Traffic noise exposure affects telomere length in nestling house sparrows

International audienceIn a consistently urbanizing world, anthropogenic noise has become almostomnipresent, and there are increasing evidence that high noise levels canhave major impacts on wildlife. While the effects of anthropogenic noiseexposure on adult animals have been widely studied, surprisingly, therehas been little consideration of the effects of noise pollution on developingorganisms. Yet, environmental conditions experienced in early life can havedramatic lifelong consequences for fitness. Here, we experimentally manipulatedthe acoustic environment of free-living house sparrows (Passerdomesticus) breeding in nest boxes. We focused on the impact of such disturbanceon nestlings’ telomere length and fledging success, as telomeres(the protective ends of chromosomes) appear to be a promising predictor oflongevity.We showed that despite the absence of any obvious immediate consequences(growth and fledging success), nestlings reared under traffic noiseexposure exhibited reduced telomere lengths compared with their unexposedneighbours. Although the mechanisms responsible for this effect remain tobe determined, our results provide the first experimental evidence that noisealone can affect a wild vertebrate’s early-life telomere length. This suggeststhat noise exposure may entail important costs for developing organisms

Landscape genetics of a flightless grasshopper in an agricultural lanscape

International audienceDispersal may be strongly influenced by landscape structure and habitat characteristics that could either enhance or restrict movements of organisms. Therefore, spatial heterogeneity in landscape structure could influence gene flow and the spatial structure of populations. In the past decades, agricultural intensification has led to the reduction of grassland surfaces, their fragmentation and intensification. Since these changes are not homogeneously distributed in space, they might result in spatial heterogeneity in population’s genetic structure. Understanding the effect of landscape structure and habitat characteristics is thus critical for both studies in biodiversity conservation andpest’s management. In this study, we used eight microsatellite loci to assess spatial genetic structure and landscape genetics relationships of Pezotettix giornae, a small-sized grasshopper specialized on grassland and herbaceous habitats. Because it has wings unfit for flight, its ability to disperse long distances is supposed to be weak. We collected 1097 individuals from 231 grasslands in a 100 x 100 km agricultural area of Western France. While the northern part of the study area consists of preserved hedged farmland, the southern part has been profoundly converted for intensive crop production after WWII, with generally less intensified hedged farmland areas remaining alongside streams and rivers. Over the entire study area, we did not detect genetic clusters in relation with landscape features. Spatial genetic autocorrelation analysis suggested small-scale dispersal, and the grasshopper population was characterized by a heterogeneous pattern of isolation by distance. We used individual-based landscape genetics approaches to investigate how landscape structure and habitats characteristics affect P. giornae genetic diversity and gene flow. Altogether, results suggested that, in the most intensive agricultural areas, P. giornae dispersal is enhanced by disturbance due to increasing habitat turnover. As a long-term consequence, one could expect the selection of increasing dispersal capacities. This hypothesis is consistent with differences measured on dispersal-related traits among P. giornae individuals from areas with contrasted level of disturbance

Physiological and morphological correlates of blood parasite infection in urban and non-urban house sparrow populations

International audienceIn the last decade, house sparrow populations have shown a general decline, especially in cities. Avian malaria has been recently suggested as one of the potential causes of this decline, and its detrimental effects could be exacerbated in urban habitats. It was initially thought that avian malaria parasites would not have large negative effects on wild birds because of their long co-evolution with their hosts. However, it is now well-documented that they can have detrimental effects at both the primo- and chronical infection stages. In this study, we examined avian malaria infection and its physiological and morphological consequences in four populations of wild house sparrows (2 urban and 2 rural). We did not find any relationship between the proportions of infected individuals and the urbanisation score calculated for our populations. However, we observed that the proportion of infected individuals increased during the course of the season, and that juveniles were less infected than adults. We did not detect a strong effect of malaria infection on physiological, morphological and condition indexes. Complex parasite dynamics and the presence of confounding factors could have masked the potential effects of infection. Thus, longitudinal and experimental studies are needed to understand the evolutionary ecology of this very common, but still poorly understood, wild bird parasite

First characterization of eight polymorphic microsatellites for Cystoseira amentacea var. stricta (Fucales, Sargassaceae)

First characterization of eight polymorphic microsatellites for Cystoseira amentacea var. stricta (Fucales, Sargassaceae

A lack of spatial genetic structure of Gymnothorax chilospilus (moray eel) suggests peculiar population functioning

International audienceMoray eels form a speciose lineage that belongs to Elopomorpha, a super-order with a worldwide distribution.As is the case for many anguilliform fish, moray eels are characterized by distinctive life history traits, notably aprolonged larval dispersal phase that determines settlement to distant reef habitats, thus influencing the spatialstructuring of their populations. They can be very abundant in coral reef ecosystems and represent major mesopredators,playing a crucial role in food webs. Yet, due to their elusive nature (i.e. cryptic behaviour, nocturnalactivity), these organisms are generally difficult to study and collect. To our knowledge, only a few studies performedover large geographical and phylogenetic scales have been conducted. We used a unique and cost-efficientsampling approach, involving forced regurgitation from sea snake predators, to collect large numbers of a widespreadmoray eel species (Gymnothorax chilospilus). When combined with the development of 11 new microsatellitemarkers, this efficient sampling technique allowed us to examine the genetic structure of Gymnothoraxpopulations occurring in the South Lagoon of New Caledonia. Analyses revealed a lack of genetic differentiationamong populations. This result echoes the strong genetic homogeneity of populations of their main predator, thesea snake. This convergence might result from a distinctive trait involved in population functioning of both morayeels and sea snakes, where immature individuals emerge from common breeding grounds and disperse over longdistances before settlement

Using genetic tools for sustainable management of kelps: a literature review and the example of Laminaria digitata

International audienceKelp forests are threatened by human activities that result in habitat loss or deplete natural stocks, but little is known about genetic diversity, importance of gene flow and effect of population fragmentation on genetic structure. We reviewed the literature to characterize the patterns of connectivity and scales of population structure in kelps. In all, 44 papers have been published on the patterns of genetic differentiation in 17 kelp species, using various kinds of molecular markers. Our literature review showed that population connectivity depends mainly on species' dispersal abilities and habitat characteristics (intertidal vs. subtidal), but little on their life-span characteristics. Data on within-population gene diversity were found for only seven species and reflect differences in effective population sizes. In addition, we focused on the Brittany populations of Laminaria digitata, one of the most commonly harvested species in Europe, and re-sampled populations studied seven years prior. Our analyses of spatio-temporal variation clearly demonstrate the effect of small population sizes on the genetic instability of isolated L. digitata populations and have implications for managing this genetic resource

Direct and indirect effects of multiple environmental stressors on fish health in human-altered rivers

International audience• Multiple environmental stressors can affect fish health at different biological levels. • Parasitism and water temperature had limited effects on gudgeon health. • Trace metal contamination indirectly increased liver lesions through over-inflammation. • Combined contamination and temperature decreased fish growth. • Multiple stressors have complex interactive effects on fish health in human-altered rivers. Freshwater fish face multiple challenges in human-altered rivers such as trace metal contamination, temperature increase and parasitism. These multiple stressors could have unexpected interactive effects on fish health due to shared physiological pathways, but few studies investigated this question in wild fish populations. In this study, we compared 16 populations of gudgeon (Gobio occitaniae) distributed along perturbation gradients in human-altered rivers in the South of France. We tested the effects of single and combined stressors (i.e., metal contamination , temperature, parasitism) on key traits linked to fish health across different biological levels using a Structural Equation Modelling approach. Parasitism and temperature alone had limited deleterious effects on fish health. In contrast, fish living in metal-contaminated sites had higher metal bioaccumulation and higher levels of cellular damage in the liver through the induction of an inflammatory response. In addition, temperature and contamination had interactive negative effects on growth. These results suggest that trace metal contamination has deleterious effects on fish health at environmentally realistic concentrations and that temperature can modulate the effects of trace metals on fish growth. With this study, we hope to encourage integrative approaches in realistic field conditions to better predict the effects of natural and anthropogenic stressors on aquatic organisms

Chronic water restriction triggers sex-specific oxidative stress and telomere shortening in lizards

International audienceAnimals use a variety of strategies to avoid acute dehydration and death. Yet, how chronic exposure to sub-lethal dehydration may entail physiological and fitness costs remains elusive. In this study, we experimentally tested if water restriction causes increased oxidative stress (OS) and telomere length (TL) shortening, two well-described mediators of environment–fitness relationships. We exposed 100 yearling female and male common lizards (Zootoca vivipara) either to a 51-day period ofwater restriction or towater ad libitum, followed by 45 days in common garden outdoor conditions. We measured the kinetic changes in OS and TL and found that water restricted males enhanced antioxidant defences and decreased oxidative damage at day 36, whereas females did not immediately respond.Amonth and half afterwater restriction, both sexes experienced a drop in antioxidant capacity but onlymales exhibited significant TL shortening. In the following 3 years, we found that lizards with longer initial TL and those who maintained stronger antioxidant defences experienced higher longevity, irrespective of sex and water restriction. Together, these results unravelled sex-specific responses to water restriction, with potential applications in better understanding the physiological costs of increasing summer droughts as a result of global climate change

Physiological effects of PFAS exposure in seabird chicks: A multi-species study of thyroid hormone triiodothyronine, body condition and telomere length in South Western France

There is growing evidence that poly and perfluoroalkyl substances (PFAS) exposure leads to the disruption of thyroid hormones including thyroxine (T4) and triiodothyronine (T3), and may affect telomeres, repetitive nucleotide sequences which protect chromosome ends. Many seabird species are long-lived top predators thus exhibit high contaminant levels, and PFAS-disrupting effects on their physiology have been documented especially in relation to the endocrine system in adults. On the contrary, studies on the developmental period (i.e., chicks), during which exposure to environmental contaminants may have a greater impact on physiological traits, remain scarce to this date. We carried out a multi-species study with the aim to assess whether and to which extent chicks of four gull species (herring gull, great and lesser black-backed gull, yellow-legged gull) in South Western France are contaminated by PFAS, and to bring further evidence about their potential physiological consequences. Linear PFOS showed concentrations of concern as it was generally >10 times higher than the other PFAS, and exceeded a threshold toxicity level (calculated from previous studies in birds) in almost all sampled chicks. Nonetheless, in herring gull male chicks, total T3 levels were significantly and negatively associated with perfluorodecanoate (PFDA) and perfluorododecanoate (PFDoDA) and positively associated with perfluorotetradecanoate (PFTeDA) in female chicks. Total T3 levels were also positively associated with PFDoDA in great black backed gull male chicks and with perfluorotridecanoate (PFTrDA) in lesser black backed gull chicks. In lesser and great black-backed gulls, both females and males showed significant negative associations between several PFAS and their body condition, and a positive association between telomere length and L-PFOS in the yellow-legged gull was also found. These results corroborate previous findings and need to be further explored as they suggest that PFAS may interfere with the physiological status of chicks during the developmental period, potentially inducing long-lasting consequences.COntinental To coastal Ecosystems: evolution, adaptability and governanc