Social and Emotional Values of Sounds Influence Human (Homo sapiens) and Non-Human Primate (Cercopithecus campbelli) Auditory Laterality

The last decades evidenced auditory laterality in vertebrates, offering new important insights for the understanding of the origin of human language. Factors such as the social (e.g. specificity, familiarity) and emotional value of sounds have been proved to influence hemispheric specialization. However, little is known about the crossed effect of these two factors in animals. In addition, human-animal comparative studies, using the same methodology, are rare. In our study, we adapted the head turn paradigm, a widely used non invasive method, on 8–9-year-old schoolgirls and on adult female Campbell's monkeys, by focusing on head and/or eye orientations in response to sound playbacks. We broadcast communicative signals (monkeys: calls, humans: speech) emitted by familiar individuals presenting distinct degrees of social value (female monkeys: conspecific group members vs heterospecific neighbours, human girls: from the same vs different classroom) and emotional value (monkeys: contact vs threat calls; humans: friendly vs aggressive intonation). We evidenced a crossed-categorical effect of social and emotional values in both species since only “negative” voices from same class/group members elicited a significant auditory laterality (Wilcoxon tests: monkeys, T = 0 p = 0.03; girls: T = 4.5 p = 0.03). Moreover, we found differences between species as a left and right hemisphere preference was found respectively in humans and monkeys. Furthermore while monkeys almost exclusively responded by turning their head, girls sometimes also just moved their eyes. This study supports theories defending differential roles played by the two hemispheres in primates' auditory laterality and evidenced that more systematic species comparisons are needed before raising evolutionary scenario. Moreover, the choice of sound stimuli and behavioural measures in such studies should be the focus of careful attention

Animal Welfare:Could Adult Play be a False Friend?

International audienceThere is no consensus regarding the functions of play. As play behavior is a characteristic of young stages of development, it has been suggested that the higher prevalence of adult play observed in domestic animals could be the result of their “neotenic retardation.” Functional hypotheses have dealt with the long term benefits, such as “rehearsal,” “motor training” for future adult competencies or “training for the unexpected.” However, there is little consistent experimental evidence favoring a particular hypothesis. The present study aimed to test the functional significance of adult play as a potential reliable indicator of good welfare, a by-product of domestication or a tool for social cohesion. Observations of both a domestic species (the horse) and wild/captive animals (cercopithecids) confirm the literature data that show the greater prevalence of adult play in the domestic/captive situations. This convergence between a domestic and a wild species argue against the idea that adult play may be a mere product of domestication. Moreover, animals living in naturalistic situations had the same low level of adult play as observed in wild animals suggesting that captive/domestic animals do not play only because they are stress free or well fed. Play is not a reliable indicator of welfare: Horses and adult macaques that played the most were also those that exhibited the greatest signals of poor welfare as stereotypic behaviors. Furthermore, adult play was more frequent at times of social disturbances and instability. Adult play is a sign showing that the adult organism needs to evacuate stress

Visual laterality in dolphins: importance of the familiarity of stimuli

<p>Abstract</p> <p>Background</p> <p>Many studies of cerebral asymmetries in different species lead, on the one hand, to a better understanding of the functions of each cerebral hemisphere and, on the other hand, to develop an evolutionary history of hemispheric laterality. Our animal model is particularly interesting because of its original evolutionary path, i.e. return to aquatic life after a terrestrial phase. The rare reports concerning visual laterality of marine mammals investigated mainly discrimination processes. As dolphins are migrant species they are confronted to a changing environment. Being able to categorize new versus familiar objects would allow dolphins a rapid adaptation to novel environments. Visual laterality could be a prerequisite to this adaptability. To date, no study, to our knowledge, has analyzed the environmental factors that could influence their visual laterality.</p> <p>Results</p> <p>We investigated visual laterality expressed spontaneously at the water surface by a group of five common bottlenose dolphins (<it>Tursiops truncatus</it>) in response to various stimuli. The stimuli presented ranged from very familiar objects (known and manipulated previously) to familiar objects (known but never manipulated) to unfamiliar objects (unknown, never seen previously). At the group level, dolphins used their left eye to observe very familiar objects and their right eye to observe unfamiliar objects. However, eyes are used indifferently to observe familiar objects with intermediate valence.</p> <p>Conclusion</p> <p>Our results suggest different visual cerebral processes based either on the global shape of well-known objects or on local details of unknown objects. Moreover, the manipulation of an object appears necessary for these dolphins to construct a global representation of an object enabling its immediate categorization for subsequent use. Our experimental results pointed out some cognitive capacities of dolphins which might be crucial for their wild life given their fission-fusion social system and migratory behaviour.</p

Diets and Resource Partitioning Between Larvae of 3 Anisopteran Species

WOS:A1985APX6200004International audienceAnalysis of resource partitioning between larvae of three Anisopteran species showed that Aeshna cyanea and Anax imperator (both Aeshnidae) tended to occupy similar ecological niches which were not shared by Libellula depressa (Libellulidae).The diets of these predators and comparisons between trophic availability and diets indicated that prey species eaten varied according to season and predator species, and that some selection of prey species occurred

Distribution spatiale des larves de trois espèces d'Anisoptères

International audienceThe interspecific and ontogenetic variations in the larval distribution of Aeshna cyanea, Anax imperator and Libellula depressa were estimated on the basis of monthly samples in a pond in Brittany, France. The aeshnids co-occurred, but L. depressa usually inhabits the shallow parts only. The younger A. cyanea instars tend to congregate. In the FO and F-l aeshnid instars, the spatial overlap index decreases from April to May. No relationship between larval age and water depth could be evidenced

Sélection de proies de tailles différentes en fonction de leur abondance absolue et relative par les larves d'Anax imperator

International audienceTwo groups of larvae ( r + F-l, F-2 + F-3) were presented 2 different sizes of Daphnia magna at various densities. F + F-l larvae chose preferentially the bigger prey when overall prey densities were high, independently of relative densities. Larvae from the 2 other instars chose bigger prey even when density was low, but were more selective when prey densities were high than when they were low. This preferential choice was not exclusive: Anax larvae never completely ignored smaller prey. The analysis of selectivity at different phases of feeding behaviour shows that selection generally occurs prior to the orientation towards a prey item

Spatial distribution and interactions between Anax imperator (Anisoptera Odonata) larvae at different developmental stage

International audienceThe influence of 4 different factors on spatial distribution was tested experimentally: developmental stage, predator density, duration of site occupation and presence or absence of larvae of different developmental stages. Six parameters were used to characterize spatial distribution. — Three of the factors tested influenced spatial occupation in A. imperator: the size of home ranges increased with larval development, the coexistence of larvae of two different larval instars induced an increase of the volume occupied by medium-sized larvae and an instability of the home ranges of final-instar larvae, and the frequency of agonistic interactions increased with larval density. Analysis of the spatial distribution of aquatic insects is required to understand the dynamics of insects in aquatic environments (HILDREW et al., 1980; JOHNSON & CROWLEY, 1980; SPENCE & SCUDDER, 1980; ALLAN, 1982; HUGGINS & DUBOIS, 1982; MARTIN, 1985). Recent reports have stressed the value of an ethological approach towards interactions (between insects) for understanding modalities of spatial occupation (SIH, 1982; PECKARSKY & PENTON, 1985; SJOSTROM, 1985)

Influence of prey densities on prey selection in Anax imperator larvae (Odonata: Aeshnidae)

International audienceVarious relative and absolute densities of two prey species, chironomid larvae and adult Corixa were presented to individual larvae of Anax imperator. Although these larvae preferred chironomid larvae, the quantity of each prey species eaten depended mainly on the density of that prey species. No indication of switching was found. However only when their relative density was low at the beginning of an experiment, were items of that prey species eaten in proportion to their relative density

Circadian variations of food intake in Anax imperator and Aeshna cyanea larvae

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