Дисертації з теми "Social polymorphism"

The sex-specific effects of reproductives and of soldiers on the reproductivity (i.e., tendency to develop into replacement reproductives) of pseudergates of Zootermopsis nevadensis were studied. Reproductives inhibit reproductivity in pseudergates of their own sex only. Reproductives neither inhibit nor stimulate reproductivity in pseudergates of the opposite sex. Reproductives do not require the presence of a reproductive of the opposite sex to stimulate them to inhibit reproductivity in pseudergates. Soldiers had no effect on the reproductivity of pseudergates. The effects of group size and of the presence or absence of reproductives on the development of last-stage nymphs of Z. nevadensis were studied. The size of experimental groups had no effect on the rates of stationary molts or alate molts, suggesting that the correlation between colony size and the onset of alate production in nature may be spurious. The presence or absence of reproductives had no effect on the rate of stationary molts or alate molts, suggesting that in Z. nevadensis neither group size nor the presence of reproductives has any direct effect on alate determination. It is suggested that in Z. nevadensis a form of nutritional castration can delay the onset of alate development; that is to say, that the onset of alate development is determined by the ratio of nutrient-gathering castes to nutrient-receiving castes in the colony. I have found what I believe to be an extraordinary example of deception in Z. nevadensis and Zootermopsis angusticollis. This is the first reported example of caste mimicry in a social insect, and may explain why supernumerary replacement reproductives are common in Z. nevadensis and Z. angusticollis but not in Zootermopsis laticeps. The compositions of 41 field-collected colonies of Zootermopsis were given and the data were analyzed for trends. Most notably, supernumerary replacement reproductives were common in Z. nevadensis and in Z. angusticollis but have never been found in Z. laticeps, by us or by anybody else. These findings are in accordance with our hypothesis of "caste mimicry" in Z. nevadensis and Z. angusticollis.

I use field observations, experiments and molecular techniques to describe the social biology of the sweat bee Lasioglossum calceatum, and to investigate the mechanisms underlying social polymorphism and body size in this species. I also investigate environmental constraints on sociality, and the impact that workers have on productivity, in the obligate social species L. malachurum. Chapter 1 introduces sweat bees as a study system, and reviews social behaviour within the group. I then provide concise introductions to the study species. In Chapter 2 I show that L. calceatum exhibits latitudinal social polymorphism in the UK, with only bees in the south expressing primitive eusociality. I then describe the social life cycle from continuous field observations, with reference to genetic data. In Chapter 3 in I examine environmental and genetic components of social phenotype in L. calceatum by conducting a field transplant of bees from the north of the UK to the south. Social phenotype is likely to be predominantly determined by fixed genetic differences between social and solitary populations. Chapter 4 examines whether the transition between social and solitary nesting results in saw-tooth size clines in L. calceatum and Halictus rubicundus. Overall, both species exhibit converse-Bergmann clines but not saw-tooth clines. In Chapter 5 I transplant the obligate social sweat bee L. malachurum to the north of the UK, to test whether sociality is constrained by season length. Phenology was considerably delayed such that the life cycle could not be completed. In Chapter 6 I investigate queen quality, productivity and costs of worker production in L. malachurum, by manipulating the number of workers per nest. I show that queens probably incurs costs from producing more workers, and that a possible mechanism is that workers from larger groups may be of lower quality. In Chapter 7 I bring together key findings of the thesis, and comment on future directions.

Les supergènes, des régions génétiques où des loci coadaptés sont transmis comme une seule unité mendélienne, jouent un rôle crucial dans la mise en place des polymorphismes complexes mais démêler la complexité de leur évolution et de leur maintien reste un défi de taille. Les fourmis offrent un contexte unique pour mettre en évidence de nouveau supergènes et étudier les principes généraux régissant leur mise en place et leur évolution puisqu'elles présentent de grandes variations inter et intra-espèces dans tous les aspects de leur organisation sociale et qu'un nombre inhabituellement élevé de supergènes a déjà été mis en évidence dans différentes espèces. Notamment, dans cinq lignées différentes un supergène en lien avec l'organisation sociale des colonies, c'est-à-dire le nombre de reines accouplées par colonie, a été mis en évidence. Cependant, son origine et son maintien restent à élucider clairement et de nouveaux modèles sont nécessaires. L'espèce de fourmi Myrmecina graminicola suscite un intérêt particulier pour l'étude des supergènes chez les insectes sociaux puisqu'elle présente à la fois un polymorphisme social (présence de colonies monogynes et de colonies polygynes) et un polymorphisme alaire (présences de reines ailées et de reines aptères).Dans cette thèse, nous avons exploré la présence de supergènes chez M. graminicola, en lien notamment avec ces deux polymorphismes. Dans le premier chapitre, à l'aide de données de reséquençage, nous avons mis en évidence la présence d'un supergène lié au polymorphisme social (~10 Mb) daté de ~1 Ma en déséquilibre de liaison avec un supergène lié au polymorphisme alaire (~110 kb) apparu plus récemment (~ 0,4 Ma). Dans le deuxième chapitre, nous avons étudié les liens entre les traits d'histoire de vie des deux principaux types de colonies retrouvés dans cette espèce, à savoir les colonies monogynes avec des reines ailées et les colonies polygynes avec des reines aptères. Nous avons montré que ces deux types de colonies ne différaient pas quant au nombre d'ouvrières et de larves au moment de l'échantillonnage. Une fois élevées en laboratoire, nous avons observé que ces deux types de colonies produisaient un nombre similaire de nymphes et d'adultes mais que les colonies polygynes produisaient plus d'œufs et de nouvelles larves que les colonies monogynes. Dans le troisième chapitre, nous avons exploré la possibilité qu'il existe dans cette espèce d'autres supergènes non liés directement à la socialité ou à la présence/absence d'ailes. Nous avons identifié un troisième supergène (~7 Mb) et démontré qu'il n'était pas associé au sex ratio des colonies. Dans l'ensemble, cette thèse révèle la présence de trois supergènes chez la fourmi M. graminicola, dont un lié au polymorphisme social, un autre au polymorphisme alaire, et propose des pistes sur les mécanismes contribuant au maintien de ces polymorphismes
Supergenes, genetic regions where coadapted loci are inherited as a single Mendelian unit, play a crucial role in establishing complex polymorphisms. However, unraveling the complexity of their evolution and maintenance remains a significant challenge. Ants offer a unique context to identify new supergenes and study the general principles governing their establishment and evolution due to their extensive inter- and intra-species variations in all aspects of social organization. Notably, in five different lineages, a supergene related to colony social organization, specifically the number of mated queens per colony, has been identified. However, its origin and maintenance remain to be clearly elucidated, and new models are needed. The ant species Myrmecina graminicola is of particular interest for studying supergenes in social insects as it exhibits both social polymorphism (presence of monogynous and polygynous colonies) and wing polymorphism (presence of winged and apterous queens).In this thesis, we explored the presence of supergenes in M. graminicola, particularly in relation to these two polymorphisms. In the first chapter, using resequencing data, we identified a supergene associated with social polymorphism (~10 Mb) dating back to ~1 Mya, in linkage disequilibrium with a supergene linked to wing polymorphism (~110 kb) that appeared more recently (~0.4 Mya). In the second chapter, we examined the life history traits of the two main types of colonies found in this species, namely monogynous colonies with winged queens and polygynous colonies with apterous queens. We showed that these two colony types did not differ in the number of workers and larvae at the time of sampling. When reared in the laboratory, we observed that both types of colonies produced a similar number of nymphs and adults but that polygynous colonies produced more eggs and new larvae than monogynous colonies. In the third chapter, we explored the possibility of other supergenes in this species not directly linked to sociality or wing presence/absence. I identified a third supergene (~7 Mb) and demonstrated that it was not associated with colony sex ratio. Overall, this thesis reveals the presence of three supergenes in the ant M. graminicola, one linked to social polymorphism, another to wing polymorphism, and provides insights into the mechanisms contributing to the maintenance of these polymorphisms

Polymorphism is the existence of multiple phenotypes within a given species in a population. In social insects, worker polymorphism plays a key role in maximizing the effectiveness of the division of labor. Some ants have an extreme form of worker polymorphism where workers have a broad size range and multiple size modes. Pheidole ants, for example, consist of both highly polymorphic species as well as those with relatively low polymorphism. Here, we examined why different Pheidole species have different degrees of polymorphism and how polymorphism is produced. We thoroughly characterized the worker caste systems of P. spadonia, P. rhea, P. obtusospinosa, and P. tepicana. There were significant differences among the four species in size range, number of size modes, caste ratios, allometry, and caste biomass allocation. An examination of worker caste traits of P. spadonia, P. rhea, and P. obtusospinosa revealed that as head size increased for all three species: (1) mandibles became broader and less serrated, (2) head muscle volume increased, and (3) bite force increased. These traits of large supersoldiers are likely adapted for crushing while those of small minors are likely for cutting. Foraging experiments showed that P. spadonia, P. rhea, and P. obtusospinosa used their workforce in different ways for food processing outside the nest. For P. rhea, the frequency of supersoldiers involved in food processing increased as the processing level required increased. However, P. obtusospinosa supersoldiers were rarely found processing food outside the nest and P. spadonia soldiers assisted in processing dead prey but did not help at all in processing live prey. P. obtusospinosa and P. spadonia workers may be more involved with other colony tasks. This hypothesis was confirmed when field observations of P. obtusospinosa showed supersoldiers participating in head-blocking at their entrance to fend off invading army ants; no other castes exhibited this behavior. Lastly, we tested genetic influences on worker polymorphism. We found that as colony genetic diversity increased (via polyandry), the degree of polymorphism increased. We also showed evidence of paternal genes influences on the development of worker castes in the highly polymorphic P. rhea.

La variation des comportements sociaux est une problématique très importante pour appréhender l’évolution de la socialité dans le règne animal. Par l’étude des interactions entre les paramètres génétiques et environnementaux sur les comportements sociaux de la drosophile (Drosophila melanogaster), cette thèse s’inscrit dans cette problématique et cherche à mettre en évidence les paramètres déterminants pour la expliquer la variation des comportements sociaux des individus. Au cours de ce travail de recherche, on a pu étudier et mettre en évidence l’existence de comportements sociaux chez la drosophile tels que l’apprentissage et l’utilisation des informations sociales dans un contexte de recherche spatiale, le comportement d’agrégation et l’établissement de nombreuses interactions. Ces comportements sont les premiers pas vers plus de socialité et leur étude est indispensable pour comprendre l’évolution vers plus de coopération et de communication entre les individus. L’utilisation de deux lignées issues du polymorphisme génétique du gène foraging (phénotypes Rover et Sitter) a permis de mettre en évidence des différences de comportements entre les individus et d’étudier les interactions entre paramètres génétiques et environnementaux. Les individus de phénotype Sitter témoignent d’un comportement plus social que les individus Rover, utilisant préférentiellement l’information sociale, ils forment aussi des agrégats plus importants semblant attirés par le plus grand nombre. On note aussi que la variation de la composition génétique du groupe entraine une modification du comportement d’agrégation du groupe. Ainsi, les variations interindividuelles influencent le comportement collectif. Le dernier volet de cette thèse s’intéresse aux interactions entre les individus au sein de 12 populations différentes de l’espèce Drosophila melanogaster. Cette approche a permis de révéler une grande variation de l’organisation sociale des individus au sein d’une même espèce et ouvre de nouvelles perspectives pour étudier l’évolution de la socialité.Ce travail de recherche permet d’apporter de nouveaux éléments sur les facteurs influençant la variation des comportements sociaux et de mettre en avant de nouvelles perspectives pour l’étude de leur évolution
The social behavior variation is a very important issue for understanding evolution of sociality in animal kingdom. By studying genetic and environmental interactions influence on social behavior in Drosophila melanogaster, this thesis fits with this problematic and focus on the parameters which could explain the social behavior variations. In this research work, we studied and highlighted the existence of social behavior in Drosophila like learning and using social information in a spatial learning task, aggregation behavior and numerous social interactions. These behaviors are the first step before more sociality and their study with no-social species is essential to understand the evolution toward more sociality. The use of two lines from genetic polymorphism of the foraging gene (Rover and Sitter phenotypes) reveals differences in behavior between individuals and enable us to study the influence of genetic and environment parameters. Sitter individuals show more social behavior than Rover ones, using more social information and adopting more aggregation behavior. Variation of the genetic composition of the group influence the aggregation level of Rover individuals. They show more gregarious behavior with majority of Sitter individuals. These observations raise the question of the effects of the information source variations on the social behavior and their implication in interactions variations. The last part of this thesis focuses on the interactions between individuals in 12 different populations of Drosophila melanogaster. This approach revealed an important variation in social organization within species and opens new perspectives to study the evolution of sociality.This research bring new elements on factors influencing the change in social behavior and highlight new perspectives for the study of their evolution

The metabolic expense of producing and operating neural tissue required for adaptive behaviour is considered a significant selective force in brain evolution. In primates, brain size correlates positively with group size, presumably owing to the greater cognitive demands of complex social relationships in large societies. Social complexity in eusocial insects is also associated with large groups, as well as collective intelligence and division of labour among sterile workers. However, superorganism phenotypes may lower cognitive demands on behaviourally specialized workers resulting in selection for decreased brain size and/or energetic costs of brain metabolism. To test this hypothesis, we compared brain investment patterns and cytochrome oxidase (COX) activity, a proxy for ATP usage, in two ant species contrasting in social organization. Socially complex Oecophylla smaragdina workers had larger brain size and relative investment in the mushroom bodies (MBs)-higher order sensory processing compartments-than the more socially basic Formica subsericea workers. Oecophylla smaragdina workers, however, had reduced COX activity in the MBs. Our results suggest that as in primates, ant group size is associated with large brain size. The elevated costs of investment in metabolically expensive brain tissue in the socially complex O. smaragdina, however, appear to be offset by decreased energetic costs.

The placebo effect, a beneficial effect attributable to a treatment containing no specific properties for the condition being treated, has been demonstrated in a variety of medical conditions. This thesis includes four studies aimed at increasing our knowledge on the neurobiology of placebo. Study I, a review of the placebo neuroimaging literature, suggested that the anterior cingulate cortex (ACC) may be a common site of action for placebo responses. However, because placebo neuroimaging studies in clinical disorders are largely lacking, the clinical relevance of this needs further clarification. The subsequent three empirical studies were thus designed from a clinical perspective. Using positron emission tomography (PET) these studies investigated the underlying neurobiology of sustained placebo responses in patients with social anxiety disorder (SAD), a disabling psychiatric condition that nonetheless may be mitigated by placebo interventions. Study II demonstrated that serotonergic gene polymorphisms affect anxiety-induced neural activity and the resultant placebo phenotype. In particular, anxiety reduction resulting from placebo treatment was tied to the attenuating effects of the TPH2 G-703T polymorphism on amygdala activity. Study III further compared the neural response profile of placebo with selective serotonin reuptake inhibitors (SSRIs), i.e the first-line pharmacological treatment for SAD. A similar anxiety reduction was noted in responders of both treatments. PET-data further revealed that placebo and SSRI responders had similar decreases of the neural response in amygdala subregions including the left basomedial/basolateral (BM/BLA) and the right ventrolateral (VLA) sections. To clarify whether successful placebo and SSRI treatments operate via similar or distinct neuromodulatory pathways, study IV focused on the connectivity patterns between the amygdala and prefrontal cortex that may be crucial for normal emotion regulation. In responders of both treatment modalities, the left amygdala (BM/BLA) exhibited negative coupling with the dorsolateral prefrontal cortex and the rostral ACC as well as a shared positive coupling with the dorsal ACC. This may represent shared treatment mechanisms involving improved emotion regulation and decreased rumination. This thesis constitutes a first step towards better understanding of the neurobiology of placebo in the treatment of anxiety, including the neural mechanisms that unite and segregate placebo and SSRI treatment.

Regulators of G-protein coupled signaling (RGS) accelerate GTP hydrolysis and consequently influence signal termination. The RGS-4 gene has recently been reported to be implicated in a wide range of neuropsychiatric disorders including schizophrenia, Alzheimer's disease and addictions.
In this study, the vervet RGS-4 gene was sequenced on a CEQ 8000 genetic analysis system (Beckman Coulter) and characterized using molecular and bioinformatic tools. The obtained vervet sequence overall showed 95.3% sequence identity with the human RGS4 gene.
Thereafter, SNPs in the region encompassing the proximal promoter, exon 1 and the first 450 bp of intron 1 were identified by direct sequencing of 8 unrelated individuals. One of the identified SNPs, +35 [A/G], was genotyped in 155 juvenile vervets previously phenotyped for personality traits, including social isolation. Although preliminary association analysis fails to attain statistical significance (p=0.074), the sample size is small. Additional genotyping of phenotypically defined individuals needs to be undertaken.

Theoretical models of sexual selection assume that female mating preferences are fixed and variation found between individuals resulting solely from allelic variation at specific loci coding for sexual preferences. For the last decade, an increasing number of studies have demonstrated that individual phenotypic variation in preferences was common across a wide range of taxa and induced by the environmental context and the females’ condition. Further, developmental stages of life are crucial in the formation of behaviours in general and have proven to be determinant to learn sexual preferences in some species that dispense care for their young. However, very little studies have analysed how the early social and physical environments shape female mate choice in species that lack parental care. In this thesis, I used guppies (Poecilia reticulata), firstly, to investigate the influence of various aspects of the social environment provided by males during two ontogenetic phases. Secondly, I explored whether learned preferences in a foraging context during development could be transferred into a mating context. Considering the early social environment, I explored three distinctive features potentially displayed by males and that females might experience while growing. Females were reared with different values of a sexual trait not genetically preferred in the population (orange colour) and different values of a trait for which they had innate predisposition (total colour area). In both cases, females were exposed to the different treatments for the whole developmental period or for its later phase. My results indicated that females changed their sexual behaviours in response to both type of traits experienced, reversing sometimes their genetic preferences. Moreover, the timing of exposure seemed to be a key factor in the acquisition of preferences as females exposed only to the later part of development with different values of total colour didn’t rely anymore on colour patterns to discriminate among males. In a third body of experiment, I examined whether the overall phenotypic variance exhibited by males during whole development, independently of the values of a specific sexual cue, mediated female’s behaviours. In a context of high variance, female became choosier relatively to those experiencing less variance. As a response, males switched mating tactics and attempted more forced copulations. In its final part, my thesis searched for a link that might have arisen, owing to developmental conditions, between preferences using the same sensory modality in two behavioural contexts. Maturing females were given food that was associated to a certain colour and subsequently tested for both their coloured preference in a foraging and a sexual context. Although no foraging preference for the corresponding colour was detected, females that experienced a yellow stimulus preferred yellower males compared to females with other experiences. Taken together these results suggest that developmental conditions and especially the social environment play a pivotal role in the process of mate choice. Under some circumstances, learned mate preferences override genetically-based preferences highlighting the importance of non-genetic mechanisms. Accordingly, it is urgent to integrate in the study of sexual selection and reproductive isolation this dimension. In guppies, for instance, the effect of early social life might contribute to the maintenance of colour pattern polymorphism found in males.

Ce travail de thèse interroge la représentation du héros au sein des mouvements réaliste et naturaliste du XIXe siècle. Il s'agit, au travers d'un corpus de six romans et nouvelles, de mettre en lumière la tension inhérente à la figure héroïque chez Honoré de Balzac, Gustave Flaubert, Guy de Maupassant et Émile Zola. Malgré un refus apparent du modèle classique antique qui se signe par une banalisation du personnage principal, les romanciers réalistes-naturalistes n'échappent finalement pas à la tentation héroïque; en proposant un parcours initiatique et des formes originales de sacralisation, ils fabriquent un nouveau type de héros, à la fois plus proche des préoccupations de la société de l'époque et traversé par des représentations mythiques, éternelles (qu'elles soient issues du domaine mythologique, biblique, littéraire, psychanalytique ou religieux). La dialectique entre temporalité sociétale et permanence du légendaire se donne alors à lire. Cette thèse de doctorat cherche donc à démontrer l'exécution immuable d'une symphonie héroïque au sein de la poétique réaliste et naturaliste tout en rappelant la nature spécifique du héros chez chaque auteur étudié.

Cette thèse porte sur l'histoire et les formes de la poésie en langue créole à La Réunion et à Maurice. Elle propose de faire le point sur l'émergence, l'élaboration, la circulation et la réception d'un genre littéraire polymorphe qui occupe une place essentielle dans les productions artistiques des territoires créoles. L'objectif est de caractériser les rapports qu'entretiennent des poèmes considérés comme novateurs avec les sociétés, fondamentalement travaillées par des processus de créolisations (linguistique, littéraire, culturelle), qui les produisent. Afin d'observer le passage à l'écriture littéraire en langue créole, des origines à aujourd'hui, les formes poétiques – qu'elles soient thématiques, énonciatives, formelles, discursives ou encore intertextuelles – sont systématiquement replacées dans leurs mouvements historiques et dans leurs contextes d'énonciation. Face à des productions qui manipulent des références et des filiations en prise directe sur leurs espaces insulaires et sur leurs pratiques anthropologiques, les notions, ailleurs courantes, de poème, de poète, d'écriture et de lecteur demandent, parce qu'elles sont chargées, dans les faits, d'autres dynamiques, à être redéfinies
This thesis examines the history and types of creole poetry in La Reunion and Mauritius. It proposes to summarise the emergence, elaboration, circulation and reception of a type of a polymorphous literary type which plays a vital role in the artistic creativity of the creole islands. The objective is to establish a link between those poems, regarded as innovative, and the nations (La Reunion and Mauritius) in which they are written. These nations are fundamentally shaped by this process of ‘Creolization’. In order to observe the transition to literary writing in creole, from its origins to today, the poetic forms whether thematic, enunciatively, formal, discursive or intertextual, are systematically placed in their historical and enunciative context. With works that manipulate references and links to their own island and their anthropological practice, the concepts, otherwise common, of poem, poet, writing and reader need other dynamics to be redefined

Microbes live in complex environments where competitive and cooperative interactions occur that dictate their success and the status of their environment. By furthering our understanding of the interactions between microbes, questions into the evolution of cooperation, disease virulence and biodiversity can be addressed. This will help develop strategies to overcome problems concerning disease, socioeconomics and conservation. We use an approach that combines evolutionary ecology theory with genetics and molecular biology to establish and develop model microbial ecological systems to examine feeding strategies, in what has been termed synthetic ecology. Using the model fungal plant pathogen system of rice blast disease, we generated less virulent gene deletion mutants to examine the sociality of feeding strategies during infection and test a nascent virulence reduction strategy based on competitive exclusion. We revealed that the success of the pathogen is unexpectedly enhanced in mixed strain infections containing the virulent wild-type strain with a less virulent gene deletion mutant of the metabolic enzyme invertase. Our finding is explained by interference between different social traits that occur during sucrose feeding. To test the generality of our result, gene deletion mutants of putative proteases were generated and characterised. We found that if virulence related genes acted ‘privately’, as predicted by social theory, the associated mutants would not make viable strains to use for this virulence reduction strategy by competitive exclusion. Our study then went on to study the fitness of digesting resources extracellularly, as many microbes do, given that this strategy is exposed to social exploitation by individuals who do not pay the metabolic costs. This was investigated by developing an experimental system with Saccharomyces cerevisiae. Though internalising digestion could suppress cheats, the relative fitness of opposing strategies was dependent upon the environmental and demographic conditions. Using this polymorphic system, the influence of competitors on the stability of cooperation, and the influence of cheats on the maintenance of diversity were assessed. To test the fitness of internal versus external digestion in a more natural setting, we generated an internally digesting strain of the rice blast fungus. In addition to suppressing cheats, the strain had enhanced fitness and virulence over the wild-type. We propose that this is caused by a shift in a trade-off between yield and rate. We show how a synthetic ecology approach can capture details of the biology underlying complex ecological processes, while having control over the factors that drive them, so that the underlying mechanisms can be teased apart.

A fundamental variable in cooperative breeding animal species is the degree to which reproduction is partitioned among group members - termed reproductive skew. Understanding the causes for variation in skew contributes to our understanding of social evolution because skew directly impacts on the inclusive fitness gained through cooperation. In this thesis I present a novel model system for investigating skew, by providing detailed sociogenetic data to show a polymorphism in colony social organisation in a species of ant, Leptothorax acervorum. In multiple queen colonies queens reproduce relatively evenly in most populations (polygyny), but I show that skew is particularly high in a Spanish and Japanese population where just one queen out of many monopolises all reproduction (functional monogyny). I further investigated how high skew among queens was maintained in the functionally monogynous Spanish population by undertaking behavioural observations and experiments. In contrast to what is assumed by the majority of skew theory - that control lies with individuals in direct competition over reproduction (queens) - I show that a third party (the workers) plays a principle role in determining which queen reproduces in the colony. Genetic analyses also revealed that workers favour the queen who meets their fitness interest, showing that workers posses both the information and power for their interests to prevail. Furthermore, such worker influence is not observed in polygynous colonies and tellingly multiple queens reproduce. Functional monogyny maintains high relatedness and therefore high indirect fitness benefits among colony members, yet polygyny reduces such benefits because of multiple genetic lineages within the colony. Polygyny is therefore seemingly paradoxical when only considering relatedness, so presumably other parameters are important. Icompared life-history traits and ecological factors associated with each social organisation and discuss the potential importance of habitat patchiness, limited dispersal and queen turnover in shaping the marked contrast in skew between populations. Furthermore, I detected high levels of triploid females in the functionally monogynous populations supporting a high frequency of matched matings between sexuals at the complementary sex determination locus. Importantly, there have been no reports of triploidy in polygynous populations showing that variation in social organisation, along with associated life-history traits and ecological factors, can determine the frequency of matched matings and increase the risk of genetic load. The research presented in this thesis overall highlights two important issues: first,the basic assumptions of skew theory must be tested if skew models are to be applicable,and the gap which has developed between skew theory and associated empirical testingneeds to be bridged. Second, we cannot focus on relatedness alone to explain skew or test kin selection theory, because factors within an ecological parameter are also fundamental.

La pizza a connu au vingtième siècle une diffusion quasi-universelle. Devenue aux Etats-Unis l'une des nourritures les plus familières, elle vient aujourd'hui sous ses formes américanisées réinvestir l'Europe et conquérir les autres continents. La vicariance de ce mets à travers les cultures et les grammaires culinaires les plus diverses en fait une voie royale pour explorer les modalités du contact interculturel, identifier les conditions de l'emprunt mutuel, de l'appropriation ou de la réappropriation. L'analyse montre que, quel que soit le vecteur d'introduction du " nouveau ", industriel ou artisanal, l'appropriation des aliments par un groupe procède d'un même ensemble de mécanismes. En outre, un mets " allogène " rappelant, par la forme ou le nom, une préparation propre à la culture considérée est toujours " retravaillé " en fonction du modèle local. Ce fait vient infirmer la thèse d'une homogénéisation culturelle et culinaire dont la pizza serait l'une des manifestations.

Un polymorphisme est défini par la coexistence au sein d’une population de variants phénotypiques discrets pour un caractère donné. Dans la plupart des cas, de nombreux traits morphologiques, physiologiques ou comportementaux sont corrélés au caractère polymorphe, qui devient alors le marqueur d’un syndrome phénotypique particulier, ou stratégie alternative. Chez le lézard vivipare, les femelles montrent un polymorphisme de couleur ventrale, celle-ci pouvant être jaune, orange ou mixte (mélange de jaune et d’orange). Chez cette espèce, les conditions écologiques sont favorables à l’évolution de stratégies alternatives, qui pourraient être signalées par le polymorphisme de couleur ventrale. Au cours de cette thèse, j’ai cherché à tester cette hypothèse, en caractérisant les différences morphologiques, comportementales, et d’histoire de vie entre les morphes de couleur. Il semble que les couleurs ventrales soient corrélées à des syndromes phénotypiques complexes, définissant des stratégies alternatives. J’ai également cherché à identifier le mécanisme sélectif permettant le maintien de ce polymorphisme dans les populations naturelles, en étudiant les effets d’une manipulation de la fréquence des morphes sur la fitness des individus. Sous l’hypothèse d’un déterminisme génétique simple de la couleur ventrale, les femelles hétérozygotes (couleur mixte) bénéficieraient d’un avantage sélectif dans certains contextes sociaux, ce qui permettrait le maintien du polymorphisme dans un environnement spatialement hétérogène. Les exemples de stratégies alternatives chez les femelles restent rares, et cette étude confirme l’importance de la compétition sociale dans l’évolution de ces stratégies. Dans un contexte phylogénétique, la similarité des résultats obtenus chez le lézard vivipare avec le système du lézard à flancs tachetés, Uta stansburiana, souligne également la généralité des processus à l’origine de l’évolution des stratégies alternatives, aussi bien chez les femelles que chez les mâles, et ouvre des perspectives à plus large échelle sur les conséquences des polymorphismes de stratégies sur la dynamique des populations.

The unifying concept of endosymbiosis and the ‘holobiont’ is that the interaction of the microbial community and the host’s biology can affect myriad processes from speciation to physiology to behavior. This study explored the role of the microbiome as a potential facilitator of rapid evolution of social behavior in a socially polymorphic species of spider, Anelosimus studiosus. Adult females were collected from solitary and social colonies at two geographically distinct locations, and behaviorally assayed to assign individuals to ‘docile’ or ‘aggressive’ phenotypes. Microbiomes of each individual were analyzed by 16s rRNA sequencing. Correlations were found with external influences on the microbiome (colony type, local environmental microbiota, and among colony), and also between the microbiome and individual’s behavioral phenotype. While causation has not yet been established, these data suggest that demographics and ecology affect the microbiome, and that behavior may be affected by the microbiome.

Eusocial species show incredible variation in all aspects of social living, which has facilitated their ecological success. Investigating the mechanisms which regulate variation in social traits is an important goal for evolutionary biology, since understanding fundamental mechanisms underpinning variation can inform social evolutionary theory. In this thesis, I investigate aggressive behaviour and genome architecture as essential mechanisms in regulating variation in the polymorphic social phenotype of the multiple queened ant species L. acervorum. I investigated the role of enforcement behaviour in maintaining reproductive skew in functionally monogynous colonies. I show that in the absence of worker aggression (enforcement), functionally monogynous queens continue to engage in highly aggressive interactions and, crucially, high colony skew was not affected. Furthermore, I show that low skew is not affected by aggressive worker enforcement in polygynous colonies. Therefore, enforcement behaviour is likely to be important in regulating skew in functionally monogynous colonies but not in polygynous colonies, where potentially the loss of sensitivity to enforcement may be an evolved response to fitness benefits associated with the polygynous social phenotype. Furthermore, I investigated the role of genome architecture in regulating variation between the two social phenotypes. I scanned the genomes of four populations (two polygynous and two functionally monogynous) for extreme population differentiation (FST) at SNP loci, which were associated with a difference in the social phenotype. I found a large (6.2Mb) contiguous region associated with different social phenotypes (the social region), which mapped to LG2 on the S. invicta linkage map. The social region displayed some similarities with the social chromosomes in S. invicta and F. selysi. Furthermore, the region contained potential gene candidates, such as odorant binding proteins, which have been associated with divergent social phenotypes in S. invicta. The work presented in this thesis highlights the importance of different mechanisms, both behavioural and genomic, in regulating variation in fundamental social traits. Furthermore, it demonstrates the importance of understanding how mechanisms can bridge the gap between genotype and phenotype.

La prévalence de l'obésité a considérablement augmenté au cours des dernières décennies et est généralement expliquée par l'interaction entre les changements environnementaux et la prédisposition génétique. Le premier objectif était d’examiner l'impact des changements socioprofessionnels et éducatifs sur la prévalence de l'obésité en France. Cette analyse a été effectuée dans la population MONICA (5423 hommes et 5271 femmes âgés de 35 à 64 ans) en 1986, 1996 et 2006 dans trois régions géographiques de la France. Un questionnaire et un examen clinique standardisé ont permis de recueillir les données. Une analyse contrefactuelle a évalué la contribution des changements socioprofessionnels et éducatifs sur la prévalence de l'obésité. Nous avons ainsi observé que la prévalence de l'obésité a augmenté pour chaque catégorie professionnelle, sauf pour les femmes au chômage, où elle est restée stable. La contribution des changements professionnels sur la prévalence de l'obésité a été estimée à -0,3% et -1,9% chez les hommes et les femmes, respectivement. La prévalence de l'obésité a augmenté également pour chaque niveau d’éducation, cependant davantage pour le groupe moins instruit. La contribution des changements du niveau d'éducation sur la prévalence de l’obésité a été estimée à - 1,8% pour les hommes et -4,7% pour les femmes. Ces tendances ont été partiellement masquées par la contribution défavorable des facteurs séculaires, estimés à +3,9% et +2,5% chez les hommes et les femmes, respectivement. En conséquence, la prévalence de l'obésité est passée de 15,0% à 18,4% chez les hommes et de 15,9% à 17,2% chez les femmes entre 1986 et 2006. Le second objectif était d’étudier l'influence des comportements liés au poids sur l'indice de masse corporelle (IMC) en fonction du sexe et de la classe sociale, ainsi que la perception du poids, dans un échantillon représentatif de la population adulte française. L’analyse a été effectuée dans l’enquête transversale Nutrialis, comportant 1646 sujets adultes vivant en France. Les participants ont été pesés à la maison et ont ensuite répondu à un questionnaire standardisé. Nos résultats montrent que la classe sociale est liée à l'IMC chez les femmes, et non chez les hommes. La perception du poids diffère selon la classe sociale chez les femmes et non chez les hommes et contribuent aux différences observées entre les comportements visant à contrôler le poids. Dans la classe sociale la plus élevée, la restriction est plus élevée et le temps passé devant la télévision plus faible, pour les deux sexes ; l'externalité alimentaire est plus élevée chez les femmes et moins élevée chez les hommes, comparativement aux autres classes sociales. L'IMC est positivement corrélée avec le score de restriction alimentaire et négativement avec le score d’externalité alimentaire dans les deux sexes. La proportion de sujets pratiquant une activité physique de loisirs augmente avec la classe sociale pour les deux sexes. La proportion de fumeurs est plus élevée chez les hommes de classe sociale inférieure. Enfin, la restriction alimentaire, le tabagisme, le temps passé devant la télévision et l'activité physique sont indépendamment corrélés à l'IMC dans les deux sexes, alors que le score d’externalité alimentaire est corrélé à l'IMC que chez les femmes. Le troisième objectif était d’étudier l’interaction entre les polymorphismes d’un gène impliqué dans le comportement alimentaire et les facteurs socio-économiques, sur le développement de l’adiposité. Nous avons choisi le gène de la neuromedine B (NMB) pour lequel le polymorphisme P73T a été associé à l'obésité et aux anomalies du comportement alimentaire chez les adultes. Nous avons ainsi analysé l'association entre les 4 polymorphismes du gène NMB (rs1107179, rs17598561, rs3809508 et rs1051168 (P73T)) et les phénotypes liés à l'obésité dans la population HELENA (1144 adolescents européens âgés de 12 à 17 ans). L'obésité a été définie en fonction des critères de Cole et al. ; les données ont été recueillies via un questionnaire standardisé. Nos données montrent que seul le polymorphisme rs3809508 est associé à l’obésité, et le génotype TT est plus fréquent chez les adolescents obèses que chez les non obèses (ORajusté=2,85 [1,11-7,31], p=0,03). De plus, les sujets TT ont un IMC, un tour de taille, un rapport tour de taille/hanches et un rapport tour de taille/taille plus élevés que les porteurs de l’allèle C. Par ailleurs, nous avons montré que les effets de ce polymorphisme sur toutes les valeurs anthropométriques ont été influencée par le statut socio-économique de la mère, en ce sens qu'un faible niveau d'éducation maternelle aggrave le phénotype des adolescents porteurs du génotype TT (interaction p<0,02). En conclusion, entre 1986 et 2006, l'obésité a augmenté en France dans toutes les catégories socioprofessionnelles et davantage chez les hommes que chez les femmes. Cette tendance séculaire a été partiellement contrée par l'amélioration du niveau socioprofessionnel et éducatif qui a eu lieu au cours de la même période. Notre étude confirme également qu’ils existent des différences liées au sexe dans la relation entre l'IMC et la classe sociale, qui pourraient être dues à une perception du poids et des comportements visant à contrôler le poids différents. Enfin, un faible niveau d'éducation maternelle peut aggraver l’expression phénotypique d’un gène associé au comportement alimentaire, sur le développement de l’obésité des adolescents.

L'objectif de ce travail est d'analyser l'impact de l'intégration européenne sur les systèmes nationaux de politiques fiscales. La concurrence fiscale internationale, inhérente à l'internationalisation croissante des économies, induit une course au moins disant fiscal. Ce type de stratégies, que nous nommons " darwinisme institutionnel ", pose la question de la convergence des systèmes fiscaux vers un modèle unique non satisfaisant pour chaque économie. C'est encore plus vrai à l'échelle de l'Union européenne : alors que les effets externes de l'intégration poussent, en théorie, à l'harmonisation, nous constatons une absence de convergence depuis 2001. En l'absence de théories de la concurrence fiscale aptes à rendre compte de la nature complexe de l'ensemble des phénomènes fiscaux en Europe, et afin de mieux prendre en compte les ressorts dynamiques de la fiscalité, notre travail propose une grille de lecture de l'hétérogénéité fiscale européenne. Notre étude élabore une typologie des différents " modèles " fiscaux et institutionnels existants, évalués à six : continental développé, scandinave, libéral, continental en développement, micro-insulaire et oriental en transition. Sur la base de cette typologie, nous établissons des correspondances, pour chacun des États européens, entre leur modèle d'économie de marché et le type de structure fiscale. De plus, nos résultats mettent en avant que l'appartenance à un de ces modèles n'explique pas les différences de performances financières. Enfin, leur analyse en dynamique (1995-2007) nous conduit à caractériser les évolutions de ces différents modèles comme un phénomène de polymorphisme fiscal européen, où leur hétérogénéité n'a eu de cesse de s'accentuer sur la période considérée. Par conséquent, pour que chaque État-membre puisse suivre sa trajectoire institutionnelle tout en minimisant les effets externes résultant de stratégies nationales non-coopératives, il apparaît que le renforcement d'une coordination européenne des politiques fiscales est nécessaire au niveau des clubs de convergence définis à l'échelle des modèles fiscaux identifiés.

Cette thèse se propose d’examiner la présence des populations étrangères et d’origine étrangère à Marseille en relation avec leur représentation dans la population des donneurs de sang. L’histoire des populations étrangères à Marseille (chapitre 2), la démographie actuelle de ces populations (chapitre 3) et la présentation de nos échantillons d’étude (chapitre 4) permettent, dans le chapitre 5, de questionner les notions d’intégration et d’insertion appliquée à ces populations. Le chapitre 6, consacré à l’étude de la représentation des différentes composantes de la population étrangère chez les donneurs de sang marseillais (chapitre 6), permet de concevoir l’Etablissement Français du Sang Alpes-Méditerranée comme un observatoire socio-économique des populations étrangères et d’origine étrangère. Enfin, le dernier chapitre se propose de mettre en relation les questions d’insertion, de citoyenneté et de don de sang compris comme créateur d’un certain type de lien social (chapitre 7)
The aim of this thesis is to study foreign populations’ presence in Marseilles in relation to their representation in the blood donors population. The history of foreign population in Marseilles (chapter 2), current demography of theses populations (chapter 3) and presentation of our samples (chapter 4) allow us, in chapter 5, to examine integration and insertion notions, generally applied to theses populations. Chapter 6, devoted to the study of the representation of the different component of foreign population in Marseilles’ blood donors, permit to conceive Etablissement Français du Sang Alpes-Méditerannée as a socio-economic observatory of foreign populations and their descendants. Finally, the last chapter propose to examine the questions of insertion, citizenship and blood donation, understood as a creator of a certain social link (chapter 7)

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Pterygium is an inflammatory and degenerative ocular surface disease in which the conjunctiva on the cornea grows forming a fibrous tissue in the shape of a triangle. The disorder may be characterized by cell proliferation, inflammatory processes, fibrosis, angiogenesis and destruction of the extracellular matrix. It is erroneously confused the cataract, and the anomaly is considered as a degenerative eye disease. The disease displays similar features to those of tumors in local invasion, metaplasia of epithelial cells, the presence of oncogenic viruses (Human Papilloma Virus - HPV), inactivation of tumor suppressor gene (such as the well-known p53) and loss of heterozygosity. This study aims to compare the frequency of the GSTT1 genotypes in relation to pterygium. The genotypic profile of the GSTT1 null polymorphism in Goiânia showed no statistically significant difference when comparing the frequency of the null genotype in the control and experimental groups. The null genotype is more frequent in the population studied. The GSTT1 genotype is not related to the risk factors analyzed: gender, ethnicity, family cases, occupational exposure, smoking, hypertension and Diabetes.
O pterígio é uma doença inflamatória e degenerativa da superfície ocular onde a conjuntiva avança sobre a córnea formando uma espécie de triângulo fibroso. O distúrbio pode ser caracterizado por uma proliferação celular, processos inflamatórios, fibrose, angiogênese e destruição da matriz extracelular. É popularmente  conhecido  como   carne  no  olho  e  erroneamente  confundido  com   a   catarata ,  sendo  já  considerado  uma  doença  ocular  degenerativa.  A  doença   exibe propriedades semelhantes às de tumores como invasão local, metaplasias de células epiteliais, presença de vírus oncogênicos (Papiloma Vírus Humano HPV), a inativação do gene supressor de tumor (p53) e perda de heterozigosidade. Este trabalho visa comparar a frequência dos genótipos do gene GSTT1 em relação ao pterígio. O perfil genotípico do polimorfismo do gene GSTT1 na cidade de Goiânia mostrou que não há diferença estatisticamente significativa quando se compara a frequência do genótipo nulo nos grupos controle e experimental. O genótipo nulo é o mais frequente na população estudada. O genótipo GSTT1 não está relacionado aos fatores de risco analisados: sexo, etnia, casos na família, exposição ocupacional, fumo, HAS e DM.

La pigmentación basal es un rasgo de carácter poligénico con alta heredabilidad, influenciada por factores ambientales, genéticos y endocrinos. La incidencia del cáncer de piel revela una clara relación entre ciertos rasgos de pigmentación y los daños causados por la exposición solar. Además, estudios recientes muestran una diferencia tanto en las características de pigmentación así como en la prevalencia e incidencia de melanoma entre sexos. El objetivo principal de esta tesis doctoral es ampliar el conocimiento actual sobre las bases moleculares de la pigmentación humana y la predisposición a melanoma cutáneo. Los análisis genéticos revelan la existencia de efectos genéticos que influyen en la pigmentación humana y el riesgo a melanoma según el sexo. Asimismo, polimorfismos localizados en la región 3’UTR de genes relacionados con la pigmentación estarían implicados en la aparición de lesiones cutáneas benignas relacionadas con el sol. Los estudios in vitro revelan que el riesgo a melanoma observado en individuos portadores de mutaciones en CDKN2A no es consecuencia de un comportamiento anormal del melanocito, siendo necesarias alteraciones genéticas y epigenéticas adicionales para transformar dichos melanocitos.
Human pigmentation traits are some of the most visible and differentiable human characteristics. Basal cutaneous pigmentation is a polygenic quantitative trait with high heritability, being influenced by genetic, environmental and sex-endocrine factors. Skin cancer incidence reveals a clear relationship between genetically controlled pigmentation traits and sunlight damage. Besides, sexual disparity in skin pigmentation and melanoma incidence and outcome has been recently shown. The general objective of this thesis is to expand the current knowledge on the molecular bases of human pigmentation and predisposition to cutaneous melanoma. Genetic analyses reveal a strong evidence for sex-differentiated genetic effects in human pigmentation as well as in melanoma risk. Additionally, there is a potential implication of polymorphisms in the 3'UTR regions of pigmentation-associated genes in the appearance of different sun-related benign pigmented skin lesions. In vitro studies show that the increased melanoma risk seen in CDKN2A mutation carriers is not the result of intrinsic abnormalities in melanocytes, being additional somatic genetic or epigenetic changes needed to transform melanocytes.

La population actuelle de l'archipel des Comores est considérée comme étant le résultat de contacts entre des populations d'origine Africaine Bantoue, Arabe et Austronésienne. Le but de cette étude est de décrire sa structure génétique, au travers de l'analyse de six groupes sanguins érythrocytaires, du polymorphisme du locus HLA-DR-B1 et des gènes KIR. 164 individus, non apparentés, d'origine Comorienne résidant à Marseille ont été étudiés. Les résultats révèlent que la contribution génétique des populations originaires de l'Afrique Bantoue est la plus importante (50 à 60%) et est en accord avec la forte influence culturelle encore présente. La contribution des populations en provenance de la Péninsule Arabique est plus faible (30%) et semble à la hauteur de leur influence religieuse et linguistique. Enfin, comme au niveau linguistique, l'impact du Sud Est Asiatique sur le pool génétique Comorien paraît quasiment absent. De plus, cette étude génétique, en révélant les écarts phénotypiques qui existent entre une population migrante et celle des donneurs de sang du pays d'accueil, souligne la nécessité d'actions spécifiques de sensibilisation au don de sang.

Ce travail s'integre dans une problematique generale cherchant a determiner quels aspects de l'environnement de la souris domestique peuvent participer a l'etablissement d'une divergence chromosomique (par suite de fixation de fusions robertsoniennes) dans certaines de ses populations. La souris domestique occupe deux types d'habitat exterieur et commensal. Le phenomene robertsonien est correle avec l'habitat commensal. Ici le commensalisme est considere dans ses aspects sociaux resultant des fortes densites et de la reproduction continue dans ce type d'habitat. La sensibilite des individus de differentes populations a un stress psychogenique est mesuree a l'aide d'un indice physiologique: le taux de corticosterone plasmatique. Differents stress sont experimentes: la capture, l'exposition a un environnement nouveau et la rencontre d'un congenere inconnu. La corticosteronemie basale en periode diurne permet d'evaluer la reactivite quotidienne des individus. Ces differents indices permettent de differencier au sein de chaque population etudiee les femelles plus emotives que les males, et parmi les differentes populations de distinguer celles qui proviennent d'un habitat commensal de celles provenant de l'habitat exterieur. En habitat commensal les individus montrent une faible sensibilite vis-a-vis d'un stress psychogenique et une forte reactivite quotidienne, le contraire est observe chez les souris exterieures. Les resultats sont interpretes en terme d'adaptation. Les souris robertsoniennes semblent montrer une strategie mixte qui pourrait etre a l'origine d'un avantage adaptatif. Un nouveau modele sur la mise en place du phenomene est propose

Entre le XIème et le XVIème siècle, la Mer des Indes fut le théâtre de nombreux mouvements populationnels aux fins essentiellement commerciales ou coloniales. Madagascar se trouve à la croisée des mondes asiatiques et africains. La côte sud-est malgache a vu l'arrivée de plusieurs migrations : la dernière, probablement vers la fin du XVème siècle, serait celle des Antemoro dont une partie d'entre eux se réclame d'une origine arabe et se rattache à La Mecque. L'éthnie des Antemoro a fait l'objet de nombreuses études anthropologiques et linguistiques. Néanmoins, le débat sur l'origine des migrants fait toujours l'objet d'hypothèses contradictoires. Leurs origines génétiques pourraient ainsi être l'Arabie, l'Afrique de l'Est, l'Inde ou encore l'Asie du Sud-Est à une époque où ces régions étaient déjà islamisées. Ce travail a consisté à étudier la diversité génétique d'une population Antemoro afin d'apporter des éléments de réponse à la question de leur origine biologique. Ce projet interdisciplinaire a pour objectif de mettre en relation l'anthropologie culturelle et sociale avec l'anthropologie biologique. Le polymorphisme du chromosome Y a été étudié afin de rechercher les origines des lignées paternelles par l'analyse de 17 marqueurs microsatellites ainsi que des mutations ponctuelles de l'ADN de la partie non recombinante du chromosome Y. De même, la variabilité génétique des lignées maternelles a été analysée par séquençage des régions hypervariables I et II de l'ADN mitochondrial, et par la définition de polymorphismes bialléliques dans sa région codante. Nous avons mis en évidence la présence de deux haplogroupes du chromosome Y chez certains groupes Antemoro, qui les différencient de la diversité habituellement rencontrée dans les populations malgaches. Bien que la majeure partie des Antemoro entre dans la diversité observée en Afrique sub-Saharienne et en Asie du Sud-Est, quelques haplotypes, des lignées paternelles, les lieraient au Moyen-Orient. Les lignées maternelles, quant à elles, ne les différencient pas de celles des autres populations malgaches. L'isolat génétique formé par certaines " pseudo-castes " Antemoro confirme bien l'isolat culturel. Ce travail apporte une nouvelle vision de la diversité génétique humaine à Madagascar.

"Social behaviour is fundamental for the survival and reproduction of organisms, and most animals are social to some degree. It is generally recognized that many neuropsychiatric diseases are associated with some form of social deficit or are accompanied by social impairments. There is also evidence that actual and perceived social isolation are both related with increased mortality risk. Given that social behaviour is central in both humans and other animals’ lives, many researchers with different backgrounds have been actively engaged in the challenge of understanding the nature of this highly complex and dynamic phenomenon. Social behaviour that independently evolved multiple times across animals is an extremely diverse behavioural category, influenced by multiple factors (genes, hormones, environment, ecology, development, life history trait, etc.) requiring a multidisciplinary approach, integrative analysis and standardized terminologies. However, despite its great diversity (both between and within species), there are similarities namely at mechanistic and functional level, which allows organizing social behaviours in functional modules, similar to those used in gene ontology categories. "

In leaf-cutting ants (genera Atta and Acromyrmex), the worker caste exhibits a pronounced size-polymorphism, and division of labor is largely dependent on worker size (alloethism). Behavioral studies have shown a rich diversity of olfactory-guided behaviors, and the olfactory system seems to be highly developed and very sensitive. To allow fine-tuned behavioral responses to different tasks, adaptations within the olfactory system of different sized workers are expected. In a recent study, two different phenotypes of the antennal lobe of Atta vollenweideri workers were found: MG- and RG-phenotype (with and without a macroglomerulus, MG). The existence of the macroglomerulus is correlated to the body size of workers, with small workers showing the RG-phenotype and large workers showing the MG-phenotype. In the MG, the information about the releaser component of the trail-pheromone is processed. In the first part of my PhD-project, I focus on quantifying behavioral differences between different sized workers in Atta vollenweideri. The study analyzes the trail following behavior; which can be generally performed by all workers. An artificial trail consisting of the releaser component of the trail-pheromone in decreasing concentration was used to test the trail-following performance of individual workers. The trail-following performance of the polymorphic workers is depended of the existence of the MG in the antennal lobe. Workers possessing the MG-phenotype were significantly better in following a decreasing trail then workers showing the RG-phenotype. In the second part I address the question if there are more structural differences, besides the MG, in the olfactory system of different sized workers. Therefore I analyze whether the glomerular numbers are related to worker size. The antennal lobes of small workers contain ~390 glomeruli (low-number; LN-phenotype), and in large workers I found a substantially higher number of ~440 glomeruli (high-number; HN-phenotype). All LN-phenotype workers and some of the small HN-phenotype workers do not possess an MG (LN-RG-phenotype and HN-RG-phenotype) at all, whereas the remaining majority of HN-phenotype workers do possess an MG (HN-MG-phenotype). Mass-stainings of antennal olfactory receptor neurons revealed that the sensory tracts divide the antennal lobe into six clusters of glomeruli (T1-T6). In the T4-cluster ~50 glomeruli are missing in the LN-phenotype workers. Selective staining of single sensilla and their associated receptor neurons showed that T4-glomeruli are innervated by receptor neurons from the main type of olfactory sensilla, the Sensilla trichodea curvata which are also projecting to glomeruli in all other clusters. The other type of olfactory sensilla, the Sensilla basiconica, exclusively innervates T6-glomeruli. Quantitative analyses revealed a correlation between the number of Sensilla basiconica and the volume of T6 glomeruli in different sized workers. The results of both behavioral and neuroanatomical studies in Atta vollenweideri suggest that developmental plasticity of antennal-lobe phenotypes promotes differences in olfactory-guided behavior which may underlie task specialization within ant colonies. The last part of my project focuses on the evolutionary origin of the macroglomerulus and the number of glomeruli in the antennal lobe. I compared the number, volumes and position of the glomeruli of the antennal lobe of 25 different species from all three major Attini groups (lower, higher and leaf-cutting Attini). The antennal lobes of all investigated Attini comprise a high number of glomeruli (257-630). The highest number was found in Apterostigma cf. mayri. This species is at a basal position within the Attini phylogeny, and a high number of glomeruli might have been advantageous in the evolution of the advanced olfactory systems of this Taxa. The macroglomerulus can be found in all investigated leaf-cutting Attini, but in none of the lower and higher Attini species. It is found only in large workers, and is located close to the entrance of the antennal nerve in all investigated species. The results indicate that the presence of a macroglomerulus in large workers of leaf-cutting Attini is a derived overexpression of a trait in the polymorphic leaf-cutting species. It presumably represents an olfactory adaptation to elaborate foraging and mass recruitment systems, and adds to the complexity of division of labor and social organization known for this group
Die Arbeiterinnenkaste der Blattschneideameisen zeigt einen ausgeprägten Größenpolymorphismus. Man findet hier einen Alloethismus; unterschiedlich große Arbeiterinnen führen verschiedene Arbeiten im Stock durch. Verschiedene Verhaltensversuche haben gezeigt, dass viele Verhaltensweisen der Arbeiterinnen olfaktorisch gesteuert werden und dass das olfaktorische System hoch entwickelt und sehr sensitiv ist. Es ist wahrscheinlich, dass sich im olfaktorischen System verschieden großer Arbeiterinnen Anpassungen finden lassen, die gut abgestimmte Verhaltensantworten auf die verschiedenen Aufgaben der Tiere ermöglichen. Und tatsächlich zeigt eine aktuelle Studie, dass zwei verschiedene Phänotypen des Antennallobus der Arbeiterin bei Atta vollenweideri existieren, der MG- und der RG-Phänotyp (mit oder ohne Makroglomerulus, MG). Die Existenz des Makroglomerulus kann mit der Körpergröße der Tiere korreliert werden: bei kleinen Arbeiterinnen findet man den RG-Phänotyp, bei großen den MG-Phänotyp. Im Makroglomerulus wird die olfaktorische Information über den verhaltensauslösenden Bestandteil des Spurpheromons verarbeitet. Im ersten Tel meiner Doktorarbeit versuche ich, Verhaltensunterschiede verschieden großer Atta vollenweideri Arbeiterinnen zu quantifizieren. Dazu konzentriere ich mich auf das Spurfolgeverhalten, dass bei Arbeiterinnen jeder Größe beobachtet werden kann. Um die Spurfolgeleistung einzelner Arbeiterinnen zu testen, wurde eine künstlich gelegte Spur mit abnehmender Konzentration des verhaltensauslösenden Bestandteils des Spurpheromons verwendet. Die Spurfolgeleistung der Arbeiterinnen hängt von der Existenz des Makroglomerulus im Antennallobus ab. Im zweiten Teil meiner Doktorarbeit untersuche ich die Neuroanatomie des olfaktorischen Systems bei verschieden großen Atta vollenweideri Arbeiterinnen auf eventuelle weitere anatomische Unterschiede neben dem Makroglomerulus – im Besonderen ob die Anzahl an Glomeruli bei verschieden großen Tieren unterschiedlich ist. Die Antennalloben kleiner Arbeiterinnen beinhalten cirka 390 Glomeruli (geringe Anzahl, LN-Phänotyp), die Antennalloben großer Arbeiterinnen dagegen cirka 440 Glomeruli (hohe Anzahl, HN-Phänotyp). Alle Arbeiterinnen mit dem LN-Phänotyp und einige mit dem HN-Phänotyp besitzen keinen Makroglomerulus (LN-RG-Phänotyp und HN-RG-Phänotyp). Die meisten Tiere mit HN-Phänotyp besitzen jedoch einen Makroglomerulus (HN-MG-Phänotyp). Massenfärbungen der olfaktorischen Rezeptorneuron-Axone zeigen, dass der Antennennerv sich in sechs Trakte teilt und so die Glomeruli in sechs verschiedene Glomerulicluster unterteilt werden können (T1-T6). Bei den Arbeiterinnen mit LN-Phänotyp fehlen cirka 50 Glomeruli im T4-Cluster. Einzelsensillenfärbungen zeigen, dass die Rezeptorneuronen der olfaktorischen Sensilla trichodea curvata alle sechs Cluster, also auch das T4-Cluster innervieren. Ein weiterer Sensillentyp, die Sensilla basiconica, innerviert ausschließlich Glomeruli im T6-Cluster. Quantitative Analysen ergeben eine Korrelation zwischen der Anzahl der Sensilla basiconica auf der Arbeiterinnenantenne und des durchschnittlichen Volumens der T6-Glomeruli bei verschieden großen Tieren. Die Ergebnisse der Verhaltensversuche und der neuroanatomischen Studien könnten darauf hinweisen, dass Unterschiede im Verhalten auf olfaktorische Reize möglicherweise durch die Entwicklungsplastizität der Antenallobus-Phänotypen ausgelöst werden. Dies könnte innerhalb der Kolonie die Grundlage der Spezialisierung von Arbeiterinnen auf bestimmte Arbeiten sein. Den letzten Teil meiner Doktorarbeit nimmt eine Untersuchung über den evolutionären Ursprung des Makroglomerulus und der Anzahl der Glomeruli im Antennallobus ein. Dazu verglich ich in den Antennalloben 25 verschiedener Arten aus den drei Attini-Gruppen (basale, höhere und blattschneidende Attini) die Anzahl, das Volumen und die Position der Glomeruli. Die Antennalloben aller untersuchten Arten bestehen aus sehr vielen Glomeruli (257-630). Der Makroglomerulus findet sich in allen untersuchten blattschneidenden Attini-Arten, aber nie in den untersuchten basalen und höheren Attini-Arten. Er findet sich nur bei größeren Arbeiterinnen und befindet sich immer in der Nähe des Antennennerveingangs. Dies bedeutet, dass es sich bei der Existenz des Makroglomerulus in den großen Blattschneidearbeiterinnen um eine abgeleitete Überexpression eines Merkmals innerhalb der polymorphen blattschneidenden Attini-Arten handelt. Der Makroglomerulus ist wahrscheinlich eine olfaktorische Anpassung an das hoch entwickelte Fouragier- und Rekrutiersystem dieser Arten. Er ist ein Baustein der komplexen Arbeitsteilung und der komplexen sozialen Organisation, die für die Arten dieser Gruppe bekannt sind

Childhood adversity is often associated with devastating physical, cognitive, and psychosocial outcomes, and is a major public health problem in terms of its prevalence and economic cost. Childhood adversity is associated with increased risk for psychopathology, as well as with dysregulation of the neurobiological stress response. An additional factor known to alter neuroendocrine functioning and increase psychopathology risk is polymorphisms within the FKBP5 gene. The goal of the current study was to examine the gene-environment interaction of childhood adversity and variation in the FKBP5 gene on the cortisol response to a psychosocial stress task (i.e., the Trier Social Stress Test). The final sample consisted of 90 depressed and non-depressed adolescents and young adults (11 - 21 years). Childhood adversity was assessed using the Childhood Experience and Abuse Scale (CECA; Bifulco et al., 1994), and was defined as the presence versus absence prior to 18 years of age of severe physical, sexual, or emotional abuse or neglect, witness to domestic discord/violence, or peer-perpetrated bullying. Participants were genotyped at the rs1360780 site of the FKBP5 gene and grouped according to whether they had at least one risk T allele (i.e., TT or TC genotype versus the CC genotype). Controlling for depression and anxiety psychopathology, I found a significant interaction of FKBP5 and childhood adversity status such that individuals with the FKBP5 risk allele (i.e., TT or TC genotype) and a history of childhood adversity showed a distinct cortisol response pattern characterized by decreasing cortisol from baseline and less cortisol output compared to individuals without childhood adversity. This relationship was specific to the experience of severe adversity and appeared to be strongest when adversity was defined as witnessing domestic discord/violence. These results are consistent with a diathesis-stress model in which the FKBP5 risk allele leaves individuals vulnerable to neurobiological dysregulation in the face of severe adverse experience in childhood. The implications of this research for understanding stress-related psychopathology and the limitations of this gene-environment interaction design are discussed.
Thesis (Master, Psychology) -- Queen's University, 2013-09-05 11:24:45.764

Tese de Doutoramento em Psicologia Aplicada
Maternal behaviour, particularly sensitive parenting, is fundamental for child development and functioning. Is has been vastly studied, with recent considerable interest on its determinants, expanding the research from environmental (eg. maternal variables and contextual experience), to genetic predictors (eg. polymorphisms in the oxytocinergic system, given its link to affiliation). Despite this growing interest, research is still in many ways preliminary and, when reviewing the literature, results prove inconsistent. Maternal behaviour has indeed been shown to impact on diverse aspects of child’s adjustment, including children’s behaviour, but also at the physiological level, such as neuroendocrine functioning. Nonetheless, literature on this domain is still scarce. The goal of the present doctoral dissertation was to contribute to the gaps in this field of research. Its two main aims were: firstly, to investigate genetic and environmental determinants of maternal interactive behaviour; secondly, to assess the impact of such behaviour on child’s functioning, particularly at the behavioural and neuroendocrine levels. Therefore, Chapter 1 introduced the research background behind the proposed field of study. Chapter 2 and 3 then focus the first aim of this dissertation: to examine the determinants of maternal behaviour. Specifically, Chapter 2 analysed the role of a polymorphism (SNP rs53576) on the Oxytocin Receptor Gene (OXTR) on maternal behaviour in two studies. In the first study, based on a sample of 215 Caucasian mothers, a non-significant association was found between the OXTR SNP rs53576 and maternal behaviour. In the second study, results of a meta-analysis on the available literature on the same OXTR SNP and maternal behaviour revealed a statistically significant, small magnitude effect. Chapter 3 then took into consideration the link between the oxytocinergic and serotonergic systems, and serotonin’s role as a modulator of neural circuitry that controls several behavioural and physiological processes, which may be critical for parenting. It analysed the role of the maternal 5-HTTLPR polymorphism on maternal behaviour, testing the quality of environmental context as a possible moderator of such association. Results proved consistent with the weak differential susceptibility model of person-Xcontext interaction. Chapters 4 and 5 then focused the second aim of this dissertation, which relates to child’s functioning. Chapter 4 provided an adaptation and validation of the child codings of the Coding System for Mother–Child Interactions (CSMCI, Healey et al., 2010). The codings’ inter-rater agreement was confirmed, and convergent and divergent validity established. Its applications for the assessment of preschoolers’ interactive behaviour, and its implications to future research and practice are discussed. Finally, Chapter 5 explored the child’s oxytocin (OT) response to mother-child interaction, and found that it was predicted by the interaction between individual (child’s OXTR genotype) and environmental (maternal behaviour) factors. Drawing from these analysis, the identified interaction was investigated as a predictor of the child’s interactive behaviour, considering the possible mediator role of the child’s OT level. This dissertation underlines the relevance of considering the interaction between individual and environmental factors in shaping both behavioural and neuroendocrine responses. Building on this work, future studies should consider larger scale samples, and follow approaches which include different biological, psychological and environmental aspects for a broader comprehension of affiliative behaviour.
O comportamento materno, e particularmente a parentalidade sensível, é fundamental para o desenvolvimento e funcionamento da criança. Recentemente, este comportamento tem sido vastamente estudado, com considerável interesse prestado aos seus determinantes, alargando a investigação de preditores ambientais (p.ex., variáveis maternas e experiências relacionadas com o contexto), para preditores genéticos (p.ex., polimorfismos no sistema oxitocinergico, dada a sua relação com a afiliação). Apesar do interesse crescente, a investigação é, ainda, em grande medida, preliminar, e, ao rever a literatura, os resultados demonstram-se inconsistentes. De facto, o comportamento materno tem demonstrado ter impacto em diversos aspectos do ajustamento da criança, quer a nível comportamental, quer em aspectos mais fisiológicos, como o funcionamento neuroendócrino. No entanto, a literatura neste domínio é ainda escassa. O propósito desta dissertação de doutoramento é contribuir para as lacunas neste campo de investigação. Os dois objetivos fundamentais são: em primeiro lugar, investigar determinantes genéticos e ambientais do comportamento interativo materno; seguidamente, avaliar o impacto de tal comportamento no funcionamento da criança, particularmente ao nível comportamental e neuroendócrino. Assim, o Capítulo 1 incide sobre a revisão da literatura da área em estudo. De seguida, os capítulos 2 e 3 focam o primeiro objetivo desta dissertação: o estudo dos determinantes do comportamento materno. Especificamente, o Capítulo 2 analisa o papel de um polimorfismo (SNP rs53576) no Gene Receptor da Oxitocina (OXTR) no comportamento materno, reunindo 2 estudos. No primeiro estudo, com base numa amostra de 215 mães Caucasianas, não é encontrada uma associação significativa entre o OXTR SNP rs53576 e o comportamento materno. No segundo estudo, os resultados de uma meta-análise com base na literatura disponível revelam um efeito de associação significativo, embora de pequena magnitude, entre o referido polimorfismo e o comportamento materno. O Capítulo 3 tem em consideração a relação entre os sistemas oxitocinérgico e serotoninérgico, bem como o papel da serotonina como modulador de circuitos neuronais que controlam diversos processos comportamentais e fisiológicos, que podem ser críticos para a parentalidade. Este capítulo analisa o papel do polimorfismo 5-HTTLPR no comportamento materno, e testa a qualidade do contexto ambiental como possível moderador desta associação. Os resultados revelam-se consistentes com a versão fraca do modelo de susceptibilidade diferencial de interação Gene-X-Ambiente. De seguida, os capítulos 4 e 5 focam-se no segundo objetivo desta dissertação, que se relaciona com o funcionamento da criança. O Capítulo 4 faz a adaptação e validação das escalas da criança do instrumento Coding System for Mother–Child Interactions (CSMCI, Healey et al., 2010). O acordo inter-cotador é estabelecido, bem como a sua validade convergente e discriminante. São discutidos o seu uso para a codificação do comportamento interactivo de crianças em idade pré-escolar, e as suas implicações para a investigação futura e para a prática. Finalmente, o Capítulo 5 explora a resposta oxitocinérgica da criança numa tarefa de interação mãe-criança. Esta resposta é predita pela interação entre factores individuais (o genótipo OXTR da criança) e ambientais (comportamento materno). Com base nestas análises, o efeito de interação encontrado é investigado como preditor do comportamento interactivo da criança, considerando o possível papel mediador dos níveis de OT da criança. De forma global, esta dissertação sublinha a relevância de considerar o impacto da interação entre factores individuais e ambientais nas respostas comportamentais e neuroendócrinas. Partindo deste trabalho, estudos futuros deverão considerar amostras de maior escala, e seguir abordagens que incluam diferentes aspectos biológicos, psicológicos e ambientais, para uma compreensão mais alargada do comportamento afiliativo.
This research was conducted at the Psychology Research Centre (UID/PSI/01662/2013), University of Minho. It was supported by the Portuguese Foundation for Science and Technology (PhD Fellowship SFRH/BD/96001/2013) and the Portuguese Ministry of Science, Technology and Higher Education through national funds, and in the scope of QREN – POPH – Typology 4.1 – Advanced Training, reimbursed by the European Social Found and MSTHE funds. It was conducted as part of the PTDC/PSI-PCL/116897/2010 project, which was financed by national funds through the FCT/MEC (PIDDAC) and co-funded by the European Regional Development Fund (FEDER) through COMPETE – Operational Programme Competitiveness Factors (POFC).