Fine-scale population structure analysis in Armadillidium vulgare (Isopoda: Oniscidea) reveals strong female philopatry

In the last decades, dispersal studies have benefited from the use of molecular markers for detecting patterns differing between categories of individuals and have highlighted sex-biased dispersal in several species. To explain this phenomenon, several hypotheses implying mating systems, intrasexual competition or sex-related handicaps have been proposed. In this context, we investigated sex-biased dispersal in Armadillidium vulgare, a terrestrial isopod with a promiscuous mating system. As a proxy for effective dispersal, we performed a fine-scale investigation of the spatial genetic structure in males and females, using individuals originating from five sampling points located within 70 meters of each other. Based on microsatellite markers and spatial autocorrelation analyses, our results revealed that while males did not present a significant genetic structure at this geographic scale, females were significantly and genetically more similar to each other when they were collected in the same sampling point. As females invest more parental care than males in A. vulgare, but also because this species is promiscuous and males experience a high intrasexual competition, our results meet the predictions of most classical hypotheses for sex-biased dispersal. We suggest that widening dispersal studies to other isopods or crustaceans, differing in their ecology or mating system and displaying varying levels of parental care, might shed light on the processes underlying the evolution of sex-biased dispersal.Comment: 23 pages (including 2 figures and one table) and two supplementary files containing 5 pages with 3 tables S1 to S3 and one figure S1, Last two authors have contributed equally to this stud

Obesity and the Risk of Cryptogenic Ischemic Stroke in Young Adults

Objectives: We examined the association between obesity and early-onset cryptogenic ischemic stroke (CIS) and whether fat distribution or sex altered this association. Materials and Methods: This prospective, multi-center, case-control study included 345 patients, aged 18-49 years, with first-ever, acute CIS. The control group included 345 age-and sex-matched stroke-free individuals. We measured height, weight, waist circumference, and hip circumference. Obesity metrics analyzed included body mass index (BMI), waist-to-hip ratio (WHR), waist-to-stature ratio (WSR), and a body shape index (ABSI). Models were adjusted for age, level of education, vascular risk factors, and migraine with aura. Results: After adjusting for demographics, vascular risk factors, and migraine with aura, the highest tertile of WHR was associated with CIS (OR for highest versus lowest WHR tertile 2.81, 95%CI 1.43-5.51; P=0.003). In sex-specific analyses, WHR tertiles were not associated with CIS. However, using WHO WHR cutoff values (>0.85 for women, >0.90 for men), abdominally obese women were at increased risk of CIS (OR 2.09, 95%CI 1.02-4.27; P=0.045). After adjusting for confounders, WC, BMI, WSR, or ABSI were not associated with CIS. Conclusions: Abdominal obesity measured with WHR was an independent risk factor for CIS in young adults after rigorous adjustment for concomitant risk factors.Peer reviewe

Génétique de la conservation et du paysage : étude des populations de lagopède alpin et de perdrix grise en France.

The alpine grouse (Lagopus muta) and the grey partridge (Perdix perdix) reaches in Pyrenees the Southern limits of their areas of world distribution. The Pyrenean populations of these two subspecies (Lagopus muta pyrenaica and Perdix perdix hispaniensis) are thus in situation of biogeographical isolate. Both sorts(species) are excellent bio-indicators of the evolution of the open circles of height. Under the combined pressure of the environmental and anthropological requirements, these circles know at present a sensitive evolution characterized by an altitudinal increase of the levels of vegetation and thus a shrinkage of the available housing environment for the species of height. The regression of the agro-pastoral activities stresses this phenomenon generalized by reforestation of the circles. A consequence expected from these upheavals is the increase of the degree of fragmentation of housing environments in particular for the populations of height. Beyond the influence of the landscape on the structuring of the populations, another factor could structure the populations of partridges grey: individuals' releases of breeding in wild populations. In this thesis, we are interested in the genetic structuring of the alpine grouse of Pyrenees and grey partridge in France to help in the decision of the plans of preservation.Le lagopède alpin (Lagopus muta) et la perdrix grise (Perdix perdix) atteignent dans les Pyrénées les limites méridionales de leurs aires de répartition mondiale. Les populations pyrénéennes de ces deux sous-espèces (Lagopus muta pyrenaica et Perdix perdix hispaniensis) sont donc en situation d'isolat biogéographique. Les deux espèces sont d'excellents bio-indicateurs de l'évolution des milieux ouverts d'altitude. Sous la pression conjuguée des contraintes environnementales et anthropiques, ces milieux connaissent actuellement une évolution sensible caractérisée par un relèvement altitudinal des étages de végétation et donc un rétrécissement de l'habitat disponible pour les espèces d'altitude. La régression des activités agro-pastorales accentue ce phénomène généralisé de reforestation des milieux. Une conséquence attendue de ces bouleversements est l'augmentation du degré de fragmentation des habitats notamment pour les populations d'altitude. Au-delà de l'influence du paysage sur la structuration des populations, un autre facteur pourrait structurer les populations de perdrix grise : les lâchers d'individus d'élevage dans des populations sauvages. Dans cette thèse, nous nous intéressons à la structuration génétique du lagopède alpin des Pyrénées et de la perdrix grise en France afin d'aider à la décision des plans de conservation

Data from: Multiple paternity in a wild population of Armadillidium vulgare: influence of infection with Wolbachia?

Female multiple mating has been extensively studied to understand how non-obvious benefits, generally thought to be of genetic nature, could overcome heavy costs such as an increased risk of infection during mating. However, the impact of infection itself on multiple mating has rarely been addressed. The interaction between the bacterium Wolbachia and its terrestrial crustacean host, Armadillidium vulgare, is a relevant model to investigate this question. In this association, Wolbachia is able to turn genetic males into functional females (i.e. feminization), thereby distorting the sex ratio and decreasing the number of available males at the population scale. Moreover, in A. vulgare, females have been shown to mate multiply under laboratory conditions and males prefer uninfected females over infected ones. Additionally, three different Wolbachia strains are known to infect A. vulgare and these strains differ in their transmission rate and virulence. All these elements suggest a potential impact of different Wolbachia strains on multiple mating. To investigate this assumption, we collected gravid females in a wild A. vulgare population consisting of both uninfected females and females infected with two different Wolbachia strains (wVulM and wVulC) and performed paternity analyses on the obtained broods using microsatellite markers. We demonstrate that (a) multiple paternity is common in this wild population of A. vulgare, with a mean number of fathers of 4.48 ± 1.24 per brood and (b) females infected with wVulC produced broods with a lower multiple paternity level compared to females infected with wVulM and uninfected ones. This work improves our knowledge of the impact of infections on reproductive strategies

When GIS zooms in: spatio-genetic maps of multipaternity in Armadillidium vulgare

International audienc

Isolation, characterization and PCR multiplexing of microsatellite loci for two sub-species of terrestrial isopod Porcellio dilatatus (Crustacea, Oniscidea).

International audienceSeveral microsatellite markers have already been developed for different terrestrial isopod species such as Armadillidium vulgare, A. nasatum and Porcellionides pruinosus. In all these species, the endosymbiont Wolbachia has a feminizing effect that generates a female bias in sex ratio and reduces the number of reproductive males. Thus this can potentially decrease the genetic diversity of host populations. However, in some other isopod species, Wolbachia induces cytoplasmic incompatibility (CI); the most commonly described effect of Wolbachia in arthropods. The CI by rendering some crossings incompatible can reduce the gene flow and strengthen genetic differentiation between isopod populations. To date, the influence of Wolbachia inducing CI on population structure of terrestrial isopods has never been investigated. In this study, we developed 10 polymorphic microsatellite markers shared by two sub-species of Porcellio dilatatus. Crossings between the two sub-species are partially incompatible due to two CI-inducing Wolbachia strains. These new microsatellite markers will allow us to investigate the effect of CI on host genetic differentiation in this species complex

Genotyping of mothers and offspring

This table represents the genotypes of mothers and offspring used in the publication

Spatial and genetic distribution of a north American termite, Reticulitermes flavipes, across the landscape of Paris

International audienc

Genetic connectivity of the grey partridge in central northern France in a highly man dominated landscape

International audienceThe loss and fragmentation of the landscape are the main causes of the decline and the extinction of many wildlife species. In this study we test the impact of landscape features on the genetic connectivity of a sedentary bird. Populations of our case study, the grey partridge (Perdix perdix armoricana), occur in central northern France. This is considered as the last bastion of high grey partridge densities in Europe and thus represents a relevant zone for the conservation of P. p. armoricana. Despite a highly man dominated landscape, results from the analysis of 12 microsatellite genotypes suggest the beginning of a genetic structure. This emerging genetic structure can result from the last historical event having occurred in the study area: a massive urbanization since the nineteenth century following the increase of the human density and town surface. Another hypothesis suggests that the weak genetic structure can result from a massive restocking with captive-bred individuals at a more or less recent point in time

Data from: Isolation and characterization of microsatellite loci for the isopod crustacean Armadillidium vulgare and transferability in terrestrial isopods

Armadillidium vulgare is a terrestrial isopod (Crustacea, Oniscidea) which harbors Wolbachia bacterial endosymbionts. A. vulgare is the major model for the study of Wolbachia-mediated feminization of genetic males in crustaceans. As a consequence of their impact on host sex determination mechanisms, Wolbachia endosymbionts are thought to significantly influence A. vulgare evolution on various grounds, including population genetic structure, diversity and reproduction strategies. To provide molecular tools for examining these questions, we isolated microsatellite loci through 454 pyrosequencing of a repeat-enriched A. vulgare genomic library. We selected 14 markers and developed three polymorphic microsatellite multiplex kits. We tested the kits on two A. vulgare natural populations and found high genetic variation, thereby making it possible to investigate the impact of Wolbachia endosymbionts on A. vulgare nuclear variation at unprecedented resolution. In addition, we tested the transferability of these kits by cross-species amplification in five other terrestrial isopod species harboring Wolbachia endosymbionts. The microsatellite loci showed good transferability in particular in Armadillidium nasatum and Chaetophiloscia elongata, for which these markers represent promising tools for future genetic studies