Nestedness of habitat specialists within habitat generalists in a butterfly assemblage

The habitat requirements of a species are the resources, conditions and space required for survival and reproduction. The habitat requirements of butterflies have been well studied, but the extent to which individuals within a species and between species utilise and share the habitat is poorly known. In a butterfly assemblage in northern Italy, we found that adults from 30 species avoid deciduous high-density forests and their ecotones, and they were positively related to open areas and their ecotones. Besides these common features, five groups of species can be discriminated in relation to a gradient from open area to forest, and species within groups were not equally specialised, as observed from a bipartite network analysis. In particular, some species appeared to be specialised and others appeared to be generalist, suggesting a nested pattern of resource use, rather than a clustered pattern in which each species uses a different subset of habitat types. The degree of variation in specialisation among species varied with the number of species falling in each group. Thus, an increased number of species, and thus possibly competition, is more likely to promote the co-occurrence of generalist and specialised species (nested patterns) rather than an increased niche segregation among species. Ascertaining how species overlap their habitat use at a local scale can be relevant for conservation purposes, because specialised populations are potentially more susceptible to network distortions

Testing for the presence of coping styles in a wild mammal

Coping styles represent alternative response patterns in reaction to a stressor. The coping style model provides a set of predictions about correlations between behavioural and neurophysiological reactions to a stressful situation. According to this model, high levels of activity should be correlated with high levels of aggressiveness at the behavioural level, and to high sympathetic reactivity, low parasympathetic reactivity (higher heart rate levels) and low hypothalamus-pituitary-adrenocortical (HPA) axis reactivity (low production of glucocorticoids in response to a stressor). More recent versions of the model, however, are challenging this view and consider the possibility of independent axes of coping style and stress reactivity. The coping style model has mainly been tested on artificially selected or inbred lines in laboratory settings. Such a situation restricts its generalization to a larger number of species and there is a need for studies testing it in the wild under more natural situations. Here, we test the predictions of the coping style model in a wild alpine marmot, Marmota marmota, population. We show that several behavioural (i.e. exploration in an open field, impulsivity and docility) and neurophysiological traits (i.e. heart rate, breathing rate and cortisol production) assumed to represent individual differences in coping style were significantly repeatable over 2-3 years. Not all the correlations between traits predicted by the coping style model were found in marmots, which supports the more recent two-axes model. Furthermore, most correlations were observed at the between-individual level, and the within-individual correlations (i.e. phenotypic plasticity) were weaker. Overall, our results support the prediction of the coping style model, but highlight the fact that the association between traits found in artificial conditions may be weaker in a more natural setting. (C) 2013 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved

Interplay between plasma oxidative status, cortisol and coping styles in wild alpine marmots, <i>Marmota marmota</i>

Variation in how individuals cope behaviourally and physiologically with stressors is widespread and can have a significant impact on life-history traits and fitness. Individual coping styles are characterised by differential behavioural and adrenocortical reactivity to various challenges. As stress hormones can affect the production of reactive chemical species and the antioxidant status, individuals with different coping styles may differ also in oxidative status. Field studies on wild mammalian populations are few in number and none so far has simultaneously tested the relationship between coping style, adrenocortical reactivity and oxidative status in the same individuals. We measured individual variation in coping styles along a proactive-reactive continuum together with variation in baseline and stress-induced plasma oxidative damage, plasma non-enzymatic antioxidant capacity and cortisol in wild alpine marmots, &lt;i&gt;Marmota marmota&lt;/i&gt;. Confirmatory path analysis revealed that different coping styles are accompanied by different baseline and stress-induced plasma oxidative statuses. Our findings also highlight the potential role of cortisol as a mediator of such differences

Interplay between plasma oxidative status, cortisol and coping styles in wild alpine marmots, Marmota marmota

Variation in how individuals cope behaviourally and physiologically with stressors is widespread and can have a significant impact on life-history traits and fitness. Individual coping styles are characterised by differential behavioural and adrenocortical reactivity to various challenges. As stress hormones can affect the production of reactive chemical species and the antioxidant status, individuals with different coping styles may differ also in oxidative status. Field studies on wild mammalian populations are few in number and none so far has simultaneously tested the relationship between coping style, adrenocortical reactivity and oxidative status in the same individuals. We measured individual variation in coping styles along a proactive-reactive continuum together with variation in baseline and stress-induced plasma oxidative damage, plasma non-enzymatic antioxidant capacity and Cortisol in wild alpine marmots, Marmota marmota. Confirmatory path analysis revealed that different coping styles are accompanied by different baseline and stress-induced plasma oxidative statuses. Our findings also highlight the potential role of Cortisol as a mediator of such differences. © 2012. Published by The Company of Biologists Ltd

Extrinsic and intrinsic factors affecting the activity budget of alpine marmots (Marmota marmota)

Extrinsic and intrinsic factors may influence the activity budget of wild animals, resulting in a variation in the time spent in different activities among populations or individuals of the same species. In this study, we examined how extrinsic and intrinsic factors affect the behaviour of the alpine marmot (Marmota marmota), a hibernating social rodent inhabiting high-elevation prairies in the European Alps. We collected behavioural observations during scan sampling sessions on marked individuals at two study sites with different environmental characteristics. We used Bayesian hierarchical multinomial regression models to analyse the influence of both intrinsic (sex and age-dominance status) and extrinsic (environmental and climatic variables) factors on the above-ground activity budget. Marmots spent most of their time above ground foraging, and were more likely to forage when it was cloudy. Extrinsic factors such as the site, period of the season (June, July–August, and August–September), and time of the day were all related to the probability of engaging in vigilance behaviour, which reaches its peak in early morning and late afternoon and during July, the second period included in the study. Social behaviours, such as affiliative and agonistic behaviours, were associated mostly with sex and age-dominance status, and yearlings were the more affiliative individuals compared to other status. Overall, our results suggest that in alpine marmots, intrinsic factors mostly regulate agonistic and affiliative behaviours, while extrinsic factors, with the unexpected exception of temperature, affect the probabilities of engaging in all types of behavioural categories

Group‐level variation in co‐feeding tolerance between two sanctuary‐housed communities of chimpanzees ( Pan troglodytes

Social tolerance in group-living animals can be viewed as a counterweight against competitive interests necessary to obtain coexistence equilibrium and maintain group cohesion. As such, it forms an interesting phenomenon to study at the group level, but how can this be done most informatively? Here, we use three group-level co-feeding assays and social network analysis to study social tolerance in two groups of chimpanzees living under similar circumstances within a sanctuary to i) reassess whether social tolerance may be a group-specific parameter in chimpanzees and derive inferences about its long-term stability, and ii) compare the characteristics and resultant patterns between two established and one new assay. We show that the three assays expose the same (predicted) group-level differences in social tolerance as in the previous study eight years ago, thereby providing preliminary evidence for stability in group-specific levels of social tolerance in chimpanzees, despite changing group compositions. Furthermore, from an experimental point of view, we identify the new assay as more valid than the two established ones based on the consideration that resources may deplete at different rates across groups, which would consequently alter the need for tolerance differentially. We discuss implications for the study of social tolerance and highlight the importance of taking into account intraspecific variation in social animals

Social network and decision-making in primates: a report on Franco-Japanese research collaborations

International audienceSociality is suggested to evolve as a strategy foranimals to cope with challenges in their environment.Within a population, each individual can be seen as part ofa network of social interactions that vary in strength, typeand dynamics (Sueur et al. 2011a). The structure of thissocial network can strongly impact upon not only on thefitness of individuals and their decision-making, but also onthe ecology of populations and the evolution of a species.Our Franco-Japanese collaboration allowed us to studysocial networks in several species (Japanese macaques,chimpanzees, colobines, etc.) and on different topics (socialepidemiology, social evolution, information transmission).Individual attributes such as stress, rank or age canaffect how individuals take decisions and the structure ofthe social network. This heterogeneity is linked to theassortativity of individuals and to the efficiency of the flowwithin a network. It is important, therefore, that thisheterogeneity is integrated in the process or pattern understudy in order to provide a better resolution of investigationand, ultimately, a better understanding of behaviouralstrategies, social dynamics and social evolution. Howsocial information affects decision-making could beimportant to understand how social groups make collectivedecisions and how information may spread throughout thesocial group. In human beings, road-crossing behaviours inthe presence of other individuals is a good way to study theinfluence of social information on individual behaviour anddecision-making, for instance. Culture directly affectswhich information — personal vs social — individualsprefer to follow. Our collaboration contributed to theunderstanding of the relative influence of different factors,cultural and the presence of other individuals is a good way to study theinfluence of social information on individual behaviour anddecision-making, for instance. Culture directly affectswhich information — personal vs social — individualsprefer to follow. Our collaboration contributed to theunderstanding of the relative influence of different factors,cultural and ecological, on primate, including human,sociality