Página 1 dos resultados de 2305 itens digitais encontrados em 0.029 segundos

EVOLUTIONARY AESTHETICS AND SEXUAL SELECTION IN THE EVOLUTION OF ROCK ART AESTHETICS

VARELLA, Marco Antonio Correa; SOUZA, Altay Alves Lino de; FERREIRA, Jose Henrique Benedetti Piccoli
Fonte: ARCHAEOLOGICAL PUBL Publicador: ARCHAEOLOGICAL PUBL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.18%
This theoretical proposal applies evolutionary aesthetic, animal signalling and sexual selection to understand our artistic cognition, especially rock art aesthetics. Iconographic motifs, universally found in rock art, indicate which set of pre-artistic aesthetic psychological bias has been co-opted to catch the viewer`s attention. The co-evolutionary process of sexual selection could have shaped the design features of both rock art images and their aesthetic cognition by conferring mutual benefits on both producers, via manipulation, and receivers, via information extraction. We show some strategic techniques identified in rock art and art that indicate the occurrence of this co-evolution between producers and receivers.

Análise morfológica e morfométrica do trato reprodutor feminino e masculino de duas espécies de Serracutisoma (Arachnida: Opiliones: Gonyleptidae): evidências de seleção sexual em machos; Morphological and morphometric analysis of the reproductive system of females and males of two species of Serracutisoma harvestmen (Arachnida: Opiliones: Gonyleptidae): evidences of sexual selection among males

Sobral, Marcella
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/09/2010 PT
Relevância na Pesquisa
66.35%
Machos dos opiliões goniosomatíneos Serracutisoma spelaeum e Serracutisoma guaricana, cujas fêmeas copulam com mais de um parceiro em um único período reprodutivo, apresentam uma grande variedade morfológica, especialmente relacionada a caracteres sexuais secundários. Considerando-se que machos menores frequentemente perdem disputas por fêmeas, esta tese objetivou verificar possíveis estratégias reprodutivas alternativas, resultantes de seleção sexual pré e pós-copulatória, adotadas por machos de pequeno porte dessas espécies assim como o papel da fêmea nesses mecanismos. Este trabalho foi, então, dividido em três capítulos, cada um com objetivos específicos. O primeiro deles refere-se à organização do trato reprodutor feminino e caracterização das espermatecas, órgãos de armazenamento de espermatozóides. Imagens de microscopia de luz e de microscopia eletrônica de varredura associadas às obtidas sob estereomicroscópio revelaram a existência de quatro espermatecas inseridas na musculatura da porção distal do ovipositor. Cada uma delas é constituída por quatro sáculos individuais de fundo cego e se comunica com a luz do ovipositor através de um único canal. A complexidade das espermatecas indica que a fêmea pode ser capaz de armazenar separadamente os espermatozóides dos diferentes machos com os quais vier a copular...

Evolução da musicalidade humana: seleção sexual e coesão de grupo; The evolution of human musicality: sexual selection and group cohesion

Varella, Marco Antonio Corrêa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/08/2011 PT
Relevância na Pesquisa
66.36%
A musicalidade, concebida como o conjunto da capacidade cognitiva subjacente à dança e à comunicação sonora por meio de melodias harmonizadas e ritmadas, satisfaz vários critérios que caracterizam as adaptações biológicas. A música é muito antiga, universal e um importante aspecto em todas as culturas e épocas conhecidas. Ela provoca emoções e reações estéticas fortes, se desenvolve segundo um roteiro ontogenético padrão, envolve uma capacidade neurocognitiva especializada em receber, processar e produzir música, traz benefícios à saúde e apresenta fatores hereditários nas diferenças individuais, consome muita energia e tempo, e tem análogos na sinalização acústica de outras espécies sugerindo homologia e convergência adaptativa. Existem duas principais teorias acerca do valor adaptativo para a musicalidade: coesão grupal e seleção sexual. Elas não são excludentes ou incompatíveis e apresentam muitas sobreposições. Ambas buscam, em diferentes contextos sociais, as pressões seletivas envolvidas na valorização ancestral dos responsáveis pela produção musical e sua apreciação. Entretanto, elas diferem quanto ao grau de diferenças sexuais previsto: a coesão de grupo prevê poucas diferenças sexuais...

Sexual Dimorphism in Primate Aerobic Capacity: A Phylogenetic Test

Nunn, Charles Lindsay; Lindenfors, P.; Revell, L.J.
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
56.32%
Male intrasexual competition should favour increased male physical prowess. This should in turn result in greater aerobic capacity in males than in females (i.e. sexual dimorphism) and a correlation between sexual dimorphism in aerobic capacity and the strength of sexual selection among species. However, physiological scaling laws predict that aerobic capacity should be lower per unit body mass in larger than in smaller animals, potentially reducing or reversing the sex difference and its association with measures of sexual selection. We used measures of haematocrit and red blood cell (RBC) counts from 45 species of primates to test four predictions related to sexual selection and body mass: (i) on average, males should have higher aerobic capacity than females, (ii) aerobic capacity should be higher in adult than juvenile males, (iii) aerobic capacity should increase with increasing sexual selection, but also that (iv) measures of aerobic capacity should co-vary negatively with body mass. For the first two predictions, we used a phylogenetic paired t-test developed for this study. We found support for predictions (i) and (ii). For prediction (iii), however, we found a negative correlation between the degree of sexual selection and aerobic capacity...

Comportamento de corte e cópula e papel do tamanho e simetria na seleção sexual de Dysdercus maurus Distant, 1901 (Hemiptera: Pirrhococoridae); Courtship behavior and sexual selection determined by size and symmetry in Dysdercus maurus Distant, 1901 (Hemiptera: Pirrhocoridae)

Jorge, André de Sousa
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
Relevância na Pesquisa
66.28%
Este estudo investigou o papel do tamanho corpóreo e da simetria corporal na seleção sexual de D. maurus. Além disso, foram descritos aspectos do comportamento de corte e cópula. Foram utilizados 30 machos solteiros e 30 casais na confecção de lâminas destinadas às medidas morfométricas. Para obtenção de peso corporal foram utilizados 40 machos solteiros e 90 casais. Além disso, foram utilizadas 50 fêmeas solteiras e 50 machos solteiros para a observação do comportamento de corte e cópula. As medidas morfométricas obtidas foram simplificadas pela Análise de Componentes Principais para obtenção de um índice multivariado de tamanho. A assimetria corporal foi estimada calculando-se a Assimetria Flutuante (AF). As medidas morfométricas, o peso e os índices de tamanho e AF foram comparados por test t entre as categorias: macho casado e solteiro. A relação entre tamanhos de machos e fêmeas foi verificada utilizando-se regressão linear simples. Em todas as tentativas de cópula observadas houve lutas entre machos e fêmeas e a corte foi sempre realizada pelo macho. O teste t indicou diferenças significativas no peso, no comprimento dos primeiros tarsômeros anteriores e na AF das tíbias posteriores entre machos casados e solteiros. Existe relação entre o peso de machos e fêmeas em cópula. Assim...

Influence of Sympatry and Sexual Selection on Colour Pattern Divergence in Birds-of-Paradise (Paradisaeidae)

Giglio, Victoria
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
66.18%
The extraordinary colour patterns displayed by the birds-of-paradise have interested biologists for many generations and yet our understanding of the evolution these colour patterns remains limited. In this study, we first test for and find that degree of sympatry is associated with degree of colour pattern divergence among males and females. Secondly, we test for relations between degree of sexual selection and colour pattern divergence, and find that degree of sexual selection is only associated with degree of ranked colour pattern evolution among older lineages of females. Thirdly, we compare rates of colour pattern evolution among birds-of-paradise, high latitude birds and low latitude birds, and find that the rate of colour pattern evolution among birds-of-paradise is not significantly different from the rate of colour pattern evolution among high latitude birds or low latitude birds. We suggest that sympatry is important to the evolution of colour patterns among birds-of-paradise. We argue that colour patterns diverged in sympatry via reinforcement as a result of females’ preference for the elaborate male, high rates of hybridization and the general low fitness of hybrids.; N/A

Selección sexual post-copulatoria en Drosophila: ¿cuántas moscas no nacen por causa de la competencia espermática?; Postmating sexual selection in cactophilic Drosophila: how many flies are not born because of sperm competition?

Hurtado, Juan
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2014 SPA
Relevância na Pesquisa
66.3%
La competencia espermática (CE), ampliamente extendida entre las especies sexuales cuyas hembras son promiscuas, podría representar potentes presiones selectivas promoviendo conflictos intra e intersexuales. Por ello, es considerada un componente dominante de la selección sexual que teóricamente puede disparar evolución adaptativa rápida en caracteres sexuales. Estos caracteres constituyen potenciales barreras reproductivas entre poblaciones divergentes, por lo que la CE también podría facilitar la especiación. El verdadero rol de la CE en la evolución rápida o la especiación, sin embargo, permanece oculto. ¿Que tan frecuente es la promiscuidad de las hembras como para posibilitar la CE? ¿es la CE una fuerza selectiva intensa? ¿su intensidad varía entre las especies? Frente a estas cuestiones, en este trabajo estudiamos la intensidad de la CE y los factores del sistema de apareamiento (conjunto de comportamientos sexuales y reproductivos) que dan cuenta de ella en las especies hermanas Drosophila buzzatii y D. koepferae. Los análisis de promiscuidad que realizamos con hembras inseminadas en la naturaleza revelaron que la incidencia de paternidad múltiple y, por tanto, el riesgo de CE es mayor en D. buzzatii que en D. koepferae. El número estimado de padres por camada fue 3...

Unifying and Testing Models of Sexual Selection

Kokko, Hanna; Jennions, Michael; Brooks, Rob
Fonte: Annual Reviews Inc Publicador: Annual Reviews Inc
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.2%
Sexual reproduction is associated with the evolution of anisogamy and sperm-producing males and egg-laying females. The ensuing competition for mates has led to sexual selection and coevolution of the sexes. Mathematical models are extensively used to tes

Swingin' in the rain: condition dependence and sexual selection in a capricious world

Cockburn, Andrew; Osmond, Helen; Double, Michael
Fonte: Royal Society of London Publicador: Royal Society of London
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.18%
Signals used in mate attraction are predicted to be highly condition dependent, and thus should be sensitive to environmental contributions to condition. However, the effects of temporal fluctuations in the environment on sexual selection in long-lived an

Unifying and Testing Models of Sexual Selection

Kokko, Hanna; Jennions, Michael; Brooks, Rob
Fonte: Annual Reviews Inc Publicador: Annual Reviews Inc
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.2%
Sexual reproduction is associated with the evolution of anisogamy and sperm-producing males and egg-laying females. The ensuing competition for mates has led to sexual selection and coevolution of the sexes. Mathematical models are extensively used to tes

Flight, fitness, and sexual selection

Møller, Anders Pape; Barbosa, Andrés
Fonte: International Society for Behavioral Ecology Publicador: International Society for Behavioral Ecology
Tipo: Artículo Formato: 25088 bytes; application/msword
ENG
Relevância na Pesquisa
66.27%
Buchanan and Evans (2000) have recently suggested that the length of the tail streamer of the barn swallow Hirundo rustica is influenced to a large extent by natural selection, although sexual selection also plays a role. This conclusion was reached from analyses of video films of the flight of males and females after reducing the length of their tails by a variable amount ranging from 0 to 20 mm. Evans (1998) has previously made a similar experiment with a 20 mm manipulation. The optimum phenotype was subsequently derived from analyses of the flight parameters, while taking a number of other factors such as sex, farm, morphology, and date into account. Here we suggest that although it is likely that in fact streamer evolution was due to both natural and sexual selection, there is little direct evidence to support the reported conclusions. Although natural selection obviously plays a role in determining the selective landscape affecting tail length (e.g., Møller, 1989; Møller et al., 1995; Saino and Møller, 1996; Saino et al., 1997), it is far from clear that the cost is mainly measured in terms of foraging ability. Other factors like parasitism and disease have already been shown to be important (Saino and Møller, 1996; Saino et al....

Tail streamers and flight performance in barn swallows:natural or sexual selection?

Barbosa, Andrés
Fonte: Sociedad Española de Ornitología Publicador: Sociedad Española de Ornitología
Tipo: Artículo Formato: 25088 bytes; application/msword
ENG
Relevância na Pesquisa
66.28%
[EN] Tail streamers and flight performance in Barn Swallows: natural or sexual selection? The paper of Evans (1998) published in the journal Nature on the evolution of tail streamers in male Barn Swallows Hirundo rustica is discussed in the light of some methodological problems commited by this author. The conclusions are that the interpretation of Evans’ results must be taken with caution and that the importance of natural selection, as compared with the well established role of sexual selection, in the evolution of tail streamers in Barn Swallows remains to be assessed.; [ES] La forma de la cola y la eficacia del vuelo en la Golondrina Común: ¿selección natural o selección sexual? En este trabajo se discuten algunos problemas metodológicos graves que afectan a las conclusiones presentadas en un artículo reciente, publicado por Evans (1998) en la revista Nature, sobre la evolución de la forma de la cola en los machos de Golondrina Común Hirundo rustica. Se concluye que la interpretación desarrollada en ese artículo debe ser considerada con mucha cautela y que la importancia relativa de la selección natural en la evolución de la cola de los machos de Golondrina Común está aún por determinar, sobre todo en comparación con el bien establecido papel de la selección sexual en la evolución de este carácter.; Peer reviewed

Sexual selection and tail streamers in the barn swallow: appropriate tests of the function of size-dimorphic long tails

Barbosa, Andrés; Møller, Anders Pape
Fonte: International Society for Behavioral Ecology Publicador: International Society for Behavioral Ecology
Tipo: Artículo Formato: 25088 bytes; application/msword
ENG
Relevância na Pesquisa
66.1%
In their recent forum paper, Thomas and Rowe (1997) question our tail manipulation experiments used to test sexual selection theory (Cuervo et al., 1996; de Lope and Møller, 1993; Møller, 1988, 1989, 1992b, 1994b; Møller and de Lope, 1994; Saino and Møller, 1996; Saino et al., 1997a, b). In summary, Thomas and Rowe claim that manipulations shortening and elongating the outermost tail feathers of barn swallows Hirundo rustica (see Møller, 1988, for a description of methods) are based on faulty logic and therefore cannot test the function of long tails. Several of their statements are unclear, incorrect, or need clarification for understanding the significance of tail manipulation experiments, and we will discuss these statements here. Thomas and Rowe repeat what has already been stated by Evans and Thomas (1997). We have responded to that paper elsewhere (Møller et al., 1998), and here we concentrate on the aerodynamic issues.; A.B. was supported by a Marie Curie post-doctoral grant from the European Union and A.P.M. was supported by grants from the Swedish and Danish Natural Science Research Councils; Peer reviewed

Sexual selection and tail streamers in the barn swallow

Møller, Anders Pape; Barbosa, Andrés; Cuervo, José Javier; Lope, F. de; Merino, Santiago; Saino, N.
Fonte: Royal Society (Great Britain) Publicador: Royal Society (Great Britain)
Tipo: Artículo Formato: 25088 bytes; application/msword
ENG
Relevância na Pesquisa
66.37%
The functional signi¢cance of elongated, narrow tips of the tail feathers of certain birds, so-called tail streamers, has recently been discussed from an aerodynamic point of view, and the e¡ects of sexual selection on such traits have been questioned. We review our long-term ¢eld studies using observational and experimental approaches to investigate natural and sexual selection in the barn swallow, Hirundo rustica, which has sexually size-dimorphic outermost tail feathers. Experimental manipulation of the length of the outermost tail feathers has demonstrated sexual selection advantages of tail elongation and disadvantages of tail shortening, with opposite e¡ects for natural selection in terms of foraging e¤ciency, haematocrit and survival. These ¢ndings are contrary to the prediction of a general deterioration from both shortening and elongation, if the tail trait was determined solely by its e¡ects on aerodynamic e¤ciency and £ight manoeuvrability. Patterns of sexual selection in manipulated birds conform with patterns in unmanipulated birds, and selection di¡erentials for di¡erent components of sexual selection in manipulated birds are strongly positively correlated with di¡erentials in unmanipulated birds. Age and sex di¡erences in tail length...

Sexual Selection in Mantled Howling Monkeys (Alouatta palliata), With an Emphasis on the Role of Female Mate Choice

Ford, Randall Thomas
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2010
Relevância na Pesquisa
66.1%

Despite early neglect, recent studies of sexual selection have shown a renewed interest in female reproductive strategies. Clearly the traditional portrayal of female animals as passive participants in mating is incorrect, but much is still unknown about female reproductive strategies, including the extent of female mate choice. The primary goal of this dissertation was to explore the role of female mate choice in mantled howling monkeys (Alouatta palliata), a species in which males have previously been assumed to control mating.

From March 2006 through February 2007, I used continuous focal-animal sampling to record the behavior of adult female mantled howlers at Hacienda La Pacifica, Guanacaste, Costa Rica. The focal animals in the study were nine adult females in a social group that has been regularly monitored since 1984. There were also three capture sessions performed by K. Glander to collect blood samples for genetic paternity analysis. A total of 29 individuals in the study group and eight adult males from surrounding groups were captured.

The genetic paternity analyses were largely inconclusive. Of the eight microsatellite markers used previously in this species, only four were polymorphic in this sample. Additionally...

Revisiting Sexual Selection: An Exaggerated Signal of Fertility in the Amboseli Baboons

Fitzpatrick, Courtney
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2012
Relevância na Pesquisa
66.38%

Sexual selection has long been accepted as a widespread force of evolution shaping male traits across taxa. In recent years, biologists have begun to investigate the extent to which sexual selection may also shape traits among females. However, current models of sexual selection have largely been developed using assumptions that--while generally met in males--often do not apply to females. Thus, attempts to apply these contemporary models to the study of sexual selection in females reveal weaknesses in the theoretical framework for sexual selection research. One consequence of this for empirical research is that researchers often infer the action of sexual selection upon evidence of male mate choice. Although male mate choice is increasingly common, it is much less likely to exert selection pressure than its female counterpart. I begin by proposing a conceptual framework that explicitly accounts for ...Next, I investigate a female trait that has recently become an iconic example of sexual selection in females; that is the exaggerated estrous swellings of cercopithecine primates. By combining morphological data collected with a non-invasive photographic method and observational behavioral data with longitudinal ecological and demographic data from the ongoing Amboseli Baboon Research Project...

Complex Multivariate Sexual Selection on Male Acoustic Signaling in a Wild Population of Teleogryllus commodus

Bentsen, Caroline; Hunt, John E; Jennions, Michael; Brooks, Rob
Fonte: University of Chicago Press Publicador: University of Chicago Press
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.34%
Mate choice may impose both linear (i.e., directional) and nonlinear (i.e., quadratic and correlational) sexual selection on advertisement traits. Traditionally, mate recognition and sensory tuning have been thought to impose stabilizing (i.e., negative quadratic) sexual selection, whereas adaptive mate choice effects directional selection. It has been suggested that adaptive choice may exert positive quadratic and/or correlational sexual selection. Earlier, we showed that five structural components of the advertisement call of male field crickets (Teleogryllus commodus) were under multivariate stabilizing selection under laboratory conditions. Here we experimentally estimate selection on these five traits plus a measure of calling activity (the number of repeats in a looped bout of calling) in the field. There was general support for multivariate stabilizing selection on call structure, and calling activity was under strong positive directional selection, as predicted for a signal of genetic quality. There was, however, also appreciable correlational selection, suggesting an interaction between male call structure and calling effort. Interestingly, selection for short interbout durations of silence favored longer intercall durations in the field...

Operational sex ratio and density do not affect directional selection on male sexual ornaments and behavior

Head, Megan; Lindholm, Anna K.; Brooks, Rob
Fonte: Society for the Study of Evolution Publicador: Society for the Study of Evolution
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.43%
Demographic parameters including operational sex ratio (OSR) and population density may influence the opportunity for, and strength of sexual selection. Traditionally, male-biased OSRs and high population densities have been thought to increase the opportunity for sexual selection on male sexual traits due to increased male competition for mates. Recent experimental evidence, however, suggests that male-biased OSRs might reduce the opportunity for sexual selection due to increased sexual coercion experienced by females. How OSR, density, and any resultant changes in the opportunity for sexual selection actually affect selection on male sexual traits is unclear. In this study, we independently manipulated OSR and density in the guppy (Poecilia reticulata) without altering the number of males present. We recorded male and female behavior and used DNA microsatellite data to assign paternity to offspring and estimate male reproductive success. We then used linear selection analyses to examine the effects of OSR and density on directional sexual selection on male behavioral and morphological traits. We found that females were pursued more by males in male-biased treatments, despite no change in individual male behavior. There were no differences in sexual behavior experienced by females or performed by males in relation to density. Neither OSR nor density significantly altered the opportunity for sexual selection. Also...

Sexy to die for? Sexual selection and the risk of extinction

Kokko, Hanna; Brooks, Rob
Fonte: Finnish Zoological Botanical Publishing Board Publicador: Finnish Zoological Botanical Publishing Board
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.29%
Sexual selection is a field with a strong focus on the 'costs' of traits. However, whether such costs have an influence on the demography of the population is very rarely discussed. Here we present various processes through which sexual selection might have an impact on population viability and thus increase or decrease the risk of extinction. We argue that evolutionary 'suicide' - as sometimes suggested e.g. to have caused the extinction of the Irish elk - is unlikely in deterministic environments, except if costs are not paid by the same individual that bears the trait. Thus, intra- or inter-locus sexual conflict could in principle drive a population extinct, and we do not know why this does not frequently happen. Whether sexual selection increases or decreases extinction risks when populations face variable or unforeseen environmental conditions is likewise unknown, and we outline mechanisms that could account for either pattern. Inbreeding is another factor that could either increase or decrease population viability in sexually selected species. Inbreeding may be caused by a high mating skew, but it could also be reduced if females adaptively choose mates to avoid inbred offspring. Finally, when intraspecific competition for resources is taken into account...

Sexual selection when fertilization is not guaranteed

Kokko, Hanna; Mappes, Johanna
Fonte: Society for the Study of Evolution Publicador: Society for the Study of Evolution
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.36%
Much of the theory of sexual selection assumes that females do not generally experience difficulties getting their eggs fertilized, yet sperm limitation is occasionally documented. How often does male limitation form a selection for female traits that improve their mating rate? The question is difficult to test, because if such traits evolve to be efficient, sperm limitation will no longer appear to be a problem to females. Here, we suggest that changes in choosiness between populations, and in particular between virgin and mated females, offer an efficient way to test this hypothesis. We model the "wallflower effect," that is, changes in female preferences due to time and mortality costs of remaining unmated (for at least some time). We show that these costs cause adaptive reductions of female choice, even if mate encounter rates appear high and females only rarely end their lives unfertilized. We also consider the population consequences of plastic or fixed mate preferences at different mate encounter rates. If mate choice is plastic, we confirm earlier verbal models that virgins should mate relatively indiscriminately, but plastic increase of choosiness in later matings can compensate and intensify sexual selection on the male trait...