In fish, maternal stress prior to spawn has been reported to have effects on offspring phenotype. Cortisol, the main glucocorticoid (GC) stress hormone, has been proposed as a potential mediator of such effects because of its organizational role in early teleost development. The present thesis tested whether maternal social stress or treatment with cortisol (as a proxy for maternal stress) prior to spawn affects the cortisol response to stress and anxiety-related behaviours in offspring. In zebrafish (Danio rerio), offspring of dominant females exhibited greater boldness at 6 days post-fertilization (DPF). Interestingly, offspring of females that engaged in social interactions, regardless of the resulting social status of the two females, exhibited greater survival at 1 DPF, a greater fear-related decrease in activity in response to bright light at 6 DPF, and decreased baseline whole-body cortisol content at 0 and 30 DPF. A field experiment with wild largemouth bass (Micropterus salmoides) revealed that maternal cortisol treatment prior to spawn also affected offspring phenotype; offspring of cortisol-treated females had higher masses right after hatch, had greater fear responses, were less bold and less anxious, and exhibited an attenuated cortisol response to an acute stressor. Together, the results of the present thesis suggest that effects of maternal stress prior to spawn on offspring survival, growth, responses to stress, and anxiety-related behaviours are mediated, at least in part, by elevated maternal cortisol but not likely via increased deposition of maternal cortisol into eggs. The effects of maternal stress and cortisol treatment on offspring reported in the present thesis also suggest that maternal stress may prime offspring with adaptive traits to better survive in a stressful environment.

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No description available.

Selective serotonin re-uptake inhibitors (SSRIs) are a class of anxiolytic and anti-depressant drugs. SSRIs act on the evolutionarily ancient serotonergic system which is virtually identical throughout the vertebrate phylum. Serotonin is involved in a wide range of processes ranging from neuronal and craniofacial embryonic development to regulation of behaviour. However, SSRIs are also emerging pollutants, mainly entering the environment via sewage treatment plants. Since the serotonergic system is virtually identical in humans and other animals, exposed animals will be affected in similar ways as humans and suspicions are rising that ecologically important behaviours may be affected in subtle ways. Using the three-spined stickleback (Gasterosteus aculeatus) and zebrafish (Danio rerio) as model organisms, this thesis focuses on the behavioural effects of SSRIs in fish. The SSRI used throughout this thesis is citalopram, which has been found in fish in coastal areas of the Baltic Sea and other parts of the world. Effects on behaviour were investigated using several different tests measuring stress response, feeding behaviour, aggression and locomotor activity. Anxiolytic effects of 0.1 μg/l, 1.5 μg/l 15 μg/l were investigated as well as effects of 0.15 μg/l and 1.5 μg/l on feeding behaviour. Because serotonin is involved in the development of the nervous system, the effects of developmental exposure to 1.5 μg/l was studied after 100 days of remediation. Finally, because SSRIs rarely occur alone in natural waters, the effects on zebrafish of citalopram in a cocktail scenario, with the anxiogenic compound 17α-ethinyl estradiol (EE2 ) was also investigated. Citalopram was found to have anxiolytic effects on the three-spined stickleback at 0.1 μg/l, 1.5 μg/l and 15 μg/l. Citalopram also suppressed feeding behaviour within a week of exposure and at concentrations as low as 0.15 μg/l. Developmental exposure to 1.5 μg/l for 30 days was found to increase aggression and feeding behaviour and to reduce locomotor activity. The changes were persistent and remained in adult fish. In the cocktail scenario, citalopram in single-substance exposure had anxiolytic effects on one parameter in the novel tank test at 0.1 μg/l. Citalopram enhanced the anxiogenic effects of EE2 in the novel tank test, but in the scototaxis test citalopram appeared to counteract the effects of EE2. It is concluded that citalopram has the potential to affect behaviour in fish at concentrations that have been found in close proximity of sewage treatment plants. / Det serotonerga systemet är i stort sett identiskt hos människor och övriga vertebrater. Serotonin är inblandat i ett stort antal kroppsliga funktioner, bland annat stressreaktioner, reglering av födobeteende och aggression. Vidare är serotonin med och reglerar nervsystemets tillväxt under embryonalutvecklingen. Selektiva serotoninåterupptagshämmare (SSRI) är en grupp antidepressiva och lugnande läkemedel vars användning har ökat snabbt på senare år då de är effektiva och har få allvarliga bieffekter. SSRI verkar på det serotonerga systemet, genom att blockera återupptaget av serotonin i den presynaptiska nervänden. SSRI har tilldragit sig en viss uppmärksamhet som potentiella miljöhot då de visats kunna påverka ekologiskt relevanta beteenden hos fisk och andra akvatiska organismer vid relativt låga koncentrationer i miljön samtidigt som de bryts ned dåligt i avloppsreningsverk. Avhandlingen fokuserar på ekologiskt relevanta beteendeeffekter av SSRI på fisk, med storspigg (Gasterosteus aculeatus) och zebrafisk (Danio rerio) som modellorganismer. Citalopram har använts som försökssubstans då det anses vara den SSRI som har minst antal sidoeffekter på till exempel det dopaminerga systemet. Citalopram förekommer i utloppsvatten från reningsverk i alla industrialiserade länder och har även hittats i abborre i Östersjön. Effekter av exponering för SSRI har påvisats med hjälp av olika beteendetest. Skototaxi-test och novel tank diving test mäter stressresponsen genom att kvantifiera preferensen för närhet till botten och mörka omgivningar. Ätbeteende har mätts som antal utfall mot en matbit under en given tidsperiod och aggression har mätts genom att räkna antal bett mot en spegel. Anxiolytiska effekter undersöktes vid koncentrationer på 0,1 µg/l, 15 µg/l och 1,5 µg/l. Effekter på ätbeteende undersöktes vid 0,15 µg/l och 1,5 µg/l. Eftersom serotonin är inblandat i embryonalutvecklingen testades de beteendemässiga effekterna av exponering för 1,5 µg/l under utvecklingen. Då citalopram sällan förekommer ensamt i miljön testades ett cocktailscenario där zebrafisk samtidigt exponerades för citalopram och den anxiogena substansen 17α-etinylestradiol (EE2). Citalopram befanns ha anxiolytisk verkan på storspigg samt undertrycka ätbeteendet. Effekter på ätbeteendet uppstod inom en vecka efter exponering och vid den minsta testade dosen vilken var 0,15 µg/l. Storspigg som exponerats under embryonalutvecklingen var mer aggressiva, hade lägre lokomotoraktivitetoch gjorde fler utfall mot mat då de testades 100 dagar efter att exponeringen avslutats. Samtidigt exponering för citalopram och den anxiogena substansen 17α-etinylestradiol (EE2) gav tvetydiga resultat. Citalopram ensamt hade ingen signifikant påverkan på beteendet i detta försök. I skototaxitestet motverkade citalopram den anxiogena effekten av EE2 medan det förstärkte den anxiogena effekten i novel tank. Sammanfattningsvis har citalopram effekter på ekologiskt relevanta beteenden hos fisk i koncentrationer som förekommer i ytvatten. Det har också permanenta effekter på beteende om exponeringen sker under embryonalutvecklingen. Dessa resultat gör det sannolikt att citalopram och andra SSRI har ekologiska effekter i påverkade vattendrag.

L’objet de cette thèse de doctorat est un homme d’État (diplomate, politique et stratège) de la guerre du Péloponnèse qui a marqué la production littéraire de son siècle, avant de devenir une figure historique présente dans la littérature grecque et latine jusqu’à la fin de l’Antiquité tardive. Son dessein n’est pas de composer une nouvelle biographie d’Alcibiade, mais de proposer une étude renouvelée du personnage en prenant en considération les spécificités du corpus littéraire (genres, aspects fragmentaires, éloignement chronologique, idéologies etc.) et en intégrant les sources archéologiques et épigraphiques, trop peu mobilisées dans les précédentes études biographiques.Le titre de la thèse, Alcibiade entre hybris et tolma (entre démesure et audace) chez Thucydide, décrit par les termes grecs eux-mêmes l’ambivalence du portrait d’Alcibiade dans le corpus des sources littéraires. Il est l’homme des excès, de la démesure, des violences, de l’audace et des grands projets. Son sous-titre, Approche critique des sources, indique la nécessité d’un réexamen détaillé d’un vaste corpus de textes antiques. Nous démontrons cette nécessité dans notre introduction, tout en établissant les problèmes inhérents au texte de Thucydide. / The subject of this PhD is actually a stateman (a diplomat, a politician, a strategist) of the Peloponnesian war who influenced the literary production of his century even before he became a historical figure in Greek and Latin literature, up until late Antiquity. The purpose of this dissertation is not to write a new biography of Alcibiades but to carry out a renewed study of the character by taking into account the specificities of the literary body of works (genres, fragmentary aspects, distance in time, ideologies, etc.) and integrating archaeological and epigraphic sources which have been sidelined too often in previous biographies.The dissertation’s title itself, Alcibiades, between hybris and tolma (between immoderation and boldness) in Thucydides’ work describes even in Greek the ambivalence of Alcibiades’ portrait in literary sources. He is a man of excess, of transgression, of violence, of boldness and great perspectives. The subtitle, A critical approach of sources, indicates that it is necessary to reexamine in a detailed way a vast and detailed body of works. The introduction shows that this reexamination is necessary, though it also shows how difficult it is to study Thucydides’ text.

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No description available.

Throughout the animal kingdom, individuals often differ consistently from one another in how they cope with their environment. In particular, consistent behavioural variation, known as animal personality, is a substantial driver of a range of important ecological and evolutionary processes. As most animal species are social for at least part of their lives and group living is common, a crucial link between personality and the social context may be expected. In this thesis I systematically investigate this link, using three-spined stickleback fish (Gasterosteus aculeatus) as my model system. I begin by showing that fish vary consistently in their boldness and sociability, with only boldness being positively linked to food intake for fish at rest. This finding provides support for evolutionary theory that links personality variation to life-history strategies, and lays the basis for work related to the social context. I continue by investigating how the social context may modulate personality variation and show that short contact with a social group may have carry-over effects and obfuscate personality expression when individuals are alone. Next, I observed fish in different pairs over time and found that social experience from both the current as well as previous social contexts are integrated in the risk-taking and leadership decisions of individuals but also depends on their boldness type. This result provides support for the importance of social feedback in the expression of personality differences. I go on to demonstrate that, in a pair, bolder fish have lower social attraction, with positive effects on individual’s leadership but negative effects on social coordination. Finally, by detailed tracking of the collective movements and group foraging of free-swimming shoals, I reveal boldness and sociability have complementary driving effects of on social structure, collective behaviour, and group functioning. Furthermore, I show that in turn the group composition determines the performance of individual personality types, providing a potential adaptive explanation for the maintenance of personality variation. Taken together, these studies provide an integrated account of animal personality and the social context and highlight the presence of a feedback loop between them, with personality variation being a key driver of collective behaviour and group functioning but also strongly affected and potentially maintained by it.