Les poissons de la Grande Grotte d'Arcy-sur-Cure (Yonne)

Un original método de investigacion, mediante adelgazamiento de la calcita, utilizado por primera vez en una cueva con decoración paleolítica ha permitido sacar a la luz, entre otras cosas, cuatro peces pintados en negro sobre las paredes de la Grande Grotte d'Arcy-sur-Cure (Yonne, France). Dichos peces, salmónidos y lucio, confirman el carácter excepcional el bestiario de esta gruta constituido por animales que no están presentes en las demás, a excepción de la de la cueva Chauvet (Ardechè) ; mamuts, rinocerontes, osos, felino, aves, megáceros. Los vestigios, bien conservados, encontrados sobre su suelo nos han permitido determinar que fue utilizada en la época auriñaciense gravetiense

Programme de recherches interdisciplinaires « Vérité et fiction »

Stéphane Breton, Jean-Paul Colleyn, André Gunthert, Jean-Claude Penrad, Annick Bouleau, Sabine Chalvon, Daniel Dayan, Renaud Dulong, Éliane de Latour, Catarina Pasqualino, Dominique Pasquier, Marc-Henri Piault, Jean-Pierre Bertin-Maghit, Jacqueline Chervin, Emmannuel Grimaud, Roger Odin, Laurence Allard Allard, Gilles Saussier, Elodie Perreau Nous avons poursuivi nos travaux sur la tension (majeure), entre la vérité et la fiction dans les formes d’expression audiovisuelles. Roger Odin (Univer..

Programme de recherches interdisciplinaires « Vérité et fiction »

Stéphane Breton, Jean-Paul Colleyn, André Gunthert, Jean-Claude Penrad, Annick Bouleau, Sabine Chalvon, Daniel Dayan, Renaud Dulong, Éliane de Latour, Catarina Pasqualino, Dominique Pasquier, Marc-Henri Piault, Jean-Pierre Bertin-Maghit, Jacqueline Chervin, Emmannuel Grimaud, Roger Odin, Laurence Allard Allard, Gilles Saussier, Elodie Perreau Nous avons poursuivi nos travaux sur la tension (majeure), entre la vérité et la fiction dans les formes d’expression audiovisuelles. Roger Odin (Univer..

A higher inherent trait for fearfulness is associated with increased anxiety-like behaviours and diazepam sensitivity in Japanese quail

This study tested whether lines of Japanese quails divergently selected for a fear response, the tonic immobility, might constitute a reliable bird model for studying anxiety. Previous studies demonstrated that the selection modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. The behavioural effects of intraperitoneal injections of diazepam, an anxiolytic drug, were assessed in two lines of quail selected either for their short (STI) or long (LTI) duration of tonic immobility. Effects of diazepam were examined in two tests used for measuring emotionality in birds, the open field and the tonic immobility tests. After being placed in the centre of the open field, birds with a high emotionality (LTI quails) stayed longer in the centre of the apparatus than STI quail. Diazepam had anxiolytic effect in LTI birds as it increased the time spent in the outer area. This effect of diazepam appears to be selective because the drug has no effect another behaviours such as distress calls or escape attempts. The drug has also no effect on the tonic immobility response in any of the two lines. These findings reveal an "anxiogenic" trait of LTI birds in the open field test that can be modulated by the administration of an anxiolytic drug. Therefore quails selected for LTI and STI represent a valuable model to study the mechanisms underlying anxiety in birds

Individual trait for emotionality operates as a switch between memory systems

National audienc

Shifts from pulled to pushed range expansions caused by reduction of landscape connectivity

International audienceRange expansions are key processes shaping the distribution of species; their ecological and evolutionary dynamics have become especially relevant today, as human influence reshapes ecosystems worldwide. Many attempts to explain and predict range expansions assume, explicitly or implicitly, so-called 'pulled' expansion dynamics, in which the low-density edge populations provide most of the 'fuel' for the species advance. Some expansions, however, exhibit very different dynamics, with high-density populations behind the front 'pushing' the expansion forward. These two types of expansions are predicted to have different effects on e.g. genetic diversity and habitat quality sensitivity. However, empirical studies are lacking due to the challenge of generating reliably pushed versus pulled expansions in the laboratory, or discriminating them in the field. We here propose that manipulating the degree of connectivity among populations may prove a more generalizable way to create pushed expansions. We demonstrate this with individual-based simulations as well as replicated experimental range expansions (using the parasitoid wasp Trichogramma brassicae as model). By analyzing expansion velocities and neutral genetic diversity, we showed that reducing connectivity led to pushed dynamics. Low connectivity alone, i.e. without density-dependent dispersal, can only lead to 'weakly pushed' expansions, where invasion speed conforms to pushed expectations, but the decline in genetic diversity does not. In empirical expansions however, low connectivity may in some cases also lead to adjustments to the dispersal-density function, recreating 'classical' pushed expansions. In the current context of habitat loss and fragmentation, we need to better account for this relationship between connectivity and expansion regimes to successfully predict the ecological and evolutionary consequences of range expansions

Landscape connectivity alters the evolution of density-dependent dispersal during pushed range expansions

A bstract As human influence reshapes communities worldwide, many species expand or shift their ranges as a result, with extensive consequences across levels of biological organization. Range expansions can be ranked on a continuum going from pulled dynamics, in which low-density edge populations provide the “fuel” for the advance, to pushed dynamics in which high-density rear populations “push” the expansion forward. While theory suggests that evolution during range expansions could lead pushed expansions to become pulled with time, empirical comparisons of phenotypic divergence in pushed vs. pulled contexts are lacking. In a previous experiment using Trichogramma brassicae wasps as a model, we showed that expansions were more pushed when connectivity was lower. Here we used descendants from these experimental landscapes to look at how the range expansion process and connectivity interact to shape phenotypic evolution. Interestingly, we found no clear and consistent phenotypic shifts, whether along expansion gradients or between reference and low connectivity replicates, when we focused on low-density trait expression. However, we found evidence of changes in density-dependence, in particular regarding dispersal: populations went from positive to negative density-dependent dispersal at the expansion edge, but only when connectivity was high. As positive density-dependent dispersal leads to pushed expansions, our results confirm predictions that evolution during range expansions may lead pushed expansions to become pulled, but add nuance by showing landscape conditions may slow down or cancel this process. This shows we need to jointly consider evolution and landscape context to accurately predict range expansion dynamics and their consequences

Impact of individual trait for emotionality on behavioural, physiological and neurobiological consequences of chronic stress in birds

International audienceThere is considerable variability in the susceptibility of individuals to the adverse effects of chronic stress. In humans and other mammals, individual traits such as high anxiety are proposed as a vulnerability factor for the development of stress-related disorders. In the present study, we tested whether a similar behavioural trait in birds, a higher emotional reactivity, also favours the occurrence of chronic stress related behavioural, physiological and neurobiological dysfunctions. For this, two lines of Japanese quail divergently selected for the duration of tonic immobility, a typical fear response in birds, were subjected to unpredictable aversive stimulations over 2 weeks. Previous studies demonstrate that the selection program modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. Chronic stress was associated with severe changes both at the physiological and behavioural level. Indeed, stress birds displayed decreased body weight, started laying later and decreased basal corticosterone level in comparison with control non stressed birds. Behaviourally, chronic stress enhanced anxiety behaviours during the open field test, the novel object test and a food neophobia test. Stressed birds were also more inactive in a restraint box suggesting potential effect of the stress treatment on behaviours related with resignation. Current investigations are under process to unravel the impact of chronic stress on social behaviours and neurobiological functions. Interestingly, the effects of chronic stress on anxiety behaviours in the open field test and on basal corticosterone level were more severe in birds selected for their higher emotionality. These findings thus highlight emotional reactivity as an important predisposing factor for the occurrence of the adverse effects of chronic stress in birds

Does emotivity modulate stress effects on memory and brain plasticity in quail?

Does emotivity modulate stress effects on memory and brain plasticity in quail?. 35. International Ethological Conferenc

Emotionality modulates the impact of chronic stress on memory and neurogenesis in birds

International audienceChronic stress is a strong modulator of cognitive processes, such as learning and memory. There is, however, great within-individual variation in how an animal perceives and reacts to stressors. These differences in coping with stress modulate the development of stress-induced memory alterations. The present study investigated whether and how chronic stress and individual emotionality interrelate and influence memory performances and brain neurogenesis in birds. For that, we used two lines of Japanese quail (Coturnix japonica) with divergent emotionality levels. Highly (E+) and less (E−) emotional quail were submitted to chronic unpredictable stress (CUS) for 3 weeks and trained in a spatial task and a discrimination task, a form of cue-based memory. E + and E− birds were also used to assess the impact of CUS and emotionality on neurogenesis within the hippocampus and the striatum. CUS negatively impacted spatial memory, and cell proliferation, and survival in the hippocampus. High emotionality was associated with a decreased hippocampal neurogenesis. CUS improved discrimination performances and favored the differentiation of newborn cells into mature neurons in the striatum, specifically in E+ birds. Our results provide evidence that CUS consequences on memory and neural plasticity depends both on the memory system and individual differences in behavior