Divergent selection is a powerful driver of speciation and has been widely studied in relation to the physical characters of organisms. Behavioural traits also significantly contribute to the ...evolutionary processes of divergence. However, studying such effects is fraught with difficulties as the development of behavioural traits is likely to be complex and is moulded by ontogenetic processes such as shifts in habitat use. Here we explored how several aspects of juvenile behavioural variation may relate to adaptive divergence in a freshwater fish. We assessed whether and how juveniles of two recently evolved, sympatric morphs of Arctic charr, Salvelinus alpinus, a small benthivorous and a planktivorous charr, show genetically based differences in personality that conform to their respective ecological niches, and whether these differences could contribute to reproductive isolation by generating maladaptive hybrid behaviours. Studying three aspects of behavioural variation (average trait value, consistent individual differences and trait correlations), we assessed the sociality and risk-taking propensity of hybrids and pure-morph offspring reared in common conditions. While no difference in average behavioural responses could be observed, the hybrids tended to show less repeatable behaviours and were not intermediate for behavioural syndromes that appear to differ between the two morphs. These results provide limited evidence of personality trait divergence among polymorphic fish, and suggest subtle, nonadditive effects of hybridization on the development of such traits.
•Average personality traits differences between charr morphs were not observed.•Trait correlations appear to differ between morphs.•Consistent individual differences tended to be altered in their hybrids.•Intermediate trait correlations were not observed in the hybrids.
•European seabass personality (i.e. bold–shy and motivation to escape stressful situation) was characterized.•Latency to emerge from a shelter and latency to escape during a restraint test were ...correlated.•Placed under self-feeding, individual triggering activity level was higher in shy individuals.
Most studies carried out with seabass under self-feeding conditions report an intriguing social structure that is built around the device and the food dispenser with three coexisting triggering categories: high-triggering (HT), low-triggering (LT) and zero-triggering (ZT) fish. However, neither sex nor feeding motivation or hierarchy can explain the establishment of this specialization. We characterized the personality of seabass with the commonly used restraint and open field tests and assessed the link between personality traits and individual triggering activity towards the self-feeder apparatus. We found no differences between triggering categories during the restraint test but high triggering fish were characterized as shyer than low- and zero-triggering fish during the open field test. Triggering activity was negatively correlated with exploratory capacities and boldness. This experiment provides for the first time evidence that high triggering status in seabass is correlated with personality traits, which could partly explain the social structure that builds around a self-feeder device.
•We compared the self-feeding behaviour between Nile and Black-chinned tilapia.•We estimated the links between the social structure and personality traits.•The social structure was similar between NT ...and BCT.•We found a strong positive correlation between the triggering activity and female shyness.
Hybridization aims at combining valuable traits from two species into a single group. Nile tilapia Oreochromis niloticus (NT) and Black-chinned tilapia Sarotherodon melanotheron (BCT) are respectively characterized by fast growth and water salinity tolerance which attract the breeders who could take advantage of both species. The first step is to characterize both species behavior in different contexts. The aim of this study was to compare the self-feeding behaviour between NT and BCT with a design allowing to reveal individual and group feed demand behaviour and then to identify the individual specialization that builds around the device and the food dispenser. The second objective was to estimate the links between the individual specialization and personality traits. To this aim, we recorded feed demand behaviour of both species using a computerized self-feeding device (two tanks for each species containing 20 PIT-tagged individuals with a male-female ratio of about 47%). Personality traits of all individuals were subsequently characterized with an open field test (OFT). The links between feed-demand and personality were then analyzed. Growth performances were not significantly different between NT and BCT but there was a strong tank effect. The individual specialization was similar in NT and BCT and similar to that previously observed in sea bass i.e. 1–3 individuals responsible for most of the feed demand activity in the tanks. Most NT individuals stayed in the shelter during the open field test while most of BCT individuals moved out of it. Overall, NT were shyer than BCT or the OFT was not adapted to NT. Linking the results of the self-feeding experiment and OFT in BCT, we found a strong positive correlation between the triggering activity and females’ shyness. Fish that spent more time inside than outside the shelter and which latency to emerge from shelter was longer, were characterized by a higher triggering activity (high-triggering fish). This study confirms the NT ability to use self-feeder devices and provides the first insight into the same ability in BCT and demonstrates links with personality traits. These results have a potential interest for the success of BCT and NT hybridization.
Intersubjectivité et lien Benhaïm, David
Revue de psychothérapie psychanalytique de groupe,
6/2011, Letnik:
n° 56, Številka:
1
Journal Article
Recenzirano
Résumé L’auteur s’interroge sur le rapport entre la notion d’intersubjectivité et celle de lien à partir de l’œuvre de René Kaës. Il convoque d’abord deux conceptions de l’intersubjectivité : la ...première, partagée par de nombreux analystes, d’essence philosophique, prend son inspiration dans la phénoménologie existentielle. Bernard Brusset l’expose dans son rapport présenté au 66 e congrès des psychanalystes de langue française. La seconde est celle de René Kaës. Son paradigme méthodologique est le groupe qui permet l’émergence d’un nouvel espace psychique intersubjectif, lieu où se déroulent des processus, où se constituent des formations psychiques et une expérience spécifique, inaccessibles autrement, résultat de la composition d’un ensemble et des liens qui s’y tissent. L’auteur montre ensuite comment la construction de la problématique des liens, inséparable de cette conception de l’intersubjectivité, part du modèle de l’appareil psychique groupal pour élaborer une théorie psychanalytique du lien, ancrée dans le pulsionnel. Il souligne la distinction entre lien et relation d’objet et développe pour finir trois questions qui permettent de compléter l’analyse du lien : la question des organisateurs psychiques, celle des exigences du travail psychique pour faire lien et enfin celle des alliances inconscientes.
Behavioural studies comparing hatchery and wild-caught fish are useful to improve selection for aquaculture and restocking programmes. We examined swimming behaviour characteristics in wild captured ...and domesticated sea bass juveniles before and after eliciting a startle response at 8 different ages and always on naive individuals. We specifically investigated whether domestication impacts juvenile sea bass behaviour and whether the first months of captivity induce behavioural modifications in wild juveniles. An apparatus was designed to mimic a predator attack by presenting a sudden visual and mechanical stimuli simultaneously in 8 arenas where single individuals were placed and video recorded. The reactivity response was evaluated and different swimming variables including angular velocity, total distance travelled, mean velocity, immobility and distance from stimulus point were analysed from videos taken 5min before stimulus actuation, 5 and 15min after. Otolith readings showed that wild and domesticated juveniles were of similar age (∼55 days at the start of the experiment and ∼125 at the end of experiment). There were consistent behavioural differences (e.g. higher angular velocity and distance from stimulus point in wild fish) demonstrating that domestication reduces flight response behaviour. There were also similarities between both fish origins (similar response to stimulus actuation: decrease of total distance travelled and mean velocity, increase of angular velocity and immobility). A decrease over time in reactivity and variability in swimming responses among fish of both origins showed that captivity only does not fully explain wild fish behaviour changes and ontogenic modifications are likely interplaying.
•We assessed sea bass preference for familiar congener.•We assessed sea bass boldness.•Shy individuals prefer to spend time near familiar congeners.•We suggest the link between familiarity and ...shyness is a general aspect of both animal and human behaviour.
The shy–bold continuum is both a fundamental aspect of human behavior and a relatively stable behavioral trait for many other species. Here we assessed whether shy individuals prefer familiar congeners, taking the European sea bass, a recently domesticated fish showing similar behavioral responses to wild fish, as a model to better understand the inter-individual variability in social behavior previously observed in this species. In the wild, the link between familiarity i.e., the preference of fish for familiar congeners and boldness could be part of the mechanism underlying shoaling formation in fish. Thirty fish were individually tested in a device designed to assess the preference for a familiar vs. an unfamiliar congener on the basis of visual cues only. An open field test (OFT) with shelter was performed on the same fish 32 days later to assess the boldness of each individual. Variables of interest included the proportion of time spent in the shelter, border and center zone of the arena and variables of activity. Variables measured in OFT were collapsed into first principal component scores using Principal Components Analysis (PCA) which allowed characterizing a shy-bold continuum. Time spent near the familiar congener was negatively correlated with boldness i.e., shy individuals spent most of the time near the familiar congener. We discuss the relevance of these findings to the understanding of the behavior of European sea bass and suggest that the link between familiarity and shyness is a general aspect of both animal and human behavior.
Fish learning and cognition are usually approached by testing single individuals in various devices such as mazes that have serious drawbacks, especially in gregarious species, including the stress ...induced by the test procedure. This might impair the results and lead to misinterpretation about the learning abilities of the targeted species. In order to provide an alternative to the individual-based tests, we investigated for the first time the operant conditioning of four similar groups (50 individuals per tank) of sea bass. We used two computerized self-feeder devices per tank, each coupled with individual electronic identification and that were alternately activated during varying positive appetitive reinforcement period of time (7 to 1 day). Learning abilities were examined at both group and individual levels. At the group level, the operant conditioning was demonstrated as the triggering activity significantly decreased when the device was turned off and increased when it was turned on, whatever the reinforcement period duration. The individual level analysis revealed a more complex situation with fish showing different learning performances that can be best explained through the producer-scrounger game theory.
While most animals have received increasing attention for their welfare, consideration for fish welfare has started more recently, particularly since the recognition that fish have emotions and ...complex cognitive abilities. Housing conditions in fish farms do not always meet fish ethological requirements as these conditions lack sufficient sensory and cognitive stimulations. An approach to address this issue involves enriching the rearing environment by including social, food, physical, or cognitive stimuli. Cognitive enrichment (CE) is a recent but promising concept to improve fish welfare by manipulating the predictability and controllability of their environment. It relies not only on the ability of fish to predict positive and negative events but also on their ability to perform and succeed in operant conditioning. In our present review, we identified four categories of CE: (i) feeding predictability, (ii) predictability of a negative event, (iii) operant conditioning through self-feeders, and (iv) learning experiences. Existing CEs were reviewed for their effects on behaviour, brain, zootechnical performances, and welfare in terms of physiological stress or physical integrity in the aquarium and farmed teleost fish. The review highlights unbalanced categories and the lack of adequate multidisciplinary analyses to assess the effects of these categories on fish welfare. Providing free access to self-feeders seems to be a good strategy, given its positive effects on zootechnical and physiological parameters. Other categories showed contradictory and species-dependent results; hence, further studies are required to confirm the benefits of CE on fish welfare. Finally, further investigations should also validate current CE systems and assess other strategies that may trigger positive emotions in fish.
•Fish have the cognitive abilities required to use cognitive enrichments properly.•Promising effects of feeding predictability as a cognitive enrichment strategy on fish welfare.•Cognitive enrichments still deserve further consideration, namely validate the current existing strategies and more comprehensive analyses on fish welfare.•Cognitive enrichment needs to be designed according to the ecology of the fish species.•Cognitive enrichments must contain an appropriate level of stimulations to ensure positive effects on fish welfare: nor too low to avoid boredom, nor too high to avoid chronic stress and frustration.
Because captivity constitutes a drastic environmental change, domestication is expected to induce a rapid genetic selection for behavioural traits. In this study, we searched for genetic differences ...in behaviour among brown trout juveniles from two strains differing for their domestication history, i.e. an almost pure native wild Mediterranean population (W) and an Atlantic domesticated strain (D). In order to assess pure genetic differences among strains, males from the two origins were mated with Mediterranean females to produce two experimental crosses (WW and WD). The swimming activity characteristics of individual WW and WD juveniles were compared before and after the application of a stress (light switched off suddenly, followed by a 5-min period of darkness). For each of the fish observed, mating type origin (WW or WD) was unambiguously reassigned by genotyping. Behavioural responses differed between WD and WW fish. Angular velocity and the time spent immobile were greater for WW fish both before and after the short period of darkness, indicating higher reactivity. Once the light had been turned on again, mean velocity and total distance travelled were higher in WD than in WW fish. WD fish tended to recover levels of swimming activity higher than those before the dark period. This study therefore demonstrates an impact of genetic origin and domestication on swimming activity repertoire (higher reactivity in WW fish), a behavioural trait of particular importance for individual ecological performance. Owing to the contrasted domestication history of the two strains used in the comparison, we assume that the domestication level largely contributes to the behavioural changes observed.
In various experiments under self-feeding conditions, sea bass groups could be divided into three categories regarding feeder actuation: high, low and zero-triggering fish. In all cases few ...high-triggering fish were responsible for a high percentage of the feed delivery. A question was raised about the role played by feeding motivation in such high-triggering status acquisition. It was approached by applying a 3-week fasting period in order to induce similar negative specific growth rate (SGR) in two groups of fish of similar mean weight but with either a low or a high coefficient of variation for weight (CV
w) (T
low: CV
w
∼
11%, 3 tanks of 60 fish each; T
high: CV
w
∼
20%, 3 tanks of 60 fish each). These groups were created to test the consistency of behavioural responses in two different contexts (
i.e. two population size-distributions). During the follow-up period of 40 days, the group level feed-demand behaviour was not strongly modified by the fasting period and there were no differences between T
low and T
high groups. Complete growth compensation was the same in all tanks as observed at the end of the experiment. At the individual level, high-triggering fish were exactly the same individuals before and after the fasting period. Up to four high-triggering fish could be observed according to the tank and when several fish were performing high-triggering activity, their rankings were sometimes reversed after the fasting period. High-triggering fish increased their activity levels after the fasting period showing behavioural plasticity. High-triggering status could neither be explained by an initial lower SGR nor a sex effect, nor by any of the measured physiological blood parameters. Thus, individual's triggering activity levels could be related to personality and/or metabolic traits but further research is required to confirm this assumption.
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