Responses of king penguin Aptenodytes patagonicus adults and chicks to two food-related odours

Increasing evidence suggests that penguins are sensitive to dimethyl sulphide (DMS), a scented airborne compound that a variety of marine animals use to find productive areas of the ocean where prey is likely to be found. Here we present data showing that king penguins Aptenodytes patagonicus are also sensitive to DMS. We deployed DMS on a lake near a king penguin colony at Ratmanoff beach in the Kerguelen archipelago. We also presented DMS to ‘sleeping’ adults on the beach. On the lake, penguins responded to the DMS deployments by swimming more, while on the beach, penguins twitched their heads and woke up more for the DMS than for the control presentations. Interestingly, penguins did not respond to cod liver oil deployments on the lake; mirroring at-sea studies of other penguins. Although at-sea studies are needed to confirm that king penguins use DMS as a surface cue that informs them of productivity under the water, this study is an important first step in understanding how these birds locate prey over significant distances

Sommes-nous de bons juges de notre stress? Marqueurs subjectifs et physiologiques de stress chez de jeunes adultes se disant ‘zen’ versus très stressés

C’est au domaine de la psychoneuroendocrinologie, développé dans les années 60, que nous devons l’étude combinée des dimensions subjective et physiologique du stress au sein d’un même protocole. Étonnamment, bien qu’une soixantaine d’années de recherche se soient écoulées depuis, une question fondamentale reste sans réponse : « Sommes-nous de bons juges de notre stress ? » Or, un manque de considération pour le stress subjectif chronique serait possiblement au centre de cette problématique. Ainsi, ce projet de recherche a comparé des marqueurs psychologiques de stress, la réactivité au stress (subjective et physiologique) ainsi que la sécrétion diurne de cortisol (hormone de stress) d’individus chroniquement très stressés ou zen. Soixante adultes de 18 à 35 ans ont été recrutés par auto-catégorisation, c’est-à-dire que les participants se catégorisaient eux-mêmes dans l’un ou l’autre de nos deux groupes (individus très stressés versus zen), selon qu’ils répondaient à l’une ou l’autre de nos deux annonces de recrutement. La symptomatologie dépressive, l’anxiété de trait et le stress subjectif aigu ont été mesurés à l’aide de questionnaires. Des mesures cardiaques et de cortisol salivaire ont été collectés lors de l’exposition à un stresseur psychosocial, soit le Trier social stress test. Finalement, des échantillons salivaires ont été collectés à la maison pour mesurer le cortisol diurne. Les analyses montrent que le stress subjectif auto-catégorisé est un bon prédicteur des niveaux de détresse psychologique, mais pas de la réactivité au stress. En ce qui concerne le cortisol diurne, nous observons que les individus ‘zen’ possèdent une réponse de cortisol au réveil significativement plus faible que les ‘très stressés’. Nos résultats confirment d’autres études démontrant qu’il y a peu de corrélation entre les dimensions subjective et physiologique du stress et étendent ce domaine de recherche au stress chronique. Ces résultats soulignent aussi l’importance d’implanter des interventions spécifiques à la détresse psychologique dans tous les programmes éducatifs visant la réduction du stress.Until the early 1960s, the physiological and subjective dimensions of stress were studied independently. It is with the development of psychoneuroendocrine research domain that studies began to combine the two dimensions of stress within a single protocol. Surprisingly, even though 60 years have passed since the development of psychoneuroendocrinology, a fundamental question remains unanswered: "Are we good judges of our stress?” A lack of consideration in the literature for the chronic aspect of subjective stress may be central to this problem. Thus, the purpose of this thesis was to compare psychological markers of stress, stress reactivity and diurnal cortisol secretion in individuals feeling chronically 'very stressed out' or 'zen'. To do this, 60 adults aged between 18 and 35 were recruited with an auto-categorization method, i.e. participants were categorizing themselves into one of our two groups by answering to one of our two different ads seeking the recruitment of either 'very stressed out' or 'zen' individuals. Depressive symptomatology, trait anxiety and acute subjective stress were measured with questionnaires. Cardiac measures and salivary cortisol were collected while the participants were exposed to a psychosocial stressor, i.e. the Trier social stress test. Participants further had to collect saliva samples at home to measure diurnal cortisol (a stress hormone). The results show that auto-categorized subjective stress is a good predictor of levels of distress, but not of reactivity to a stressor. Nevertheless, the ‘zen’ individuals showed a significantly lower awakening cortisol response when compared to stressed out individuals. Our results confirm previous studies showing a lack of correlation between psychological and physiological markers of stress and extend these data to the domain of chronic stress. These results underline the importance of implementing specific interventions targeting the subjective dimension of stress in educational programs aiming to reduce stress

Uropygial gland size and composition varies according to experimentally modified microbiome in Great tits

International audienceBackground: Parasites exert important selective pressures on host life history traits. In birds, feathers are inhabited by numerous microorganisms, some of them being able to degrade feathers or lead to infections. Preening feathers with secretions of the uropygial gland has been found to act as an antimicrobial defence mechanism, expected to regulate feather microbial communities and thus limit feather abrasion and infections. Here, we used an experimental approach to test whether Great tits (Parus major) modify their investment in the uropygial gland in response to differences in environmental microorganisms.Results: We found that males, but not females, modified the size of their gland when exposed to higher bacterial densities on feathers. We also identified 16 wax esters in the uropygial gland secretions. The relative abundance of some of these esters changed in males and females, while the relative abundance of others changed only in females when exposed to greater bacterial loads on feathers.Conclusion: Birds live in a bacterial world composed of commensal and pathogenic microorganisms. This study provides the first experimental evidence for modifications of investment in the defensive trait that is the uropygial gland in response to environmental microorganisms in a wild bird

Behavioral and physiological responses to male handicap in chick-rearing black-legged kittiwakes

Parental investment entails a trade-off between the benefits of effort in current offspring and the costs to future reproduction. Long-lived species are predicted to be reluctant to increase parental effort to avoid affecting their survival. We tested this hypothesis in black-legged kittiwakes Rissa tridactyla by clipping flight feathers of experimental males at the beginning of the chick-rearing period. We analyzed the consequences of this handicap on feeding and attendance behavior, body condition, integument coloration, and circulating levels of corticosterone and prolactin in handicapped males and their mates in comparison to unmanipulated controls. Chicks in both groups were compared in terms of aggressive behavior, growth, and mortality. Handicapped males lost more mass, had less bright integuments, and attended the nest less often than controls. Nevertheless, they fed their chicks at the same rate and had similar corticosterone and prolactin levels. Compared with control females, females mated with handicapped males showed a lower provisioning rate and higher nest attendance in the first days after manipulation. Their lower feeding rate probably triggered the increased sibling aggression and mortality observed in experimental broods. Our findings suggest that experimental females adaptively adjusted their effort to their mate's perceived quality or that their provisioning was constrained by their higher nest attendance. Overall, our results suggest that kittiwake males can decrease their condition for the sake of their chicks, which seems to contradict the hypothesis that kittiwakes should be reluctant to increase parental effort to avoid affecting their surviva

Freedom from Violence: Tools for Working with Trauma, Mental Health and Substance Use: Resource Tool Kit

First paragraph: The aim of this tool kit is to actively engage readers in applying a feminist analysis to women's experiences of mental health, substance use and past and current experiences of violence. The tool kit contains a wide variety of voices that speak to these issues by drawing on a range of sources: the experience of providing services to women, theory, research, feminist activism and scholarship and, naturally, by the writers' own experiences of substance use, mental health problems and violence

Age-related differences in the cloacal microbiota of a wild bird species

Background: Gastrointestinal bacteria play a central role in the health of animals. The bacteria that individuals acquire as they age may therefore have profound consequences for their future fitness. However, changes in microbial community structure with host age remain poorly understood. We characterised the cloacal bacteria assemblages of chicks and adults in a natural population of black-legged kittiwakes (Rissa tridactyla), using molecular methods. Results: We show that the kittiwake cloaca hosts a diverse assemblage of bacteria. A greater number of total bacterial OTUs (operational taxonomic units) were identified in chicks than adults, and chicks appeared to host a greater number of OTUs that were only isolated from single individuals. In contrast, the number of bacteria identified per individual was higher in adults than chicks, while older chicks hosted more OTUs than younger chicks. Finally, chicks and adults shared only seven OTUs, resulting in pronounced differences in microbial assemblages. This result is surprising given that adults regurgitate food to chicks and share the same nesting environment. Conclusions: Our findings suggest that chick gastrointestinal tracts are colonised by many transient species and that bacterial assemblages gradually transition to a more stable adult state. Phenotypic differences between chicks and adults may lead to these strong differences in bacterial communities. These data provide the framework for future studies targeting the causes and consequences of variation in bacterial assemblages in wild birds

The investment into sperm depends on genetic compatibility between pair mates in a monogamous species

Sperm quality determines offspring fitness. However, investment into sperm being costly, it depends on the health or condition of males. According to the differential allocation hypothesis, males should decrease their investment into sperm when mated with a low-quality female. In this study, we show that, in the black-legged kittiwake, a monogamous seabird, sperm quality affects chick performance and that good-quality males produce a sperm of good quality. In addition, males mated with more genetically compatible females produce better quality sperm. This study suggests that the effects of sperm quality on offspring fitness may act as a natural selective pressure on males' differential allocation strategies