Reciprocal preening and food sharing in colour-polymorphic nestling barn owls.

Barn owl (Tyto alba) siblings preen and offer food items to one another, behaviours that can be considered prosocial because they benefit a conspecific by relieving distress or need. In experimental broods, we analysed whether such behaviours were reciprocated, preferentially exchanged between specific phenotypes, performed to avoid harassment and food theft or signals of hierarchy status. Three of the results are consistent with the hypothesis of direct reciprocity. First, food sharing was reciprocated in three-chick broods but not in pairs of siblings, that is when nestlings could choose a partner with whom to develop a reciprocating interaction. Second, a nestling was more likely to give a prey item to its sibling if the latter individual had preened the former. Third, siblings matched their investment in preening each other. Manipulation of age hierarchy showed that food stealing was directed towards older siblings but was not performed to compensate for a low level of cooperation received. Social behaviours were related to melanin-based coloration, suggesting that animals may signal their propensity to interact socially. The most prosocial phenotype (darker reddish) was also the phenotype that stole more food, and the effect of coloration on prosocial behaviour depended upon rank and sex, suggesting that colour-related prosociality is state dependent.

Most and Least Preferred Colours Differ According to Object Context : New Insights from an Unrestricted Colour Range

Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.

Listening to parents: The role of symptom perception in pediatric palliative home care.

OBJECTIVE: This study analyzes symptom perception by parents and healthcare professionals and the quality of symptom management in a pediatric palliative home care setting and identifies which factors contribute to a high quality of palliative and end-of-life care for children. METHODS: In this retrospective, cross-sectional study, parents were surveyed at the earliest three months after their child's death. All children were cared for by a specialized home pediatric palliative care team that provides a 24/7 medical on-call service. Questionnaires assessed symptom prevalence and intensity during the child's last month of life as perceived by parents, symptom perception, and treatment by medical staff. The responses were correlated with essential palliative care outcome measures (e.g., satisfaction with the care provided, quality-of-life of affected children and parents, and peacefulness of the dying phase). RESULTS: Thirty-eight parent dyads participated (return rate 84%; 35% oncological disorders). According to parental report, dyspnea (61%) and pain (58%) were the dominant symptoms with an overall high symptom load (83%). Pain, agitation, and seizures could be treated more successfully than other symptoms. Successful symptom perception was achieved in most cases and predicted the quality of symptom treatment (R 2, 0.612). Concordant assessment of symptom severity between parents and healthcare professionals (HCPs) improved the satisfaction with the care provided (p = 0.037) as well as the parental quality-of-life (p = 0.041). Even in cases with unsuccessful symptom control, parents were very satisfied with the SHPPC team's care (median 10; numeric rating scale 0-10) and rated the child's death as highly peaceful (median 9). Significance of the results: The quality and the concordance of symptom perception between parents and HCPs essentially influence parental quality-of-life as well as parental satisfaction and constitute a predictive factor for the quality of symptom treatment and palliative care.

Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration.

The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.

Perception du timing pubertaire et comportements à risque chez des adolescents suisses

Il faut distinguer timing pubertaire objectif (TPO ; comparaison du timing pubertaire réel d'un sujet avec celui d'un groupe de référence) et timing pubertaire subjectif (TPS ; perception subjective par le sujet de son timing pubertaire par rapport à celui de ses pairs). Chez l'adolescente, la ménarche est couramment utilisée comme marqueur du TPO. La littérature s'intéressant aux variations physiologiques (normales) du timing pubertaire montre qu'un TPO précoce est corrélé chez les adolescentes avec de nombreux problèmes de santé (p.ex. dépression, abus de substances, comportements à risques, niveau d'études inférieur). Un TPO tardif chez l'adolescente serait quant à lui associé à une meilleure réussite scolaire. Les diverses hypothèses expliquant ces corrélations sont brièvement décrites dans notre travail. Certaines hypothèses impliquent des facteurs objectifs tels les changements du corps à la puberté, alors que d'autres privilégient des facteurs plus subjectifs, dans le registre de la perception de soi. A ce jour, la littérature ne s'est que très peu intéressée au TPS en soi. Une adolescente percevant son timing pubertaire comme précoce est-elle à risque même si sa puberté survient objectivement au même âge que la majorité de ses pairs ? L'objectif de ce travail est de rechercher d'éventuelles corrélations entre TPS et adoption de comportements à risque chez des adolescentes rapportant un TPO dans la moyenne. Nos données proviennent de l'enquête SMASH 2002, une étude par questionnaire auto-administré conduite parmi un échantillon de 7548 adolescentes et adolescents suisses âgés de 16-20 ans. Des 3658 adolescentes de l'échantillon initial, nous ne sélectionnons que les 1003 d'entre elles qui ont répondu à la question sur le TPS et qui ont rapporté un âge à la ménarche de 13 ans, soit la moyenne et la médiane de l'âge à la ménarche rapporté par les 3658 adolescentes de l'échantillon initial. Ces 1003 adolescentes sélectionnées sont considérées comme ayant un TPO dans la moyenne. Ces 1003 adolescentes sont séparées en 3 groupes en fonction de leur TPS (précoce/correspondant à la moyenne/tardif). A l'aide d'analyses bivariées et logistiques, nous comparons ces 3 groupes en termes d'adoption de comportements à risque dans le champ de la sexualité (précocité des rapports sexuels) et dans celui de la consommation de substances (tabac, cannabis, drogues dures). Nos résultats montrent principalement qu'une perception de précocité pubertaire est associée avec une précocité des premiers rapports sexuels et de l'usage de drogues dures. A l'inverse, les adolescentes percevant leur puberté comme tardive rapportent moins fréquemment des rapports sexuels avant 16 ans que les adolescentes percevant leur puberté comme dans la moyenne. Les implications cliniques sont les suivantes : face à une adolescente percevant sa puberté comme étant ou ayant été précoce, le praticien devrait investiguer l'existence de comportements à risque même si la puberté survient ou est survenue à un âge similaire à ce qui est retrouvé chez la majorité des pairs. En effet, notre étude suggère que même si cette adolescente se trompe en percevant sa puberté comme précoce, la probabilité de comportements à risque est augmentée dans le champ de la sexualité et de la consommation de substances. Nos résultats suggèrent aussi que l'association retrouvée dans la littérature entre précocité objective de la puberté et comportements à risque chez les adolescentes n'est pas uniquement médiée par les changements corporels pubertaires mais qu'un facteur psychologique tel que la perception subjective est également impliqué.