Mélanisme, coloration atypique et assombrissement ontogénique chez la Vipère péliade Vipera berus (Linnaeus, 1758) dans l’ouest de la France

Melanism, atypic coloration, and ontongenic darkening in the adder (Vipera berus) in western France. Over the past few decades, several field surveys of the common adder have been conducted in western France. Despite this effort, only limited polymorphisms cases have been reported with rare occurrences of melanism. We report here three recent observations of melanistic individuals and five cases of atypical colouration in the French departments of “Loire-Atlantique”, ”Côtes-d’Armor”, and “Ile-et- Vilaine”. We also describe a progressive darkening of the head colouration related to age in mature males.Depuis quarante ans, de nombreux inventaires et suivis ont été réalisés sur la Vipère péliade Vipera berus (Linné, 1758) dans l’ouest de la France. On constate un faible polymorphisme des individus ainsi qu’une grande rareté des spécimens mélaniques. Nous rapportons ici trois observations inédites d’individus fortement mélanisants à mélaniques et cinq cas de coloration sombre et atypique entre les départements de la Loire-Atlantique, de l’Ille-et-Vilaine et des Côtes-d’Armor. Nous mettons également en évidence l’existence d’un assombrissement progressif de l’écaillure céphalique (pileus) chez les mâles après l’âge de la maturité

Hydric "costs" of reproduction: pregnancy increases evaporative water loss in the snake Vipera aspis

International audienceWater constraints can mediate evolutionary conflict either among individuals (e.g., parent-offspring conflict, sexual conflict) or within an individual (e.g., cost of reproduction). During pregnancy, water is of particular importance because the female provides all water needed for embryonic development and experiences important maternal shifts in behavior and physiology that, together, can compromise female water balance if water availability is limited. We examined the effect of pregnancy on evaporative water loss and microhabitat selection in a viviparous snake, the aspic viper. We found that both physiological (increased metabolism and body temperature) and morphological (body distension) changes contribute to an increased evaporative water loss in pregnant females. We also found that pregnant females in the wild select warmer and moister basking locations than nonreproductive females, likely to mitigate the conflict between thermal needs and water loss. Water resources likely induce significant reproductive constraints across diverse taxa and thus warrant further consideration in ecological research. From an evolutionary perspective, water constraints during reproduction may contribute to shaping reproductive effort

Water deprivation compromises maternal physiology and reproductive success in a cold and wet adapted snake Vipera berus

International audienceAbstract Droughts are becoming more intense and frequent with climate change. These extreme weather events can lead to mass mortality and reproduction failure, and therefore cause population declines. Understanding how the reproductive physiology of organisms is affected by water shortages will help clarify whether females can adjust their reproductive strategy to dry conditions or may fail to reproduce and survive. In this study, we investigated the consequences of a short period of water deprivation (2 weeks) during early pregnancy on the physiology and behaviour of a cold- and wet-adapted ectotherm (Vipera berus). We also examined water allocation to developing embryos and embryonic survival. Water-deprived females exhibited significant dehydration, physiological stress and loss of muscle mass. These effects of water deprivation on water balance and muscle loss were correlated with the number of developing embryos. While water-deprived females maintained water transfer to embryos at the expense of their own maintenance, water deprivation also led to embryonic mortality. Overall, water deprivation amplifies the reproductive costs of water allocation to support embryonic development. The deleterious impacts of water deprivation on female current reproductive performance and on potential survival and future reproduction could lead to severe population declines in this species

Contribution of host species and pathogen clade to snake fungal disease hotspots in Europe.

Infectious diseases are influenced by interactions between host and pathogen, and the number of infected hosts is rarely homogenous across the landscape. Areas with elevated pathogen prevalence can maintain a high force of infection and may indicate areas with disease impacts on host populations. However, isolating the ecological processes that result in increases in infection prevalence and intensity remains a challenge. Here we elucidate the contribution of pathogen clade and host species in disease hotspots caused by Ophidiomyces ophidiicola, the pathogen responsible for snake fungal disease, in 21 species of snakes infected with multiple pathogen strains across 10 countries in Europe. We found isolated areas of disease hotspots in a landscape where infections were otherwise low. O. ophidiicola clade had important effects on transmission, and areas with multiple pathogen clades had higher host infection prevalence. Snake species further influenced infection, with most positive detections coming from species within the Natrix genus. Our results suggest that both host and pathogen identity are essential components contributing to increased pathogen prevalence

Quelle éducation avec la Covid-19

APPEL A CONTRIBUTION : QUE NOUS APPREND LA PANDEMIE? Numéro HS Recherches et Educations (Juillet 2020) (HCERES 70ème section) Qu'est ce que la pandémie nous apprend de nos sociétés, de nos politiques de santé publique, des souverainetés épistémologiques de la recherche et des praxis individuelles et collectives? Solidarités ou/ et d'exclusions? Stratégies d'adaptation au confinement ou de rejet? Comment agit-on dans ce monde incertain, soumis à l'autorité des politiques de gestion d'un virus? Soumission volontaire à l'autorité ou organisation des résistances? Quels sont les savoirs exercés sur quels pouvoirs ? Quelles sont les légitimités et les responsabilités plurielles : individuelles, collectives, politiques et sociales ? Quels sont les usages sociaux et politiques des résultats de la recherche des experts ? Qu’apprenons nous des expériences de prévention individuelles, européennes et internationales ? Comment s’exercent les pouvoirs à partir des savoirs des épistémologies et des évidence-base medecine ? Comment l’histoire des épidémies pourrait répondre à notre présent ? Quel futur pour notre société après la pandémie ? Quelles seront nos inégalités sociales ? Vers quelles écologies ? Quelles résistances ? Quel mode de vie ? Quelles expériences corporelles de l’absence de toucher et de la distanciation ? Quelle croissance ? Quelle décroissance ? Quelles solidarités face à la techno-économique ? La revue Recherches & Educations lance un appel à contribution, multi disciplinaire, sur le « dispositif covid 19 » pendant le confinement imposé aux populations. Elle propose de réunir les textes critiques et réflexifs sur ce que nous apprend l’épidémie et la pandémie de nous même, de notre relation au vivant, à la mondialisation néolibérale, aux souverainetés de santé, au gouvernement des corps, de la psyché et de la vie, aux politiques de prévention, aux représentations de l’épidémie, aux pratiques corporelles visuelles et tactiles, aux modes de résistances et aux praxis du quotidien du présent et de demain. Texte à adresser (avant le 30 mai 2020) en 30.000 signes à [email protected] [email protected] [email protected]

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging