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Judge, P. G., & De Waa, l F. B. M. (1997). Rhesus monkey behaviour under diverse population densities: coping with long-term crowding. Anim. Behav., 54(3), 643–662.
Abstract: A popular view is that high population density promotes behavioural pathology, particularly increased aggression. In contrast, according to a coping model, some primates have behavioural mechanisms (e.g. formal displays, reconciliation and grooming) that regulate social tensions and control the negative consequences of crowding. Seven captive rhesus monkey groups, Macaca mulattawere observed over a wide range of population densities where high-density groups were over 2000 times more crowded than low-density free-ranging groups. As density increased, male rhesus monkeys increased grooming and huddling but did not increase rates of aggression. Females increased all categories of behaviour examined (heavy aggression, mild aggression, formal bared-teeth displays, grooming and huddling), but the increases were not distributed uniformly to all classes of partners. Females increased only grooming, huddling and appeasement displays to males, increased only aggression and huddling with kin and increased all categories of behaviour to non-kin adult females. There were no differences in the percentage of aggressive conflicts reconciled across density conditions. Increased density had different effects on particular relationships. Relationships between females and males were characterized by a coping pattern in which animals modified their behaviour in ways that may decrease aggression under crowded conditions. Female relationships with kin and non-kin were characterized by increases in both aggression and friendly interactions as density increased. The different patterns of response to higher density may reflect different strategies depending on the strength and stability of relationships and the potential consequences if certain relationships are disrupted.1997The Association for the Study of Animal Behaviour
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Judge, P. G., & Mullen, S. H. (2005). Quadratic postconflict affiliation among bystanders in a hamadryas baboon group. Anim. Behav., 69(6), 1345–1355.
Abstract: The tendency in primate groups for two opponents to affiliate shortly after a fight has been described as dyadic reconciliation. The response has been shown to restore disrupted relationships and curtail ongoing aggression. Rates of self-directed behaviour (e.g. scratching) are positively correlated with anxiety in primates and the rates decline after reconciliation, indicating that the response also functions to reduce postconflict tension. Third parties not involved in an aggressive interaction are also likely to affiliate with one of the combatants subsequent to a fight. Such `triadic' interactions may also promote conflict resolution when, for instance, the relatives of a victim affiliate with their relative's aggressor. Because aggression in a group influences a bystander's behaviour with combatants, we hypothesized that aggression between two animals would also influence a bystander's behaviour with other bystanders. Such `quadratic' postconflict interactions might also function to reduce postconflict tension or occur in patterns among kin subgroups to resolve conflict. We tested for quadratic interactions in an 18-member group of captive hamadryas baboons, Papio hamadryas hamadryas. Immediately following a fight, an uninvolved bystander was randomly selected for observation and its affiliative interactions with other bystanders and its displacement activities were recorded for 3 min. Rates of behaviour during these postconflict periods were compared to rates during 3-min baseline periods not preceded by aggression. Bystanders engaged in quadratic interactions by increasing affiliation with other bystanders following aggression. Bystanders directed affiliation to nonkin bystanders that were their preferred social partners. Displacement activities of bystanders were significantly higher during postconflict intervals compared to baseline intervals, and bystander displacement activity levels before affiliative contact with other bystanders were significantly higher than after contact. Apparently, bystanders become tense or anxious after witnessing aggression and affiliate with preferred partners to reduce the arousal.
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Wittemyer, G., & Getz, W. M. (2007). Hierarchical dominance structure and social organization in African elephants, Loxodonta africana. Anim. Behav., 73(4), 671–681.
Abstract: According to the socioecological framework, transitivity (or linearity) in dominance relationships is related to competition over critical resources. When a population is structured into groups, the intensity of between- versus within-group competition influences the form and function of its social organization. Few studies have compared the type and relative intensity of competition at these two levels. African elephants have well-structured social relations, providing an exemplary system for such a study. We report on dominance hierarchies among free-ranging elephants and evaluate the factors that drive their socioecological structure to lie in a region of the three-dimensional nepotism/despotism/tolerance space rarely observed among social species; namely, where non-nepotistic, transitive dominance hierarchies within groups emerge despite kin-based philopatry and infrequent agonistic interactions over widely distributed resources. We found significant transitivity in dominance hierarchies between groups. Dominance relations among the matriarchs of different social groups were primarily age based, rather than driven by physical or group size, and group matriarch rank influenced the dominance relationships among nonmatriarchal females in the population. Our results suggest that between-group dominance relationships induce tolerance among group members, which in combination with high group relatedness, reduces the benefits of nepotism. We postulate that cognitive abilities and high risk of injury in contests enhance winner and loser effects, facilitating the formation of transitive dominance relationships, despite widely distributed resources over which infrequent competition occurs. The interplay of cognitive abilities, winner and loser effects, resource distribution, and within- and between-group dominance relationships may produce behaviour in other strongly social mammals that differs from that predicted by a superficial application of current socioecological models.
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de Vries, H., Stevens, J. M. G., & Vervaecke, H. (2006). Measuring and testing the steepness of dominance hierarchies. Anim. Behav., 71(3), 585–592.
Abstract: In the analysis of social dominance in groups of animals, linearity has been used by many researchers as the main structural characteristic of a dominance hierarchy. In this paper we propose, alongside linearity, a quantitative measure for another property of a dominance hierarchy, namely its steepness. Steepness of a hierarchy is defined here as the absolute slope of the straight line fitted to the normalized David's scores (calculated on the basis of a dyadic dominance index corrected for chance) plotted against the subjects' ranks. This correction for chance is an improvement of an earlier proposal by de Vries (appendix 2 in de Vries, Animal Behaviour, 1998, 55, 827-843). In addition, we present a randomization procedure for determining the statistical significance of a hierarchy's steepness, which can be used to test the observed steepness against the steepness expected under the null hypothesis of random win chances for all pairs of individuals. Whereas linearity depends on the number of established binary dominance relationships and the degree of transitivity in these relationships, steepness measures the degree to which individuals differ from each other in winning dominance encounters. Linearity and steepness are complementary measures to characterize a dominance hierarchy.
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Lafleur, D. L., Lozano, G. A., & Sclafani, M. (1997). Female mate-choice copying in guppies,Poecilia reticulata: a re-evaluation. Anim. Behav., 54(3), 579–586.
Abstract: It has been argued that intraspecific mate-choice copying can be adaptive under certain conditions. Dugatkin's (1992,Am. Nat.139, 1384-1389) work with guppies,Poecilia reticulataremains the most influential experimental demonstration of this phenomenon. We replicated Dugatkin's work using several choice criteria to ensure that our results were not dependent upon any single method of judging mate choice. We also tested our findings against two null hypotheses of differing stringency. Irrespective of the choice criteria or null hypothesis used, we did not observe any relationship between female mate choice and copying. We conclude that further experimental evidence of female mate-choice copying is required before the existence of this behaviour can be affirmed.
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Godin, J. - G. J., Herdman, E. J. E., & Dugatkin, L. A. (2005). Social influences on female mate choice in the guppy, Poecilia reticulata: generalized and repeatable trait-copying behaviour. Anim. Behav., 69(4), 999–1005.
Abstract: In vertebrates, the mating preferences of individual females can be flexible and the probability of a female mating with a particular male can be significantly increased by her having previously observed another conspecific female affiliate and mate with that same male. In theory, such mate-choice-copying behaviour has potentially important consequences for both the genetic and social (`cultural') transmission of female mating preferences. For copying to result in the `cultural inheritance' of mating preferences, individual females must not only copy the mate choice decisions of other females but they also should tend to repeat this type of behaviour (i.e. make similar mating decisions) subsequently and to generalize their socially induced preference for a particular male to other males that share his distinctive characteristics. Here, we show experimentally that individual female guppies, Poecilia reticulata, not only copy the observed mating preferences of other females for particular males, but that the preference now assumed via copying is subsequently repeated and generalized to other males of a similar colour phenotype. These results provide empirical evidence for social enhancement of female preference for particular phenotypic traits of chosen males rather than for the particular males possessing those traits, and thus have important implications for our understanding of the role of social learning in the evolution of female mating preferences and of male epigamic traits.
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Godin, J. - G. J., & Dugatkin, L. A. (1995). Variability and repeatability of female mating preference in the guppy. Anim. Behav., 49(6), 1427–1433.
Abstract: Models of inter-sexual selection generally assume heritable variation in mating preferences among females within populations. However, little is known about the nature of such variation. The aim of this study was to characterize quantitatively the phenotypic variation in female preference for a sexually selected male trait, body colour pattern, within a population of the Trinidadian guppy, Poecilia reticulata. Significantly more female guppies preferred the more brightly coloured of two similar-sized males presented simultaneously as potential mates. Mating preference scores for individual females were significantly and positively correlated between two repeated trials on successive days. Females were thus individually consistent in their particular choice of mates, and the calculated repeatability of their mating preference was relatively high. Notwithstanding the aforementioned, significant variation existed among females in the degree of their preference for brightly coloured males. Individual mating preference scores were not normally distributed, but were rather skewed to the right (i.e. towards greater values). These results suggest that additive genetic variation for mating preferences based on male colour pattern is maintained, and the opportunity for the further evolution of both bright male colour patterns and female preference for this trait appears to exist in the study population from the Quare River, Trinidad.
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McLeod, P. G., & Huntingford, F. A. (1994). Social rank and predator inspection in sticklebacks. Anim. Behav., 47(5), 1238–1240.
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Galef, B. G. (1996). The adaptive value of social learning: a reply to Laland. Anim. Behav., 52(3), 641–644.
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Griffin, A. S., & Galef, J., Bennett G. (2005). Social learning about predators: does timing matter? Anim. Behav., 69(3), 669–678.
Abstract: In Pavlovian conditioning, animals acquire a response to a previously neutral stimulus (conditioned stimulus, CS), such as a light, if that stimulus predicts a biologically important event (unconditioned stimulus, US), such as delivery of food. Learning typically occurs when the CS precedes the US (forward conditioning), and not when the CS follows the US (backward conditioning). In social learning about predators, the predator stimulus is considered to be the CS to which observers acquire avoidance responses after the stimulus has been presented in contiguity with an alarmed demonstrator, the US. We tested the prediction that social learning of response to a predator would occur even if the social alarm cues (the US) appeared before the predatory stimulus (the CS). Carib grackles, Quiscalus lugubris, responded to a familiar predator presented at close range by suppressing alarm calls. Presentation of an unfamiliar avian model (black-and-yellow pigeon) also decreased calling, and this inhibition of calling was enhanced following a training session in which the model stimulus was presented in association with grackle alarm calls. Acquired inhibition of calling was independent of the order of presentation of the model and an alarm chorus. These are the first results to indicate that social acquisition of predator avoidance is not dependent upon a particular temporal relationship between predators and social alarm cues. Evolution may have modified some properties of Pavlovian conditioning to accommodate social learning about potentially dangerous stimuli.
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