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Edwards, P. J., & Hollis, S. (1982). The Distribution of Excreta on New Forest Grassland Used by Cattle, Ponies and Deer. J Appl Ecol, 19(3), 953–964.
Abstract: (1) The distribution of excreta on areas of reseeded grassland in the New Forest used by free-ranging cattle, ponies and fallow deer was shown to be non-random. Distinct latrine areas were recognized where the faeces of all three herbivore species were concentrated, and where the majority of urinations occurred. The mosaic of latrine and non-latrine areas can be detected in aerial photographs in which non-latrine areas appear as light-grey patches set in a matrix of the dark grey latrine areas. During the 3 years of the study the position of the mosaic proved to be relatively stable. (2) The latrine areas were characterized by an uneven sward about 50 mm tall with abundant thistles (Cirsium spp.) and ragwort (Senecio jacobaea). Non-latrine areas had an even and very closely cropped sward between 10 and 20 mm tall. Soil chemical analysis of the two kinds of area revealed significantly higher levels of exchangeable potassium in latrine areas, and on one site significantly higher levels of magnesium and organic matter. No significant differences were detected in soil reaction, nor in phosphorus or calcium levels. (3) Observations of grazing animals revealed a tendency, at all times of year, for ponies to avoid grazing in latrine areas. In winter and spring this tendency was very slight, but from midsummer until late autumn a substantial majority of grazing ponies were to be found in non-latrine areas. In contrast, only 2% of the cattle observations made over a period of 20 months were of animals grazing in non-latrine areas. (4) The standing crop of dung and the rate of dung production on the two kinds of area were monitored for 12 months on one lawn. The amount of pony dung produced on non-latrine areas was only 16.5% of that in latrine areas, while for cattle the corresponding value was 28.7%. It is argued that the observed pattern has been created by selective grazing and eliminatory behaviour of the ponies, and that the excreta of cattle and deer are largely confined to pony latrine areas because these animals are unable to graze the very short herbage of non-latrine areas.
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List, C. (2004). Democracy in animal groups: a political science perspective. Trends Ecol Evol, 19(4), 168–169.
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Smith, B. R., & Blumstein, D. T. (2008). Fitness consequences of personality: a meta-analysis. Behav. Ecol., 19(2), 448–455.
Abstract: The study of nonhuman personality capitalizes on the fact that individuals of many species behave in predictable, variable, and quantifiable ways. Although a few empirical studies have examined the ultimate consequences of personality differences, there has been no synthesis of results. We conducted a formal meta-analysis of published studies reporting fitness consequences of single personality dimensions to identify general trends across species. We found bolder individuals had increased reproductive success, particularly in males, but incurred a survival cost, thus, supporting the hypothesis that variation in boldness was maintained due to a “trade-off” in fitness consequences across contexts. Potential mechanisms maintaining variation in exploration and aggression are not as clear. Exploration had a positive effect only on survival, whereas aggression had a positive effect on both reproductive success and, not significantly, on survival. Such results would suggest that selection is driving populations to become more explorative and aggressive. However, limitations in meta-analytic techniques preclude us from testing for the effects of fluctuating environmental conditions or other forms of selection on these dimensions. Results do, however, provide evidence for general relationships between personality and fitness, and we provide a framework for future studies to follow in the hopes of spurring more in-depth, long-term research into the evolutionary mechanisms maintaining variation in personality dimensions and overall behavioral syndromes. We conclude with a discussion on how understanding and managing personality traits may play a key role in the captive breeding and recovery programs of endangered species.
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Dall, S. R. X., Giraldeau, L. - A., Olsson, O., McNamara, J. M., & Stephens, D. W. (2005). Information and its use by animals in evolutionary ecology. Trends Ecol Evol, 20(4), 187–193.
Abstract: Information is a crucial currency for animals from both a behavioural and evolutionary perspective. Adaptive behaviour relies upon accurate estimation of relevant ecological parameters; the better informed an individual, the better it can develop and adjust its behaviour to meet the demands of a variable world. Here, we focus on the burgeoning interest in the impact of ecological uncertainty on adaptation, and the means by which it can be reduced by gathering information, from both 'passive' and 'responsive' sources. Our overview demonstrates the value of adopting an explicitly informational approach, and highlights the components that one needs to develop useful approaches to studying information use by animals. We propose a quantitative framework, based on statistical decision theory, for analysing animal information use in evolutionary ecology. Our purpose is to promote an integrative approach to studying information use by animals, which is itself integral to adaptive animal behaviour and organismal biology.
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Baba, M., T., Doi, H., Ikeda, T., Iwamoto, & Ono Y. (1982). A census of large mammals in Omo National Park, Ethiopia. Afr. J. Ecol., 20(3), 207–210.
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Conradt, L., & Roper, T. J. (2005). Consensus decision making in animals. Trends Ecol Evol, 20(8), 449–456.
Abstract: Individual animals routinely face decisions that are crucial to their fitness. In social species, however, many of these decisions need to be made jointly with other group members because the group will split apart unless a consensus is reached. Here, we review empirical and theoretical studies of consensus decision making, and place them in a coherent framework. In particular, we classify consensus decisions according to the degree to which they involve conflict of interest between group members, and whether they involve either local or global communication; we ask, for different categories of consensus decision, who makes the decision, what are the underlying mechanisms, and what are the functional consequences. We conclude that consensus decision making is common in non-human animals, and that cooperation between group members in the decision-making process is likely to be the norm, even when the decision involves significant conflict of interest.
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Purvis, A. (2006). The h index: playing the numbers game. Trends. Ecol. Evol, 21(8), 422.
Abstract: Article Outline
References The ‘h index’ was developed recently as a measure of research performance [1]: a researcher's h is the number of his or her papers that have been cited at least h times. In their thoughtful critique of the index, Kelly and Jennions [2] point out many ways in which h is no better than ‘traditional’ bibliometrics, such as total citation counts. However, there is one way in which, for researchers, it could be very much better, especially if (as Hirsch suggests [1]) it is to inform hiring and promotion decisions. The skewed nature of the distribution of citations among publications means that most researchers have several papers that nearly but not quite count. Consequently, h can be distorted much more easily than can total citation count just by finding a subtle way to cite one's own papers that are ‘bubbling under’. Incidentally, bats show broadly the same life-history allometries as other mammalian clades [3]. |
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Lusseau, D. (2007). Evidence for social role in a dolphin social network. Evol. Ecol., 21(3), 357–366.
Abstract: Abstract Social animals have to take into consideration the behaviour of conspecifics when making decisions to go by their daily lives. These decisions affect their fitness and there is therefore an evolutionary pressure to try making the right choices. In many instances individuals will make their own choices and the behaviour of the group will be a democratic integration of everyone’s decision. However, in some instances it can be advantageous to follow the choice of a few individuals in the group if they have more information regarding the situation that has arisen. Here I provide early evidence that decisions about shifts in activity states in a population of bottlenose dolphin follow such a decision-making process. This unshared consensus is mediated by a non-vocal signal, which can be communicated globally within the dolphin school. These signals are emitted by individuals that tend to have more information about the behaviour of potential competitors because of their position in the social network. I hypothesise that this decision-making process emerged from the social structure of the population and the need to maintain mixed-sex schools.
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Shultz, S., & Finlayson, L. V. (2010). Large body and small brain and group sizes are associated with predator preferences for mammalian prey. Behav. Ecol., 21(5), 1073–1079.
Abstract: Predation is a major force in shaping biological communities, both over ecological and evolutionary timescales. In response to predation pressure, prey have evolved characteristics designed to mitigate predation pressure. We evaluated predator foraging biases in relation to prey characteristics across 16 vertebrate communities. We show that although predator biases vary, some prey traits are consistently associated with predator diet composition. Within their acceptable prey size range, predators show positive bias toward larger bodied prey, small-brained prey (controlling for body size), small group size, and terrestriality. Thus, whether predator foraging decisions are passive or active, predator choice exerts differential pressure on prey species according to prey characteristics. Predator biases also were positively associated with early age at maturity, supporting the role of mortality in driving life-history characteristics. These results support several theoretical models of predation including its role as a selective force driving evolutionary changes in life history, brain size and sociality, optimal diet theory, and antiapostatic predation.
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Smith, J. E., Van Horn, R. C., Powning, K. S., Cole, A. R., Graham, K. E., Memenis, S. K., et al. (2010). Evolutionary forces favoring intragroup coalitions among spotted hyenas and other animals. Behav. Ecol., 21(2), 284–303.
Abstract: Coalitionary support in agonistic interactions represents cooperation because intervening in a fight is potentially costly to the donor of support but benefits the recipient. Here, we first review the characteristics of, and evolutionary forces favoring, intragroup coalitions in 49 species and find that patterns of intragroup coalition formation are remarkably similar between primates and nonprimates. We then test hypotheses suggesting kin selection, reciprocal altruism, and direct benefits as adaptive explanations for coalitionary interventions among adult female spotted hyenas (Crocuta crocuta) belonging to a large social group in Kenya. As predicted by kin selection theory, females supported close kin most often, and the density (connectedness) of cooperation networks increased with genetic relatedness. Nevertheless, kinship failed to protect females from coalitionary attacks. We found no evidence of enduring alliances based on reciprocal support among unrelated adult females. Instead, donors generally minimized costs to themselves, intervening most often during low-intensity fights and when feeding opportunities were unavailable. Females also gained direct benefits from directing coalitionary attacks toward subordinates. Finally, females monitored the number of dominant bystanders in the “audience” at fights and modified their level of cooperation based on this knowledge. Overall, hyenas made flexible decisions regarding whether or not to intervene in fights, modifying their tendency to cooperate based on multiple types of information about their immediate social and ecological environments. Taken together, these findings indicate that the combined evolutionary forces of kin selection and direct benefits derived from reinforcing the status quo drive coalitionary interventions among adult female spotted hyenas.
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