Os comportamentos agonísticos sociais dispostos por animais dominantes e subordinados podem ser notados no paradigma residente intruso. No hipotálamo há o núcleo pré-mamilar ventral (PMv) ligado a um sistema sexualmente dimórfico e relacionado a reprodução e comportamentos agonísticos. A cópula é fundamental para a modulação do comportamento de dominância e aumenta os níveis de CART (Cocaine and Amphetamine Regulated Transcript) no PMv. Animais knockout de Sintase do Óxido Nítrico (NOS) apresentam agressão acentuada. Através da hibridização in situ estudamos a expressão de CART e de NOS nos animais com experiência sexual prévia ao encontro agonístico e sem experiência sexual (naive). No grupo que copulou foi visto aumento na expressão de CART e comportamento diferente do grupo naive visto que buscam a dominância e não apresentam posturas de submissão. Este aumento não foi observado nos níveis de NOS. Sugere-se que a experiência sexual esteja relacionada ao aumento de CART no PMv e possivelmente perda do comportamento subordinado e aumento da busca da dominância. / Aggressive behavior occurs when the interests of one or more individuals conflict. Territory is one of these interests, and the resident intruder paradigm is widely used to observe the expression of social agonistic behaviors. The dominance behavior has been studied under several views and it was shown that it can be raised by the presence of the female, its olfactory clues and by the sexual behavior. In the hypothalamus there is the premammillary ventralis nucleus (PMv) connected to a sexual dimorphic system and related to reproduction and agonistic behaviors. This nucleus was suggested as being involved in the modulation of aggressive behavior, and PMvs neuropeptides can have a direct relation with the expression of those agonistic behaviors. Males exposed to females olfactory clues show an increase in the expression of CART (C Cocaine and Amphetamine Regulated Transcript) in the PMv. Nitric oxide synthase (NOS) knockout animals show increased aggression. In the present investigation, using in situ hybridization we studied the expression of the mRNA of CART and NOS on intruders exposed to the resident-intruder paradigm. Two experimental groups were examined: one with sexual experience before the agonistic encounter and other naïve. It was observed increased expression of CART in the PMv in the sexual-experienced intruder. More, these animals behaved differently from naive intruders, and did not display submissive postures and start searching for dominance. Sexual experienced intruders presented increased expression of CART, but not NOS, mRNA. Thus, suggesting that the sexual experience is related to an increase in CART expression in the PMv and possibly with the lost of submissive behavior and increased search for dominance status.

" In this study, I investigated the ritualized fights of male Nannacara anomala to show that each distinct phase (lateral display, tail beating, and mouth wrestling) of the fight is used to assess a different aspect of resource holding potential (aggressiveness, body size and swimming performance). When animals go into an agonistic encounter, they often have little or no previous knowledge of their opponent's fighting ability (or resource holding potential). Assessment is the process by which strangers gain information about each other through repetition of informative behaviors. Generally fights are ritualized so that specific behaviors are associated with distinct phases within the fight. Aggressiveness of fish was established by measuring response time to an aggressive conspecific. Weight was used as a measure of body size. Swimming performance (stamina and maximum swimming speed) was determined by swimming each fish in a variable speed flow tank. If all fights are taken into consideration, weight is the only factor for which winners were significantly different from losers (p = 0.009). However, if the fights are classified by the phase in which they ended, fights ending in tail beating have larger winners (p = 0.003) and fights ending in mouth wrestling have faster winners (p = 0.008). Opponents are using early stages of fights to assess body size and escalated stages to assess performance characteristics."

A agressão maternal tem como função preservar a vida da prole. O desenvolvimento desse comportamento depende vastamente do reconhecimento do adversário como uma ameaça potencial e esse reconhecimento envolve a detecção de pistas feromonais. O núcleo pré-mamilar ventral (PMv) é um dos principais alvos do núcleo medial da amígdala, que representa o setor amigdalar crítico para o processamento de pistas feromonais. Desta forma, postulamos que possivelmente o PMv seja sensível às pistas feromonais do macho intruso, servindo como uma possível interface para os sistemas neurais envolvidos na agressão maternal. Neste sentido, inicialmente avaliamos o padrão de ativação do PMv, bem como alguns de seus alvos de projeção, durante o comportamento maternal e durante a agressão maternal. Notamos que tanto o PMv como a maioria de seus alvos principais (tais como, o núcleo posterior da amígdala, a parte posterodorsal do núcleo medial da amígdala, a área hipotalâmica lateral tuberal e a parte ventrolateral do núcleo ventromedial) apresentam um aumento significativo na expressão da proteína Fos durante a agressão maternal. Em seguida, avaliamos o papel do PMv na organização neural do comportamento de agressão maternal, em ratas lactantes portadoras de lesões citotóxicas com NMDA do PMv. Os resultados obtidos neste estudo demonstram que as fêmeas lactantes com lesão no PMv não apresentam qualquer alteração nos parâmetros comportamentais relacionados ao comportamento maternal, mas apresentam uma significante diminuição no comportamento agressivo maternal. Observamos ainda, que a lesão citotóxica do PMv resultou numa drástica diminuição da expressão da proteína Fos em alguns sítios de projeção do PMv que se apresentavam mobilizados durante a agressão maternal (tais como a parte ventrolateral do hipotálamo ventromedial, a área hipotalâmica lateral tuberal e o núcleo pré-óptico medial), sugerindo a participação destes sítios neurais como críticos na expressão do comportamento de agressão maternal. / Maternal aggression is critical to preserve the litters from male intruders, and the pheromonal cues from the males are important to drive such responses. The ventral premamillary nucleus (PMv) is one of the main targets of the medial amygdalar nucleus, and is critically involved in processing pheromonal information. In this regard, in the present study, we investigated whether the PMv would work as a putative interface between the pheromonal processing of the male intruder and the neural sites potentially involved in the expression of maternal aggression. First, we analyzed the pattern of Fos expression in dams expressing aggressive maternal behavior, and found a significant increase in Fos levels in the PMv, as well as, in most of its main targets, such as the posterior amygdalar nucleus, the posterodorsal part of the medial amygdalar nucleus, the tuberal nucleus of the lateral hypothalamic area, and the ventrolateral part of the ventromedial nucleus. Next, we examined how NMDA lesions bilaterally placed in the PMv would interfere in maternal aggression, and found that dams bearing those lesions presented a significant reduction in the expression of aggressive behavior, but showed no alterations on the maternal behavior responses. Moreover, we were able to see that PMv lesions resulted in significant drop in Fos expression in selected PMv targets, namely the tuberal nucleus of the lateral hypothalamic area and the ventrolateral part of the ventromedial nucleus, likely to be critically involved in the expression of the maternal aggression. Overall, the present results support the idea that the PMv is seemingly a key site in the network controlling maternal aggression; on one hand, the nucleus is likely to processes pheromonal cues from the intruder male, and, on the other, it conveys this information to sites critically related to the expression of maternal aggression.

本研究試圖通過在進化心理學理論的框架內解釋和預測男性的攻擊和創造力。該框架基於性選擇理論，該理論認為人類的許多特質，包括攻擊和創造力可能與性選擇的進化過程有關。人的很多行為因受到性間和性內選擇壓力的影響，而會對具體的擇偶情境作出特定的反應。達爾文的性選擇理論提出，性間選擇壓力與裝飾品式的行為有關，而性內選擇壓力與武器式的行為有關。本論文通過三個實證研究，同時探討這兩種選擇壓力引發的擇偶情境與男性行為之間的關係。我假設性間選擇與創造力相關，而性內競爭與攻擊性相關。 / 在研究1和2中，通過實驗區分兩種擇偶情境來啟動性間和性內選擇相應的動機。具體來說，我要求大學生被試實際參與一個與異性約會的模擬遊戲（研究1）或者想像一個約會情景（研究2），並告知他們的行為表現會讓這一異性評價或者讓其他同性追求者評價。接著他們分別完成測量創造力（即，“納入類別任務“和“不同尋常用法任務“）和攻擊行為（“競爭性反應時任務“）的任務，被試在兩個任務的表現分別代表他們的裝飾品式行為和武器式行為。研究1和2的結果都一致地顯示，與男性大學生在性內選擇條件下相比，男性大學生在性間選擇條件下表現出更高的創造力但是更低的攻擊性。而對於女性大學生來說，他們在性間和性內兩個條件下的創造力和攻擊性表現沒有差異。研究3進一步探討對於裝飾品式行為和武器式行為特點不同的男性，他們是否會參與不同的擇偶策略（異性吸引或同性競爭）來獲得異性配偶。也就是說，有創造力的男性更傾向於採取異性吸引的策略，而攻擊性的男性則更傾向於採取同性競爭的策略。該研究使用問卷調查，118名男性大學生被試完成創造力和攻擊性相關的人格量表以及自編擇偶策略問卷。多元回歸分析結果顯示，創造力與異性吸引策略相關，而攻擊性與同性競爭策略相關。 / 本論文的三個研究結果支持了基於達爾文的性選擇理論的假設，男性使用創造力作為吸引女性的裝飾品，因此性間選擇與創造力相關；而男性也會使用攻擊來作為武器去跟同性競爭，因此性內選擇與攻擊相關。本研究結果具有如下的研究和實際意義。首先，現有的文獻只是在比較不同物種所具有的專門化擇偶策略時，才會功能性地區分性間與性內選擇壓力。本研究顯示這兩類選擇壓力對人類男性同樣適用。不同的選擇壓力還會造成物種內的個體差異性。如本研究的結果所示，男性在應對這兩種類型選擇壓力時會選擇性地做出反應，表現出獨特的行為來。其次，裝飾品式和武器式的擇偶策略不僅能夠依據不同的情境而被啟動，而且還會被看做是不同的人格特質，允許個體優化他們的性間選擇或性內競爭。第三，基於對人類這兩類行為的終極功能的進化理解，本研究結果有助於發展教育情境內（干預）專案或者課程，以提高學生的創造力及降低攻擊性。 / The present study examines male aggression and creativity as functions of inter-and intra-sex context within the framework of sexual selection. According to sexual selection theory, both intra-sexual competition, mainly among the unlimited sex, or males, and mate choice, mostly by the limiting sex, or females, lead to wide ranging sex dimorphic attributes, which are referred to as weapons (e.g., aggression) and ornaments (e.g., creativity). Within this evolutionary framework, I tested the hypothesis that inter-sexual courtship was associated with creativity as an ornament-like behavior, whereas intra-sexual competition was associated with aggression as a weapon-like behavior. / In the first two studies, I experimentally manipulated two mating situations to prime the motivation either for inter- or intra-sex selection in the laboratory. Specifically, these two motivations were manipulated by having university undergraduate students participate in a simulated dating game (Study 1) or imagine a romantic mating situation (Study 2) with their performance being evaluated either by a female date or male suitors. A set of creativity tasks (i.e., Category Inclusion Task and Unusual Uses Task) and an aggression task (Competitive Reaction Time Task) were used to measure ornament- and weapon-like behavior, respectively. The results in both Study 1 and 2 provided the consistent evidence, showing that men under the intra-sexual selection condition showed a higher level of aggression and lower level of creativity than men under the inter-sexual selection condition. For women, there was no difference between inter-sexual and intra-sexual selection conditions. In Study 3, I further examined whether individual differences in ornament- and weapon-like traits might influence men’s mating behaviors. I hypothesized that creative men tended to engage in inter-sexual courtship, whereas aggressive men tended to engage in intra-sexual competition. Survey data based on 118 male undergraduate students from a Chinese university showed that creativity, but not aggression, predicted inter-sexual courtship whereas aggression, but not creativity, predicted intra-sexual competition. / Together, these studies support the evolutionary theory that inter-sex courtship was related to creativity which men employed as an ornament to attract females, whereas intra-sex competition was related to aggression which men used as weapons. These findings have several implications. First, I showed the same functional distinction between intra- and inter-sex selection pressures on human males. The existing literature draws such functional distinction only when comparing different species with specialized mating strategies. Different selection pressures also act on individuals within the same species to create individual differences. As shown in the present study, men might selectively respond to these two kinds of sexual selection pressures with distinct behaviors. Second, both ornament- and weapon-like mating strategies are not only situationally activated but can also be regarded as personality traits that allow individuals to optimize either intra-sexual competition or inter-sexual courtship. Third, the results may help to develop educational programs aimed at increasing creativity and reducing aggression that are based on the evolutionary understanding of the ultimate functions of these two human behaviors. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chen, Binbin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 60-83). / Abstract also in Chinese; appendixes include Chinese. / Abstract --- p.ii / 摘 要 --- p.v / Acknowledgements --- p.vii / Chapter CHAPTER 1： --- INTRODUCATION --- p.1 / The Evolutionary Framework of Sexual Selection --- p.2 / Sexual Selection --- p.2 / Weapon and Ornament --- p.6 / Evidence on Inter-sexual Selection on Ornaments --- p.7 / Evidence on Intra-sexual Selection on Weapons --- p.8 / Men’s Mating Psychology --- p.9 / Sexual Over-perception Bias --- p.9 / Unrestricted Sexual Behavior --- p.10 / Sexual Jealous --- p.11 / Ornament- and Weapon-like Behaviors --- p.12 / Sexual Selection on Creativity and Aggression --- p.16 / Creativity as an Ornament under Inter-sexual Selection --- p.17 / Aggression as a Weapon under Intra-sexual Selection --- p.19 / The Current Research --- p.21 / Chapter CHAPTER 2: --- EMPERICAL EVIDENCE --- p.23 / Study 1 --- p.23 / Method --- p.23 / Results and Discussion --- p.27 / Study 2 --- p.30 / Method --- p.30 / Results and Discussion --- p.32 / Study 3 --- p.35 / Method --- p.37 / Results and Discussion --- p.39 / Chapter CHAPTER 3: --- GENERAL DISCUSSION AND CONCLUSION --- p.41 / Inter- and Intra-sexual Selection on Creativity and Aggression --- p.41 / Educational Implications --- p.47 / Limitations and Future Directions --- p.50 / Conclusion --- p.55 / APPENDIX --- p.56 / REFERENCES --- p.60

Os eglídeos (Anomura, Aeglidae) são um grupo de crustáceos endêmicos do sul da América do Sul e restritos ao ambiente de água doce. Muitos aspectos da biologia e ecologia desses animais são bem conhecidos, porém, pouco se sabe sobre seu comportamento, principalmente o comportamento agressivo e a atividade em ambiente natural. É sabido que entre os animais, os conflitos são resolvidos por comportamentos agonísticos, termo que abrange uma gama de comportamentos de escape, exibições (“displays”), até um extremo do combate físico. Em um contexto ecológico, informações sobre os movimentos e a atividade dos animais são importantes para uma compreensão das exigências de hábitat, padrões de utilização dos recursos e o potencial de interações interespecíficas. A presente tese teve como objetivos: padronizar uma metodologia para análise do comportamento agressivo de eglídeos em laboratório; descrever o comportamento agressivo de Aegla longirostri; avaliar o comportamento agonístico de espécies provenientes de vertentes do lado Pacífico (espécies basais) e Atlântico (espécies derivadas) da América do Sul; comparar os padrões agressivos de fêmeas de A. longirostri e A. manuinflata, e; examinar os padrões de deslocamento, de atividade diária e de ocupação dos diferentes substratos por A. manuinflata em ambiente natural. Para os estudos sobre comportamento agressivo, os animais coletados foram mantidos em aclimatação por uma semana em aquários individuais, pareados para realização de interações intra-específicas e filmados durante 20 minutos, período que foi subdivido para realização das análises. A parir dos confrontos com A. longirostri foram descritos os atos comportamentais, com 16 atos agressivos, e foi estabelecida uma tabela de intensidade da agressividade, variando de -2 (fuga) a 5 (combate intenso). No estudo comparativo entre quatro espécies de Aegla, foi verificado que todas apresentaram comportamentos semelhantes, porém um indivíduo de Aegla denticulata denticulata, apresentou tanatose. O período de latência foi superior ao tempo investido em todos os encontros agressivos. Aegla longirostri, a espécie mais derivada (da vertente do Atlântico) foi a que apresentou maior intensidade agressiva média e a mais basal (da vertente do Pacífico), A. d. denticulata a menor intensidade. Aegla abtao, A. longirostri e A. manuinflata gastaram significativamente mais tempo lutando, prendendo ou agarrando o oponente do que os demais atos, enquanto A. d. denticulata passou 18,2% do tempo sem deslocamento, e não apresentou confronto intenso. Em todas as espécies foi verificada reversão da dominância. Entre as fêmeas, o comportamento é semelhante àquele observado nos machos das mesmas espécies. O período de latência foi mais longo do que qualquer encontro, e o primeiro foi em média mais longo que os demais. Houve uma baixa freqüência na reversão da dominância, o animal que venceu o primeiro encontro, conseqüentemente teve uma probabilidade maior de ser o vencedor final. Para ambas as espécies, o ato mais freqüente foi o de lutar e/ou prender e agarrar com o quelípodo, seguido pelo uso das antenas. A agressividade das fêmeas pode chegar a altos níveis, por vezes, superando a agressividade observada em machos. Para avaliar o deslocamento e a atividade de A. manuinflata em ambiente natural, machos adultos e em intermuda foram monitorados a cada três horas durante nove dias, através da técnica de rádio-telemetria. Os eglídeos apresentaram um deslocamento significativamente maior à montante e apresentaram maior atividade de deslocamento na fotofase escura; a atividade locomotora não foi constante, sendo verificado que os animais passaram um ou mais dias sem deslocamento. Os indivíduos apresentaram especificidade em relação à ocupação dos diferentes tipos de substrato. Esses estudos trazem informações inéditas relativas ao comportamento agressivo de eglídeos, o qual é semelhante ao observado em outros decápodos com quelípodos bem desenvolvidos, porém, muitas peculiaridades foram observadas. Além disso, os resultados do estudo de rádio-telemetria forneceram mais uma informação importante para estudos de conservação das espécies, demonstrando a importância da manutenção dos ambientes naturais para esses indivíduos. / The aeglids (Anomura, Aeglidae) are endemic crustaceans from south region of South America and restricted to freshwater environments. Although several biological and ecological aspects of these animals has already been studied little is known about their behavior, mainly its aggressive behavior and activity in the natural environment. It is known that among animals, conflicts are resolved through agonistic behavior, an expression of which embraces a range of fleeing behaviors, displays, up to the extreme of physical combat. In an ecological context, information on the movements and activity of animals is important for understanding their requirements of habitat, resource usage patterns and the potential of interspecific interactions. This thesis has the following goals: to standardize a method in order to analyze the aggressive behavior of aeglids in laboratory; to describe the aggressive acts of Aegla longirostri; to evaluate the agonistic behavior of species originated from slopes on the Pacific (basal species) and Atlantic (derived species) sides of South America; to compare aggressive pattern of A. longirostri and A. manuinflata females; and to examine the displacement pattern on daily activity and occupancy of substrates by A. manuinflata in natural environment. For the aggressive behavior studies the animals were kept for one week of acclimation in individual fishbowls, then paired for experiments of intraspecific interactions and videotaped for 20 minutes, period which were subdivided for analyzes. From combats with A. longirostri the behavioral acts were described, 16 were considered aggressive acts, and a table of aggression intensity was established, ranging from -2 (fleeing) to 5 (intense combat). Concerning the comparative study among four species of Aegla it was verified that all of them exhibited similar behaviors, but one individual of Aegla denticulata denticulata displayed thanatosis. The latency period was greater than the time invested in all aggressive encounters. Aegla longirostri, the most derived species (from Atlantic slope), was the species that displayed the highest average aggressive intensity and, the most basal species (from Pacific slope), A. d. denticulata the lowest intensity. Aegla abtao, A. longirostri and A. manuinflata spent significantly more time fighting, holding or catching the opponent than the other acts, while A. d. denticulata spent 18.2% of the time without any displacement and did not exhibit intense combat. Reversal of dominance was observed in all species. Female’s behavior is similar to that observed in conspecific males. The latency period was longest than any other encounter and the first one was in average the longest. There was a low reversal of dominance; the animal which won the first encounter consequently had a higher probability of being the final winner. For both species the most frequent act was fighting and/or holding and catching with the cheliped, following by the use of antennae. Female’s aggressiveness can reach high levels, overcoming sometimes the aggressiveness observed in males. To evaluate the displacement and activity of A. manuinflata in natural environment adult males in intermolt stage were monitored at every three hours during nine days through radio-telemetry technique. The aeglids showed a significantly greater displacement toward upstream and had the highest displacement activity on dark photophase; the locomotor activity was not constant, it was observed that the animals spent one or more days without any displacement. Individuals showed specific occupation of different types of substrate. These studies bring novel information concerning aggressive behavior of aeglids which is similar to the behavior observed in other decapods with developed chelipeds, although several peculiarities were noticed. Besides, the results from the radio-telemetry study provided more important information for conservation studies of species, demonstrating the importance of maintenance of natural environment for these animals.

Orientador: Eliane Gonçalves de Freitas / Banca: Eduardo Benedicto Ottoni / Banca: Eduardo Fernando dos Santos / Banca: Fernando Barbosa Noll / Banca: Fernando Rodrigues da Silva / Resumo: Este trabalho tem como objetivo testar se uma abordagem Bayesiana aprimora à análise de modelos longitudinais em estudo de comportamento agressivo em peixes. Discutimos as vantagens da análise Bayesiana ao lidar com variáveis agrupadas, resultados não estatisticamente significativos e número de réplicas utilizando o Acará Bandeira (Pterophyllum scalare), como estudo de caso. Além disso, em um segundo estudo com dados de quatro espécies de ciclídeo (Pterophyllum scalare, Oreochromis niloticus, Astronotus ocellatus e Cichlasoma), verificamos os diferentes tipos de viés que combinar variáveis baseando-se em critérios energéticos, pode causar na análise de dados. Por fim, em um terceiro estudo, nós construímos uma ferramenta estatística usando o pacote Shiny para permitir que modelos Bayesianos se tornem mais acessíveis para estudos longitudinais com agressividade. O delineamento dos dois primeiros estudos foi semelhante. Para cada espécie, 15 grupos de 3 indivíduos foram submetidos a observações diárias durante 10 minutos em 5 dias. Para o primeiro estudo, as variáveis comportamentais foram analisadas parcialmente combinadas de acordo com a intensidade do comportamento (Ataques e Displays), e completamente combinadas (soma de todas variáveis). Para o segundo, as variáveis comportamentais foram analisadas individualmente e parcialmente combinadas de acordo com a intensidade do comportamento (Ataques e Displays). As freqüências de cada registro foram modeladas usando cadeias de Mo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aims to test if a Bayesian approach improves the analysis of longitudinal models in the study of aggressive behavior in fish. We discuss the advantages of Bayesian analysis when dealing with combined variables, non-statistically significant results and the number of replicates using the Acará Bandeira (Pterophyllum scalare), as a case study. In addition, in a second study with data of four species of cichlid (Pterophyllum scalare, Oreochromis niloticus, Astronotus ocellatus and Cichlasoma), we have checked in more detail the possible bias types that pooling variables based on energetic criterion, can cause in the data analysis. Finally, we have developed a statistical tool using the Shiny package to allow Bayesian models to become more accessible for aggressive longitudinal studies. We have adopted a similar experimental design for the first two studies. For each species, 15 groups of 3 subjects were submitted to daily observations for 10 minutes, in 5 days. For the first study, the behavioral variables were analyzed partially combined according to the intensity of the behavior (Attacks and Displays) and completely combined (sum of all variables). For the second, the behavioral variables were analyzed individually and partially combined according to the intensity of the behavior (Attacks and Displays). The frequencies of each record were modeled using Monte Carlo Markov chains. The results show that combining variables, regardless of the criterion, can lead to biase... (Complete abstract click electronic access below) / Doutor

Orientador: Gilson Luiz Volpato / Banca: Leonardo José Gil Barcellos / Banca: Amauri Gouveia Junior / Banca: Rodrigo Egydio Barreto / Banca: Anette Hoffmann / Resumo: Os confrontos do peixe matrinxã Brycon amazonicus são agressivos e geralmente resultam até mesmo em morte do subordinado. Como é uma espécie bem armada, inicialmente o matrinxã é cauteloso e, com o estabelecimento hierárquico, o dominante progride em ataques até a morte do oponente, mesmo sem este os revidar. Aqui mostramos também que o matrinxã possui alta motivação agressiva mesmo ainda na fase cautelosa da luta. No entanto, esse comportamento agressivo não ocorre sob qualquer contexto. Testamos díades de matrinxãs e observamos que com aumento do espaço disponível os matrinxãs convivem nadando em schooling, com pouca ou nenhuma interação agressiva. Já em espaço reduzido, disputam agressivamente a dominância; entretanto, mesmo que tenha sido definido um dominante, se o espaço disponível aumentar os peixes não ocupam territórios distintos, mas nadam juntos sem interação agressiva. Mais ainda, quando nadam em schooling a distância entre os peixes da díade é menor do que a distância máxima que deflagra ataques quando os peixes estão em uma arena menor. Ou seja, não é a distância entre os peixes que deflagra a agressividade, e sim o tamanho do espaço físico disponível ao redor. Portanto, o matrinxã modula sua estratégia de interação com coespecíficos de acordo com o espaço disponível, que provavelmente sinaliza a disponibilidade de recursos para a espécie dado seu habitat natural. No rio Amazonas, os regimes de cheia e seca formam lagoas temporárias, onde os peixes podem ficam restritos. Nesse ambiente de recursos escassos, eliminar o competidor é uma boa estratégia, e características intrínsecas da espécie dão a ela ferramentas que justificam esse tipo de estratégia. Já quando há espaço e recursos disponíveis permanecer em grupo, sem disputas agressivas, favorece a proteção dos matrinxãs contra predadores / Abstract: Not available / Doutor

Hur beter sig skärpiplärkor (Anthus petrosus) när de försvarar reviret mot en inkräktare under häckning? Eskalerar de aggressivitet olika eller har de en gemensam strategi? Påverkas beteendet av häckningsfas? Kan använd tid säga något om motivation att försvara revir? För att besvara dessa frågor placerades en burhållen artfrände av endera kön i etablerade revir. I studien mättes ägnad tid åt olika aggressiva beteenden, vilka hade klassats och graderats beroende av styrkan i hoten. Resultatet visade att alla hanar eskalerar aggression på ett likartat sätt och ägnade i medeltal lika lång tid åt olika nivåer. Individuella skillnader förekom dock då några individer eskalerade lite snabbare men det tolkades inte som ökad motivation att försvara revir. Tiden de ägnade åt de olika nivåerna varierade inte beroende av häckningsfas. / How do rock pipits (Anthus petrosus) behave when they defend a territory against an intruder during their breeding season? Do they escalate aggression differently, or do they have a common strategy? Does breeding phase influence the behavior? May used time tell something about the motivation to defend the territory? To answer these questions a caged conspecific of either sex were placed in established territories. In the study the time was measured of each different aggressive behavior, which had been classified into levels according to the intensity of the threat. The results showed that all males escalated aggression in the same way and devoted similar lengths of time to the different levels. Some individual differences occurred as a few individuals escalated somewhat rapidly, however, this was not interpreted as increased motivation to defend the territory. The time they devoted to different levels did not vary depending on breeding phase.

Social conflict is a part of everyday life, and it can be a potent stressor for both humans and other animals. In the laboratory, when two Syrian hamsters (Mesocricetus auratus) compete for territory, a dominance hierarchy is quickly formed. Becoming subordinate is a significant stressor resulting in increased release of adrenocorticotropic hormone, β-endorphin, and cortisol. Defeated hamsters will also subsequently fail to display territorial aggression in future social encounters and will instead display increased submissive behavior, even in the presence of a smaller, non-aggressive intruder. This change in behavior is consistent and long-lasting and has been termed conditioned defeat (CD). Corticotropin releasing factor (CRF) is an important neuropeptide in the control of the hypothalamo-pituitary-adrenal (HPA) axis response to stress. It is also involved in a number of behaviors such as anxiety, stress responding, food intake, learning, and memory. The widespread distribution of CRF, CRF-like peptides, and CRF receptors, particularly in brain sites related to anxiety, fear, and stress responses, suggests a role for CRF and CRF-like peptides in modulating emotional responses other than via HPA axis activity. It has also been shown that CRF may have a role in the acquisition and expression of CD. Non-specific and CRF type 2-specific CRF antagonists reduce the acquisition and expression of CD in male hamsters while injection of a CRF type 1-specific antagonist does not. Therefore, the goal of this dissertation was to investigate the role of CRF type 1 and 2 receptors in CD in hamsters and to identify neuroanatomical locations where CRF may be acting. It was found that non-specific or CRF type 1 receptor specific agonists enhance the expression, but not acquisition, of CD. Further, these agonists appear to enhance aggressive behavior in animals that were not previously defeated, suggesting a modulatory role for CRF type 1 receptors in agonistic behavior that depends on an animal’s previous social experience. Further, localization of CRF receptors was determined in hamster brain in sites thought important for CD and agonistic behavior, but changes in receptor binding following defeat were not observed. Implications of these results and future directions are discussed.

Multiple theories suggest that the early parent-child relationship plays an important role in development. Past research has shown linkages between parenting style and aggression as well as between language and aggression. Emerging evidence suggests that attachment security is an important predictor of language development. It was hypothesized that there would be an effect of parent-child relationship quality at 36 months on aggression at school entry via language ability at 54 months. To test this hypothesis, path analysis in M-Plus was used. Data for this study were collected as a part of the NICHD, Study of Early Child Care and Youth Development (N = 1,364). Mediation was tested with bootstrapped estimates of indirect effects. The results did not support the hypothesized m