Showing results 1561 to 1580 on 1601 in total
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Queens strongly influence offspring social behaviors across the diverse eusocial taxa, suggesting that maternal influence might be involved in the origin of eusociality. Such ancestral maternal influence could have been manipulative or an honest signal, but a manipulative maternal influence could make eusociality unstable as offspring resistance evolves. Using an analytical model and individual based simulations, we show that an ancestral manipulative maternal influence becomes an honest signal under feasible conditions as maternal specialization into reproduction evolves. The reason is that specialization can move the population out of the zone of parent-offspring conflict over helping, a process that we term conflict dissolution. The key for this process is that helpers alleviate life-history trade-offs faced by mothers. Our results can simultaneously explain the origin of eusociality and its widespread association to a maternal influence via evolutionarily shifts of manipulation into honest signals.
Thèse de William Gaudry le vendredi 18 décembre 2015 à 14 h - amphithéâtre Déambulatoire 1 (Doua)
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Thèse de Julien Cattel le vendredi 16 décembre 2016 à 14 h - Amphithéâtre Dirac (Physique Nucléaire, La Doua)
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Thèse de Adrian ARELLANO DAVIN le mardi 5 décembre 2017 à 14 h, amphithéâtre CNRS (Villeurbanne)
HDR de Marie Fablet - Vendredi 20 mai 2016 - 14:00 - Salle de Conférence - BU La Doua
Thèse de Floriane Plard - jeudi 6 mars 2014 à 14 h, amphithéâtre Thémis 7
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Thèse de Carole Forfait - Mecredi 27 mars 2013 - 14h30 - Amphithéâtre Ampère - Bât Lippmann
Thèse de Magali JAILLARD le mercredi 12 décembre 2018 à 14 h, salle de conférence BU (La doua)
Thèse de Marion Roussel le vendredi 27 novembre 2015 à 9 h - amphithéâtre CNRS (Villeurbanne)
Vibrios have been associated with successive mortality outbreaks ofCrassostrea gigas) in France that have resulted in losses up to 100% of production. Given the near monoculture of C. gigas in Europe, there is an urgent need to understand the epidemiology of these outbreaks, particularly the role of Vibrio in the diseases.The study of the Vibrios distribution on fine phylogenetic and spatial scales has demonstrated that vibrios coexisting in the water column can be divided into closely related populations, which pursue different lifestyles i.e. ecological population (Hunt et al., 2008). However, a link between ecological populations and pathogenicity has not been demonstrated, and it is unclear whether pathogenicity is a trait primarily linked to clones or to populations comprising a large number of distinct genotypes.In the presentVibrio populations in an intensive oyster cultivation area. We demonstrate that Vibrio populations do not assemble neutrally in oysters from water column populations i.e. specific genotypes colonize the oysters. Combining experimental ecology, high throughput infection assay and genome sequencing, we showed that the onset of disease in oysters is associated with progressive replacement of diverse, benign colonizers by members of a phylogenetically coherent virulent population together with quorum sensing pheromone producers. Analyses of oyster mortality following experimental infection suggest that disease onset can be facilitated by the presence of non-virulent strains. Oyster disease may thus represent a new form of polymicrobial disease, in which non-pathogenic strains contribute to increased mortality.Hunt DE, et al. (2008) Resource partitioning and sympatric differentiation among closely related bacterioplankton. Science 320(5879):1081-1085.Lemire A, Goudenège D, Versigny T, Petton B, Calteau A, Labreuche Y, Le Roux F. (2014) Populations, not clones, are the unit of vibrio pathogenesis in naturally infected oysters. ISME J. Dec 9. doi: 10.1038/ismej.2014.233