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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

Comparative studies of the reproductive strategies of New Zealand grapsid crabs (Brachyura : Grapsidae) and the effects of parasites on their reproductive success

Brockerhoff, Annette Maria January 2002 (has links)
The reproductive strategies of four intertidal grapsid crabs, Hemigrapsus sexdentatus, H. crenulatus, Cyclograpsus lavauxi, and Helice cressa, were studied in the field and laboratory, with emphasis on mating behaviour, duration of female receptivity, and sperm competition. Mating occurred in all species during the intermoult on the days prior to oviposition, when the gonoporo opercula of females became temporarily mobile. Female Helice crassa mated up to three weeks after oviposition, but in all other species mating typically ceased at egg-laying. Male Hemigrapsus pp. used a female-centered competition strategy in which they searched for and defended receptive females until they laid eggs. In contrast, male C. lavauxi searched for and intercepted receptive females only for the duration of copulation and then pursued other receptive females (a mating system termed encounter rate competition with pure search and interception). Male Helice crassa searched for receptive females in their immediate neighbourhood and mated with them briefly on the substrate or in the burrow after which the female left (a mating system termed encounter rate competition with neighbourhoods of dominance). The mating season was short and highly synchronous for Hemigrapsus exdentatus and Cyclograpsus lavauxi and asynchronous for Hemigrapsus crenulatus and Helice crassa. In the laboratory, the mean duration of receptivity for females housed with three males varied between 4.1 and 12.4 days, and the copulation frequency of females varied before oviposition between 2.1 and 24.3 times (mean) depending on the species. Female Hemigrapsus spp. isolated from males stayed receptive significantly longer than females held continuously with males. This suggests that females are able to control the duration of their receptivity, and therefore the time available for mating, according to the absence or presence of males. The operational sex ratio (OSR) had no effect on the duration of female receptivity, but female Hemigrapsus crenulatus mated more often when several males were competing for access. Therefore, male-male competition increased the number of matings per female and hence sperm competition within the female spermathecae. Larger males mated significantly more often than smaller males in all species. However, male size did not affect ejaculate size, meaning that small and large males transferred similar-sized ejaculates, e.g., in Hemigrapsus spp. Males of the two Hemigrapsus species followed a different strategy of sperm allocation. Male H. crenulatus, which are typically confronted with a high mating frequency of the female and a long, asynchronous mating season, distributed similar-sized ejaculates, irrespective of female size. By contrast, male H. sexdentatus, which experience a comparatively lower risk of sperm competition during a short, synchronised mating season, invested larger ejaculates for larger females than for smaller females. In addition, the size of the first and second ejaculates transferred to a female by a male H. crenulatus were not significantly different, whereas the first was larger than the second for H. sexdentatus. A parasitological survey was undertaken of the four grapsid crabs and the presence, seasonal variation and relationship with host gender and size of parasites determined. Four internal parasites were discovered: Nectonema zealandica n. Sp. (Nematomorpha: Nectonematoidea), portunion sp. (Isopoda: Entoniscidae), Profilicollis novaezelandensis n. sp. and profilicollis antarcticus (Acanthocephala: P olymorphidae). Portunion sp. castrated its female hosts, but not the males thereby creating a more male-biased sex ratio. Males parasitised with portunion sp. were equally successful during male-male competition and the number of matings they achieved. The above findings are important for our current understanding of mating strategies in Grapsidae, which are more diverse than previously thought. Females with a restricted duration of sexual receptivity have some control over their receptive period and can therefore influence the OSR and the extent of male-male competition. As females mated multiple times during their receptive period, sperm competition is a common feature in Grapsidae. However, males employed different tactics in regards to sperm competition such as longer mating duration (e.g., C. lavauxi), high number of matings (Helice crassa), or post-copulatory mate guarding until oviposition (Hemigrapsus spp.).
12

Association between perceived social support and induced abortion: A study in maternal health centers in Lima, Peru

Sánchez-Siancas, Luis E., Rodríguez-Medina, Angélica, Piscoya, Alejandro, Bernabe-Ortiz, Antonio 12 April 2018 (has links)
Objectives This study aimed to assess the association between perceived social support and induced abortion among young women in Lima, Peru. In addition, prevalence and incidence of induced abortion was estimated. Methods/Principal findings A cross-sectional study enrolling women aged 18–25 years from maternal health centers in Southern Lima, Peru, was conducted. Induced abortion was defined as the difference between the total number of pregnancies ended in abortion and the number of spontaneous abortions; whereas perceived social support was assessed using the DUKE-UNC scale. Prevalence and incidence of induced abortion (per 100 person-years risk) was estimated, and the association of interest was evaluated using Poisson regression models with robust variance. A total of 298 women were enrolled, mean age 21.7 (± 2.2) years. Low levels of social support were found in 43.6% (95%CI 38.0%–49.3%), and 17.4% (95%CI: 13.1%–21.8%) women reported at least one induced abortion. The incidence of induced abortion was 2.37 (95%CI: 1.81–3.11) per 100 person-years risk. The multivariable model showed evidence of the association between low perceived social support and induced abortion (RR = 1.94; 95%CI: 1.14–3.30) after controlling for confounders. Conclusions There was evidence of an association between low perceived social support and induced abortion among women aged 18 to 25 years. Incidence of induced abortion was similar or even greater than rates of countries where abortion is legal. Strategies to increase social support and reduce induced abortion rates are needed.
13

Mechanisms of reproductive interference in seed beetles: experimental tests of alternative hypotheses / マメゾウムシ2種における繁殖干渉の機構:対立仮説の実験的検証

Kyogoku, Daisuke 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18826号 / 理博第4084号 / 新制||理||1587(附属図書館) / 31777 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 曽田 貞滋, 准教授 渡辺 勝敏, 教授 高橋 淑子 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
14

Comportamento sexual da vespa escavadora Sphex ingens Smith 1856 (Hymenoptera, Sphecidae)

Souza, Carlos Alberto dos Santos 08 February 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-20T15:18:24Z No. of bitstreams: 1 carlosalbertodossantossouza.pdf: 1765667 bytes, checksum: 50df1c267e4657d7cc09cb359cc8f9ab (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T11:24:49Z (GMT) No. of bitstreams: 1 carlosalbertodossantossouza.pdf: 1765667 bytes, checksum: 50df1c267e4657d7cc09cb359cc8f9ab (MD5) / Made available in DSpace on 2016-07-02T11:24:49Z (GMT). No. of bitstreams: 1 carlosalbertodossantossouza.pdf: 1765667 bytes, checksum: 50df1c267e4657d7cc09cb359cc8f9ab (MD5) Previous issue date: 2012-02-08 / A vespa escavadora Sphex ingens apresenta distribuição conhecida na Bahia e no litoral Atlântico do Sudeste brasileiro representando uma espécie pouco compreendida em termos comportamentais, ecológicos e biológicos. O estudo visou descrever o comportamento sexual in natura da espécie e avaliar as estratégias comportamentais e padrões morfológicos sujeitos a seleção sexual, sendo conduzido nas praias dos Meros e do Aventureiro entre a 2ª quinzena de 2010 e a 1ª e 2ª quinzena de 2011 através da tabulação e filmagem dos comportamentos de acasalamento de indivíduos em ambas fisionomias. O etograma foi elaborado pelos métodos ad libitum e sequence samples. Diagramas de fluxos foram construídos a partir do estado atual e das probabilidades estocásticas dos comportamentos. O acasalamento foi constituído por 4 etapas seqüenciais através de um sistema promíscuo. Um total de 10 comportamentos foram exclusivos para as fêmeas e 9 para os machos. Sete comportamentos foram comuns entre os sexos não havendo diferença significativa (x2=16,622; Gl=n-1; p<0,01). Comportamentos de comunicação constituíram maior freqüência de estado entre os sexos no acasalamento, entretanto, as predições registradas pelo Diagrama de Cadeia de Markov indicaram que estes comportamentos pouco influenciam no acasalamento, sendo mais relevante a permanência da monta pelos machos e os comportamentos agonísticos e de insociabilidade das fêmeas. O número de tentativas de cópulas entre machos patrulheiros e residentes foram significativamente diferentes na 2ª quinzena de 2010 e na 1ª quinzena de 2011, respectivamente, t=3,767; Gl=n-1; p<0,01 e t=12,780; Gl=n-1; p<0,01. Embora, não tenha existido diferença significativa para o número de cópulas entre machos patrulheiros e residentes na 2ª quinzena de 2011 (t=0,285; Gl=n-1; p<0,01), os resultados sugerem que o sucesso copulatório entre estes padrões se mostra variável ao longo da estação reprodutiva. O número de toques de antenas e o tempo de investimento entre cópula bem sucedidas e mal sucedidas foram significativamente correlacionados (rs=0,838; t=14,127; p<0,001 e rs=0,847; t=14,083; p<0,001), porém, o número de toques de antenas entre cópulas bem sucedidas e mal-sucedidas não houve diferiram significativamente (t=0,607; Gl=n-1; p<0,01), ao contrário do tempo de investimento entre as respectivas cópulas (t=4,236; Gl=n-1; p<0,01). Análises de variância demonstraram diferenças significativas nos caracteres morfológicos mensurados, enquanto as análises multivariadas predisseram a existência de assimetria entre fêmeas, machos residentes e patrulheiros. A assimetria entre machos residente e patrulheiro indica maior adaptação ao territorialismo do que a seleção das fêmeas para este padrão, enquanto a promiscuidade e a agressividade das fêmeas interferem no esforço de corte dos machos e fomenta o aparecimento de coercividade copulatória. / Wasps of the genus Sphex ingens (commonly known as digger wasps) are widely distributed in Bahia and in Brazil’s southeast Atlantic coast, representing a poorly understood species in terms of behavior, ecology and biology. The present study aims to describe the sexual behaviour in natura of the species, as well as to evaluate behavioral strategies and morphological patterns subject to sexual selection. The study was conducted on Meros and Aventureiro beaches, between the 2nd fortnight of 2010 and the 1st and 2nd fortnights of 2011, using tabulation and footage of the mating behaviors of individuals in both faces. The ethogram was developed using ad libitum and sequence samples methods. Flow diagrams were drawn based on the current state and on the stochastic probabilities of the behaviors. The mating was composed of four sequential steps of a promiscuous mating system. There were 10 types of behavior which were exclusive to females and 9 other types which were exclusive of males. Seven behaviors were common between the sexes, with no significant difference (x2=16,622; Gl=n-1; p<0,01). Communication behaviors were more frequent between the sexes during the mating process, however, the recorded predictions in the Markov chain diagram indicated that these behaviors have little influence on mating, being the males’ permanency and the females’ agonistic & intractability behaviors much more relevant. The number of attempted copulations between patrol and resident males were significantly different in the 2nd fortnight of 2010 and 1st fortnight of 2011, respectively, t=3,767; n=Gl-1; p<0,01 and t=12,780; Gl=n-1, p<0,01. Although no significant differences existed for the quantities of mating between patrol x residents males in the 2nd fortnight of 2011 (t=0,285, Gl=n-1, p<0,01), the results suggest that the copulatory success between these patterns is variable along the reproductive season. The number of touches on each other antennas and the investment time between successful x unsuccessful mating were significantly correlated (rs=0,838; t=14,127, p<0,001 and rs=0,847; t=14,083; p<0,001), however, the number of antennas touches occurring between successful x unsuccessful copulations did not differ significantly (t=0,607; Gl=n-1; p<0,01), unlike the investment period between the matings (t=4,236; Gl=n-1; p<0,01). A variance analysis demonstrated significant differences in measured morphological traits, while a multivariate analysis predicted an asymmetry between females, patrol males and resident males. The asymmetry between resident and trooper males indicates a greater adaptation to the territorialism than the females selection for this pattern. Meanwhile, the females aggression and promiscuity may interfere on the males' courtship behaviour and fosters the development of copulatory coercivity.
15

THE GENETIC AND BEHAVIOURAL UNDERPINNINGS OF NATURAL VARIATION IN SOCIAL BEHAVIOUR / THE GENETIC AND BEHAVIOURAL UNDERPINNINGS OF SOCIAL BEHAVIOUR

Scott, Andrew M. January 2021 (has links)
A rich diversity of social behaviours exists in the animal kingdom, and these behaviours have evolved to perform a variety of adaptive functions. Social behaviours show variation both among and within species, however the mechanisms that give rise to this variation are not well understood. Using fruit flies (Drosophila melanogaster), my goal was to uncover the genetic and behavioural mechanisms that underpin natural variation in two different social behaviours: sociability and sexual aggression. First, I showed that sociability, which is the tendency of animals to engage in friendly activities together, is influenced by indirect genetic effects (IGEs), and that encounters among individuals drive these effects (Chapter 2). I then showed that sociability and social plasticity have low-moderate heritability (Chapter 3), and sociability is not correlated between the sexes or with activity. I then generated lineages of flies with high and low sociability using artificial selection (Chapter 4). The evolved lineages had significantly diverged sociability which was not associated with fitness measures or nearest-neighbor distances, but was negatively correlated with intrasexual aggression (Chapter 4). Finally, in sexual aggression, which I quantified as male forced copulation rate, I showed that evolved differences and differences due to social plasticity were both associated with the differential expression of many genes, but only a few of these genes were significant in both (Chapter 5). I also showed that these sets of genes are enriched in neuropeptide hormone and serotonin gene ontology categories, and that 4 of 7 chosen genes were validated for their effects on sexual aggression. Overall, this thesis sheds light on the complex mechanisms that underlie variation in these social behaviours, and it paves the way for future research to further elucidate some of these mechanisms, especially on the genetic basis of sociability using the evolved lineages I generated. / Thesis / Doctor of Philosophy (PhD) / Individual animals tend to vary in many traits including social behaviours. Using fruit flies, my goal was to understand what causes individuals to vary in two social behaviours: sociability and sexual aggression. I found that highly sociable flies tended to influence other flies to become more sociable due to a change in how much these flies interacted. I also found that individual differences in sociability are moderately heritable, and the genetic variation contributing to this is different between the sexes. Also, less sociable flies tended to be more aggressive than highly sociable flies. Finally, for sexual aggression, I showed that variation in a male’s success in forcibly mating with a female was associated with changes in the expression of hundreds of genes, but these changes were mostly unique for evolved versus environmentally induced variation. Future work will similarly look to identify genes involved with individual differences in sociability.
16

[pt] MODELOS ESTATÍSTICOS COM PARÂMETROS VARIANDO SEGUNDO UM MECANISMO ADAPTATIVO / [en] STATISTICAL MODELS WITH PARAMETERS CHANGING THROUGH AN ADAPTIVE MECHANISM

HENRIQUE HELFER HOELTGEBAUM 23 October 2019 (has links)
[pt] Esta tese é composta de três artigos em que a ligação entre eles são modelos estatísticos com parametros variantes no tempo. Todos os artigos adotam um arcabouço que utiliza um mecanismo guiado pelos dados para a atualização dos parâmetros dos modelos. O primeiro explora a aplicação de uma nova classe de modelos de séries temporais não Gaussianas denominada modelos Generalized Autegressive Scores (GAS). Nessa classe de modelos, os parâmetros são atualizados utilizando o score da densidade preditiva. Motivamos o uso de modelos GAS simulando cenários conjuntos de fator de capacidade eólico. Nos últimos dois artigos, o gradiente descentente estocástico (SGD) é adotado para atualizar os parâmetros que variam no tempo. Tal metodologia utiliza a derivada de uma função custo especificada pelo usuário para guiar a otimização. A estrutura desenvolvida foi projetada para ser aplicada em um contexto de fluxo de dados contínuo, portanto, técnicas de filtragem adaptativa são exploradas para levar em consideração o concept-drift. Exploramos esse arcabouço com aplicações em segurança cibernética e infra-estrutura instrumentada. / [en] This thesis is composed of three papers in which the common ground among them is statistical models with time-varying parameters. All of them adopt a framework that uses a data-driven mechanism to update its coefficients. The first paper explores the application of a new class of non-Gaussian time series framework named Generalized Autoregressive Scores (GAS) models. In this class of models the parameters are updated using the score of the predictive density. We motivate the use of GAS models by simulating joint scenarios of wind power generation. In the last two papers, Stochastic Gradient Descent (SGD) is adopted to update time-varying parameters. This methodology uses the derivative of a user specified cost function to drive the optimization. The developed framework is designed to be applied in a streaming data context, therefore adaptive filtering techniques are explored to account for concept-drift.We explore this framework on cyber-security and instrumented infrastructure applications.
17

Vocal communication in bonobos (Pan paniscus) : studies in the contexts of feeding and sex

Clay, Zanna January 2011 (has links)
Despite having being discovered nearly 80 years ago, bonobos (Pan paniscus) are still one of the least well understood of the great apes, largely remaining in the shadow of their better known cousins, the chimpanzees (Pan troglodytes). This is especially evident in the domain of communication, with bonobo vocal behaviour still a neglected field of study, especially compared to that of chimpanzees. In this thesis, I address this issue by exploring the natural vocal communication of bonobos and its underlying cognition, focusing on the role that vocalisations play during two key contexts, food discovery and sex. In the context of food-discovery, I combine observational and experimental techniques to examine whether bonobos produce and understand vocalisations that convey meaningful information about the quality of food encountered by the caller. Results indicate that bonobos produce an array of vocalisations when finding food, and combine different food-associated calls together into sequences in a way that relates to perceived food quality. In a subsequent playback study, it was demonstrated that receivers are able to extract meaning about perceived food quality by attending to these calls and integrating information across call sequences. In the context of sexual interactions, I examine the acoustic structure of female copulation calls, as well as patterns in call usage, to explore how these signals are used by individuals. My results show that females emit copulation calls in similar ways with both male and female partners, suggesting that these signals have become partly divorced from a function in reproduction, to assume a greater social role. Overall, my results highlight the relevance of studying primate vocalisations to investigate the underlying cognition and suggest that vocalisations are important behavioural tools for bonobos to navigate their social and physical worlds.
18

L'influence de la compétition alimentaire, des pressions de prédation, d'infanticide et de copulation sur les comportements dirigés vers soi des femelles Colobus vellerosus

St-Onge, Charlotte 12 1900 (has links)
Les comportements dirigés vers soi (CDS) tels que l'autotoilettage, les grattements et les bâillements peuvent être des indicateurs indirects de stress chez les mammifères. Comprendre si ces comportements associés au stress coïncident avec des facteurs de stress sociaux ou écologiques devrait permettre d'identifier les éléments de la vie en groupe qui causent plus de stress chez les femelles. Pour déterminer les pressions de la vie en groupe pouvant générer du stress chez les femelles Colobus vellerosus à Boabeng-Fiema Monkey Sanctuary (BFMS), au Ghana, j’ai cherché à savoir si les CDS variaient selon : H1) La compétition alimentaire, qui peut augmenter en intensité avec le nombre de congénères qui sont en compétition pour les mêmes ressources nutritionnelles ; H2) La pression de prédation, qui peut augmenter avec un nombre total d'individus moins élevé, car cela réduit la détection des prédateurs; H3) Le risque d'infanticide, qui augmente avec le nombre de mâles adultes et les renversements de pouvoir par les mâles, car les relations de dominance masculine sont souvent contestées dans les groupes multimâles ; et H4) La pression de copulation, qui augmente lorsque les femelles sont en oestrus et s'engagent dans des comportements sexuels, ce qui peut conduire les mâles à être agressifs et coercitifs envers elles. Pour ce faire, j'ai utilisé des données longitudinales sur les grattements, l’autotoilettage et les bâillements collectées auprès de 64 femelles adultes à BFMS de 2004 à 2019. J'ai comparé les taux mensuels de CDS des femelles en fonction de la taille des groupes, de l'interaction entre le nombre de mâles et la survenue ou non d'un renversement par les mâles, et de la présence de comportements sexuels féminins. Alors que l'autotoilettage et le bâillement ne variaient pas de manière significative en fonction de nos variables, les femelles se grattaient davantage au cours des mois où il y avait plus de mâles et/ou un renversement (équations d'estimation généralisées : P < 0,05), ainsi que lorsqu'elles ont exprimé plus de comportements sexuels (P < 0,05). Ces résultats soutiennent les hypothèses du risque d'infanticide et de la pression de copulation suggérant que les stratégies reproductives des mâles expliquent le mieux le stress chez les femelles. Ceci apporte une évidence supplémentaire que la pression d'infanticide, déjà connue pour influencer la composition des groupes et le développement de la progéniture chez C. vellerosus, affecte les comportements des femelles et leur réponse au stress. Cela permet donc une meilleure compréhension de la socialité chez les primates par l’étude des facteurs de stress vécus par les femelles qui déterminent, dans une certaine mesure, la formation des groupes. / Self-directed behaviors (SDB) such as self-grooming, scratching, and yawning can be indirect stress indicators in mammals. Understanding whether behaviors associated with stress co-occur with social or ecological pressures can help identify the elements of group life that cause more stress for females. To determine which pressures of group-living may lead to stress in female Colobus vellerosus at Boabeng-Fiema Monkey Sanctuary (BFMS), Ghana, I investigated whether SDBs varied according to: H1) Feeding competition, which may increase in intensity with the number of conspecifics competing for the same nutritional resources; H2) Predation pressure, which may increase with fewer total individuals, as this reduces predator detection; H3) Infanticide risk, which increases during male group take-over and with the number of adult males because male dominance relationships are often contested in multi-male groups in this population; and H4) Mating pressure, which increases when females are in estrus and engage in copulations, and may lead to males being aggressive and coercive toward females. I used longitudinal data on three SDBs, namely scratching, self-grooming and yawning, by 64 adult females at BFMS from 2004 to 2019. I compared female monthly SDB rates according to group size, an interaction effect between the number of males and whether a male group takeover occurred, and the presence of female sexual behaviors. While self-grooming and yawning did not vary significantly with the predictor variables, females scratched themselves more during months in which more males were present and/or a takeover occurred (Generalized Estimating Equations: P < 0.05), as well as when more sexual behaviors occurred (P < 0.05). The results support the infanticide risk and mating pressure hypotheses and suggest that the reproductive strategies of adult males best explain female stress. This provides further evidence that infanticide pressure, already known to influence group composition and offspring development in C. vellerosus, affects female behaviors and their stress response. This allows a better understanding of sociality in primates by studying the stressors experienced by females that determine, to some extent, group formation.

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