Wolf, M., van Doorn, G. S., Leimar, O., & Weissing, F. J. (2007). Life-history trade-offs favour the evolution of animal personalities. Nature, 447(7144), 581–584.
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.
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Bell, A. M. (2007). Evolutionary biology: animal personalities (Vol. 447).
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Berger, J. (1983). Induced abortion and social factors in wild horses. Nature, 303(5912), 59–61.
Abstract: Much evidence now suggests that the postnatal killing of young in primates and carnivores, and induced abortions in some rodents, are evolved traits exerting strong selective pressures on adult male and female behaviour. Among ungulates it is perplexing that either no species have developed convergent tactics or that these behaviours are not reported, especially as ungulates have social systems similar to those of members of the above groups. Only in captive horses (Equus caballus) has infant killing been reported. It has been estimated that 40,000 wild horses live in remote areas of the Great Basin Desert of North America (US Department of Interior (Bureau of Land Management), unpublished report), where they occur in harems (females and young) defended by males. Here I present evidence that, rather than killing infants directly, invading males induce abortions in females unprotected by their resident stallions and these females are then inseminated by the new males.
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Franks, N. R., & Richardson, T. (2006). Teaching in tandem-running ants. Nature, 439(7073), 153.
Abstract: The ant Temnothorax albipennis uses a technique known as tandem running to lead another ant from the nest to food--with signals between the two ants controlling both the speed and course of the run. Here we analyse the results of this communication and show that tandem running is an example of teaching, to our knowledge the first in a non-human animal, that involves bidirectional feedback between teacher and pupil. This behaviour indicates that it could be the value of information, rather than the constraint of brain size, that has influenced the evolution of teaching.
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Packer, C. (1977). Reciprocal altruism in Papio anubis. Nature, 265, 441–445.
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Nowak, M. A., & Sigmund, K. (1992). Tit for tat in heterogeneous populations. Nature, 355, 250–253.
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Maynard Smith, J., & Price, G. R. (1973). The Logic of Animal Conflict. Nature, 246, 15–18.
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Hamilton, W. D. (1970). Selfish and Spiteful Behaviour in an Evolutionary Model. Nature, 228, 1218–1220.
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Reeve, H. K. (1992). Queen activation of lazy workers in colonies of the eusocial naked mole-rat. Nature, 358, 147–149.
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Prather, J. F., Peters, S., Nowicki, S., & Mooney, R. (2008). Precise auditory-vocal mirroring in neurons for learned vocal communication. Nature, 451(7176), 305–310.
Abstract: Brain mechanisms for communication must establish a correspondence between sensory and motor codes used to represent
the signal. One idea is that this correspondence is established at the level of single neurons that are active when the
individual performs a particular gesture or observes a similar gesture performed by another individual. Although neurons
that display a precise auditory–vocal correspondence could facilitate vocal communication, they have yet to be identified.
Here we report that a certain class of neurons in the swamp sparrow forebrain displays a precise auditory–vocal
correspondence. We show that these neurons respond in a temporally precise fashion to auditory presentation of certain
note sequences in this songbird’s repertoire and to similar note sequences in other birds’ songs. These neurons display
nearly identical patterns of activity when the bird sings the same sequence, and disrupting auditory feedback does not alter
this singing-related activity, indicating it is motor in nature. Furthermore, these neurons innervate striatal structures
important for song learning, raising the possibility that singing-related activity in these cells is compared to auditory
feedback to guide vocal learning.
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