L’estimation des effectifs d’une population nécessite de prendre en compte la biologie l’espèce mais aussi contraintes logistiques comme le coût humain et matériel. Les méthodes classiques basées sur comptages individuels fournissent estimations précises sont général lourdes à mettre œuvre. En parallèle, les recensement d’indices présence ne permettent pas une estimation absolue population. Une manière résoudre cette limite est connaître relation entre indices l’effectif Dans ce papier, nous...

Les aloses et les lamproies anadromes sont menacées dans une grande partie de leur aire réparti-tion. Ce travail vise à déterminer tendances des populations en France identifier pressions plus probables. Des séries temporelles provenant différentes sources (vidéo-comptage, pêche professionnelle amateur, nids, bulls fronts migration) ont été collectées regroupées selon la similarité leurs tendances. Ces groupes révèlent un déclin important au cours dernières an-nées tant pour que lamproies....

1 Animals usually require information about the current state of their habitat to optimize behaviour. For this, they can use a learning process through which estimate is continually updated according cues perceive. Identifying these long-standing but still inveterate challenge for ecologists. 2 The plant by aphid parasitoids assessment profitability and adaptation patch exploitation was studied. Grounding on predictions from optimal foraging theory, we tested whether exploited host patches...

Animals foraging for patchily distributed resources may optimize their decisions concerning the patches they encounter, provided that base these on reliable information about profitability of habitat as a whole. Females parasitoid Lysiphlebus testaceipes exploit aphid hosts, which typically aggregate in discrete colonies. We show here how between-colony travel time and number aphids previously visited colonies affect behavior. first assumed parasitoids use previous colony size to estimate...

Abstract Salmonid females invest heavily in reproduction, through gamete production, habitat selection and maternal care. Habitat care are expected to provide shelter for eggs against scouring predators. However, also tend produce variable egg sizes, this trait may interact with quality influence the survival of offspring. In study, we aimed at evaluating role female on conditional individual size body size. We monitored reproductive activity two natural rivers 3 years, order relate nest...

Abstract. 1. Optimal foraging models ultimately predict that female parasitoids should exploit rich host patches for longer than poorer ones. At the proximate level, mechanistic and experimental studies show use both chemicals produced by their hosts direct encounters with to estimate patch quality. Although it has been extensively studied in context of location, herbivore‐induced plant response insect never considered time allocation. 2. In this study, respective roles contact on behaviour...

This study assesses whether the effective number of breeders (Nb ) can be estimated using a time and cost-effective protocol genetic sibship reconstruction from single sample young-of-the-year (YOY) for purposes Atlantic salmon Salmo salar population monitoring. Nb was 10 consecutive reproductive seasons S. in River Nivelle, small located at rear-edge species distribution area France, chronically under its conservation limit subjected to anthropogenic environmental changes. Subsampling real...

Methodologies enabling the monitoring of animal movement and behavior in 3-dimensions (3D; x, y, z, latter accounting for vertical dimension) are becoming increasingly accessible can be deployed on entire groups animals inhabiting 3D habitats. When 2-dimensional (2D; y) space-use analyses used such groups, their spatial organization is represented as a planar projection individuals' space-use. Movement dimension ignored could biased ecological inference made from structure group. We digital...

Habitat selection by dispersers is the focus of much theoretical models, most which are based on assumption negative density dependence. The archetype these models ideal free distribution, characterized an evolutionary stable state where more competitors aggregate in better habitats, so that fitness benefit resource abundance equally offset cost competition all habitats. In this study, we used parentage analysis microsatellite genotypes to test distribution a natural population aphid...

We combined habitat mapping, radio tracking of adults, redd and genetic parentage analysis on juveniles for 2 consecutive years to test eight predictions the reproductive payoffs individual features associated with space use tactics anadromous Atlantic salmon (Salmo salar) in a natural population. Regarding payoffs, we found that (1) males settled better habitat, visited more redds, tended get mates than poorer habitat; (2) they also sired offspring; (3) latter effect was stronger first...

Abstract Microsatellite loci were isolated from the aphid parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae). Ten obtained an enriched partial genomic library. Genetic diversity was analysed at seven of these and two natural populations, one on oleander citrus. The observed number alleles ranged to 17, heterozygosity 0.37 0.82. In both no departure Hardy–Weinberg equilibrium detected except for locus. differentiation between populations characterized by F ST 0.09.

Abstract – Programmes of habitat restoration usually assume that the targeted populations will readily colonise newly provided habitat. However, this assumption may not always hold, and success be impaired if individuals are driven to aggregate in areas already available instead spreading new ones. We investigated how weirs situated along a river could drive Atlantic salmon ( Salmo salar ) their redds tested whether aggregation intensified at low fish density. For this, we applied spatial...

Assortative mating is thought to play a key role in reproductive isolation. However, most experimental studies of assortative do not take place multiple natural environments, and hence, they ignore its potential context dependence. We implemented an experiment which two populations brown trout (Salmo trutta) with different flow regimes were placed into semi-natural stream channels under artificial regimes. Natural reproduction was allowed, isolation measured by means parentage assignment...

Abstract – The evolution of parental care depends on the sex‐dependent resolution a trade‐off between present and future reproduction. In salmonids, mating systems are often characterised by fierce male–male competition, absence paternal is widely admitted in these species. However, fact that brown trout eggs can be cannibalised peripheral individuals just after spawning suggests dominant males would benefit from protecting their offspring keeping cannibals away nest. We used 77 field...

Abstract Animals of many species lay their eggs in nests built to provide offspring a suitable microhabitat during critical phase development. Nest characteristics result from two processes: habitat choice and modification that may impact differently nest suitability for eggs. This field-based study aimed estimate independent effects interaction on the capacity sea lamprey retain Physical variables linked both affected suitability, but higher effect sizes indicated prevalence modification....

Abstract Nest building relates to reproductive effort, sexual selection, intersexual conflict and cooperation may be linked individual phenotype interindividual interactions. In particular, larger individuals having more energy reserves are expected build more, nests, without trade intrasexual competition for cooperative nest building. Capture–mark–recapture survey of sea lamprey ( Petromyzon marinus L. 1758) were combined assess the relationship between nesting activity on a spawning...

Melanins are the most widespread pigments in animals but their adaptive significance remains elusive. Recent studies suggest that intraspecific variation melanin-based coloration reflects individual genetic-based alternative strategies to cope with environment variability, which could be crucial for responses climate changes. However, empirical evidence is still scarce. In this study, we tested how skin natural populations of brown trout Salmo trutta fario would reflect reproductive...