Tracking the ghost of coevolution in specific plant-insect interactions : the case of the pollination system between the globeflower Trollius europaeus and seven european Chiastocheta flies

This study aims at understanding the evolutionary processes at work in specialized species interactions. Prom the macroevolutionary perspective, coevolution among specialized taxa was proposed to be one of the major processes generating biodiversity. We challenge this idea from the theoretical and practical perspective and through a literature review and show that the major hypotheses linking coevolutionary process with macroevolutionary patterns do not necessarily predict lineage co diversification and parallel speciation, limit¬ing the utility of the comparative phylogenenetic approach for investigating coevolution¬ary processes. We also point to the rarity of observed long-term coevolutionary dynamics among lineages and propose that coevolution rather occurs in shorter timescales, followed by ecological fitting. Prom the empirical point, we focus on the nursery pollination interaction between the European globeflower Trollius europaeus (Ranunculaceae) and its associated Chiastocheta flies (Anthomyiidae; Diptera) as a model system of evolution and maintenance of special¬ized interactions. The flies are obligate parasites of the seeds, but also pollinate the plant - it was thus proposed that both species are mutually dependent. Contrasting with the paradigm used for two decades of research on this system, we show that the female fitness component of the plant is similar in the populations with and without Chiastocheta. The plant is thus not exclusively dependent on the flies for reproduction. We discuss this result in the context of the factors responsible for the evolution of mutualistic systems. Understanding the evolution of a biological system requires understanding of its phylo- genetic context. Previous studies showed large mismatch between mtDNA phylogeny and morphological taxonomy in Chiastocheta. By using a large set of RAD-sequencing loci, we delineate the species limits that are congruent with morphology, and show that the discordance is best explained by the scenario of mitochondrial capture among fly species. Finally, we examine this system from a phylogeographic perspective, and identify the lack of congruence in spatial genetic structures of the plant and associated insects across their whole geographic range. The flies show lower numbers of spatial genetic groups than the plant, indicating that not all of the plant réfugia were shared by all the fly species or that the migration dynamics homogenized some of the groups. The incongruence in spatial genetic patterns indicates that fly migrations were largely independent from the genetic background of the plant, following rather a scenario of resource tracking, without the signature of coevolutionary process at this scale. Indeed, while the flies require the plant to survive climatic oscillations, the opposite is not true. Eventually, we show that there is no phylogenetic signal of spatial genetic structures, meaning that neither histories nor life- history traits are shared among closely related species and that species are characterized by unique trajectories of their genes. -- Cette étude vise à comprendre les processus évolutifs à l'oeuvre au sein d'interactions en¬tre espèces spécialisées. Du point de vue macroévolutif, la coévolution entre les taxons spécialisée a été considérée comme l'un des principaux processus générateur de biodiversité. Nous contestons cette idée du point de vue théorique et pratique à travers une revue de la littérature. Nous montrons que les hypothèses majeures reliant les processus coévolutifs avec les patterns de diversité au niveau macroévolutif ne prédisent pas nécessairement la co- diversification des lignées et leur spéciation parallèle, ce qui limite l'utilité de l'approche de phylogénie comparative pour étudier les processus coévolutifs . Nous rappelons également le peu d'exemples de dynamique coévolutive à long terme et proposons que la coévolution se produit plutôt dans des intervalles courts, suivis d'ajustements écologiques. Du point empirique, nous nous concentrons sur l'interaction de pollinisation entre le Trolle d'Europe Trollius europaeus (Ranunculaceae) et ses pollinisateurs associés, du genre Chiastocheta (Anthomyiidae; Diptera) en tant que système-modèle pour étudier l'évolution et le maintien des interactions spécialisées. Les mouches sont des parasites obligatoires des semences, mais pollinisent également la plante. Il a donc été proposé que les deux espèces soient mutuellement dépendantes. Contrastant avec le paradigme utilisé pendant deux décennies de recherche sur ce système, nous montrons, que la composante de fitness femelle de la plante est similaire dans les populations avec et sans Chiastocheta. La plante ne dépend donc pas exclusivement de son interaction avec les mouches pour la reproduction. Nous discutons de ce résultat dans le contexte des facteurs responsables de l'évolution des systèmes mutualistes. Comprendre l'évolution d'un système biologique nécessite la compréhension de son con- texte phylogénétique. Des études antérieures ont montré, chez Chiastocheta, de grandes disparités entre les phylogénies obtenues à partir d'ADN mitochondrial et la taxonomie basée sur les critères morphologiques. En utilisant un grand nombre de loci obtenus par RAD-sequencing, nous traçons les limites des espèces, qui concordent avec les car¬actéristiques morphologies, et montrons que la discordance s'explique en fait par un scénario de capture mitochondriale entre espèces de mouches. Enfin, nous examinons le système d'un point de vue phylogéographique, et identi¬fions les incohérences entre structurations génétiques spatiales de la plante et des insectes associés dans toute leur aire de distribution géographique. Les mouches présentent un nombre de groupes génétiques inférieur à la plante, indiquant que tous les refuges de la plante n'étaient pas partagés par toutes les espèces de mouches ou que les dynamiques migratoires ont homogénéisés certains des groupes chez les mouches. Les différences ob¬servées dans les patrons de structuration génétique spatiale indique que les migrations et dispersions des mouches ont été indépendantes du contexte génétique de la plante, et ces dernières ont été uniquement tributaires de la disponibilité des ressources, sans qu'il n'y ait de signature du processus de coévolution à cette échelle. En effet, tandis que les mouches ont besoin de la plante pour survivre aux oscillations climatiques, le contraire n'est pas exact. Finalement, nous montrons qu'il n'y a pas de signal phylogénétique des structurations génétiques spatiales chez les mouches, ce qui signifie que ni l'histoire, ni les traits d'histoire de vie ne sont partagés entre les espèces phylogénétiquement proches et que les espèces sont caractérisées par des trajectoires uniques de leurs gènes.

The vertical dimension of social relations and accurate interpersonal perception: A meta-analysis (Publishd online: 24 Oct. 2014)

There is little consensus regarding how verticality (social power, dominance, and status) is related to accurate interpersonal perception. The relation could be either positive or negative, and there could be many causal processes at play. The present article discusses the theoretical possibilities and presents a meta-analysis of this question. In studies using a standard test of interpersonal accuracy, higher socioeconomic status (SES) predicted higher accuracy defined as accurate inference about the meanings of cues; also, higher experimentally manipulated vertical position predicted higher accuracy defined as accurate recall of others' words. In addition, although personality dominance did not predict accurate inference overall, the type of personality dominance did, such that empathic/responsible dominance had a positive relation and egoistic/aggressive dominance had a negative relation to accuracy. In studies involving live interaction, higher experimentally manipulated vertical position produced lower accuracy defined as accurate inference about cues; however, methodological problems place this result in doubt.

Studying social interactions through immersive virtual environment technology: Virtues, pitfalls, and future challenges

Thegoalofthepresentreviewistoexplainhowimmersivevirtualenvironmenttechnology(IVET)canbeusedforthestudyofsocialinteractionsandhowtheuseofvirtualhumansinimmersivevirtualenvironmentscanadvanceresearchandapplicationinmanydifferentfields.Researchersstudyingindividualdifferencesinsocialinteractionsaretypicallyinterestedinkeepingthebehaviorandtheappearanceoftheinteractionpartnerconstantacrossparticipants.WithIVETresearchershavefullcontrolovertheinteractionpartners,canstandardizethemwhilestillkeepingthesimulationrealistic.Virtualsimulationsarevalid:growingevidenceshowsthatindeedstudiesconductedwithIVETcanreplicatesomewell-knownfindingsofsocialpsychology.Moreover,IVETallowsresearcherstosubtlymanipulatecharacteristicsoftheenvironment(e.g.,visualcuestoprimeparticipants)orofthesocialpartner(e.g.,his/herrace)toinvestigatetheirinfluencesonparticipants'behaviorandcognition.Furthermore,manipulationsthatwouldbedifficultorimpossibleinreallife(e.g.,changingparticipants'height)canbeeasilyobtainedwithIVET.Besidetheadvantagesfortheoreticalresearch,weexplorethemostrecenttrainingandclinicalapplicationsofIVET,itsintegrationwithothertechnologies(e.g.,socialsensing)andfuturechallengesforresearchers(e.g.,makingthecommunicationbetweenvirtualhumansandparticipantssmoother).

Reliability and validity of nonverbal thin slices in social interactions

Four studies investigated the reliability and validity of thin slices of nonverbal behavior from social interactions including (1) how well individual slices of a given behavior predict other slices in the same interaction; (2) how well a slice of a given behavior represents the entirety of that behavior within an interaction; (3) how long a slice is necessary to sufficiently represent the entirety of a behavior within an interaction; (4) which slices best capture the entirety of behavior, across different behaviors; and (5) which behaviors (of six measured behaviors) are best captured by slices. Notable findings included strong reliability and validity for thin slices of gaze and nods, and that a 1.5 min slice from the start of an interaction may adequately represent some behaviors. Results provide useful information to researchers making decisions about slice measurement of behavior.

Testing reciprocity in social interactions: A comparison between the Directional consistency and Skew symmetry statistics

In the present work we focus on two indices that quantify directionality and skew-symmetrical patterns in social interactions as measures of social reciprocity: the Directional consistency (DC) and Skew symmetry indices. Although both indices enable researchers to describe social groups, most studies require statistical inferential tests. The main aims of the present study are: firstly, to propose an overall statistical technique for testing null hypotheses regarding social reciprocity in behavioral studies, using the DC and Skew symmetry statistics (Φ) at group level; and secondly, to compare both statistics in order to allow researchers to choose the optimal measure depending on the conditions. In order to allow researchers to make statistical decisions, statistical significance for both statistics has been estimated by means of a Monte Carlo simulation. Furthermore, this study will enable researchers to choose the optimal observational conditions for carrying out their research, as the power of the statistical tests has been estimated.

Nonverbal social sensing in action: Unobtrusive recording and extracting of nonverbal behavior in social interactions illustrated with a research example

Nonverbal behavior coding is typically conducted by "hand". To remedy this time and resource intensive undertaking, we illustrate how nonverbal social sensing, defined as the automated recording and extracting of nonverbal behavior via ubiquitous social sensing platforms, can be achieved. More precisely, we show how and what kind of nonverbal cues can be extracted and to what extent automated extracted nonverbal cues can be validly obtained with an illustrative research example. In a job interview, the applicant's vocal and visual nonverbal immediacy behavior was automatically sensed and extracted. Results show that the applicant's nonverbal behavior can be validly extracted. Moreover, both visual and vocal applicant nonverbal behavior predict recruiter hiring decision, which is in line with previous findings on manually coded applicant nonverbal behavior. Finally, applicant average turn duration, tempo variation, and gazing best predict recruiter hiring decision. Results and implications of such a nonverbal social sensing for future research are discussed.

Emergent power hierarchies and group performance (Published online: 7 Oct. 2014)

In newly formed groups, informal hierarchies emerge automatically and readily. In this study, we argue that emergent group hierarchies enhance group performance (Hypothesis 1) and we assume that the more the power hierarchy within a group corresponds to the task-competence differences of the individual group members, the better the group performs (Hypothesis 2). Twelve three-person groups and 28 four-person groups were investigated while solving the Winter Survival Task. Results show that emerging power hierarchies positively impact group performance but the alignment between task-competence and power hierarchy did not affect group performance. Thus, emergent power hierarchies are beneficial for group performance and although they were on average created around individual group members' competence, this correspondence was not a prerequisite for better group performance.

How patient-centered do female physicians need to be? Analogue patients' satisfaction with male and female physicians' identical behaviors (Published online: 30 Aug 2014)

Previous research suggests that female physicians may not receive appropriate credit in patients' eyes for their patient-centered skills compared to their male counterparts. An experiment was conducted to determine whether a performance of higher (versus lower) verbal patient-centeredness would result in a greater difference in analogue patient satisfaction for male than female physicians. Two male and two female actors portrayed physicians speaking to a patient using high or low patient-centered scripts while not varying their nonverbal cues. One hundred ninety-two students served as analogue patients by assuming the patient role while watching one of the videos and rating their satisfaction and other evaluative responses to the physician. Greater verbal patient-centeredness had a stronger positive effect on satisfaction and evaluations for male than for female physicians. This pattern is consistent with the hypothesis that the different associations between patient-centeredness and patients' satisfaction for male versus female physicians occur because of the overlap between stereotypical female behavior and behaviors that comprise patient-centered medical care. If this is the case, high verbal patient-centered behavior by female physicians is not recognized as a marker of clinical competence, as it is for male physicians, but is rather seen as expected female behavior.

Establishment of a Developmental Compartment Requires Interactions between Three Synergistic Cis-regulatory Modules.

The subdivision of cell populations in compartments is a key event during animal development. In Drosophila, the gene apterous (ap) divides the wing imaginal disc in dorsal vs ventral cell lineages and is required for wing formation. ap function as a dorsal selector gene has been extensively studied. However, the regulation of its expression during wing development is poorly understood. In this study, we analyzed ap transcriptional regulation at the endogenous locus and identified three cis-regulatory modules (CRMs) essential for wing development. Only when the three CRMs are combined, robust ap expression is obtained. In addition, we genetically and molecularly analyzed the trans-factors that regulate these CRMs. Our results propose a three-step mechanism for the cell lineage compartment expression of ap that includes initial activation, positive autoregulation and Trithorax-mediated maintenance through separable CRMs.

La Representación de la mujer en la prensa internacional online durante la Primavera Árabe en Egipto

El presente trabajo de investigación tiene como objetivo principal analizar la representación del papel de la mujer egipcia en la organización y participación en la primavera árabe en Egipto. Por medio del análisis de contenido aplicado a los titulares e imágenes publicados durante un periodo deteminado de las revueltas sociales en los periódicos The New York Times, Le Monde y El Mundo en su versión on line. Concluyendo se puede indicar que la representación internacional de la mujer egipcia durante las revueltas desde el año 2011, ha sido insuficiente y además sirvió a los medios de comunicación hasta cierto punto como medida de estereotipar la situación social de la mujer.

Evolution of reduced post-copulatory molecular interactions in Drosophila populations lacking sperm competition.

In many species with internal fertilization, molecules transferred in the male ejaculate trigger and interact with physiological changes in females. It is controversial to what extent these interactions between the sexes act synergistically to mediate the female switch to a reproductive state or instead reflect sexual antagonism evolved as a by product of sexual selection on males. To address this question, we eliminated sexual selection by enforcing monogamy in populations of Drosophila melanogaster for 65 generations and then measured the expression of male seminal fluid protein genes and genes involved in the female response to mating. In the absence of sperm competition, male and female reproductive interests are perfectly aligned and any antagonism should be reduced by natural selection. Consistent with this idea, males from monogamous populations showed reduced expression of seminal fluid protein genes, 16% less on average than in polygamous males. Further, we identified 428 genes that responded to mating in females. After mating, females with an evolutionary history of monogamy exhibited lower relative expression of genes that were up regulated in response to mating and higher expression of genes that were down-regulated - in other words, their post-mating transcriptome appeared more virgin-like. Surprisingly, these genes showed a similar pattern even before mating, suggesting that monogamous females evolved to be less poised for mating and the accompanying receipt of male seminal fluid proteins. This reduced investment by both monogamous males and females in molecules involved in post-copulatory interactions points to a pervasive role of sexual conflict in shaping these interactions.

Landscape Systems and Human Land-Use Interactions in Mediterranean Highlands and Littoral Plains during the Late Holocene: Integrated Analysis from the InterAmbAr Project (North-Eastern Catalonia).

The main goal of the InterAmbAr reseach project is to analyze the relationships between landscape systems and human land-use strategies on mountains and littoral plains from a long-term perspective. The study adopts a high resolution analysis of small-scale study areas located in the Mediterranean region of north-eastern Catalonia. The study areas are distributed along an altitudinal transect from the high mountain (above 2000m a.s.l.) to the littoral plain of Empordà (Fig. 1). High resolution interdisciplinary research has been carried out from 2010, based on the integration of palaeoenvironmental and archaeological data. The micro-scale approach is used to understand human-environmental relationships. It allows better understanding of the local-regional nature of environmental changes and the synergies between catchment-based systems, hydro-sedimentary regimes, human mobility, land-uses, human environments, demography, etc.

Extracellular Subunit Interactions Control Transitions between Functional States of Acid-sensing Ion Channel 1a.

Acid-sensing ion channels (ASICs) are neuronal, voltage-independent Na(+) channels that are transiently activated by extracellular acidification. They are involved in pain sensation, the expression of fear, and in neurodegeneration after ischemic stroke. Our study investigates the role of extracellular subunit interactions in ASIC1a function. We identified two regions involved in critical intersubunit interactions. First, formation of an engineered disulfide bond between the palm and thumb domains leads to partial channel closure. Second, linking Glu-235 of a finger loop to either one of two different residues of the knuckle of a neighboring subunit opens the channel at physiological pH or disrupts its activity. This suggests that one finger-knuckle disulfide bond (E235C/K393C) sets the channel in an open state, whereas the other (E235C/Y389C) switches the channel to a non-conducting state. Voltage-clamp fluorometry experiments indicate that both the finger loop and the knuckle move away from the β-ball residue Trp-233 during acidification and subsequent desensitization. Together, these observations reveal that ASIC1a opening is accompanied by a distance increase between adjacent thumb and palm domains as well as a movement of Glu-235 relative to the knuckle helix. Our study identifies subunit interactions in the extracellular loop and shows that dynamic changes of these interactions are critical for normal ASIC function.