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Author Harcourt, J.L.; Ang, T.Z.; Sweetman, G.; Johnstone, R.A.; Manica, A. url  doi
openurl 
  Title Social feedback and the emergence of leaders and followers Type Journal Article
  Year (down) 2009 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 19 Issue 3 Pages 248-252  
  Keywords Analysis of Variance; Animals; Appetitive Behavior/physiology; *Feedback; Great Britain; *Leadership; Markov Chains; Models, Biological; Monte Carlo Method; Smegmamorpha/*physiology; *Social Behavior; Video Recording  
  Abstract In many animal groups, certain individuals consistently appear at the forefront of coordinated movements [1-4]. How such leaders emerge is poorly understood [5, 6]. Here, we show that in pairs of sticklebacks, Gasterosteus aculeatus, leadership arises from individual differences in the way that fish respond to their partner's movements. Having first established that individuals differed in their propensity to leave cover in order to look for food, we randomly paired fish of varying boldness, and we used a Markov Chain model to infer the individual rules underlying their joint behavior. Both fish in a pair responded to each other's movements-each was more likely to leave cover if the other was already out and to return if the other had already returned. However, we found that bolder individuals displayed greater initiative and were less responsive to their partners, whereas shyer individuals displayed less initiative but followed their partners more faithfully; they also, as followers, elicited greater leadership tendencies in their bold partners. We conclude that leadership in this case is reinforced by positive social feedback.  
  Address Department of Zoology, University of Cambridge, Cambridge, UK  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19185497 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5123  
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Author Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A. url  doi
openurl 
  Title The emergence of leaders and followers in foraging pairs when the qualities of individuals differ Type Journal Article
  Year (down) 2008 Publication BMC Evolutionary Biology Abbreviated Journal BMC Evol Biol  
  Volume 8 Issue Pages 51  
  Keywords Animals; *Feeding Behavior; *Food Chain; *Models, Biological; *Social Dominance  
  Abstract BACKGROUND: Foraging in groups offers animals a number of advantages, such as increasing their likelihood of finding food or detecting and avoiding predators. In order for a group to remain together, there has to be some degree of coordination of behaviour and movement between its members (which may in some cases be initiated by a decision-making leader, and in other cases may emerge as an underlying property of the group). For example, behavioural synchronisation is a phenomenon where animals within a group initiate and then continue to conduct identical behaviours, and has been characterised for a wide range of species. We examine how a pair of animals should behave using a state-dependent approach, and ask what conditions are likely to lead to behavioural synchronisation occurring, and whether one of the individuals is more likely to act as a leader. RESULTS: The model we describe considers how the energetic gain, metabolic requirements and predation risks faced by the individuals affect measures of their energetic state and behaviour (such as the degree of behavioural synchronisation seen within the pair, and the value to an individual of knowing the energetic state of its colleague). We explore how predictable changes in these measures are in response to changes in physiological requirements and predation risk. We also consider how these measures should change when the members of the pair are not identical in their metabolic requirements or their susceptibility to predation. We find that many of the changes seen in these measures are complex, especially when asymmetries exist between the members of the pair. CONCLUSION: Analyses are presented that demonstrate that, although these general patterns are robust, care needs to be taken when considering the effects of individual differences, as the relationship between individual differences and the resulting qualitative changes in behaviour may be complex. We discuss how these results are related to experimental observations, and how the model and its predictions could be extended.  
  Address Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. sean.rands@bristol.ac.uk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1471-2148 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18282297 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5126  
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Author Grosenick, L.; Clement, T.S.; Fernald, R.D. doi  openurl
  Title Fish can infer social rank by observation alone Type Journal Article
  Year (down) 2007 Publication Nature Abbreviated Journal Nature  
  Volume 445 Issue 7126 Pages 429-432  
  Keywords Aggression/physiology; Animals; Cognition/*physiology; Female; Fishes/*physiology; Learning/*physiology; Male; Models, Biological; *Social Dominance; Territoriality  
  Abstract Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, TI has since been reported in nonhuman primates, rats and birds. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units. Our findings show that fish use TI when trained on socially relevant stimuli, and that they can make such inferences by using indirect information alone. Further, these bystanders seem to have both spatial and featural representations related to rival abilities, which they can use to make correct inferences depending on what kind of information is available to them. Beyond extending TI to fish and experimentally demonstrating indirect TI learning in animals, these results indicate that a universal mechanism underlying TI is unlikely. Rather, animals probably use multiple domain-specific representations adapted to different social and ecological pressures that they encounter during the course of their natural lives.  
  Address Department of Biological Sciences, Stanford University, Stanford, California, 94305, USA. logang@stanford.edu  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17251980 Approved no  
  Call Number refbase @ user @ Serial 600  
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Author Rosa, P.A.J.; Azevedo, A.M.; Aires-Barros, M.R. doi  openurl
  Title Application of central composite design to the optimisation of aqueous two-phase extraction of human antibodies Type Journal Article
  Year (down) 2007 Publication Journal of Chromatography. A Abbreviated Journal J Chromatogr A  
  Volume 1141 Issue 1 Pages 50-60  
  Keywords Analysis of Variance; Animals; Antibodies/*chemistry/*isolation & purification; Buffers; Chemical Fractionation/*methods; Horses; Humans; Hydrophobicity; Isoelectric Point; Models, Biological; Molecular Weight; Myoglobin/chemistry/isolation & purification; Osmolar Concentration; Phase Transition; Polyethylene Glycols; Serum Albumin/chemistry/isolation & purification; Sodium Chloride  
  Abstract The partition of human antibodies in aqueous two-phase systems (ATPSs) of polyethylene glycol (PEG) and phosphate was systematically studied using first pure proteins systems and then an artificial mixture of proteins containing 1mg/ml human immunoglobulin G (IgG), 10mg/ml serum albumin and 2mg/ml myoglobin. Preliminary results obtained using pure proteins systems indicated that the PEG molecular weight and concentration, the pH value and the salts concentration had a pronounced effect on the partitioning behaviour of all proteins. For high ionic strengths and pH values higher than the isoelectric point (pI) of the contaminant proteins, IgG could be selectively recovered on the top phase. According to these results, a face centred composite design was performed in order to optimise the purification of IgG from the mixture of proteins. The optimal conditions for the isolation of IgG were observed for high concentrations of NaCl and low concentrations of both phase forming components. The best purification was achieved using an ATPS containing 8% (w/w) PEG 3350, 10% (w/w) phosphate pH 6 and 15% (w/w) NaCl. A recovery yield of 101+/-7%, a purity of 99+/-0% and a yield of native IgG of 97+/-4% were obtained. Back extraction studies of IgG to a new phosphate phase were performed and higher yields were obtained using 10% phosphate buffer at pH 6. The total extraction yield was 76% and the purity 100%.  
  Address IBB Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Tecnico, Av Rovisco Pais, 1049-001 Lisbon, Portugal  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-9673 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17196214 Approved no  
  Call Number Serial 1842  
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Author Wolf, M.; van Doorn, G.S.; Leimar, O.; Weissing, F.J. doi  openurl
  Title Life-history trade-offs favour the evolution of animal personalities Type Journal Article
  Year (down) 2007 Publication Nature Abbreviated Journal Nature  
  Volume 447 Issue 7144 Pages 581-584  
  Keywords Aggression/physiology/psychology; Animals; Behavior, Animal/*physiology; *Evolution; Exploratory Behavior/physiology; Models, Biological; Personality/*physiology; Predatory Behavior/physiology; Reproduction/physiology; Risk-Taking; Selection (Genetics)  
  Abstract In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities.  
  Address Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17538618 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4098  
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Author Bell, A.M. doi  openurl
  Title Evolutionary biology: animal personalities Type
  Year (down) 2007 Publication Nature Abbreviated Journal Nature  
  Volume 447 Issue 7144 Pages 539-540  
  Keywords Aggression/physiology/psychology; Animals; Behavior, Animal/*physiology; *Evolution; Humans; *Models, Biological; Personality/genetics/*physiology; Reproduction/genetics/physiology; Risk-Taking; Selection (Genetics)  
  Abstract  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17538607 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4099  
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Author Reimers, M.; Schwarzenberger, F.; Preuschoft, S. doi  openurl
  Title Rehabilitation of research chimpanzees: stress and coping after long-term isolation Type Journal Article
  Year (down) 2007 Publication Hormones and Behavior Abbreviated Journal Horm Behav  
  Volume 51 Issue 3 Pages 428-435  
  Keywords Adaptation, Psychological/*physiology; Animals; *Animals, Laboratory; Exploratory Behavior; Hydrocortisone/analysis/metabolism; Male; Models, Biological; *Pan troglodytes; Social Dominance; Social Environment; *Social Isolation/psychology; Stress/*rehabilitation/veterinary; Time  
  Abstract We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing.  
  Address Department of Natural Sciences, Institute of Biochemistry, University of Veterinary Medicine, Veterinarplatz 1, 1210 Vienna, Austria. reimers@wild-vet.at  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-506X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17292368 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4188  
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Author Flack, J.C.; Girvan, M.; de Waal, F.B.M.; Krakauer, D.C. doi  openurl
  Title Policing stabilizes construction of social niches in primates Type Journal Article
  Year (down) 2006 Publication Nature Abbreviated Journal Nature  
  Volume 439 Issue 7075 Pages 426-429  
  Keywords Animals; Conflict (Psychology); Female; Macaca nemestrina/*physiology/*psychology; Male; Models, Biological; *Social Behavior  
  Abstract All organisms interact with their environment, and in doing so shape it, modifying resource availability. Termed niche construction, this process has been studied primarily at the ecological level with an emphasis on the consequences of construction across generations. We focus on the behavioural process of construction within a single generation, identifying the role a robustness mechanism--conflict management--has in promoting interactions that build social resource networks or social niches. Using 'knockout' experiments on a large, captive group of pigtailed macaques (Macaca nemestrina), we show that a policing function, performed infrequently by a small subset of individuals, significantly contributes to maintaining stable resource networks in the face of chronic perturbations that arise through conflict. When policing is absent, social niches destabilize, with group members building smaller, less diverse, and less integrated grooming, play, proximity and contact-sitting networks. Instability is quantified in terms of reduced mean degree, increased clustering, reduced reach, and increased assortativity. Policing not only controls conflict, we find it significantly influences the structure of networks that constitute essential social resources in gregarious primate societies. The structure of such networks plays a critical role in infant survivorship, emergence and spread of cooperative behaviour, social learning and cultural traditions.  
  Address Santa Fe Institute, Santa Fe, New Mexico 87501, USA. jflack@santafe.edu  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16437106 Approved no  
  Call Number refbase @ user @ Serial 298  
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Author Scheffer, M.; van Nes, E.H. doi  openurl
  Title Self-organized similarity, the evolutionary emergence of groups of similar species Type Journal Article
  Year (down) 2006 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 103 Issue 16 Pages 6230-6235  
  Keywords Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological  
  Abstract Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes.  
  Address Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16585519 Approved no  
  Call Number refbase @ user @ Serial 510  
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Author Izar, P.; Ferreira, R.G.; Sato, T. doi  openurl
  Title Describing the organization of dominance relationships by dominance-directed tree method Type Journal Article
  Year (down) 2006 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 68 Issue 2 Pages 189-207  
  Keywords Animals; Cebus/physiology; *Models, Biological; *Social Dominance  
  Abstract Methods to describe dominance hierarchies are a key tool in primatology studies. Most current methods are appropriate for analyzing linear and near-linear hierarchies; however, more complex structures are common in primate groups. We propose a method termed “dominance-directed tree.” This method is based on graph theory and set theory to analyze dominance relationships in social groups. The method constructs a transitive matrix by imposing transitivity to the dominance matrix and produces a graphical representation of the dominance relationships, which allows an easy visualization of the hierarchical position of the individuals, or subsets of individuals. The method is also able to detect partial and complete hierarchies, and to describe situations in which hierarchical and nonhierarchical principles operate. To illustrate the method, we apply a dominance tree analysis to artificial data and empirical data from a group of Cebus apella.  
  Address Department of Experimental Psychology, University of Sao Paulo, Brazil. patrizar@usp.br  
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  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16429416 Approved no  
  Call Number refbase @ user @ Serial 723  
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