https://popups.lib.uliege.be/2984-0317/index.php?id=254 Numéros en texte intégral fr Fri, 19 Jan 2024 10:42:50 +0100 Fri, 19 Jan 2024 10:42:50 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=254 0 https://popups.lib.uliege.be/2984-0317/index.php?id=674 Fri, 26 Jan 2024 17:00:41 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=674 https://popups.lib.uliege.be/2984-0317/index.php?id=1218 Les oiseaux de la famille des Ardéidés (Hérons, Aigrettes , Butors) utilisent lors de leurs parades nuptiales tout un répertoire de comportements ritualisés. Les plus importants, les postures d'appel, servent au mâle à attirer sa future partenaire. D'espèce en espèce, l'analyse linéaire révèle une évolution divergente de ces postures. Elle mène progressivement des rafales de coups de bec vers le haut des Egretta, à la lente danse dandinante d'Ardeola. Chez une espèce pivot comme Bubulcus, une composante rappelle la posture d'appel de l' espèce qui la précède dans la classification tandis qu'une autre composante annonce l'espèce apparue ultérieurement. Une analyse plus approfondie révèle que la ritualisation dans chaque lignée évolutive a progressé en trois étapes distinctes. Les postures mixtes de certaines espèces (Butorides, E. tricolor) sont de véritables reliques comportementales révélant qu'initialement les trois composantes posturales de base n'étaient pas individualisées. Dans un deuxième temps, elles se séparent, puis deux composantes disparaissent, ne laissant subsister qu'une seule posture en fin de lignée, chez les espèces « modernes » (E. garzetta, Ardeola ralloides, Ardea purpurea). Au troisième stade la posture résiduelle tend à être effectuée en rafales (E. thula). Ces postures d'appel instaurant un isolement reproducteur efficace sont probablement impliquées dans les mécanismes évolutifs d'apparition des espèces. This paper deals primarily with a detailed description, out of field observations and photographic snapshots, of the pair formation displays in four ardeids species living in France : grey heron, purple heron, cattle egret ans squacco heron. It suggests that the nuptial display in cattle egret is intermediate regarding the performance of grey heron and squacco heron respectively. The seductive displays are then compared in 21 species within the ardeids. The comparison seems to indicate that a divergent evolution in seductive postures and behaviour leaded to the reproductive isolation and contributed, at least partially, to speciation within the group. It allows indeed, starting with an « ancestral display », to imagine it dividing into three main components showing, in the species concerned, different degrees of combination, intermediate steps, or progressive reduction. The hypothetical phylogeny reconstructed through that behavioural comparison matches rather correctly the phylogeny established by DNA analysis. At least some forty species belonging to the true herons (Ardea, Nycticorax, Egretta), and may be the sixty species of the whole family are concerned. Thu, 01 Feb 2024 10:40:02 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1218 https://popups.lib.uliege.be/2984-0317/index.php?id=1220 A small number of well documented case-studies of un-socialized wild childs lacking any ability to communicate with their human relatives have leaded to theories and speculations on the normal process of socialization in human and nonhuman primates. As experiments were inconceivable with the first ones, non-human primates have suffered deprivation and isolation experiments, essentially by Harlow and his co-workers, from which it was concluded that there are five main affectional systems : the well integrated systems of mother-infant and of infant-mother affection, leading to self confidence and desire to explore; the derived system of age-mate or peer affection, where group cohesion and individual and sexual roles are learned and recognized; the heterosexual affection system in adults leading to cooperation and eventually the parental affectional system necessary to reproductive and educational success. Paralleling Bowlby's findings in the human child, the first rather soft experiments by Harlow deeply contributed to the understanding of the importance of mother-child interactions in the building up of the attachment process. More radicalized experiments with severe and long lasting isolation devices leaded to more contestable results; we indeed have to evaluate the output and reward for researchers against the pain endured by the captive animals. Harlow got world-wide approval and recognition from his colleagues for his pioneer work, which would no longer be admitted today, regarding to animals' rights and present ethical standards. Thu, 01 Feb 2024 10:40:44 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1220 https://popups.lib.uliege.be/2984-0317/index.php?id=1221 Thu, 01 Feb 2024 10:41:25 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1221 https://popups.lib.uliege.be/2984-0317/index.php?id=1222 Thu, 01 Feb 2024 10:44:37 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1222 https://popups.lib.uliege.be/2984-0317/index.php?id=1223 Thu, 01 Feb 2024 10:45:13 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1223 https://popups.lib.uliege.be/2984-0317/index.php?id=1225 This video film overviews the first steps of the restoration, in the Belgian Meuse River basin, of the most fabulous salmonid fish : the Atlantic salmon (Salmo salar). In Belgium, the salmon disappeared around 1935. In 1983, sea trouts were discovered in the Meuse basin, allowing to consider salmon restoration as possible. Fertilized eggs from Scotland were reared in an experimental fishfarm for restocking purposes. Scientific studies were undertaken to assess the adaptation of stocked salmon parrs in the wild (habitat studies by means of electrofishing or diving, behaviour studies, capture of migrating smolts, radio-tracking). Before salmons come back from the sea to spawn in tributaries, fish ways have to be studied and improved. To illustrate the return of adult salmon, a French experiment is described. Thu, 01 Feb 2024 10:45:51 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1225 https://popups.lib.uliege.be/2984-0317/index.php?id=1226 Thu, 01 Feb 2024 10:49:42 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1226 https://popups.lib.uliege.be/2984-0317/index.php?id=1227 Thu, 01 Feb 2024 10:50:18 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1227 https://popups.lib.uliege.be/2984-0317/index.php?id=1229 Thu, 01 Feb 2024 10:51:25 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1229 https://popups.lib.uliege.be/2984-0317/index.php?id=1230 Thu, 01 Feb 2024 10:51:52 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=1230