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  • 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.
11

Brood sex ratio and sex differences in Tengmalm’s owl : (Aegolius funereus)

Hipkiss, Tim January 2002 (has links)
Males and females differ in morphology and behaviour, so that selection acts differently on the two sexes. This changes the relative reproductive success of males and females, and it is beneficial for parents to bias the sex ratio of their broods in favour of the sex with the best survival and breeding prospects. Differences between the sexes and brood sex ratio in Tengmalm’s owl (Aegolius funereus) in northern Sweden were investigated, using a molecular sexing technique based on PCRamplification of sex-linked CHD1 genes. Among owls caught during autumn migration, females were commoner than males, especially within juveniles. However, in contrast to earlier studies, it was shown that adult males sometimes undertake migratory movements indicatory of nomadism. Measurements of these owls revealed that sexual size dimorphism in Tengmalm’s owl is not as great as previously reported from studies carried out during the breeding season. Females were slightly larger (4% by mass) than males, probably owing to the different roles of males and females during breeding, when this dimorphism is greater. The size difference between male and female nestlings was found to be similar to that for adults in autumn, and to investigate whether this led to differential mortality, the effect of supplementary feeding on mortality of male and female nestlings was studied. Supplementary feeding reduced male mortality when vole abundance was low, and it was concluded that larger female nestlings out-competed their smaller brothers, who then suffered increased mortality when food was scarce. Recruitment of male nestlings into the breeding population declined with decreasing food supply at the time of fledging, a pattern not observed in females. Juvenile males were therefore more vulnerable to food shortage than females, both in the nest and after fledging. Mean brood sex ratio varied significantly among years characterized by different phases of the vole cycle and associated vole abundance. Broods were male-biased (63% males) in a year when the food supply was favourable during spring and summer, neutral (50%) in a year with an intermediate food supply, and female-biased (35% males) in a year when food was in short supply. Parents appeared to adaptively adjust the sex ratio of their broods according to the relative mortality risk and reproductive potential of sons and daughters.
12

Ecologia química e reprodução de Neoleucinodes elegantalis Guenée (Lepidoptera : Crambidae) / Chemical ecology and reproduction of Neoleucinodes elegantalis Guenée (Lepidoptera : Crambidae)

PONTES, Wendel José Teles 01 February 2010 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-12-02T13:08:37Z No. of bitstreams: 1 Wendel Jose Teles Pontes.pdf: 931365 bytes, checksum: 3be37ee2d65cbbb102520601b95203cb (MD5) / Made available in DSpace on 2016-12-02T13:08:37Z (GMT). No. of bitstreams: 1 Wendel Jose Teles Pontes.pdf: 931365 bytes, checksum: 3be37ee2d65cbbb102520601b95203cb (MD5) Previous issue date: 2010-02-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / he reproduction in insects is affected by a wide array of factors that acts directly on the reproductive output, related with offspring quality and quantity: the interaction, by physical, chemical and visual cues, between insects and host plants; the larval growth rate affecting adult size and mating rate, as a mechanism of reproductive sucess. Thus, studies on insect reproduction are recommended to help estimate and to understand population dynamics, for both endangered species and to control crop pests. The tomato fruit borer Neoleucinodes elegantalis Guenée (Lepidoptera: Crambidae) is one of the most important pest species on Solanaceae in Brazil, and the aims of this works is to study this species regarding to: (i) the role of physical, chemical and visual cues on oviposition; (ii) the causes of sexual dimorphism and (iii) how male mating history affects his ability to obtain new matings. This work also propose an equation that can help to estimate the initial size of fragmented spermatophores found inside the reproductive tracts of females, based on measures of the fragments. The results showed: (i) that physical and chemical cues increase significantly the oviposition of N. elegantalis, as well showed that light intensityalso affect oviposition; (ii) that differences in dayly growth rate is the cause of the observedsexual dimorphism in this species, and (iii) that recently mated males are equally able to achieve new matings as virgin ones, within at least 24-h period. / A reprodução em insetos depende de diversos fatores que afetam diretamente o sucesso reprodutivo, em relação à qualidade e quantidade da progênie: a interação mediada por sinais químicos, físicos e visuais, entre o inseto e seu hospedeiro; taxa de crescimento larval relacionado com o tamanho final do adulto e a frequência de cópulas, como mecanismo de sucesso reprodutivo. Portanto, o estudo da reprodução de insetos é recomendado para se estimar e compreender a dinâmica de populações, tanto para a preservação de espécies em extinção, como para o controle de pragas agrícolas. A broca-pequena-do-tomateiro Neoleucinodes elegantalis Guenée (Lepidoptera: Crambidae) é uma das pragas mais importantes das solanáceas no Brasil, o que estimula o desenvolvimento de qualquer estudo voltado para a melhor compreensão de sua biologia e dinâmica populacional. Assim o objetivo deste trabalho é estudar (i) o efeito dos sinais físicos, químicos e visuais que afetam sua oviposição; (ii) as causas do seu dimorfismo sexual e (iii) o efeito da experiência de cópula de machos na sua capacidade de obter novosacasalamentos. Este trabalho ainda propõe uma equação que possa auxiliar em estimar o tamanho inicial de um espermatóforo já fragmentado, baseado nas medidas do fragmento encontrado no trato reprodutivo das fêmeas. Os resultados demonstram que: (i) os sinais físicos e químicos oferecidas estimulam significativamente a oviposição de N. elegantalis, bem como revela quepistas visuais afetam a oviposição; (ii) que a diferença na taxa diária de crescimento larval é responsável pelo dimorfismo sexual nesta espécie e (iii) que machos recém-copulados têm a mesma chance de conseguir uma nova cópula que um macho virgem, num período de 24 horas.
13

Pohlavní dimorfizmus tělesné velikosti obyvatel středověkých Čech. / Sexual size dimorphism in medieval period in Bohemia.

Kaupová, Sylva January 2011 (has links)
Differences in height among human populations or changes in height over time may be associated with different degrees of sexual dimorphism in this feature. This thesis compared the height and sexual size dimorphism (SSD) between two groups of the population of Medieval Bohemia - rural residents and inhabitants of Prague. A sample of 179 adult skeletons from five Prague sites and 175 individuals from four rural sites, dating from the 11th to 14th century, was used. Sex was determined following the principle of primary and secondary sex diagnosis, which enabled the derivation of population-specific discriminant functions using the dimensions of the humerus, femur, tibia and talus. A subsequent analysis of body height did not show statistically significant differences either in height or in SSD between the Prague and the rural part of the population of Medieval Bohemia, despite the major changes which Czech Medieval society went through in the 13th century. Comparing our results with previously published data on the height of the Czech population during the early modern period indicates a statistically significant reduction in the magnitude of sexual size dimorphism in the population of the17th century, particularly associated with a decrease in the height of men. A significantly higher stature of...
14

FATORES DETERMINANTES DA VARIAÇÃO DO CRÂNIO DE CANÍDEOS SUL-AMERICANOS / DETERMINANT FACTORS OF SKULL VARIATION IN SOUTH-AMERICAN CANIDS

Bubadué, Jamile de Moura 19 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Right after the arising of the Panama isthmus, the family Canidae colonized South America, around 2.6-2.4 million years ago. Although canids radiation in South America is recent, this region holds the largest canid diversity in the world, with more than 10 extant species. This great diversity is also notable when dealing with the ecomorphological variation of these animals. The maned-wolf (Chrysocyon brachyurus), a large omnivore, and the bush-dog (Speothos venaticus), a small hypercarnivore, are the extreme exemples of this variation. Such shape diversity can be potentially explained by both abiotic, such as climate, and biotic factors, like competition. These factors may have contributed for stabilizing the south-american canids community. Thus, this study aimed to investigate what drives this ecomorphological amplitude, as well as to understand how can similar species coexist when overlapping their distributional ranges, such as the crab-eating fox (Cerdocyon thous), which has sympatric areas with Lycalopex vetulus and L. gymnocercus, two foxes ecologically similar to Cerdocyon thous. To answer these questions, 431 especies were photographed in nine South-American museums. Through geometric morphometric procedures, it was possible to quantify the phenotypic variation of eight canid species (Atelocynus microtis, C. thous, C. brachyurus, L. culpaeus, L. griseus, L. gymnocercus, L. vetulus e S. venaticus) throughout their geographical range and then test the contribution of biotic and abiotic factors driving this variation. The evidences presented in this study suggest C. thous alters its shape and body size when in sympatry with two Lycalopex species, pattern described by character displacement , which is when similar species shift their phenotype in order to minimize competition. Besides, C. thous also follows the Bergmann s rule, which predicts that body size increases at larger latitudes. When considering the canid community as a whole, climate was identified as the main factor contributing to phenotypic variation in these animals. Competition has a weaker impact in south-american canids skull morphology, although it may have played a larger role in the past, when the ecomorphological diversity in the subcontinent was even larger. / Logo após a emergência completa do istmo do Panamá, a família Canidae colonizou a América do Sul, há, aproximadamente, 2.6-2.4 milhões de anos atrás. Embora a radiação dos canídeos seja recente na América do Sul, esta região compõe a maior diversidade atual de espécies desta família no mundo, com mais de 10 espécies viventes. Esta grande biodiversidade também é notável na variação ecomorfológica destes animais. Exemplo disso são os dois extremos desta variação: o lobo-guará (Chrysocyon thous), um animal onívoro de grande tamanho corporal; e o cachorro-vinagre (Speothos venaticus), espécie hipercarnívora de pequeno porte. Tamanha diversidade de formas pode potencialmente ser explicada tanto por fatores abióticos, como o clima, e bióticos, como a competição. Ambos os fatores podem ter contribuído para a estabilização da comunidade de canídeos sul-americana. Por isso, este estudo se propôs a investigar o que impulsionou esta amplitude ecomorfológica, bem como entender como espécies mais similares coexistem quando em sobreposição distribucional, como o graxaim-do-mato (Cerdocyon thous), que possui área simpátrica a Lycalopex vetulus e L. gymnocercus, duas raposas ecologicamente similares a Cerdocyon thous. Para tanto, 431 espécimens foram fotografados em nove museus da América do Sul. Através de procedimentos de morfometria geométrica, foi possível quantificar a variação fenotípica de oito espécies de canídeos (Atelocynus microtis, C. thous, C. brachyurus, L. culpaeus, L. griseus, L. gymnocercus, L. vetulus e S. venaticus), ao longo de sua distribuição geográfica, e então testar a contribuição dos fatores bióticos e abióticos nesta variação. As evidências deste estudo sugerem que C. thous altera sua forma e tamanho corporal quando em simpatria com as duas espécies de Lycalopex, padrão descrito pelo deslocamento de caráter , quando espécies semelhantes alteram seu fenótipo em simpatria, a fim de minimizar a competição. Além disso, C. thous também segue a regra de Bergmann, que prevê um aumento de tamanho corporal com o aumento da latitude. Ao considerar a comunidade de canídeos como um todo, o clima foi identificado como o fator que mais contribuiu para a variação fenotípica destes animais. A competição, por sua vez, tem um impacto mais fraco na morfologia do crânio dos canídeos sul-americanos, embora possa ter tido uma maior contribuição no passado, quando a diversidade ecomorfológica no subcontinente era ainda maior.
15

Dinâmica populacional, comportamento reprodutivo e uso do habitat em Telebasis carmesina Calvert, 1909 (Odonata: Coenagrionidae) no Cerrado de Uberlândia - MG. / Population dynamics, breeding behavior and habitat use in Telebasis carmesina Calvert, 1909 (Odonata: Coenagrionidae) in a Neotropical Savanna at Uberlândia, Minas Gerais state

Martins, Fernanda Alves 26 February 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Neotropical damselfly Telebasis carmesina (Odonata: Coenagrionidae) is a common species in the Cerrado, a Brazilian savanna and even though, nothing is known about its natural history and ecology. This study aimed to investigate the population ecology, the habitat use and the breeding behavior of this species. It was conducted at a pond in the Natural Particular Reserve at Clube de Caça e Pesca Itororó de Uberlândia, between July/2008 and October /2009. The data was collected through the markrecapture method, using an insect net and a metal precision caliper. In addition, 81 hours of behavioral observations was taken. An amount of 1133 individuals were captured. December and November/2008 comprised the highest number of marked males, while September and October/2008 presented the higher abundance of females. The abundance of individuals was directly related to the air temperature and relative air humidity and it affects the individuals size, that is, the bigger the males abundance, the smaller was the total length of them, which generally are smaller than females. The males size also varied between the seasons of the year, except in summer and auntumn, and the females had different average of sizes between spring and summer months. The males longevity varied between the seasons and during the breeding season October to April was 7,099 (±0,719; X±SE) days. In this study, both males and females had concentrated mainly in the pond and used the macrophytes Eliocharis sp. and Pontederia parviflora as main perching surface, mating and oviposition. The polygynous mating system through scramble competition was evidenced during observations and supported by the smaller size of males and the absence of territory guarding behavior. The breeding behavior was frequently observed during the midmorning. T. carmesina s mate involved sperm transfer to edeagous, tandem and wheel positions and some evidences suggest that there is males sperm displacement in the species. The oviposition occurs together with the male, in tandem. Sex ratio varied throughout the months, with the closest value in relation to 1:1 ratio in September (1:3,48) and the most distinct value in January (1:27,4). Males exhibited three types of aggressive displays, similarly to other studies in literature: i) chase, when a male run after other male, going back to its original position or its position is displaced by the other male; ii) threat display or wing spread, when a male, realizing the approach of another male, spreads his wings, and iii) attack, which can occurs through the use of the legs, abdominal appendages or mouth parts. The agonistic behavior is directed toward to conspecific males; however aggressive interactions can also occur between heterospecific individuals. Telebasis carmesina presents important features related to sexual selection, such as sexual size dimorphism and sex ratio male biased. Moreover, the habitat use by males and females are spatially and temporarily different. / Embora seja comum no cerrado, nada se sabe sobre a história natural e ecologia da libélula neotropical Telebasis carmesina (Odonata: Coenagrionidae). Nesse sentido, os objetivos desse estudo foram investigar a ecologia populacional, uso do habitat e o comportamento reprodutivo dessa espécie. O estudo foi conduzido em uma lagoa situada na RPPN do Clube de Caça e Pesca Itororó de Uberlândia MG, entre os meses de julho de 2008 e outubro de 2009. Os dados foram obtidos utilizando-se o método de captura-marcação-recaptura, com o auxílio de uma rede entomológica e um paquímetro metálico de precisão e de observações comportamentais, totalizando 81 horas de observação. No total, 1133 indivíduos foram capturados. Os meses com maior número de machos capturados foram dezembro e novembro de 2008. Setembro e outubro de 2008 foram os meses em que houve maior abundância de fêmeas. A abundância dos indivíduos está diretamente relacionada com a temperatura e umidade relativa do ar e afeta o tamanho dos indivíduos. Quanto maior a abundância de machos, menor o comprimento total deles, que obtiveram tamanho menor que as fêmeas. O tamanho dos machos também variou entre as estações, exceto entre verão e outono e as fêmeas apresentaram médias de tamanho diferentes nos meses da primavera e verão. A longevidade dos machos variou entre as estações e durante a estação reprodutiva outubro a abril e foi de 7,099 (±0,719; X±EP) dias. Tanto machos quanto fêmeas concentraram-se principalmente na lagoa e utilizaram as macrófitas Eliocharis sp. e Pontederia parviflora como principais superfícies de pouso, cópula e oviposição. O sistema de acasalamento poligínico de competição por interferência foi evidenciado durante as observações e corroborado pelo tamanho dos machos e ausência de guarda de territórios O comportamento reprodutivo foi mais freqüente durante o meio da manhã. A cópula de T. carmesina envolveu a transferência de esperma para o edeago, o tandem , a wheel position . A oviposição ocorre sempre com o acompanhamento do macho, em tandem . A razão sexual atingiu maior equivalência em relação à razão 1:1 no mês de setembro (1:3,48) e maior diferença no mês de janeiro (1:27,4).Os machos exibiram três tipos de comportamentos agressivos: i) perseguição, quando um macho persegue o outro, voltando logo a sua posição original, ou sua posição é tomada pelo outro; ii) intimidação ou wing spread , um macho, quando percebe a aproximação de outro, abre suas asas e iii) ataque, que pode ocorrer através do uso das pernas, apêndices abdominais ou peças bucais. Machos apresentam comportamento agonístico direcionado a outros machos da mesma espécie e também são agressivos com indivíduos de outras espécies. A espécie estudada apresenta dimorfismo sexual de tamanho e razão sexual altamente direcionada para machos. Machos e fêmeas utilizam diferencialmente o habitat, tanto espacial quanto temporalmente. / Mestre em Ecologia e Conservação de Recursos Naturais
16

Vliv steroidních hormonů na pohlavně dimorfní růst kostí gekonů / The effect of steroid hormones on sexually dimorphic bone growth in geckos

Tureček, Adam January 2017 (has links)
The sexual size dimorphism (SSD) is widespread among animals but proximate mechanisms of its ontogeny are still poorly understood even in important groups of vertebrates such as reptiles. Previous experiments in geckos showed that growth of both sexes slows substantially at their older age. Their SSD develops considerably a long time after sexual maturity, it is associated with earlier growth deceleration in the smaller sex and it is controlled by ovarian rather than testicular steroids. The aim of the thesis was to explore the previous knowledge by studying the ontogenesis of the sexually-dimorphic bone growth of the gecko Paroedura picta, the male- larger species with the most explored proximate mechanisms of SSD among geckos. I was most interested in the ontogeny of the growth plates activity and the epiphyseal ossification of the femur in both sexes and their relationship to age, body length, gonadal activity and levels of sex-specific steroids (estradiol and testosterone). The results show that P. picta has determinate growth and that epiphyseal ossification does not contribute to the SSD. The femoral growth plates close at the same age in both sexes; however, their closure occurs at smaller body length in females than in males. In the context of this and the previous studies, estradiol or other...
17

Population demographics of New Zealand fur seals (Arctocephalus forsteri)

McKenzie, Jane, janemckenzie@malpage.com January 2006 (has links)
Assessment of trophic interactions between increasing populations of New Zealand fur seals (Arctocephalus forsteri) and fisheries in southern Australia is limited due to a lack of species specific demographic data and an understanding of the factors influencing population growth. To establish species specific demographic parameters a cross-sectional sample of New Zealand fur seal females (330) and males (100) were caught and individually-marked on Kangaroo Island, South Australia between 2000 and 2003. The seals were aged through examination of a postcanine tooth, which was removed from each animal to investigate age-specific life-history parameters. Annual formation of cementum layers was confirmed and accuracy in age estimation was determined by examination of teeth removed from individuals of known-age. Indirect methods of assessing reproductive maturity based on mammary teat characteristics indicated that females first gave birth between 4-8 years of age, with an average age at reproductive maturity of 5 years. Among reproductively mature females, age-specific reproductive rates increased rapidly between 4-7 years of age, reaching maximum rates of 70-81% between 8-13 years, and gradually decreased in older females. No females older than 22 years were recorded to pup. Age of first territory tenure in males ranged from 8-10 years. The oldest female and male were 25 and 19 years old, respectively. Post-weaning growth in females was monophasic, characterised by high growth rates in length and mass during the juvenile growth stage, followed by a gradual decline in growth rates after reproductive maturity. In contrast, growth in males was biphasic and displayed a secondary growth spurt in both length and mass, which coincided with sexual and social maturation, followed by a rapid decline in growth rates. Age-specific survival rates were high (0.823-0.953) among prime-age females (8-13 yrs of age) and declined in older females. Relative change in annual pup production was strongly correlated with reproductive rates of prime-age females and adult female survival between breeding seasons.

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