• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 238
  • 39
  • 18
  • 15
  • 14
  • 12
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 2
  • 1
  • Tagged with
  • 426
  • 426
  • 92
  • 89
  • 88
  • 78
  • 61
  • 59
  • 56
  • 55
  • 48
  • 41
  • 39
  • 37
  • 35
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Ecologia comportamental reprodutiva de Diastatops obscura Fabricius (Insecta, Odonata)

Irusta, Jorge Ba?uelos 19 March 2007 (has links)
Made available in DSpace on 2014-12-17T15:36:44Z (GMT). No. of bitstreams: 1 JorgeBI.pdf: 1097245 bytes, checksum: c841c05107380380ead3a9c8500eb87f (MD5) Previous issue date: 2007-03-19 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this thesis I discuss the reproductive behaviour and ecology of the libellulid Diastatops obscura Fabricius, 1775, (Insecta: Odonata) in natural conditions. Populations of this species were studied on the middle stretch of the Pitimbu River, Parnamirim municipality, Rio Grande do Norte, Brazil, during four discontinuous periods between 2002 and 2004. The objectives include the description of strategies and behaviors of both sexes, with especial interest in the intra-male competition for territories and females, the mate selection by females and the importance of male body size and other secondary characters on their reproductive success; from an adaptationist point of view. It was observed that the behavior of males and females in the reproductive areas are interrelated : the males came earlier to compete for the best territories and the females waited the result of that competition to be fertilized by dominants males, which preferably occupied areas near the river margin. The reproductive success of males with territories on the margin, estimated by number of copulations, ovipositions and days acting as territorial, was better than obtained by more separated territorial males and by satellite males. The body size of males is an important factor for the copulation and oviposition taxes and for the number of territorial days, favoring the biggest individuals. I also discuss the apparently importance of wing brilliance and wing integrity on male reproductive success. On inter-sexual relationships, I proved that females of D. obscura participate in mate selection, rejecting non-territorial males or substituting their sperm for other of higher status / Nesta tese discutem-se os aspectos ecol?gicos e comportamentais relativos ? reprodu??o do libelul?deo Diastatops obscura Fabricius, 1775, (Insecta: Odonata), em ambiente natural. Foram estudadas popula??es dessa esp?cie no trecho m?dio do rio Pitimbu, no munic?pio de Parnamirim, Rio Grande do Norte, Brasil, durante quatro per?odos descont?nuos entre os anos 2002 e 2004. Entre os objetivos encontram-se a descri??o e compreens?o das estrat?gias e comportamentos reprodutivos de ambos os sexos, com especial ?nfase na competi??o entre os machos pelo acesso aos territ?rios reprodutivos e ?s f?meas, a escolha de parceiro pelas f?meas e a implica??o do tamanho e de outros caracteres secund?rios dos machos no seu sucesso reprodutivo; tudo desde um ponto de vista adaptacionista. Foi observado que os comportamentos de machos e f?meas nas ?reas reprodutivas est?o inter-relacionados: os machos chegam antes para competir pelos melhores territ?rios e as f?meas aguardam o resultado dessa competi??o para serem fertilizadas pelos machos dominantes, que ocupam os territ?rios na margem do rio. O sucesso reprodutivo dos machos que mant?m territ?rios na margem, estimado a partir do n?mero de c?pulas e ovoposi??es conseguidas pelas suas parceiras, comprovou-se maior do que aquele dos machos defendendo territ?rios mais afastados ou dos machos sat?lites. O tamanho corporal dos machos mostrou-se um fator importante na taxa de c?pulas e ovoposi??es conseguidas, e no n?mero de dias atuando como territorial, favorecendo em todos os casos os indiv?duos maiores. Discute-se, tamb?m, a aparente import?ncia no sucesso reprodutivo do grau de brilho nas asas dos machos e da preserva??o da integridade das mesmas ao longo do tempo. Sobre as rela??es intersexuais, comprovamos que as f?meas maduras participam da escolha de parceiro, rejeitando machos n?o territoriais ou substituindo seu esperma pelo procedente de machos de mais alta hierarquia
302

Estudo das táticas reprodutivas em duas espécies de Coenagrionidae (Odonata: Zygoptera) / Reproductive tactics study of two Coenagrionid species (Odonata: Zygoptera)

Diogo Silva Vilela 04 March 2016 (has links)
Nos estudos sobre a teoria da Seleção Sexual, as libélulas têm sido amplamente estudadas devido à grande variedade de padrões comportamentais, de coloração e táticas reprodutivas. Como forma de demonstrar táticas reprodutivas adotadas por duas espécies de libélulas, esta dissertação teve como objetivos principais: i) investigar o papel de traços secundários como a coloração corporal na competição intra-sexual de uma espécie territorial e ii) analisar se os traços corporais como tamanho e morfologia das asas predizem a tática de acasalamento adotada por machos de uma espécie nãoterritorial. Sugere-se que a coloração corporal pode predizer o resultado de lutas e também se correlacionar positivamente com a condição física dos machos territoriais de Tigriagrion aurantinigrum. Ademais, traços corporais como o tamanho e a morfologia das asas influenciam na tática reprodutiva utilizada por machos não-territoriais de Epipleoneura williamsoni. Portanto, com os resultados obtidos, conclui-se que a variação nos sinais visuais exerce um papel essencial na comunicação animal e na resolução de conflitos, indicando ainda que pode haver uma sinalização da condição física dos machos. Além disso, os resultados mostraram evidências em como diferentes táticas reprodutivas se relacionam com traços corporais como agilidade e tamanho corporal, os quais podem influenciar no sucesso reprodutivo dos indivíduos. / In studies concerning Sexual Selection theory, dragonflies and damselflies have been well studied due to their wide range of behavioral, color and reproductive tactics patterns. To demonstrate reproductive tactics adopted by two damselfly species, this study aimed to: i) investigate the role of secondary traits such as body coloration in intrasexual competition of a territorial species and ii) analyze if body traits such as size and wing morphology predicts the adopted tactic by non-territorial males. It is suggested that body coloration can predict the fight outcome and also positively correlates with males physical condition in territorial males of Tigriagrion aurantinigrum and body traits such as body size and wing morphology influence the reproductive tactic adopted by non-territorial males of Epipleoneura williamsoni. Therefore, with these results, it is concluded that the visual signalling variation plays an important role on the animal comunication and conflict resolution, which also may indicate that there is a signalling on the males physical condition. Furthermore, the results showed evidence in how different reproductive tactics are related to body traits such as agility and size, which can influence on individuals reproductive success.
303

Territorialidade de Zenithoptera lanei (Anisoptera: Libellulidae) em uma área de cerrado / Territoriality of Zenithoptera lanei (Anisoptera: Libellulidae) in an area of brazilian savana.

Fernando Geronimo Ancco Valdivia 11 September 2015 (has links)
O comportamento animal associado a características morfológicas fornece evidências para um melhor entendimento de como o comportamento sexual tem evoluído, e como os organismos podem maximizar seu sucesso reprodutivo. Fatores como tamanho, reservas de energia e outros caracteres sexuais como a coloração são essenciais para o melhor desempenho em relação a outros indivíduos da mesma espécie. Estes podem transmitir informação da qualidade do macho para outros machos co-específicos como também para às fêmeas. Esta qualidade, guarda relação com a condição física (reservas de energia) que possuem, e é necessária para ter sucesso na reprodução. Sendo a reprodução uma das mais custosas em términos energéticos em comparação a outras atividades, é de se esperar que os animais invistam a maioria das reservas no comportamento reprodutivo, o qual influencia no tipo de estratégia que eles adotam e à duração em tempo das interações relacionadas a reprodução, entre outras. Portanto indivíduos com características melhor desenvolvidas ou com boa condição física, terão uma vantagem na reprodução que os outros indivíduos da comunidade. Zenithoptera lanei é uma espécie neotropical presente no Brasil, da qual se tem poucos estudos sobre sua ecologia comportamental, sendo uns dos mais importante o realizado por Guillermo-Ferreira no 2015, para descrever as estruturas que conformam esta pruinosidade e sua função na comunicação intraespecífica. Neste estudo, descrevemos o comportamento sexual de Z. lanei (Libellulidae), com a hipótese que nesta espécie apresentam machos territoriais, e que a coloração de suas asas, o tamanho corporal e a reserva de energia (gordura) devem desempenham um papel importante na condição territorial. Assim, os machos com maior quantidade de energia e maior tamanho deveriam ganhar disputas, defender territórios e, portanto, manter a condição territorial. Além, avaliamos também se essa condição de territorialidade poderia influenciar o tempo de duração das cópulas e a oviposição pelas fêmeas. Os resultados mostraram que machos são territoriais, e esta territorialidade está relacionada com a condição física e tamanho. Sendo que, machos com maior tamanho corporal e maior quantidade de reservas de energia ganharam mais disputas e mantiveram um território. Apesar dos machos serem territoriais, não houve diferença entre a duração do tempo das interações reprodutivas para machos vencedores em comparação aos machos perdedores, indicando que o tempo de duração das interações reprodutivas não são influenciadas pela condição de territorialidade do macho. / Animal behavior associated with morphological characteristics supplies evidence for a better understanding of how sexual behavior has evolved, and how organisms can maximize their reproductive success. Factors such as size, fat reserves and other sexual characters such as coloration are essential to individual better performance in relation to conspecifics. These factors? Can bring information of the male quality to other conspecifics and females. This quality keeps relation with the physical condition (energy reserves) that they have which is required to succeed in breeding, as reproduction is one of the most expensive activity in energy cost in relation to other activities. The reproductive behavior is related to the individual fat reserves that influences, among other factors, in the condition that they adopt and to the duration in time of the related interactions to reproduction. Therefore, individuals with more developed characteristics or with better physical conditions will have an advantage in the reproduction comparing with other individuals of the community. The dragonfly Zenithoptera lanei is a Neotropical species present in Brazil, only studied so far by Guillermo-Ferreira in 2015, when structures that conform this pruinosity and his function in the intraspecific communication were described. In this study, describe the sexual behavior of Z. lanei (Libellulidae). Was hypothesized that in this species males present territorial behavior, and that the coloration of wings, body size and the energy reserves (fat) may play an important role in territorial condition and reproductive success. Thus, males with higher quantity of energy and larger size should win more disputes, defend territories and, therefore, maintain the territorial condition. In addition, was also assessed whether this condition of territoriality may influence the duration of the copulation and oviposition by females. The results showed that males are territorial, and its territoriality keeps relation with size and the physical condition. In other words, males with larger body and higher energy reserves have won more disputes and maintained a territory. Although males were territorial, there was no difference between the duration of reproductive interactions, winning males and losers, thus indicating that the reproductive interactions are not influenced by the condition of territoriality of the male.
304

Disputas físicas e territorialidade da espécie de borboleta Actinote pellenea (Hubner, 1821) (Nymphalidae, Acraeinae) / Physical contests and territoriality in butterfly Actinote pellenea (Hubner, 1821) (Nymphalidae, Acraeinae)

Carvalho, Márcio Romero Marques 19 August 2018 (has links)
Orientador: Woodruff Whitman Benson / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T03:31:05Z (GMT). No. of bitstreams: 1 Carvalho_MarcioRomeroMarques_M.pdf: 919432 bytes, checksum: 1f0c159d8e11e0b88a3a120ac6ec0675 (MD5) Previous issue date: 2011 / Resumo: Os machos de várias espécies de borboletas defendem territórios de acasalamentos contra rivais da mesma espécie por meio de intensas perseguições em espirais. Tais perseguições raramente apresentam contato físico, tornando incerto como residentes obtêm vantagem territorial. No sudeste do Brasil os machos da borboleta aposemática Actinote pellenea (Nymphalidae), entretanto, defendem territórios agarrando rivais em vôo e caindo no solo em combate, indicando neste caso uma função da força física. Eu observei machos marcados de A. pellenea nos territórios com o objetivo de descrever as disputas em relação à natureza dos comportamentos, horário de ocorrência, e seus resultados. Analisei se injúrias físicas ocorreram e quais características dos machos, tais como tamanho, massa corporal, e desgaste alar (idade) poderiam relacionar-se com vitória em disputas. Avaliei o sucesso reprodutivo de machos donos de territórios (residentes) e machos sem territórios (intrusos) com base no número de cópulas realizadas por cada grupo. Realizei um experimento para analisar se a condição residente confere aos machos vantagem em vencer disputas, para isto, organizei disputas entre machos residentes previamente presos contra substitutos (intrusos) que naturalmente estabeleceram-se sobre o território vago (durante no mínimo 15 minutos). Os machos de A. pellenea começaram a defender territórios por volta das 9 h e permaneceram até aproximadamente 15:30 h. A maioria das disputas foram perseguições sem espirais (n=435; 84,3%), porém em muitas houve contatos físicos em que os rivais agarraram-se e soltaram-se no ar (n=25; 4,8%), e em que o rivais caíram no chão e lutaram (n=56; 10,8%). Danos nas asas foram arranhões com as garras, perda de escamas e em um caso perda de pedaços das asas. Os machos residentes (n=6) obtiveram mais acasalamentos do que os machos intrusos (n=2). Residentes venceram todas as disputas naturais contra intrusos, e não houve diferença de tamanho, peso ou desgaste alar de vencedores e perdedores de disputas. No experimento, residentes originais venceram 7 das 8 disputas contra residentes substitutos (intrusos). O consistente sucesso de residentes estabelecidos em territórios, até mesmo contra substitutos que aparecem durante breves ausências, sugerem que outros fatores motivacionais ou traços físicos não representados em nossas medidas são provavelmente responsáveis pelo sucesso deles em manter territórios / Abstract: The males of many butterfly species defend mating territories against conspecific rivals through intense spiraling chases. Such chases have practically no physical contact, making it unclear how residents obtain their territorial advantage. In southeastern of Brazil males of the aposematic butterfly Actinote pellenea (Nymphalidae), however, defend by seizing rivals in flight and dropping to the ground in combat, suggesting in this case a role for physical strength. I observed marked A. pellenea males at territory sites with the objective of describing contests regarding nature of contests, hours of occurrence, and their outcomes. I analyzed if physical injuries occurred and which traits such as size, body mass and wing wear (age) could relate to win contests. I evaluated the reproductive success of owner territories males (residents) and without territories males (intruders) based on number of the matings performed by each group. I realized an experiment to analyze if resident status gives to males advantage to win contests, for this, I arranged contests between resident males previously imprisoned against substitutes (intruders) that naturally settled over vacant territory (for at least 15 minutes). The males of A. pellenea began to defend territories arround for 9 h and stayed until nearly 15:30 h. The most contests were non-spiral chases (n=435; 84,3%), however in several had physical contact that rivals seized and release in the air (n=25; 4,8%), and that rivals fell on the ground and fought (n=56; 10,8%). Wings injuries were claw punctures, scales loss and one case pieces wings loss. The residents males (n=6) had more matings than intruders males (n=2). Residents won all natural contests against intruders, but there was no difference in size, body mass and wing wear between winners and losers of contests. In experiment original residents won 7 of 8 contests against substitutes residents (intruders). The consistent success of established territory residents, even against substitutes appearing during brief absences, suggests that either motivational factors or physical traits not represented in our measurements are likely responsible for their success in holding territories / Mestrado / Ecologia / Mestre em Ecologia
305

Maintien de l'ornementation mutuelle chez le manchot royal (Aptenodytes patagonicus) / Maintenance of mutual ornamentation in the king penguin (Aptenodytes patagonicus)

Keddar, Ismaël 04 November 2013 (has links)
Si la sélection sexuelle proposée par Darwin fournit un cadre théorique satisfaisant pour expliquer l'évolution et le maintien des ornements sexuellement dimorphiques, le cas de l'ornementation mutuelle requiert l'emploi du cadre plus large offert par la sélection sociale. Dans de nombreux cas en effet, l'explication du maintien de l'ornementation mutuelle nécessite de considérer non seulement la compétition pour l'accès au partenaire de reproduction, mais également la compétition pour l'accès à d'autres types de ressources telles que la nourriture ou les emplacements pour nicher. Cependant, le maintien de l'ornementation mutuelle n'est encore que partiellement compris chez les oiseaux marins. Les travaux réalisés au cours de cette thèse s'inscrivent dans la continuité des recherches initiées depuis quelques années dans le but de comprendre le maintien de l'ornementation mutuelle chez le manchot royal, un oiseau exprimant un patch orange présentant un pic de réflectance ultraviolet de chaque côté de la mandibule, des patches auriculaires jaunes de chaque côté de la tête et un patch formant un dégradé allant du marron au jaune pâle sur le poitrail. Les travaux présentés dans ce manuscrit de thèse portent (i) sur les combats entre individus du même sexe pour accéder à un partenaire de reproduction, (ii) sur le rôle des ornements colorés dans le processus d'appariement, (iii) sur l'association entre le degré de développement des ornements et la position du territoire occupé au sein de la colonie, et enfin (iv) sur l'existence de variations interannuelles concernant le degré de coloration des ornements et le processus de choix de partenaire. Les résultats révèlent que : (i) les affrontements pour l'accès au partenaire sont beaucoup plus fréquents chez les mâles que chez les femelles ; (ii) l'ornementation mutuelle du bec pourrait être maintenu pas le processus de choix mutuel ; (iii) les individus occupant les territoires les plus centraux de la colonie expriment des patches auriculaires plus large et un patch de poitrine plus coloré ; (iv) les ornements présentent des variations notables entre deux années, tout comme le processus de choix de partenaire. Pris dans leur ensemble, ces résultats révèlent que le maintien de l'ornementation mutuelle du manchot royal est multifactoriel, et des pistes de recherches sont proposées pour affiner notre compréhension de ce phénomène complexe. / Darwin devised sexual selection theory in order to explain the evolution and maintenance of secondary sexual traits. In mutually ornamented species, however, the broader theoretical framework of social selection is needed. In many cases indeed, understanding the maintenance of mutual ornamentation requires to take into account competition for both sexual (i.e. mates) and non-sexual resources (e.g. food, nest sites). How mutual ornaments maintain and evolve is actually not well understood in seabirds species. The aim of the research program within which this Ph.D. thesis took place was to understand the maintenance of mutual ornamentation in king penguin, a bird exhibiting a ultraviolet and orange beak spot on each side of the mandible, two yellow auricular patches, and a patch on the breast that grade from brown to bright yellow. We studied (i) same-sex fight over mates; (ii) mate choice for color ornaments; (iii) the relationships between conspicuousness of ornaments and position of the territory within the colony; and finally (iv) the existence of inter-annual variations in color ornaments expression and mate choice process. Our results show that: (i) same-sex fights over mates are highly male-biased; (ii) color of the beak spots may be involved in mutual mate choice; (iii) central individuals exhibit larger auricular patches and more colorful breast patch; (iv) ornament conspicuousness as well as mate choice show inter-annual changes. Taken together, these results reveal that maintenance of king penguin mutual ornaments is multifactorial, and some research avenues are suggested for future researches.
306

Genital variation in moths—evolutionary and systematic perspectives

Mutanen, M. (Marko) 10 May 2006 (has links)
Abstract genital characteristics have peculiar morphological patterns. They show great divergence between species. At the same time, they are assumed to vary little within species by taxonomists who frequently use genital features to delimit species. I studied moth (Lepidoptera) genital size and shape variation within and between species. I also tested hypotheses proposed to explain rapid genital diversification among species. Studies were carried out using traditional distance measurement morphometrics and modern geometric morphometrics. Several moth species were analyzed. d that genital structures show variation that in closely related species may show structural overlap. More surprisingly, the amount of variation in internal genitalia was equal to non-genital traits. These and some other findings are against the predictions of the lock-and-key hypothesis, which suggests that genital differences form a mechanical isolation system between species. Meanwhile, the findings are in good accordance with the various mechanisms of the sexual selection hypothesis. I found that external genital traits express varying amounts of variability. However, both external and internal genitalia consistently show small variation in size so that large individuals have disproportionately small genitalia and vice versa. This finding is consistent with the lock-and-key theory, but also with the cryptic female choice hypothesis. In conclusion, the results suggest that sexual selection plays a major role in genital diversification, but the exact mechanism remained unclear in this study. Some structures in moth genitalia strongly suggest that sexual conflict is present as well. It is possible that several mechanisms of sexual selection are in action simultaneously. dings have implications to insect taxonomy. Genital characters, although often useful, should not be considered superior to other characters because they may vary considerably within species. I have shown that subjective visual evaluation of genital characteristics and a priori assumption of their low variability may easily lead to unsound taxonomic conclusions. Sophisticated morphometric tools are very useful and objective in delimiting sibling species. Geometric morphometrics is particularly useful since it helps to evaluate limits of variation. There are, however, no theoretical grounds to assume that genitalia are not subject to intraspecific geographic variation. Such variation was detected in this study as well. Geographic relationships should therefore be taken into consideration more frequently when delimiting populations into different species.
307

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) / Sexual selection and the evolution of female ornaments : an examination of female plumage colouration using comparative analyses and long-term data sets collected in blue tit (Cyanistes caeruleus) populations

Fargevieille, Amélie 13 December 2016 (has links)
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 généralisation. / Ornamental 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.
308

Amphibian communication: Coupling of acoustic systems to the medium at the air-water interface

Tang, Justine Nicole 01 January 2016 (has links)
Sound does not transmit well across the interface of two media. Therefore, most organisms communicate using one medium. Some anurans vocalize at the interface of air and water, though reception of these vocalizations is generally unknown. The túngara frog ( Engystomops pustulosus ) may be the first anuran to have evidence suggesting simultaneous acoustic communication both above and below the air-water interface. This thesis addresses whether the female túngara frog would be receptive to underwater acoustic signals and if males project their advertisement calls at biologically relevant intensities underwater. Females floated and swam with their eardrums and body walls constantly submerged. Using laser Doppler vibrometry, peak vibrations of female eardrums were found to be centered at about 3.5 kHz in air, but dropped to about 1.4 kHz underwater. The peak velocity of the eardrum was about 0.2 mm/s in air and 0.04 mm/s in water when stimulated with tones at 80 dB relative to 20 µPa. Males projected their advertisement calls with a sound pressure level of 121 dB (at 10 cm, re. 20 µPa) in water and 98 dB (at 10 cm, re. 20 µPa) in air. In relation to air, the dominant frequency of the advertisement call (0.8 kHz) was the most intense spectral band underwater whereas the dominant frequency of the chuck (2.5 kHz in air) was less intense. The advertisement signal for the male túngara frog was broadcasted underwater with more energy than in air at its main frequencies. Female eardrums were sensitive to frequencies within the male advertisement call both in air and in water, if the frequencies were transmitted at amplitudes plausible to be encountered in nature. These results strengthen the available evidence of underwater communication, and indicate the presence of auditory specializations in the acoustic communication of this species.
309

Living in a haze: Direct and indirect impacts of turbidity and diet on an African cichlid fish

Atkinson, Tiffany L. 19 June 2019 (has links)
No description available.
310

Divergent natural selection and the parallel evolution of mating preferences : a model and empirical test for the origins of reproductive isolation

Schwartz, Amy K. January 2005 (has links)
No description available.

Page generated in 0.09 seconds