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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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Hildenbrandt, H., Carere, C., & Hemelrijk, C. K. (2010). Self-organized aerial displays of thousands of starlings: a model. Behav. Ecol., 21(6), 1349–1359.
Abstract: Through combining theoretical models and empirical data, complexity science has increased our understanding of social behavior of animals, in particular of social insects, primates, and fish. What are missing are studies of collective behavior of huge swarms of birds. Recently detailed empirical data have been collected of the swarming maneuvers of large flocks of thousands of starlings (Sturnus vulgaris) at their communal sleeping site (roost). Their flocking maneuvers are of dazzling complexity in their changes in density and flock shape, but the processes underlying them are still a mystery. Recent models show that flocking may arise by self-organization from rules of co-ordination with nearby neighbors, but patterns in these models come nowhere near the complexity of those of the real starlings. The question of this paper, therefore, is whether such complex patterns can emerge by self-organization. In our computer model, called StarDisplay, we combine the usual rules of co-ordination based on separation, attraction, and alignment with specifics of starling behavior: 1) simplified aerodynamics of flight, especially rolling during turning, 2) movement above a “roosting area” (sleeping site), and 3) the low fixed number of interaction neighbors (i.e., the topological range). Our model generates patterns that resemble remarkably not only qualitative but also quantitative empirical data collected in Rome through video recordings and position measurements by stereo photography. Our results provide new insights into the mechanisms underlying complex flocking maneuvers of starlings and other birds.
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Bruns, A., Waltert, M., & Khorozyan, I. (2020). The effectiveness of livestock protection measures against wolves (Canis lupus) and implications for their co-existence with humans. Global Ecology and Conservation, 21, e00868.
Abstract: Wolves (Canis lupus) can kill domestic livestock resulting in intense conflicts with humans. Damage to livestock should be reduced to facilitate human-wolf coexistence and ensure positive outcomes of conservation efforts. Current knowledge on the effectiveness of livestock protection measures from wolves is limited and scattered in the literature. In this study, we compiled a dataset of 30 cases describing the application of 11 measures of protecting cattle and smaller livestock against wolves, estimated their effectiveness as a relative risk of damage, and identified the best measures for damage reduction. We found that: (1) lethal control and translocation were less effective than other measures, (2) deterrents, especially fladry which is a fence with ropes marked by hanging colored flags that sway in the wind and provide a visual warning signal, were more effective than guarding dogs; (3) deterrents, fencing, calving control and herding were very effective, but the last two measures included only one case each; and (4) protection of cattle was more effective than that of small stock (sheep and goats, or sheep only) and mixed cattle and small stock. In all of these cases, the relative risk of damage was reduced by 50-100%. Considering Germany as an example of a country with a recovering wolf population and escalating human-wolf conflicts, we suggest electric fences and electrified fladry as the most promising measures, which under suitable conditions can be accompanied by well-trained livestock guarding dogs, and the temporary use of deterrents during critical periods such as calving and lambing seasons. Further research in this field is of paramount importance to efficiently mitigate human-wolf conflicts.
Keywords: Carnivore; Depredation; Efficiency; Germany; Intervention; Predator
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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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Sih, A., Bell, A., & Johnson, J. C. (2004). Behavioral syndromes: an ecological and evolutionary overview. Trends. Ecol. Evol, 19(7), 372–378.
Abstract: Recent studies suggest that populations and species often exhibit behavioral syndromes; that is, suites of correlated behaviors across situations. An example is an aggression syndrome where some individuals are more aggressive, whereas others are less aggressive across a range of situations and contexts. The existence of behavioral syndromes focuses the attention of behavioral ecologists on limited (less than optimal) behavioral plasticity and behavioral carryovers across situations, rather than on optimal plasticity in each isolated situation. Behavioral syndromes can explain behaviors that appear strikingly non-adaptive in an isolated context (e.g. inappropriately high activity when predators are present, or excessive sexual cannibalism). Behavioral syndromes can also help to explain the maintenance of individual variation in behavioral types, a phenomenon that is ubiquitous, but often ignored. Recent studies suggest that the behavioral type of an individual, population or species can have important ecological and evolutionary implications, including major effects on species distributions, on the relative tendencies of species to be invasive or to respond well to environmental change, and on speciation rates. Although most studies of behavioral syndromes to date have focused on a few organisms, mainly in the laboratory, further work on other species, particularly in the field, should yield numerous new insights.
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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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