements femelles et des modèles théoriques ont déterminé les paramètres conduisant à l’évolution du choix mâle. Par ailleurs, les approches phylogénétiques retraçant l’évolution des ornements ont montré une forte labilité des traits femelles, avec des apparitions et disparitions de traits ornementaux plus fréquentes chez les femelles que chez les mâles. Afin de mieux comprendre la relation entre la sélection sexuelle et l’évolution des ornements femelles, cette thèse s’est construite sur ces résultats précédemment acquis et a mené plusieurs approches pour mieux préciser le rôle de la sélection sexuelle dans l’évolution et le maintien de la coloration chez les femelles. Une approche comparative à l’échelle des passereaux a testé les paramètres déterminés comme conduisant à l’évolution du choix mâle par des modèles théoriques. En accord avec les modèles théoriques, les résultats mettent en avant l’importance de l’investissement du mâle dans les soins parentaux dans l’évolution de la coloration du plumage femelle. Ils montrent également comment l’investissement initial des femelles dans la reproduction limite l’évolution de la coloration femelle. Un autre axe de la thèse s’est focalisé sur la coloration chez une espèce monogame, la Mésange bleue Cyanistes caeruleus, en utilisant un vaste jeu de données à long terme avec10 ans de donnés dans quatre populations pour tester notamment(i) la force de la corrélation génétique, (ii) les liens entre indices de succès de reproduction et coloration et (iii) l’existence d’un appariement par homogamie chez cette espèce. Si les résultats principaux montrent une forte corrélation génétique et soulignent une très forte variation spatiotemporelle, l’application d’outils méta-analytiques a permis de déceler une relation entre les colorations des femelles et les indices de succès de reproduction ainsi qu’un patron faible mais positif d’appariement par homogamie pour les deux patchs étudiés (couronne et bavette). Les deux volets de la thèse représentent de nouveaux apports en faveur de l’évolution des ornements femelles. Ils soulignent la complexité associée à leur évolution et l’importance de prendre en compte la variation spatiotemporelle pour une compréhension étendue et une possibilité de généralisationOrnamental traits are classically associated with males in animal species. The asymmetrical view is related to sex roles, in which males are competing (intra-sexual selection) to attract females which chose the best mate (intersexual selection). This idea was developed with the concept of anisogamy, the asymmetry in the production of male and female gametes. Females producing few but large gametes maximize their offspring survival rate by investing more in parental care; they become the limiting sex and chose males which are thus competing for access to reproduction. Then, any ornamental trait increasing pairing success would become advantageous for males, leading to more developed secondary sexual traits in this sex. If ornamental traits are more frequent in males, there are also many examples with females, especially in socially monogamous species with biparental care. Evolutionary biologists have only started recently to test processes explaining the outbreak and maintenance of female ornaments. Genetic correlation is an unquestionable process involved in this evolution, and social selection is also a major process. Several empirical studies have also related male mate choice to female ornaments and theoretical models have defined key parameters driving the evolution of male mate choice. Furthermore, phylogenetical studies retracing the evolution of ornaments have showed a high lability in female traits, with more frequent gains and losses of ornamental traits in females compared to males. In order to link sexual selection to the evolution of female ornaments, this thesis was based on these previous achievements to develop different approaches to better understand the role of sexual selection in the evolution and maintenance of female colouration. Comparative methods in songbirds tested the key parameters defined by theoretical models as driving the evolution of male mate choice. In line with theoretical models, results highlight the importance of male investment in parental care in the evolution of female plumage colouration. They also show how female initial investment in reproduction limits this evolution. Another thesis axis focused on colouration in a monogamous species, the Blue tit Cyanistes caeruleus, using a large dataset across 10 years in four populations and tested in particular (i) the strength of genetic correlation, (ii) relations between proxies of reproductive success and colouration and (iii) the existence of assortative mating in this species. The main results highlight a strong genetic correlation and a wide spatiotemporal variation and the use of meta-analyses revealed correlation between female colouration and proxies of reproductive success as well as a weak but positive pattern of assortative mating on the two measured patches (crown and chest). Both sides of the thesis represent new insights in favour of the evolution of female ornaments. They also highlight the complexity associated with their evolution and the importance of considering spatiotemporal variation for extensive understanding and generalisation
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Nooker, Jacqueline Kay. "Factors affecting the demography of a lek-mating bird: the greater prairie-chicken." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/375.
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Lindström, Karin M. "Bird-parasite interactions : Using Sindbis virus as a model system." Doctoral thesis, Uppsala University, Department of Evolutionary Biology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-486.
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This thesis focuses on the evolutionary interactions between birds and a parasite, the mosquito-borne Sindbis virus (Togaviridae, Alphavirus). In conclusion, the results show that the Sindbis virus is widespread among birds, and that the fitness of infected hosts may be reduced by the virus. Furthermore, viruclearance ability was revealed by male plumage traits, and viraemia was related to hormonal- and social status.
The distribution of Sindbis virus infections among passerine birds was examined in five areas in Sweden. Almost all species tested were infected, and three species of thrushes weridentified as the main hosts. In a series of experimental infections, greenfinches (Carduelis chloris) kept in aviaries were used ahosts. First, the behavioural consequences of an infection were investigated. During the infection, birds tended to reduce thespontaneous locomotion activity, and when escaping from a simulated predator attack, infected birds had reduced take-off spee Furthermore, when comparing virus clearance rate between male greenfinches, I found that males with large yellow tail ornaments hafaster virus clearance rates as compared to those with smaller ornaments. Thus, male virus clearance ability was honestly revealed by the size of an ornament. Moreover, males with experimentally elevated testosterone levels experienced a delayed, but not increased viraemia as compared to controls. When the relationship between male social ranand viraemia was examined, I found no evidence that high-ranked males suffered reduced rank during the infection. Nevertheless, viraemipatterns of males were related to their social rank, so that low-ranked birds had a delayed viraemia as compared to high-ranked birds.
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Ekblom, Robert. "Immunoecology of the Great Snipe (Gallinago media) : Mate Choice, MHC Variation, and Humoral Immunocompetence in a Lekking Bird." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4585.
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Cimiano, Lavin Philipp. "Sexual selection in GAs." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9578215.
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Smith, C. A. M. "Sexual selection in yeast." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1336210/.
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Saccharomyces yeasts are unique as a model system in evolutionary biology. They offer all the traditional benefits of fast generation times and easy maintenance found in other microbes such as Escherichia coli. In addition, Saccharomyces are diploid eukaryotes capable of asexual and sexual reproduction. In this thesis I develop Saccharomyces as a model organism for the study of sexual selection. I show that its mating pheromone is costly to produce and maintain, and that this cost is greater for lower quality individuals. This suggests that the pheromone may have evolved as a sexual signal under the Handicap Principle. I show that size can offer direct benefits during mating and that these are in fact selected for. I show that preferential mating also takes place to help clear deleterious mutations from a population. I also investigate mating barriers in yeast to better understand how yeast mating may take place in nature.
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Lewis, Zenobia. "Sexual selection and sexual conflict in the Lepidoptera." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417749.
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Lorch, Patrick D. "Life history and sexual selection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0028/NQ50024.pdf.
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Bjork, Adam Clarence. "Postcopulatory sexual selection in Drosophila." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2006. http://proquest.umi.com/login?COPT=REJTPTU0NWQmSU5UPTAmVkVSPTI=&clientId=3739.
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Higgins, Sahran Louise. "Sexual selection and insect genitalia." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/83254.
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Sexual selection is generally accepted as being responsible for the rapid and divergent evolution of male genitalia and other primary reproductive characteristics in internal fertilisers, such as testes size and sperm length. Selection can act via three main processes: sperm competition, cryptic female choice and sexual conflict, however very few studies have directly addressed the patterns of selection, the degree of phenotypic and genotypic variability expected in genital morphology or the degree to which intromittent genitalia are dependent on male condition. The seedbug, Lygaeus equestris has greatly elongated intromittent genitalia, being almost as long the body. Here I determine whether this is a sexually selected trait and further assess the degree of genetic and phenotypic variability in the greatly elongated male intromittent organ in relation to other morphological components. Further to this, patterns of inheritance and allometry of such exaggerated genitalia were investigated, and of the degree of condition dependence of genital and general morphology was experimentally assessed by varying food availability during ontogeny. Finally, using experimental evolution, I manipulated the level of sexual selection by biasing adult sex-ratio (male-biased, equal-sex, female biased) and investigated potential correlated evolution of female reproductive morphology and fertile (eupyrene) and non-fertile (apyrene) sperm length and numbers in the Indian meal moth, Plodia interpunctella. The main findings indicated that genital length was sexually selected in L. equestris being negatively related to male fertilisation success and that there was great phenotypic variation in genitalia both across and within populations. Genital length was negatively allometric, in spite of being hugely elongated, and was significantly heritable with considerable evolvability. It was also evident that there was genetic variation in the condition dependence of genital length with a significant genotype-by-condition interaction and much reduced genetic variation in genital length in the poor food treatment. Male and female primary sexual traits of P. interpunctella were also shown to covary, but this pattern did not differ across treatments. Taken together, the results presented in this thesis do not support traditional hypotheses of genital evolution and instead suggests that male intromittent genital length of L. equestris is sexually selected in a similar way to secondary sexual characteristics. This is also true when examining primary sexual traits in P. interpunctella and further highlights the false dichotomy between primary and secondary sexual traits.
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Sharma, Manmohan Dev. "Sexual selection in Drosophila simulans." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/3003.
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Over the last 100 years sexual selection has advanced into a vast field of theoretical and empirical research. While Darwin’s idea of female preference being an integral mechanism of sexual selection is no longer debated, our understanding of female preference is still very limited. For example, we know little about the genetic variation in female preference, and the costs of preference over and above the costs of mating with particular male phenotypes. Additionally, while costs of mate choice are well documented, the benefits of mate choice and their implications are still debated. For example, controversy exists over the inevitability of good gene benefits and their capability to promote adaptive sexual selection. Furthermore, the adaptiveness of sexual selection itself is debated. Our understanding of the traits involved in mate choice is also far from complete. Here I investigated aspects of sexual selection in Drosophila simulans, employing a range of behavioural approaches along with artificial selection and environmental manipulations. The findings presented here indicate that female preference can evolve when directly selected on, and that preference itself is not particularly costly. There was also no conclusive evidence for the good genes benefits of mate choice in D. simulans. These benefits are considered crucial in promoting the adaptiveness of sexual selection, and although we found sexual selection to be adaptive under some test conditions it was not adaptive in other conditions. Our investigations into traits involved in mate choice established sex-specific genetic variation in cuticular hydrocarbons and the genetic architecture of this trait was found to sex-specific evolution of cuticular hydrocarbons under natural and sexual selection. Additionally, we found that a secondary sexual character, the sex combs was positively allometric – just like most signalling and weapon traits, and there was no association between trait fluctuating asymmetry and trait size. These findings collectively indicate that sexual selection in D. simulans is consistent with classical models of this process.
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Stirrat, Michael. "Sexual selection and trust games." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1014.
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In economic games the facial attributes of counterparts bias decisions to trust and decisions to enter play. We report research supporting hypotheses that trust and reciprocation decisions in trust games are biased by mechanisms of sexual selection. Hypotheses that trust game behaviour is modulated by inter-sexual competition were supported. 1) Attractive individuals elicit more cooperation. 2) Male participants display trust and reciprocation toward attractive female counterparts in excess of perceived trustworthiness (and this display is modulated by male self-reported physical dominance). 3) Female participants appear to respond to male trust as a signal of sexual interest and are therefore more likely to exploit the trust of attractive males. 4) In explicitly dating contexts females are more likely to prefer attractive males to pay for the meal. These results indicate that participants are biased by mate choice and mating display considerations while playing economic games in the lab. Hypotheses that trust game behaviour is modulated by intra-sexual competition for resources were also somewhat supported. 1) Male participants reporting an ability to win fights with same-sex peers are more exploitative of other males. 2) Cues to current circulating testosterone level in counterpart’s faces are less trusted but elicit more reciprocation. 3) The male sexually dimorphic trait facial width-to-height ratio (a trait which is related to both aggression and dominance) is related to an increased proportion of decisions to exploit others in the trust game while also being used by others as a cue to untrustworthiness. We conclude that trusting and trustworthy behaviour in both sexes is biased by mating market considerations predicted by intra- and inter-sexual selection.
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Grieshop, Karl. "Sexual conflict, sexual selection, and genetic variance in fitness." Doctoral thesis, Uppsala universitet, Zooekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327304.
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Understanding sex-specific genetic variance for fitness is of fundamental importance to our understanding of evolution. This thesis presents the findings of empirical investigations into sex-specific genetic variance in fitness. The findings are discussed in terms of their implications for our understanding of the classic evolutionary paradoxes of what maintains genetic variance in fitness and what maintains sexual reproduction, as well as more specific implications regarding adaptation and population viability. Males and females reproduce and accrue fitness in fundamentally different ways, which inevitably comes at a detriment to the fitness of individuals of the opposite sex. This is known as sexual conflict, and because males and females use largely the same genome to develop, grow and reproduce, a genetic tug-of-war ensues. Alternative alleles at sexually antagonistic (SA) genes have opposing fitness effects in males and females. The consequence of this genetic tug-of-war is that alternative allelic variants at SA loci can be maintained in the population. Such SA genetic variation can therefore maintain genetic variance for fitness. Variance in fitness can also be maintained by a constant influx of mutations with weakly deleterious effects and weak selection against them, in what is referred to as mutation-selection balance. Because the average deleterious mutation will be detrimental to both sexes, this source of genetic variance in fitness will have predominantly sexually concordant (SC) effects. This thesis uses a wild-caught population of the seed beetle Callosobruchus maculatus to investigate these two mechanisms of maintaining genetic variance in fitness, as well as the consequences they bear on adaptation, population viability, and the maintenance of sexual reproduction. Results largely support much of the theoretical expectations for sexual conflict, sexual selection and maintenance of genetic variance in fitness, as well as stimulate new thoughts and hypotheses about the nature of SA genetic variation and its interaction with weakly deleterious partially recessive mutations.Vår kunskap om könsspecifik selektion och genetisk variation för fitness är central för förståelsen av evolutionära processer. I den här avhandligen presenteras resultaten av empiriska undersökningar av just könsspecifik genetisk variation för fitness. Resultaten diskuteras med fokus på deras betydelse för de klassiska evolutionära paradoxerna angående vad som bibehåller genetisk variation i fitness och varför organismer som förökar sig sexuellt är så vanliga, men även mer specifika konsekvenser för en populations anpassningsförmåga och livskraftighet avhandlas. Evolutionen har ofta gynnat olika reproduktiva strategier hos hannar och honor, och dessa strategier kan medföra kostnader för det motsatta könet. Den könskonflikt som uppstår på grund av detta kan också inbegripa en genetisk dragkamp eftersom könen delar genetisk arvsmassa men gynnas av olika anpassningar. Konsekvensen är att alternativa varianter av gener gynnas hos honor och hanar, vilket resulterar i en form av balanserande selektion som kan bibehålla genetisk variation i en population. Genetisk variation i fitness kan även upprätthållas genom en jämvikt mellan ett konstant inflöde av genetisk variation via mutationer med svagt negativ effekt och svag selektion mot dessa mutationer. Eftersom en negativ mutation normalt kommer vara skadlig för båda könen kommer den här typen av källa till genetisk variation i fitness ha liknande effekt hos könen. I arbetet med denna avhandlig har jag använt en vilt infångad population av fröbaggaen Callosobruchus maculatus för att undersöka dessa två underliggande mekanismer bakom upprätthållandet av genetisk variation för fitness, samt vilka potentiella konsekvenser de kan ha för en populations anpassningsförmåga och för bibehållandet av sexuell reproduktion. Resultaten i denna avhandling stödjer i stort många av de antaganden som ligger till grund för teorin om könskonflikter, sexuell selektion och vad som upprätthåller genetisk variation för fitness. Resultaten ger också upphov till nya idéer och hypoteser angående genetisk variation med könsspecifika effekter och dess interaktion med partiellt recessiva negativa mutationer.
The alternative abstract I uploaded should be used as the Swedish summary.
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Andersson, Måns A. "Physiological trade-offs in reproduction and condition dependence of a secondary sexual trait /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5091-1/.
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Breault, Andre Mario. "Breeding distribution, habitat selection and factors affecting coloniality in eared grebes in British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28922.
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In this study, I first describe distribution and abundance of breeding Eared Grebes {Podiceps nigricollis) in British Columbia. Second, I characterize and examine the relationships between nesting habitat and nest site selection on breeding group size. Finally, I. examine effects of colony size, nesting chronology and nesting synchrony on reproductive success at Eared Grebe colonies.
I surveyed 421 wetlands in 1985 and 1986 and located 47 lakes used by nesting Eared Grebes. Those 47 lakes accomodated from a low estimate of 1761 to a high estimate of 4474 pairs. Breeding abundance, calculated from adult, nest and young counts, ranged from single pairs to more than 590 pairs per lake. Breeding took place in shallow lakes of various sizes, subject to extensive variations in water levels. Breeding abundance was positively correlated with lake area. Fewer breeding pairs utilized nesting areas close to shore (in shallower water) than nesting areas far from shore (in deeper waters). Nesting areas close to shore were found in smaller lakes and were used less often in consecutive years than nesting areas far from shore, presumably because of lower habitat predictability. An experiment with unattended artificial nests showed that nest predation was higher far from shore than close to shore. Nesting areas close to shore were used by small groups. These maximized concealment by being located in denser vegetation. Nesting areas far from shore were used by larger groups and were
located in more open areas.
On both years, adults arrived at nesting lakes in April and May, started laying on 27 May and departed from, nesting areas in late July and- early August. Nesting was significantly earlier and reproductive success per pair was significantly higher in 1985 than in 1986. A .stepwise multiple regression examined effects of colony-size, synchrony and chronology on nesting success. Only nesting chronology accounted for differences in nesting success. Late nesters were not birds attempting to renest. Instead, there appeared to be qualitative differences across colonies that were related to ages of breeders.
Eared Grebe colonies are likely not formed from passive aggregation at limiting resources and there are likely no foraging benefits from colonial nesting. Nesting colonies could increase detection and mobbing of predators, but no evidence supported this. Anti-predator benefits of coloniality might have been masked by differences in breeding chronology and synchrony, or were missed because of low sample size.Science, Faculty of
Zoology, Department of
Graduate
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Green, Andrew J. "Sexual behaviour and sexual selection in three species of amphibians." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253312.
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Linklater, Jon Robert. "Mechanisms underlying sexual selection and sexual conflict in drosophila melanogaster." Thesis, University College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498490.
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Hillgarth, Nigella. "Parasites and sexual selection in pheasants." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291290.
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Bazyan, Saloume. "Sexual selection and extinction in deer." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-211535.
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By performing a comparative analysis and using phylogenetic relationships of the Cervidaefamily this study aimed to address whether or not sexual selection may play a role in the extinctionof species by making species more vulnerable to extinction. The role of sexual selection in makingspecies more vulnerable to extinction is largely unexplored, and several factors such as ecologicaland life history traits may increase the risk of extinction.In all species of the family Cervidae (Gilbert et al. 2006, Geist 1998,Groves and Grubb2011,Meijaardand Groves2004,Price et al. 2005, Goss 1983) sexually selected characters plays amain role in determining species status and thus potentially their probability of extinction. In thisstudy the intensity of sexual selection (measured as sexual size dimorphism, antler size and matingsystem) and the rate of extinction (IUCN classification and anthropogenic effect) were counted asfactors to determine the role of sexual selection intensity in both species-rich and species-poorclades.By using the programme MESQUITE and phylogenetic trees, the results show an associationbetween species with larger body size and dimorphism, living in open habitats and having largerantler size expanded to more than three tines; such species are mostly non-territorial and formharems during the rutting season. The small species are territorial, live in closed habitats, aremonomorphic and have small antler size limited to two tines or less. Moreover species that aremore subjected to habitat degradation and anthropogenic effects tend to become smaller in size.Extinction risk for the species-rich clades with small sized, territorial and small antler sizedspecies is lower than for those consisting of species with larger antler size, larger body size, livingin open habitats and using harems as mating system.To sum up, the intensity of sexual selection in larger species in deer family put them in risk ofextinction; but on the other site, small species are more adapted to the environment by choosingdifferent strategy in mating system, and reducing antler and body size thus diminishing theextinction risk.
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Brown, Denise. "Postcopulatory sexual selection in Callosobruchus maculatus." Thesis, University of Sunderland, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341308.
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Bretman, Amanda Julia. "Sexual selection in a field cricket." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410630.
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Hayward, John. "Models of speciation by sexual selection." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364220.
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Suedkamp, Wells Kimberly M. "Resource selection, movement patterns, and survival of post-fledging grassland birds in Missouri." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://edt.missouri.edu/Winter2005/Dissertation/SuedkampWellsK-051105-D1298/research.pdf.
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Shuker, David Michael. "Sexual selection and sexual conflict in the seaweed fly, Coelopa frigida." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285745.
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Morrish, Daniel James. "The influence of inbreeding and parasites on sexual behaviour in birds." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611674.
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Serrano, Meneses Martin Alejandro. "Sexual size dimorphism in damselflies, dragonflies and birds : function and development." Thesis, University of Bath, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434068.
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Ingleby, Fiona Caroline. "Genotype-by-environment interactions and sexual selection." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3881.
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Genotype-by-environment interactions (G x Es) describe genetic variation for phenotypic plasticity, such that the relative performance of genotypes varies across environments. These interactions have been studied in the context of natural selection for decades, but research interest in the evolutionary consequences of G x Es in sexual traits is more recent. Theory suggests that G x Es in sexual traits could be of fundamental importance to the operation of sexual selection across heterogeneous environments, but empirical research lags behind the theory. In this thesis, I review the current literature on the role of G x Es in sexual selection and identify areas for further research. Using cuticular hydrocarbons (CHCs) in the fruit fly Drosophila simulans as a model system for sexual selection, I examine G x Es in trait expression and quantify the effect of these G x Es in terms of sexual signal reliability and the coevolution of male and female sexual traits. To do so, I use a combination of quantitative genetics and laboratory environmental manipulations. First, I demonstrate that male CHC profile is subject to sexual selection through female mate choice and find some variation in patterns of mate choice across diets and temperatures (Chapter 3). Next, I identify G x Es in male and female CHC expression across diets and temperatures, although G x Es in male CHC profile across temperatures are weak (Chapter 4). I find that G x Es in male CHC expression can cause sexual signal unreliability, as predicted by theory, since male CHCs do not reliably signal heritable aspects of male attractiveness across diets and temperatures (Chapter 5). I also find G x Es in some aspects of female mate choice across temperatures (Chapter 6). In spite of the evidence for signal unreliability and variation in female mate choice across environments, I show that the overall outcome of mate choice is unaffected by G x Es, such that the same male genotypes are attractive across diets and temperatures (Chapters 5 and 6). From my results, it seems likely that females assess male attractiveness based on multiple male sexual signals, so that whilst male CHCs influence mate choice, CHC profile does not necessarily correlate well with overall male attractiveness. I discuss the implications of these results for the evolution of sexual traits and the genetic covariance between male and female sexual traits across environments. The research in this thesis highlights the importance of multivariate studies of sexual selection across environments for a more complete understanding of the evolution of sexual traits.
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Pomiankowski, A. N. "Sexual selection : 'good genes' or 'aesthetic' preference." Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380527.
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Mendonca, Tania. "Shedding light on post-copulatory sexual selection." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19308/.
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Fertilisation requires one sperm. The selection of the 'winning' sperm out of the millions inseminated into the female is not determined by a simple lottery, but rather a complex set of interactions between sperm and the female reproductive tract. These post-mating interactions, collectively termed post-copulatory sexual selection (PCSS), are influenced by many factors from biochemical to behavioural, making PCSS dynamic, complicated, and challenging to study. In some taxa, including birds, sperm take a surprising diversion in their long journey between copulation and conception. Females of many species can store sperm for extended periods of time in specialised storage sites within their reproductive tracts. Such storage can give females the opportunity to bias fertility outcomes through PCSS mechanisms. However, these processes occur deep within the female body, making them particularly difficult to document. A critical step towards understanding these mechanisms involves visualising them in real time, inside female tissue, under physiological conditions that are as close to natural as possible. Such visualisation is not trivial - especially in birds - due to the challenges of imaging through thick, muscular tissue. In this thesis, I demonstrate the optimisation of selective plane illumination microscopy (SPIM) and the development of imaging protocols, including sample preparation and cell labelling for this novel application. SPIM is a light sheet fluorescence microscopy technique, which allowed me to optical section live oviduct tissue to reveal the three-dimensional structure of sperm storage tubules (SSTs) in zebra finch [Taeniopygia guttata] females. This imaging technique, in combination with electron microscopy, also allowed me to make volumetric observations of zebra finch sperm mid-piece structure. These studies have helped us understand the adaptive significance of these structures, as well as the functioning of SSTs and the possible sperm-female interactions that occur inside them.
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Jones, Theresa Melanie. "Sexual selection in the sandfly Lutzomyia longipalpis." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1997. http://researchonline.lshtm.ac.uk/1416606/.
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In this thesis I address several fundamental questions in sexual selection and mate choice theory, using the sandfly Lutzomyia longipalpis. I show that L. iongipalpis satisfies the criteria for a lek-breeding species. Males aggregated at sites near hosts which females visited to mate and feed, but a male's access to a resource did not appear to detennine his mating success. Females were free to reject unwanted males and male mating success was typically skewed. Field data suggest that the mating system may have evolved because of female preferences for larger leks, coupled with a hotspot-type mechanism: male distribution was correlated with resources availability, while females distribution was correlated with lek size. In the laboratory, females preferentially mated with middle-aged males. Within this age class, mating success was correlated with increased amounts of pheromone and increased investment in wing-fluttering. Across age classes, females appeared to gain a direct fitness payoff from their choice of mate through increased probability of fertilisation, but the presence of other mechanisms was not investigated. By testing simultaneously the predictions of current models using similar age males, I was able to assess their relative importance for the maintenance of female choice. I found weak evidence to support direct benefits: females that chose to mate with successful males survived longer post-oviposition than females with less successful mates. This did not translate into increased total longevity or increased fecundity. I found no evidence in favour of good-genes models: offspring of preferred males did not survive longer than offspring of less preferred males, nor were their daughters more fecund. Male attractiveness was, however, heritable: sons sired by preferred males achieved higher mating success than sons of less preferred fathers. These results suggest that a Fisherian mechanism is in part responsible for the maintenance of female mating preferences in L. iongipaipis.
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Martinossi-Allibert, Ivain. "Sexual Selection and Adaptation to Novel Environments." Doctoral thesis, Uppsala universitet, Zooekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332119.
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The work included in this thesis aims at exploring the environmental sensitivity of benefits and costs of sexual selection through a combined empirical and theoretical effort, to increase our understanding of the impact of environmental change on sexually reproducing populations.Can sexual selection promote adaptation to novel environments? Sexual selection for good genes should accelerate adaptation by granting higher reproductive success to individuals of high genetic quality. However, sexual conflict is a frequent outcome of sexual reproduction and may often be detrimental to population fitness. Experimental evolution has shown that the role of sexual selection in adaptation is variable, because of a complex balance between the detrimental and beneficial effects described above.The present thesis is investigating the role of sexual selection in adaptation by focusing on the sex-specific strength of selection and the intensity of intralocus sexual conflict (IaSC) in ancestral and novel environments. The sex-specific strength of selection is a valuable proxy for the benefits of sexual reproduction, since a male-bias in selection caused by sexual selection should allow efficient purging of deleterious alleles with little impact on female fecundity and cost to population fitness.This thesis investigates both sex-specific selection and IaSC across benign and novel environments in two species of seed beetles, Callosobruchus maculatus and Acanthoscelides obtectus, and includes a theoretical model of the effect of environmental change on of sexual selection. The empirical part of my results indicates that, generally, selection at the adult stage is male biased but that this male bias may be reduced under stress, pointing towards reduced benefits of sexual selection under rapid environmental change. Additional simulations suggest that the frequency dependent nature of sexual selection alone could explain this trend. No empirical support was found for the reduction of IaSC under stress.It is becoming crucial today to understand the impact of environmental change on natural populations. This thesis brings new material adding to our understanding of the role of sexual selection within that particular issue. The outcome of sexual selection is dependent on a variety of mechanisms, such as good genes processes and sexual conflict, which are very likely to be dependent on ecological factors and specificity of the system studied. For that reason, carefully controlled experiments on laboratory systems and mathematical modelling are necessary steps that should ultimately lead to the study of similar questions in natural systems.
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Willis, Sheridan. "Sexual conflict and sexual selection in the Indian meal moth, Plodia interpunctella." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/20736.
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Sexual conflict is a powerful evolutionary force, arising due to the differing reproductive interest of the sexes. As males and females contrast in what they require to increase their own relative fitness, this creates sexual conflict. This thesis investigates sexual conflict and sexual selection in the Indian meal moth Plodia interpunctella, a species known to be under strong intralocus sexual conflict for shared life-history traits and fitness. Through the use of experimental evolution, we altered the adult mating sex ratio to either male biased or female biased. This changes the selective forces between populations that may directly impact on intralocus sexual conflict. Male biased populations were found to have increased reproductive success for both sexes with corresponding changes in shared life-history traits compared to the female biased populations. Divergence between the two treatments is further supported by male biased populations showing increased protection from a natural viral pathogen. Post-copulatory sexual selection was examined in males through the sterile male method. Males evolving under a male biased sex ratio were subject to increased selection on traits involved in sperm competition from rival males’ ejaculates, yet sired the same total number of offspring as males evolving under a female biased sex ratio. Sexual selection is a non-mutually exclusive force acting in tandem with sexual conflict, potentially causing increased reproductive success and immunity protection in the male biased populations. Fecundity selection was examined in a stock population of P. interpunctella. Lifetime fecundity was increased without corresponding changes or trade-offs with body size or longevity, two life-history traits known to be important to increased reproductive success in females. Finally, the effects of dietary protein and carbohydrates were examined using the geometric framework. Sexually antagonistic selection over macronutrients was evident, with sexes showing preference for protein and carbohydrate in opposing regions of the nutrient landscape, indicating that intralocus conflict is unlikely to have been resolved in this moth species.