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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.
31

Self-concept, inner residue of past relationships and current social functioning. : A study of age and gender differences in normal and antisocial adolescents.

Östgård-Ybrandt, Helene January 2004 (has links)
This thesis presents several studies of normative development in adolescence, focusing specifically on internalized perceptions of parents’ early behavior and how these perceptions affect the self-concept and social functioning during. Questions of possible age and gender differences in relation to perceptions of self-concept and early parental behavior are addressed. The patterns found in a normal adolescent group are compared with those in a group of adolescents with antisocial problems. Two hundred seventy-seven normal adolescents aged 12 to18 and 30 adolescents with antisocial problems aged 13-19 were investigated. The following self-administered instruments were used: self-concept assessments, the Structural Analysis of Social Behavior (SASB) introject questionnaire, perception of early parental behavior assessment, the SASB mother/father questionnaires, and the EMBU (A Swedish acronym for “own memories of upbringing”). The Youth Self Report checklist (YSR) was used to assess internalizing and externalizing problems. Studies I and II showed that the normal adolescent self-concept and perception of early parental behavior were positive and that there were no age or gender differences. The antisocial group of adolescents, and particularly the antisocial girls, showed a more autonomous and negative self-concept and more negative perceptions of early parental behaviors. Study III showed that a positive self-concept was related to a positive perception of parent’s early behavior. Study IV showed that an adolescent’s positive self-concept was influenced by a mix of mother acting positively and father acting with control. Adolescent self-control was indirectly influenced by parental control behavior mediated through self-affiliation. Study V showed that a positive self-concept was important for adjustment. A negative self-concept combined with female gender was a risk factor for internalizing problems. Self-control had only a small effect on social adjustment in adolescence. The relationship between a negative self-concept and externalizing problem behavior was stronger for adolescents aged 15 to 16 than for younger or older adolescents. Internalizing problem behavior influenced externalizing problems. The results presented in this thesis support a modified “storm-and-stress” view of adolescence and highlight the importance of promoting a positive self-concept in every adolescent in various psychosocial contexts.
32

Biologia reprodutiva do opilião Acutisoma proximum (Arachnida: Opiliones) : estrategias alternativas de acasalamento em machos e cuidado parental em femeas / Reproductive biology of the harvestman Acutisoma proximum (Arachnida: Opiliones) : alternatives mating strategies among males and maternal care

Buzatto, Bruno Alves 14 February 2008 (has links)
Orientador: Glauco Machado / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T19:09:12Z (GMT). No. of bitstreams: 1 Buzatto_BrunoAlves_M.pdf: 2595917 bytes, checksum: 7cd5fddc87dd0679ff5084fa4c88a530 (MD5) Previous issue date: 2008 / Resumo: A presente dissertação investigou a biologia reprodutiva do opilião Acutisoma proximum no Parque Estadual Intervales, sul do estado de São Paulo. No Capítulo 1, o sistema de acasalamento da espécie é descrito em detalhes. Fêmeas depositam seus ovos sob folhas na vegetação que margeia riachos de interior de mata e utilizam preferencialmente determinadas espécies de plantas como sítio de oviposição. No começo da estação reprodutiva, machos lutam entre si pela posse de territórios na vegetação onde fêmeas se reproduzirão. Alguns meses mais tarde, na mesma estação reprodutiva, essa poliginia por defesa qe recursos muda para uma poliginia por defesa de fêmeas, e machos passam a guardar cada fêmea individualmente em seqüência. O opilião A. proximum é o primeiro aracnídeo não-acarino que apresenta uma mudança em seu sistema de acasalamento ao longo da estação reprodutiva. No Capítulo 2, são descritas duas estratégias alternativas de acasalamento entre os machos de A. proximum, e a morfologia.e o comportamento dos machos que adotam cada estratégia é investigado. Os machos de A. proximum se dividem em dois morfos distintos, de acordo com a relação alométrica do comprimento da perna lI, que é também mais longa nos machos do que nas fêmeas. A diferença na morfologia dos dois morfos só é detectável quando muitos machos são medidos e a relação entre o comprimento do segundo par de pernas e o tamanho do corpo são analisados, o que se encaixa na definição de dimorfismo intra-sexual críptico. Machos com pernas II longas defendem territórios na vegetação, brigando e repelindo outros machos que se aproximam das fêmeas dentro desses territórios. Machos com pernas II curtas nunca defendem territórios ou brigam. Eles se deslocam entre os territórios dos machos grandes, invadindo-os e copulando com as fêmeas que estão dentro deles. Este trabalho é o primeiro a descrever, com dados comportamentais e morfológicos, a existência de estratégias alternativas de acasalamento na ordem Opiliones. No Capítulo 3, o enfoque passa a ser as fêmeas e os custos e benefícios do cuidado maternal em A. proximum. Em um experimento de remoção de fêmeas guardiãs, os ovos desprotegidos sobreviveram 75,6% menos que os ovos protegidos pelas fêmeas, revelando a importância da proteção materna. Em outro experimento, as desovas de metade das fêmeas foram removidas e o sucesso reprodutivo delas foi monitorado por dois anos. Fêmeas impedidas de cuidar da prole produziram novas desovas mais frequentemente e tiveram um sucesso reprodutivo 18 % maior que o das fêmeas que cuidaram da prole. Adicionalmente, o estudo de captura-marcação-recaptura não demonstrou nenhuma diferença entre a sobrevivência de fêmeas que foram impedidas de cuidar da prole e fêmeas que cuidaram da prole. Pesando os custos e benefícios do comportamento de guarda de ovos, uma estratégia de abandono da prole implicaria em uma redução média de 73,3% no sucesso reprodutivo total das fêmeas. Apesar dos custos da guarda de ovos para a fecundidade das fêmeas, o cuidado maternal aumenta o seu sucesso reprodutivo devido à crucial proteção aos ovos fornecida pelas fêmeas / Abstract: Not informed. / Mestrado / Ecologia / Mestre em Ecologia
33

Wild at heart? : differential maternal investment in wild and domesticated zebra finches (Taeniopygia guttata)

Pariser, Emma C. January 2010 (has links)
Over the past twenty years there has been an exponential increase in the investigation of maternal effects. Understanding the adaptive function of maternal allocation strategies is integral to interpreting the evolutionary outcomes of sexual selection. Thus, model animal systems that facilitate experimental manipulation and controlled investigation of the physiological and behavioural mechanisms underlying maternal effects are important to evolutionary biologists. The zebra finch (Taeniopygia guttata) has been used as a model to investigate avian life-history, signalling behaviour, neurophysiology, mate choice, and more recently, maternal effects. However, a potentially influential and rarely addressed problem with this species is the process of domestication. Within this thesis we aimed to both test current predominant maternal allocation hypotheses, but for the first time in both domesticated and wild zebra finches. Chapter 2 develops on earlier work using domesticated zebra finches that has demonstrated differential allocation of maternally derived yolk androgens and antioxidants in eggs dependent on paternal attractiveness. This chapter specifically tests the ratio of these two yolk resources within individual eggs and shows that the balance of androgens to antioxidants varies by offspring sex and paternal attractiveness. Specifically, we found that mothers allocated a smaller androgen to antioxidant ratio to daughters when paired to green ringed (unattractive) males compared to red ringed (attractive) males. This pattern was reversed for sons, where mothers allocated a larger ratio of androgen to antioxidant when paired to red ringed (attractive) compared to green ringed (unattractive) males. We also show that brood sex ratio depended on both female condition and male attractiveness. It is concluded that investigating female allocation of individual resources within egg yolks may lead to incorrect assumptions on offspring fitness consequences, and that individual female state is an important consideration when predicting a resource allocation strategy. Throughout this thesis colour bands are used as a method to manipulate male attractiveness. In chapter 3 the influence of these bands was further tested to elucidate whether they affect male behaviour or quality. Wild birds were used for this chapter as preferences for bands based on colour have only once been demonstrated in wild birds and it was felt this should also be replicated. We confirmed a female preference for males based on colour bands worn in mate choice trials, with red bands preferred over green. Interestingly, we also found that colour of bands worn by males for an extended period in the single sex aviary influenced both their song rate and condition. Males that had worn red bands sang more in mate choice trials than both green banded or un-banded males. In addition red banded males were found to be in significantly better physical condition. These data suggest that earlier experiments in which it has been assumed that colour bands do not manipulate any form of intrinsic male quality should be re-evaluated. The final two data chapters, 4 and 5, return to investigating maternal allocation in response to male attractiveness, but for the first time in wild birds. Chapter 4 presents an experiment that was conducted on a wild, nest box breeding population of birds. Maternal resources allocation was investigated in both an experimental manipulation of male attractiveness, and also by correlating resource allocation with paternal phenotypic traits. A limited sample size meant few conclusions could be drawn from the experimental study, but significant positive correlations were found between both egg size and yolk testosterone (T) concentration and male phenotypic traits. This suggested that wild zebra finches may follow a positive investment strategy but requires further investigation. In chapter 5 experiments were repeated on wild birds that had been brought into captivity, to allow both an improved sample size and further control of influential environmental features. Again, female allocation strategies are tested using colour bands to manipulate male attractiveness, to allow direct comparisons with work on domesticated zebra finches. We found that females laid significantly heavier eggs for attractive compared to unattractive males, supporting the positive investment hypothesis. In addition we found an interaction between offspring size and paternal attractiveness treatment, with daughters of red banded (attractive) males being smaller than sons. This experiment is the first to demonstrate the influence of colour bands on maternal allocation in wild zebra finches and also provides further support for the positive investment hypothesis in this species. The final chapter discusses how overall patterns of female allocation were shown to be similar among wild and domesticated populations. It is concluded that demonstrated variations between populations and/or contexts reported in these studies cannot be explained by inherent differences between wild and domesticated individuals. Thus, the zebra finch remains a robust and reliable model for testing the evolution of avian maternal allocation strategies.
34

Life history and environmental influences on avian incubation and parental care in songbirds

Austin-Bythell, Suzanne H. 13 March 2015 (has links)
Patterns of nest attendance behavior by breeding birds represent a parent-offspring trade-off in which adults balance self-maintenance with parental care decisions. Incubation, in particular, is of interest because adults must provide an environment suitable for embryonic development through nest-building and contact-incubation. We evaluated how adult incubation constancy and nest visitation rates varied with life and natural history traits of temperate and tropical bird species. We found that constancy did not differ by latitude or with nest survival rate. A strong negative correlation between incubation constancy and egg mass relative to adult body mass was present. Birds with low constancy tended to have larger relative egg masses and higher basal metabolic rate. Because adult incubation constancy is relatively plastic (i.e., varies with ambient temperature), birds with larger relative eggs may respond to lower cooling rates rather than direct selection for higher or lower constancy. We then assessed if rates of nest visitation (trips to nests by adults during incubation and nestling phases) followed the predictions of the Skutch hypothesis. Skutch suggested that birds nesting in environments with high levels of nest predation would reduce numbers of trips to their nests so as to minimize the risk of visual detection by nest predators. We found support for the basic pattern predicted by Skutch. We also extended his hypothesis to predict other behavior associated with nesting, such as responses of parents to intruders at the nest. Despite apparently early departure from the nest site, adults with higher visitation rates remained conspicuous around the nest site. Thus, while the flight initiation distance from the human observer was earlier than expected, conspicuousness of behavior was associated with nest visitation rate. Finally, we assessed how an environmental variable, photoperiod, might influence rate of embryonic development in a wild songbird, Sylvia atricapilla. We exposed eggs throughout the incubation period to daily photoperiods consisting of 4 hours of light and 20 hours of dark (4L), 12 hours light and 12 hours dark (12L), 20 hours light and 4 hours dark (20L) and a skeleton photoperiod with two 1-hour pulses of light that framed a 20-hour day. We found that the skeleton treatment group differed significantly from our 4L and 12L, but not the 20L treatment groups. The skeleton photoperiod accelerated embryonic development. We suggest that photoperiod may influence incubation period in wild birds and could account for some portion of the widely observed latitudinal variation in incubation period of songbirds. We encourage others to assess how photoperiod interacts with parental attendance patterns to affect embryonic development. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from March 13, 2013 - March 13, 2015
35

Behavioral Observation and Paternal Investment of Eastern Kingbirds at Malheur National Wildlife Refuge

Chutter, Christopher Michael 10 July 2014 (has links)
We have been studying the population of Eastern Kingbirds breeding in riparian habitats in Malheur National Wildlife Refuge (eastern Oregon) since 2002. These efforts have created an ideal research environment wherein most adults in the population have been color banded and DNA sampled and, as part of other research projects, nearly all broods since 2003 have been paternity tested. I decided to use behavioral video recordings of parental nest behavior undertaken between 2003 and 2010 for two unrelated projects. First, I tested the effectiveness of video sampling nesting behavior (see below and chapter 2). Second, I tested whether male kingbirds were able to affect their level of paternal investment in accordance with their level or realized paternity (see below and chapter 3). Chapter 2 was split into three distinct questions: 1) are parental nesting behaviors repeatable, 2) is a one hour sample sufficient to capture variability in these behaviors, and 3) is the first hour of recording sufficient to capture variability in these behaviors. I found overwhelming evidence that the behaviors I measured were repeatable. This is truly important, for if repeatability was disproven, it would call into question the use of sampling throughout the field of animal behavior. I similarly found strong evidence that a one hour sample was sufficient to capture variability in parental behaviors. From this I was able to suggest that further sampling effort would be better spent increasing sample size rather than observation length. Testing whether the first hour of recording was sufficient to capture variability in parental behavior found more muddled results. While there generally was correlation between behavioral values in the first hour and those over a longer observation period, most behaviors were found to have significantly lower values in the first hour. I tested whether this was the result of a lingering observer effect or a natural effect of time of day and concluded that an observer effect was the more likely explanation. In chapter 3, I ran one of the more in depth and complicated tests for a relationship between paternal investment and realized paternity that I was able to find in the literature. I used the standard male feeding rate as a measure of male investment as well as a far more nuanced measure derived from the first Eigenvector of an analysis of six different paternal behaviors. These were both tested using Akaike's Information Criterion against a number of variables likely to affect parental behavior, including realized paternity. Ultimately, I found no evidence that kingbirds were able to affect paternal investment in response to lost paternity, and conclude that they likely had no means to assess realized paternity within the nest of their social mate. However, from the other parameters tested I was able to find that males increased their investment as brood size increased and as the female spent more time attending, but not feeding, the nestlings. Also, male investment decreased as territory density increased and flight feather length increased. Theory surrounding the variability of extrapair paternity in birds can be used to account for these results. In a denser population males are predicted to reduce paternal effort for one of two reasons: increased likelihood of paternity loss in his own nest and an increased investment in pursuing extrapair copulations of his own. Longer flight feathers are a sign of age and quality in kingbirds, so males with this trait are expected to spend more time pursuing extrapair copulations as they are more likely to be successful in this endeavor.

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