Sex-chromosome differentiation parallels postglacial range expansion in European tree frogs (Hyla arborea).

Occasional XY recombination is a proposed explanation for the sex-chromosome homomorphy in European tree frogs. Numerous laboratory crosses, however, failed to detect any event of male recombination, and a detailed survey of NW-European Hyla arborea populations identified male-specific alleles at sex-linked loci, pointing to the absence of XY recombination in their recent history. Here, we address this paradox in a phylogeographic framework by genotyping sex-linked microsatellite markers in populations and sibships from the entire species range. Contrasting with postglacial populations of NW Europe, which display complete absence of XY recombination and strong sex-chromosome differentiation, refugial populations of the southern Balkans and Adriatic coast show limited XY recombination and large overlaps in allele frequencies. Geographically and historically intermediate populations of the Pannonian Basin show intermediate patterns of XY differentiation. Even in populations where X and Y occasionally recombine, the genetic diversity of Y haplotypes is reduced below the levels expected from the fourfold drop in copy numbers. This study is the first in which X and Y haplotypes could be phased over the distribution range in a species with homomorphic sex chromosomes; it shows that XY-recombination patterns may differ strikingly between conspecific populations, and that recombination arrest may evolve rapidly (<5000 generations).

Fecal pellets collection as a method for assessing egesta of the marine cave-dwelling mysid Hemimysis speluncula

Egesta of a cave-dwelling mysid (Hemimysis speluncola Ledoyer, 1963) was studied in a submarine cave of Medes Islands, NW Mediterranean by in situ fecal pellet collecting. Fecal pellet production and gut fullness of mysids during incubation experiments are used to estimate mysid egestion rates. Intrinsic factors related with the natural history of this species such as population structure, density of mysids, daily rhythms and pellet decomposition rates are tested for their influence on the egestion rate. The effects of methodological artifacts, such as the stress induced by both incubation and preservation procedures, are also studied. An average mysid egests about 2.5 pellets per day into the cave. The time of day is the main factor affecting egestion. The highest deposition rate is between 2 to 4 hours after sunrise when about 38 % of the total daily pellet production becomes egested. Fecal pellet morphology changes with mysid demographic classes: immature mysids produce slender and thick pellets, whereas mature mysids produce only thick pellets. Immature classes show higher percentages of full guts than mature ones. Mysid density in the incubators does not affect the results on gut fullness, but it causes a decrease in the number of pellets collected after incubation. Coprorhexia seems to be the only plausible process to explain this paradox. The incubation procedure does not increase deposition rate significantly. Time of incubation is critical because the half-life of fecal pellets is about 2.5 hours. Fixation with liquid nitrogen decreases gut fullness and also deposition rates. Higher values are obtained with 70 % ethanol and 5 % formalin solutions which show very similar results for both gut fullness and pellet deposition rates. Nevertheless, ethanol is not suitable as fixative because it enhances the opacity of the body. Several suggestions are given in order to optimize the reliability of further in situ experiments for evaluation of egesta of Hemimysis speluncola in submarine caves.

Cuando Frankenstein encontró a Dorian Gray: dandysmo, post-identidad y sujetos virtuales

The appearance and popularization of the internet has created new forms of writing, which compel us to think anew about identity and subjectivity. Webjournals or blogs are specially interesting because they are a massive phenomenon that use autobiographical writing in a peculiar way. These forms of writing stress a particular paradox of the genre: the coexistence between a purpose of private, confessional and spontaneous writing and a public image, carefully built, as a result of its writing. The technology is new, but, in fact, the paradox is old. This paper tries to explore this old paradox, our eternal condition of cyborgs, our use of technologies in order to construct a public, unique and recognizably identity. In oder to do so, I will try to show the virtual condition of any written individual ¿this issue has already been dealt with by autobiographical studies¿, focusing on blogs, and especially on concrete example (Lord Whimsy¿s Journal). I will pay attention to gender as a technology that constructs identity and, at the same time, is deconstructed by the autobiographical narratives analyzed. In short, I attempt to show that virtual and autobiographical discourse do not bring forth a new kind of subject but the permanence of an old phenomenon "clearly developed by dandyism, for instance¿: the use of tehnologies to re-invent, re-formulate and re-construct us as multiple, hybrid and mixed subjects."

Traitement de l'asthme et de la rhinite durant la grossesse et l'allaitement [Treatment of asthma and rhinitis during pregnancy and breast feeding]

Inhaled therapies are preferred to systemic ones during pregnancy and breast feeding. A real paradox exists however between the necessity to ensure an optimal treatment for pregnant women with asthma, in order to prevent fetal hypoxia, and the precaution linked to any drug prescription during pregnancy. Thus, the use of topical corticosteroids remains the first choice for asthma as well as rhinitis. Inhaled beta2-agonists are also recommended. Systemic corticosteroids may however be prescribed without hesitation when their use is required for asthma treatment. It is also interesting to note that oral second-generation antihistamines are currently allowed during pregnancy and breast feeding. This type of antihistamines is indeed to be preferred to first-generation ones that generate more side-effects and generally are thus not to be prescribed during breast feeding.

Asexual evolution: do intragenomic parasites maintain sex?

Resolving the paradox of sex, with its twofold cost to genic transmission, remains one of the major unresolved questions in evolutionary biology. Counting this genetic cost has now gone genomic. In this issue of Molecular Ecology, Kraaijeveld et al. (2012) describe the first genome-scale comparative study of related sexual and asexual animal lineages, to test the hypothesis that asexuals bear heavier loads of deleterious transposable elements. A much higher density of such parasites might be expected, due to the inability of asexual lineages to purge transposons via mechanisms exclusive to sexual reproduction. They find that the answer is yes--and no--depending upon the family of transposons considered. Like many such advances in testing theory, more questions are raised by this study than answered, but a door has been opened to molecular evolutionary analyses of how responses to selection from intragenomic parasites might mediate the costs of sex.

Une européanisation des politiques de conciliation de la vie familiale et professionnelle? : les cas de l'Italie et de la France

Les différents pays membres de l'UE connaissent des politiques dites de « conciliation de la vie professionnelle et familiale » qui correspondent à un ensemble de dispositifs hétéroclites, plus ou moins complexes, mais rarement cohérents. Alliant des objectifs tels que la hausse de la natalité, la protection des mères et des enfants, l'égalité entre femmes et hommes, la lutte contre la pauvreté des enfants et des familles monoparentales et l'activation des femmes, ces politiques sont fortement ancrées dans des traditions nationales de politiques familiales, d'emploi et fiscales. Ces politiques portent en elles l'héritage et les tensions de l'histoire d'un pays. Au moment où un nouvel acteur international, l'Union européenne, intervient de manière de plus en plus explicite dans le débat et dans la définition de ces politiques, la présente étude tend à analyser l'influence exercées par les référentiels européens en matière de politiques de conciliation sur les discours et politiques nationales de l'Italie et de la France. A partir d'une analyse cognitive du processus d'européanisation, nous montrons que les référentiels développés au sein de l'UE, par leur caractère abstrait et flou, n'ont eu jusqu'ici qu'une faible influence sur les discours et politiques en Italie et en France. Croisant une perspective néo-institutionnaliste historique et discursive, notre recherche a été construite autour de deux axes de réflexion. Premièrement, il a été question d'analyser, d'une part, l'évolution du discours tenu par les différentes instances européennes (notamment de la Commission européenne, le Conseil européen et le Fonds Social européen) et, d'autre part, questionner comment un consensus a pu émerger entre des pays et des acteurs qui ont des traditions extrêmement différentes en matière de politique sociale, de politique familiale et de convention de genre. Deuxièmement, il a été question d'analyser si et comment un cadre de référence conçu au niveau communautaire a pu influencer les discours et politiques au niveau national. - The reconciliation of work and family life policies forms, in the EU's member States, a plurality of politics, more or less complex, but rarely coherent. Combining different objectives such as fertility increase, mothers and children protection, equality between men and women, fight against children and lone-parent families poverty and women activation, these policies are part of the national traditions of family, employment and tax policy and bear the heritage and the tensions of the country history. At a moment when a new global player, the European Union, interferes increasingly explicitly in the debate and the definition of reconciling work and family life policies, the question at the heart of this thesis was to define what kind of influence the référentiels of European discourses have on reconciliation policies since the late 1990s, in the Italian and French discourses and policies. Starting from a cognitive analysis of the Europeanization process, we show that the référentiels developed within the EU, by their abstract and vague nature, have had little influence in Italy and France. Crossing an historical and a discursive neo-institutionalist perspective, our research was based on two axes of reasoning. First, we have analysed, on the one hand, the evolution of various European institutions' discoursed (including the European Commission, the European Council and the European Social Fund) and, on the other hand, we have questioned how a consensus has emerged between countries and actors who have very different traditions in social policy, family policy and gender conventions. Secondly, we have observed if and how a framework developed at Community level, as a kind of ideal to strive for, has influenced discourses and policies at the national level.

Determinants of the omega-3 index in a Mediterranean population at increased risk for CHD.

The omega-3 index, defined as the sum of EPA and DHA in erythrocyte membranes expressed as a percentage of total fatty acids, has been proposed as both a risk marker and risk factor for CHD death. A major determinant of the omega-3 index is EPA þ DHA intake, but the impact of other dietary fatty acids has not been investigated. In a cross-sectional study on 198 subjects (102 men and 96 women, mean age 66 years) at high cardiovascular risk living in Spain, the country with low rates of cardiac death despite a high prevalence of cardiovascular risk factors, dietary data were acquired from FFQ and blood cell membrane fatty acid composition was measured by GC. The average consumption of EPA þ DHA was 0·9 g/d and the mean omega-3 index was 7·1%. In multivariate models, EPA þ DHA intake was the main predictor of the omega-3 index but explained only 12% of its variability (P,0·001). No associations with other dietary fatty acids were observed. Although the single most influential determinant of the omega-3 index measured here was the intake of EPA þ DHA, it explained little of the former"s variability; hence, the effects of other factors (genetic, dietary and lifestyle) remain to be determined. Nevertheless, the high omega-3 index could at least partially explain the paradox of low rates of fatal CHD in Spain despite a high background prevalence of cardiovascular risk factors.

Cuando Frankenstein encontró a Dorian Gray: dandysmo, post-identidad y sujetos virtuales

The appearance and popularization of the internet has created new forms of writing, which compel us to think anew about identity and subjectivity. Webjournals or blogs are specially interesting because they are a massive phenomenon that use autobiographical writing in a peculiar way. These forms of writing stress a particular paradox of the genre: the coexistence between a purpose of private, confessional and spontaneous writing and a public image, carefully built, as a result of its writing. The technology is new, but, in fact, the paradox is old. This paper tries to explore this old paradox, our eternal condition of cyborgs, our use of technologies in order to construct a public, unique and recognizably identity. In oder to do so, I will try to show the virtual condition of any written individual ¿this issue has already been dealt with by autobiographical studies¿, focusing on blogs, and especially on concrete example (Lord Whimsy¿s Journal). I will pay attention to gender as a technology that constructs identity and, at the same time, is deconstructed by the autobiographical narratives analyzed. In short, I attempt to show that virtual and autobiographical discourse do not bring forth a new kind of subject but the permanence of an old phenomenon "clearly developed by dandyism, for instance¿: the use of tehnologies to re-invent, re-formulate and re-construct us as multiple, hybrid and mixed subjects."

The evolution of unicoloniality in ant societies : recognition, dispersal and population genetic structure

Introduction Societies of ants, bees, wasps and termites dominate many terrestrial ecosystems (Wilson 1971). Their evolutionary and ecological success is based upon the regulation of internal conflicts (e.g. Ratnieks et al. 2006), control of diseases (e.g. Schmid-Hempel 1998) and individual skills and collective intelligence in resource acquisition, nest building and defence (e.g. Camazine 2001). Individuals in social species can pass on their genes not only directly trough their own offspring, but also indirectly by favouring the reproduction of relatives. The inclusive fitness theory of Hamilton (1963; 1964) provides a powerful explanation for the evolution of reproductive altruism and cooperation in groups with related individuals. The same theory also led to the realization that insect societies are subject to internal conflicts over reproduction. Relatedness of less-than-one is not sufficient to eliminate all incentive for individual selfishness. This would indeed require a relatedness of one, as found among cells of an organism (Hardin 1968; Keller 1999). The challenge for evolutionary biology is to understand how groups can prevent or reduce the selfish exploitation of resources by group members, and how societies with low relatedness are maintained. In social insects the evolutionary shift from single- to multiple queens colonies modified the relatedness structure, the dispersal, and the mode of colony founding (e.g. (Crozier & Pamilo 1996). In ants, the most common, and presumably ancestral mode of reproduction is the emission of winged males and females, which found a new colony independently after mating and dispersal flights (Hölldobler & Wilson 1990). The alternative reproductive tactic for ant queens in multiple-queen colonies (polygyne) is to seek to be re-accepted in their natal colonies, where they may remain as additional reproductives or subsequently disperse on foot with part of the colony (budding) (Bourke & Franks 1995; Crozier & Pamilo 1996; Hölldobler & Wilson 1990). Such ant colonies can contain up to several hundred reproductive queens with an even more numerous workforce (Cherix 1980; Cherix 1983). As a consequence in polygynous ants the relatedness among nestmates is very low, and workers raise brood of queens to which they are only distantly related (Crozier & Pamilo 1996; Queller & Strassmann 1998). Therefore workers could increase their inclusive fitness by preferentially caring for their closest relatives and discriminate against less related or foreign individuals (Keller 1997; Queller & Strassmann 2002; Tarpy et al. 2004). However, the bulk of the evidence suggests that social insects do not behave nepotistically, probably because of the costs entailed by decreased colony efficiency or discrimination errors (Keller 1997). Recently, the consensus that nepotistic behaviour does not occur in insect colonies was challenged by a study in the ant Formica fusca (Hannonen & Sundström 2003b) showing that the reproductive share of queens more closely related to workers increases during brood development. However, this pattern can be explained either by nepotism with workers preferentially rearing the brood of more closely related queens or intrinsic differences in the viability of eggs laid by queens. In the first chapter, we designed an experiment to disentangle nepotism and differences in brood viability. We tested if workers prefer to rear their kin when given the choice between highly related and unrelated brood in the ant F. exsecta. We also looked for differences in egg viability among queens and simulated if such differences in egg viability may mistakenly lead to the conclusion that workers behave nepotistically. The acceptance of queens in polygnous ants raises the question whether the varying degree of relatedness affects their share in reproduction. In such colonies workers should favour nestmate queens over foreign queens. Numerous studies have investigated reproductive skew and partitioning of reproduction among queens (Bourke et al. 1997; Fournier et al. 2004; Fournier & Keller 2001; Hammond et al. 2006; Hannonen & Sundström 2003a; Heinze et al. 2001; Kümmerli & Keller 2007; Langer et al. 2004; Pamilo & Seppä 1994; Ross 1988; Ross 1993; Rüppell et al. 2002), yet almost no information is available on whether differences among queens in their relatedness to other colony members affects their share in reproduction. Such data are necessary to compare the relative reproductive success of dispersing and non-dispersing individuals. Moreover, information on whether there is a difference in reproductive success between resident and dispersing queens is also important for our understanding of the genetic structure of ant colonies and the dynamics of within group conflicts. In chapter two, we created single-queen colonies and then introduced a foreign queens originating from another colony kept under similar conditions in order to estimate the rate of queen acceptance into foreign established colonies, and to quantify the reproductive share of resident and introduced queens. An increasing number of studies have investigated the discrimination ability between ant workers (e.g. Holzer et al. 2006; Pedersen et al. 2006), but few have addressed the recognition and discrimination behaviour of workers towards reproductive individuals entering colonies (Bennett 1988; Brown et al. 2003; Evans 1996; Fortelius et al. 1993; Kikuchi et al. 2007; Rosengren & Pamilo 1986; Stuart et al. 1993; Sundström 1997; Vásquez & Silverman in press). These studies are important, because accepting new queens will generally have a large impact on colony kin structure and inclusive fitness of workers (Heinze & Keller 2000). In chapter three, we examined whether resident workers reject young foreign queens that enter into their nest. We introduced mated queens into their natal nest, a foreign-female producing nest, or a foreign male-producing nest and measured their survival. In addition, we also introduced young virgin and mated queens into their natal nest to examine whether the mating status of the queens influences their survival and acceptance by workers. On top of polgyny, some ant species have evolved an extraordinary social organization called 'unicoloniality' (Hölldobler & Wilson 1977; Pedersen et al. 2006). In unicolonial ants, intercolony borders are absent and workers and queens mix among the physically separated nests, such that nests form one large supercolony. Super-colonies can become very large, so that direct cooperative interactions are impossible between individuals of distant nests. Unicoloniality is an evolutionary paradox and a potential problem for kin selection theory because the mixing of queens and workers between nests leads to extremely low relatedness among nestmates (Bourke & Franks 1995; Crozier & Pamilo 1996; Keller 1995). A better understanding of the evolution and maintenance of unicoloniality requests detailed information on the discrimination behavior, dispersal, population structure, and the scale of competition. Cryptic genetic population structure may provide important information on the relevant scale to be considered when measuring relatedness and the role of kin selection. Theoretical studies have shown that relatedness should be measured at the level of the `economic neighborhood', which is the scale at which intraspecific competition generally takes place (Griffin & West 2002; Kelly 1994; Queller 1994; Taylor 1992). In chapter four, we conducted alarge-scale study to determine whether the unicolonial ant Formica paralugubris forms populations that are organised in discrete supercolonies or whether there is a continuous gradation in the level of aggression that may correlate with genetic isolation by distance and/or spatial distance between nests. In chapter five, we investigated the fine-scale population structure in three populations of F. paralugubris. We have developed mitochondria) markers, which together with the nuclear markers allowed us to detect cryptic genetic clusters of nests, to obtain more precise information on the genetic differentiation within populations, and to separate male and female gene flow. These new data provide important information on the scale to be considered when measuring relatedness in native unicolonial populations.

Sex reversal: a fountain of youth for sex chromosomes?

Nonrecombining Y chromosomes are expected to degenerate through the progressive accumulation of deleterious mutations. In lower vertebrates, however, most species display homomorphic sex chromosomes. To address this, paradox I propose a role for sex reversal, which occasionally occurs in ectotherms due to the general dependence of physiological processes on temperature. Because sex-specific recombination patterns depend on phenotypic, rather than genotypic sex, homomorphic X and Y chromosomes are expected to recombine in sex-reversed females. These rare events should generate bursts of new Y haplotypes, which will be quickly sorted out by natural or sexual selection. By counteracting Muller's ratchet, this regular purge should prevent the evolutionary decay of Y chromosomes. I review empirical data supporting this suggestion, and propose further investigations for testing it.

Three essays on major trends in a slow clockspeed industry : the case of industrial automation

The motivation for this research initiated from the abrupt rise and fall of minicomputers which were initially used both for industrial automation and business applications due to their significantly lower cost than their predecessors, the mainframes. Later industrial automation developed its own vertically integrated hardware and software to address the application needs of uninterrupted operations, real-time control and resilience to harsh environmental conditions. This has led to the creation of an independent industry, namely industrial automation used in PLC, DCS, SCADA and robot control systems. This industry employs today over 200'000 people in a profitable slow clockspeed context in contrast to the two mainstream computing industries of information technology (IT) focused on business applications and telecommunications focused on communications networks and hand-held devices. Already in 1990s it was foreseen that IT and communication would merge into one Information and communication industry (ICT). The fundamental question of the thesis is: Could industrial automation leverage a common technology platform with the newly formed ICT industry? Computer systems dominated by complex instruction set computers (CISC) were challenged during 1990s with higher performance reduced instruction set computers (RISC). RISC started to evolve parallel to the constant advancement of Moore's law. These developments created the high performance and low energy consumption System-on-Chip architecture (SoC). Unlike to the CISC processors RISC processor architecture is a separate industry from the RISC chip manufacturing industry. It also has several hardware independent software platforms consisting of integrated operating system, development environment, user interface and application market which enables customers to have more choices due to hardware independent real time capable software applications. An architecture disruption merged and the smartphone and tablet market were formed with new rules and new key players in the ICT industry. Today there are more RISC computer systems running Linux (or other Unix variants) than any other computer system. The astonishing rise of SoC based technologies and related software platforms in smartphones created in unit terms the largest installed base ever seen in the history of computers and is now being further extended by tablets. An underlying additional element of this transition is the increasing role of open source technologies both in software and hardware. This has driven the microprocessor based personal computer industry with few dominating closed operating system platforms into a steep decline. A significant factor in this process has been the separation of processor architecture and processor chip production and operating systems and application development platforms merger into integrated software platforms with proprietary application markets. Furthermore the pay-by-click marketing has changed the way applications development is compensated: Three essays on major trends in a slow clockspeed industry: The case of industrial automation 2014 freeware, ad based or licensed - all at a lower price and used by a wider customer base than ever before. Moreover, the concept of software maintenance contract is very remote in the app world. However, as a slow clockspeed industry, industrial automation has remained intact during the disruptions based on SoC and related software platforms in the ICT industries. Industrial automation incumbents continue to supply systems based on vertically integrated systems consisting of proprietary software and proprietary mainly microprocessor based hardware. They enjoy admirable profitability levels on a very narrow customer base due to strong technology-enabled customer lock-in and customers' high risk leverage as their production is dependent on fault-free operation of the industrial automation systems. When will this balance of power be disrupted? The thesis suggests how industrial automation could join the mainstream ICT industry and create an information, communication and automation (ICAT) industry. Lately the Internet of Things (loT) and weightless networks, a new standard leveraging frequency channels earlier occupied by TV broadcasting, have gradually started to change the rigid world of Machine to Machine (M2M) interaction. It is foreseeable that enough momentum will be created that the industrial automation market will in due course face an architecture disruption empowered by these new trends. This thesis examines the current state of industrial automation subject to the competition between the incumbents firstly through a research on cost competitiveness efforts in captive outsourcing of engineering, research and development and secondly researching process re- engineering in the case of complex system global software support. Thirdly we investigate the industry actors', namely customers, incumbents and newcomers, views on the future direction of industrial automation and conclude with our assessments of the possible routes industrial automation could advance taking into account the looming rise of the Internet of Things (loT) and weightless networks. Industrial automation is an industry dominated by a handful of global players each of them focusing on maintaining their own proprietary solutions. The rise of de facto standards like IBM PC, Unix and Linux and SoC leveraged by IBM, Compaq, Dell, HP, ARM, Apple, Google, Samsung and others have created new markets of personal computers, smartphone and tablets and will eventually also impact industrial automation through game changing commoditization and related control point and business model changes. This trend will inevitably continue, but the transition to a commoditized industrial automation will not happen in the near future.

Implantació d'una plataforma informàtica en una entitat financera fusionada

Els darrers anys han estat molt convulsos en el món financer. De tots és coneguda la crisi, immobiliària en un primer moment, i financera més tard. Reestructuracions, fusions, absorcions, intervencions i nacionalitzacions han estat a l’ordre del dia en el món de les entitats financeres els últims 3 anys. El mapa financer ha passat de més de 50 entitats a poc menys de 10 en tan sols 3 anys. Els departaments de tecnologia de bancs i caixes no han estat aliens a aquests moviments. Tot i estar relativament al marge del negoci financer de l’entitat, cada fusió ha atorgat un paper protagonista a tota la plantilla informàtica. Ja que cada reestructuració ha suposat un gran esforç per integrar entitats molt diferents entre si en una de sola. Intentant que l’impacte a clients i a usuaris fos el menor possible. Caixa Manlleu és un exemple proper de la reestructuració del món financer, i ha protagonitzat, juntament amb Caixa Sabadell i Caixa Terrassa, la creació d’Unnim. Aquest cas real serà la base del treball. El projecte consisteix en la creació d’una plataforma informàtica per a la nova entitat resultant de la fusió. Una plataforma amb un doble objectiu: d’una banda, que reculli el millor de les tres plataformes d’origen i que compleixi tots els requestis que la nova entitat exigeix per tal que els usuaris puguin continuar fent les tasques diàries. I de l’altra, una plataforma que posi al dia i actualitzi tecnològicament l’entitat amb el mínim cost possible. Així doncs, cal analitzar per separat cadascuna de les 3 plataformes existents, inventariar les aplicacions comunes i les departamentals, així com les llicències de software vigents existents i no caducades. Decidir quines aplicacions es faran servir, si se’n poden aprofitar o si per contra en calen de noves. També cal analitzar quins equips informàtics (terminals) es necessitaran per tal de treure el màxim rendiment de la plataforma. Entre les conclusions obtingudes en el projecte, cal destacar els grans avantatges d’utilitzar aplicacions virtualitzades en lloc de les tradicionals aplicacions instal·lades físicament a cada terminal. Faciliten la feina i el manteniment, estalvien recursos i fan guanyar temps. A més a més s’aconsegueix una plataforma àgil, lleugera i ràpida.

When several queens reign: how polygyny affects social life in ants

Astract: The aim of this thesis was to investigate how the presence of multiple queens (polygyny) affects social organization in colonies of the ant Formica exsecta. This is important because polygyny results in reduced relatedness among colony members and therefore reflects a potential paradox for altruistic cooperation being explained by inclusive fitness theory. The reason for this is that workers in polygynous colonies rear no longer only their siblings (high inclusive fitness gain) but also more distantly ox even unrelated brood (low or no inclusive fitness gain). All research projects conducted in this thesis are novel and significant contributions to the understanding of the social evolution of insect societies. We used a mixture of experimental and observational methodologies in laboratory and field colonies of F. exsecta to examine four important aspects of social life that are impacted by polygyny. First, we investigated the influence of queen number on colony sex allocation and found that the number of queens present in a colony significantly affects colony sex ratio investment. The data were consistent with the queen-replenishment hypothesis, which is based on the observation that newly mated queens are often recruited back to their parental nest. According to this theory, colonies containing many queens should only produce males due to local resource competition (i.e. related queens compete for common resources), whereas colonies hosting few queens benefit most from producing new queens to ensure colony survival. Second, we examined how reproduction is partitioned among nestmate queens. We detected a novel pattern of reproductive partitioning whereby a high proportion of queens were completely specialized in the production of only a subset of offspring classes produced within a colony, which might translate into great differences in reproductive success between queens. Third, we could demonstrate that F. exsecta workers indiscriminately reared highly related and unrelated brood although such nepotistic behaviour (preferential rearing of relatives) would be predicted by inclusive fitness theory. The absence of nepotism is probably best explained by its negative effects on overall colony efficiency. Finally, we conducted a detailed population genetic analysis, which revealed that the genetic population structure is different for queens and workers. Our data were best explained with queens forming family-based groups (multicolonial population structure), whereas workers from several nests seemed to be grouped into larger unites (unicolonial population structure) with workers moving freely between neighbouring nests. Altogether, the presented work significantly increased our understanding of the complex organization of polygynous social insect colonies and shows how an important life history trait such as queen number affects social organization at various levels. Résumé: Le but de cette thèse était d'étudier comment la présence de plusieurs reines par colonie (polygynie) influence la vie sociale chez la fourmi Formica exsecta. Ce sujet est important parce que la polygynie chez les insectes sociaux présente un passible paradoxe au niveau de la théorie du "fitness inclusive". Ce paradoxe est basé sur le fait que les ouvrières n'élèvent plus uniquement leurs frères et soeurs (gain de "fitness inclusive" maximale), mais également des individus moins ou pas du tout apparentés (gain de "fitness inclusive" réduit ou absent). Tous les projets de recherche présentés au cours de cette thèse apportent une meilleure compréhension et connaissance au niveau de l'organisation des colonies chez les insectes sociaux. Nous avons employé des méthodes d'observation et de laboratoire afin de mettre en évidence des aspects importants de la vie sociale chez les fourmis influencés par la polygynie. Quatre aspects ont été caractérisés : (1) l'influence du nombre de reines sur le sexe ratio produit par la colonie. Nous avons démontré que les colonies contenant beaucoup de reines produisaient rarement des reines tandis que les colonies contenant peu de reines souvent investissaient beaucoup de ressources dans la production des reines. Ces résultats sont en accord avec la "queen-replenishment hypothesis" qui est basé sur l'observation que les nouvelles reines sont recrutées dans la colonie où elles étaient nées. Cette hypothèse postule que la production des reines est défavorable dans les colonies contenant beaucoup de reines, parce que ces reines apparentées, rentrent en compétition pour des ressources communes. Au contraire, la production des reines est favorable dans des colonies contenant peu de reines afin d'assurer la survie de la colonie ; (2) comment les reines dans une colonie répartissent leur reproduction. Nous avons mis en évidence un nouveau pattern de cette répartition où une grande proportion de reines est complètement spécialisée dans la production d'un seul type de couvain ce qui probablement aboutit à des différences significatives entre reines dans le succès reproducteur ; (3) la capacité des ouvrières à discriminer un couvain de soeur d'un couvain non apparenté. Les résultats ont montré que les ouvrières ne font pas de discrimination entre le couvain de soeur et le couvain non apparenté ce qui n'est pas en accord avec la théorie de la "fitness inclusive". Cette absence de discrimination est probablement due à des effets négatifs comme par exemple la diminution de la production du couvain; (4) la structure génétique d'une population de F. exsecta. Nous avons mis en évidence que la structure génétique entre des groupes de reines est significativement différente de la structure génétique entre des groupes d'ouvrières. Les données suggèrent que les reines forment des groupes basés sur une structure familiale tandis que les ouvrières sont groupées dans des unités plus grandes.

Progress in front propagation research

We review the progress in the field of front propagation in recent years. We survey many physical, biophysical and cross-disciplinary applications, including reduced-variable models of combustion flames, Reid's paradox of rapid forest range expansions, the European colonization of North America during the 19th century, the Neolithic transition in Europe from 13 000 to 5000 years ago, the description of subsistence boundaries, the formation of cultural boundaries, the spread of genetic mutations, theory and experiments on virus infections, models of cancer tumors, etc. Recent theoretical advances are unified in a single framework, encompassing very diverse systems such as those with biased random walks, distributed delays, sequential reaction and dispersion, cohabitation models, age structure and systems with several interacting species. Directions for future progress are outlined

Maintenance of polymorphism : a theoretical approach using multilocus systems

Résumé La thématique de cette thèse peut être résumée par le célèbre paradoxe de biologie évolutive sur le maintien du polymorphisme face à la sélection et par l'équation du changement de fréquence gamétique au cours du temps dû, à la sélection. La fréquence d'un gamète xi à la génération (t + 1) est: !!!Equation tronquée!!! Cette équation est utilisée pour générer des données utlisée tout au long de ce travail pour 2, 3 et 4 locus dialléliques. Le potentiel de l'avantage de l'hétérozygote pour le maintien du polymorphisme est le sujet de la première partie. La définition commune de l'avantage de l'hétérozygote n'etant applicable qu'a un locus ayant 2 allèles, cet avantage est redéfini pour un système multilocus sur les bases de précédentes études. En utilisant 5 définitions différentes de l'avantage de l'hétérozygote, je montre que cet avantage ne peut être un mécanisme général dans le maintien du polymorphisme sous sélection. L'étude de l'influence de locus non-détectés sur les processus évolutifs, seconde partie de cette thèse, est motivée par les travaux moléculaires ayant pour but de découvrir le nombre de locus codant pour un trait. La plupart de ces études sous-estiment le nombre de locus. Je montre que des locus non-détectés augmentent la probabilité d'observer du polymorphisme sous sélection. De plus, les conclusions sur les facteurs de maintien du polymorphisme peuvent être trompeuses si tous les locus ne sont pas détectés. Dans la troisième partie, je m'intéresse à la valeur attendue de variance additive après un goulot d'étranglement pour des traits sélectionés. Une études précédente montre que le niveau de variance additive après goulot d'étranglement augmente avec le nombre de loci. Je montre que le niveau de variance additive après un goulot d'étranglement augmente (comparé à des traits neutres), mais indépendamment du nombre de loci. Par contre, le taux de recombinaison a une forte influence, entre autre en regénérant les gamètes disparus suite au goulot d'étranglement. La dernière partie de ce travail de thèse décrit un programme pour le logiciel de statistique R. Ce programme permet d'itérer l'équation ci-dessus en variant les paramètres de sélection, recombinaison et de taille de populations pour 2, 3 et 4 locus dialléliques. Cette thèse montre qu'utiliser un système multilocus permet d'obtenir des résultats non-conformes à ceux issus de systèmes rnonolocus (la référence en génétique des populations). Ce programme ouvre donc d'intéressantes perspectives en génétique des populations. Abstract The subject of this PhD thesis can be summarized by one famous paradox of evolu-tionary biology: the maintenance of polymorphism in the face of selection, and one classical equation of theoretical population genetics: the changes in gametic frequencies due to selection and recombination. The frequency of gamete xi at generation (t + 1) is given by: !!! Truncated equation!!! This equation is used to generate data on selection at two, three, and four diallelic loci for the different parts of this work. The first part focuses on the potential of heterozygote advantage to maintain genetic polymorphism. Results of previous studies are used to (re)define heterozygote advantage for multilocus systems, since the classical definition is for one diallelic locus. I use 5 different definitions of heterozygote advantage. And for these five definitions, I show that heterozygote advantage is not a general mechanism for the maintenance of polymorphism. The study of the influence of undetected loci on evolutionary processes (second part of this work) is motivated by molecular works which aim at discovering the loci coding for a trait. For most of these works, some coding loci remains undetected. I show that undetected loci increases the probability of maintaining polymorphism under selection. In addition, conclusions about the factor that maintain polymorphism can be misleading if not all loci are considered. This is, therefore, only when all loci are detected that exact conclusions on the level of maintained polymorphism or on the factor(s) that maintain(s) polymorphism could be drawn. In the third part, the focus is on the expected release of additive genetic variance after bottleneck for selected traits. A previous study shows that the expected release of additive variance increases with an increase in the number of loci. I show that the expected release of additive variance after bottleneck increases for selected traits (compared with neutral), but this increase is not a function of the number of loci, but function of the recombination rate. Finally, the last part of this PhD thesis is a description of a package for the statistical software R that implements the Equation given above. It allows to generate data for different scenario regarding selection, recombination, and population size. This package opens perspectives for the theoretical population genetics that mainly focuses on one locus, while this work shows that increasing the number of loci leads not necessarily to straightforward results.