scholarly journals The legacy effects of keystone individuals on collective behaviour scale to how long they remain within a group

2015 ◽  
Vol 282 (1814) ◽  
pp. 20151766 ◽  
Author(s):  
Jonathan N. Pruitt ◽  
Noa Pinter-Wollman

The collective behaviour of social groups is often strongly influenced by one or few individuals, termed here ‘keystone individuals’. We examined whether the influence of keystone individuals on collective behaviour lingers after their departure and whether these lingering effects scale with their tenure in the group. In the social spider, Stegodyphus dumicola , colonies' boldest individuals wield a disproportionately large influence over colony behaviour. We experimentally manipulated keystones' tenure in laboratory-housed colonies and tracked their legacy effects on collective prey capture following their removal. We found that bolder keystones caused more aggressive collective foraging behaviour and catalysed greater inter-individual variation in boldness within their colonies. The longer keystones remained in a colony, the longer both of these effects lingered after their departure. Our data demonstrate that, long after their disappearance, keystones have large and lasting effects on social dynamics at both the individual and colony levels.

2014 ◽  
Vol 281 (1796) ◽  
pp. 20141424 ◽  
Author(s):  
Carl N. Keiser ◽  
Jonathan N. Pruitt

Describing the factors that shape collective behaviour is central to our understanding of animal societies. Countless studies have demonstrated an effect of group size in the emergence of collective behaviours, but comparatively few have accounted for the composition/diversity of behavioural phenotypes, which is often conflated with group size. Here, we simultaneously examine the effect of personality composition and group size on nest architecture and collective foraging aggressiveness in the social spider Stegodyphus dumicola . We created colonies of two different sizes (10 or 30 individuals) and four compositions of boldness (all bold, all shy, mixed bold and shy, or average individuals) in the field and then measured their collective behaviour. Larger colonies produced bigger capture webs, while colonies containing a higher proportion of bold individuals responded to and attacked prey more rapidly. The number of attackers during collective foraging was determined jointly by composition and size, although composition had an effect size more than twice that of colony size: our results suggest that colonies of just 10 bold spiders would attack prey with as many attackers as colonies of 110 ‘average’ spiders. Thus, personality composition is a more potent (albeit more cryptic) determinant of collective foraging in these societies.


2019 ◽  
Author(s):  
David N. Fisher ◽  
James L.L. Lichtenstein ◽  
Raul Costa-Pereira ◽  
Justin Yeager ◽  
Jonathan N. Pruitt

AbstractGroups of animals possess phenotypes such as collective behaviour, which may determine the fitness of group members. However, the stability and robustness to perturbations of collective phenotypes in natural conditions is not established. Furthermore, whether group phenotypes are transmitted from parent to offspring groups is required for understanding how selection on group phenotypes contributes to evolution, but parent-offspring resemblance at the group level is rarely estimated. We evaluated robustness to perturbation and parent-offspring resemblance of collective foraging aggressiveness in colonies of the social spider Anelosimus eximius. Among-colony differences in foraging aggressiveness were consistent over time but changed if the colony was perturbed through the removal of individuals, or via their removal and subsequent return. Offspring and parent colony behaviour were correlated, but only once the offspring colony had settled after being translocated. The parent-offspring resemblance was not driven by a shared elevation but could be due to other environmental factors. Laboratory collective behaviour was not correlated with behaviour in the field. Colony aggression seems sensitive to initial conditions and easily perturbed between behavioural states. Despite this sensitivity, offspring colonies have collective behaviour that resembles that of their parent colony, provided they are given enough time to settle into the environment.


2019 ◽  
Vol 30 (4) ◽  
pp. 938-947
Author(s):  
Bharat Parthasarathy ◽  
Hema Somanathan

Abstract Predators living in social groups often show consistent interindividual differences in prey capture behavior that may be linked to personality. Though personality predisposes individuals for certain behaviors, responses can also be influenced by context. Studies examining personality-dependent participation in prey capture have largely employed only one prey species, offering the predator no choice. In nature, predators encounter a range of prey species, therefore participation in or leading a prey capture event must also depend on prey attributes (e.g., size and risk). In the social spider Stegodyphus sarasinorum, collective prey capture is mediated by personality types as a consequence of which some individuals are consistently more likely to attack. Here, we examined if an individual’s consistency to attack persisted within and between the 2 prey species (honeybees and grasshoppers) and if the same individuals attacked first with both prey species. Our results showed that interindividual differences in attacking persisted within and between the 2 prey species. Spiders showed greater participation in attacking grasshoppers relative to bees. Identities of the first attackers were not the same for bees and grasshoppers. Spiders showed greater consistency over time in attacking bees relative to grasshoppers. Bees attracted fewer attackers than size-matched grasshoppers. These results suggest that greater task specialization may be necessary to successfully subdue bees. Spiders handled bees more cautiously, which is likely to explain the observed plasticity in attacking the 2 prey species. Thus, participation in prey capture in social spiders is influenced by the attributes of prey species.


2017 ◽  
Vol 4 (8) ◽  
pp. 170344 ◽  
Author(s):  
Thiago Mosqueiro ◽  
Chelsea Cook ◽  
Ramon Huerta ◽  
Jürgen Gadau ◽  
Brian Smith ◽  
...  

Variation in behaviour among group members often impacts collective outcomes. Individuals may vary both in the task that they perform and in the persistence with which they perform each task. Although both the distribution of individuals among tasks and differences among individuals in behavioural persistence can each impact collective behaviour, we do not know if and how they jointly affect collective outcomes. Here, we use a detailed computational model to examine the joint impact of colony-level distribution among tasks and behavioural persistence of individuals, specifically their fidelity to particular resource sites, on the collective trade-off between exploring for new resources and exploiting familiar ones. We developed an agent-based model of foraging honeybees, parametrized by data from five colonies, in which we simulated scouts, who search the environment for new resources, and individuals who are recruited by the scouts to the newly found resources, i.e. recruits. We varied the persistence of returning to a particular food source of both scouts and recruits and found that, for each value of persistence, there is a different optimal ratio of scouts to recruits that maximizes resource collection by the colony. Furthermore, changes to the persistence of scouts induced opposite effects from changes to the persistence of recruits on the collective foraging of the colony. The proportion of scouts that resulted in the most resources collected by the colony decreased as the persistence of recruits increased. However, this optimal proportion of scouts increased as the persistence of scouts increased. Thus, behavioural persistence and task participation can interact to impact a colony's collective behaviour in orthogonal directions. Our work provides new insights and generates new hypotheses into how variations in behaviour at both the individual and colony levels jointly impact the trade-off between exploring for new resources and exploiting familiar ones.


Author(s):  
Konstantin S. Sharov

The paper is concerned with a study of the changing content and style of non-canonical Christian religious preaching in the digital age. Special attention is paid to the analysis of modern rhetoric Christian preachers practice in their Internet channels, forums and blogs. It is shown that the content of the Internet sermon is largely determined by the Internet users themselves and the topics of their appeals. The fundamental characteristics of the content of the Internet sermon are: 1) focus on the individual, their private goals and objectives, not just on theological problems; 2) rethinking the phenomenon of the neighbour; 3) a shift from the Hesychast tradition of preaching the importance of inner spiritual concentration to the preaching of religious interactivity. The observed stylistic features of the digital preaching can be summarised as follows: 1) moving away from simple answers to the rhetoric of new questions addressed to the audience; 2) empathy, co-participation with a person in his/her life conflicts and experiences; 3) desire to share religious information, not to impose it; 4) resorting to various rhetorical techniques to reach different audiences; 5) a tendency to use slang, sometimes even irrespective of the audience’s language preferences and expectations. It should be pointed out that the Orthodox Internet sermon in the Russian Internet space has a dual and contradictory nature. On the one hand, this phenomenon can be regarded as positive for the Orthodox preaching in general, since it is a means of spreading Christian ideas in the social groups that do not constitute a core of parishioners of Orthodox churches, for example, schoolchildren, students, representatives of technical professions, etc. On the other hand, the effectiveness of such preaching is still unclear. Lack of reliable statistics as well as the results of the survey related to the Orthodox Internet preaching gives us no opportunity to judge about effectiveness or ineffectiveness of the phenomenon at this stage of its development.


1999 ◽  
Vol 9 (1) ◽  
pp. 127-155 ◽  
Author(s):  
Cristina Bicchieri ◽  
Yoshitaka Fukui

Norms of discrimination against women and blacks, norms of revenge still alive in some Mediterranean countries, and norms that everybody dislikes and tries to circumvent, such as the invisible norms of reciprocity that hold among the Iks studied by Turnbull, are all examples of unpopular and inefficient norms that often persist in spite of their being disliked as well as being obviously inefficient from a social or economic viewpoint. The world of business is not immune to this problem. In all those countries in which corruption is endemic, bribing public officials to get lucrative contracts is the norm, but it is often true that such a norm is disliked by many, and that it may lead to highly inefficient social outcomes (Bicchieri and Rovelli 1995).From a functionalist viewpoint such norms are anomalous, since they do not seem to fulfill any beneficial role for society at large or even for the social groups involved in sustaining the norm. In many cases it would be possible to gain in efficiency by eliminating, say, norms of racial discrimination, in that it would be possible to increase the well-being of a racial minority without harming the rest of society. To social scientists who equate persistence with efficiency, the permanence of inefficient norms thus presents an anomaly. They rest their case on two claims: when a norm is inefficient, sooner or later this fact will become evident. And evidence of inefficiency will induce quick changes in the individual choices that sustain the norm. That is, no opportunity for social improvement remains unexploited for long. Unfortunately, all too often this is not the case, and this is not because people mistakenly believe inefficient norms to be good or efficient.


Ethology ◽  
2007 ◽  
Vol 113 (9) ◽  
pp. 856-861 ◽  
Author(s):  
Andréa L.T. Souza ◽  
Marcelo O. Gonzaga ◽  
João Vasconcellos-Neto

Behaviour ◽  
2017 ◽  
Vol 154 (5) ◽  
pp. 563-581 ◽  
Author(s):  
Heidi C. Pearson

The prevalence of leaping across delphinids indicates it has an adaptive benefit. I examined leaping behaviour in dusky dolphins (Lagenorhynchus obscurus) according to signalling, social facilitation, and prey capture hypotheses. I quantified the effect of leaping on group behaviour and fission-fusion and the behavioural context of leaping. I observed dolphins in Admiralty Bay, New Zealand during 171 focal follows totalling 157 h. Data were analysed using generalized estimating equations. Clean leaping had a positive effect on party fission () and foraging behaviour (). Coordinated leaping caused a short-term wane in foraging behaviour () and had a positive effect on party fusion (). Noisy leaping had a negative effect on perpetuating resting and traveling cessation (both ). The signalling hypothesis was the most strongly supported. The social facilitation and prey capture hypotheses were moderately supported. Leaping may provide adaptive benefits such as reduced scramble competition, increased foraging efficiency, and social bonding.


2018 ◽  
Vol 21 (7) ◽  
pp. 38-43
Author(s):  
T. G. Yermakova

Education of students in today’s conditions requires new ideas and concepts that are related to the peculiarities of the socio-economic situation in society, namely: revaluation of values, changes in priorities of prestigious professions, contradictory attitude to education in the labor market, lack of a clear youth policy, adequate to modern conditions.Today’s education should become not just one of the subsystems of the social sphere, which satisfies a number of personal needs, but also a specific domain of social life, in which the future is modeled, resources of development are formed, and the negative effects of the functioning of other social institutions are compensated. As a result, the education system essentially extends its sphere of influence. One of the most important characteristics of student youth is its social needs, a large proportion of which is implemented in the field of education. Concerning higher education, certain requirements are put forward regarding the implementation of social needs of student youth; at the same time it is the institutional environment that mostly influences the formation of student social.Defining the development vectors of the education system requires the search for answers to questions relating to contemporary students, its social needs and expectations in relation to higher education, as well as the clarification of the conditions correspondence that education creates to realize its demands. The article highlights the peculiarities of student social needs in the field of education and their implementation; the content of such concepts as «needs», «social needs», «educational needs» were clarified.It was emphasized that social needs are connected with the inclusion of the individual in the family, in various social groups and communities, in the various spheres of production and non-production activities, in the life of society as a whole. These are the needs for work, social and economic activity, as well as spiritual culture, that is, everything that is a product of social life. They are needs of a special kind, the satisfaction of which is necessary to support the life of the social person, social groups and society as a whole.Social needs are met by the organizational efforts of society members through social institutions. Satisfying needs ensures social stability and social progress, dissatisfaction generates social conflicts. Social institutions are the leading components of the social structure of society, which integrate and coordinate the actions of society members, social groups and regulate social relations in various spheres of public life. Four groups of social needs were defined:- Vital for the social person needs, whose dissatisfaction leads to the elimination of a social person or the revolutionary transformation of social institutions, within which this satisfaction occurs;- Needs, the satisfaction of which ensures the functioning of the social person at the level of social norms, as well as allows the evolution of social institutions to be realized;- Needs, the satisfaction of which occurs at the level of minimum social norms, which ensures the preservation of the social person, but not its development; - Needs, the satisfaction of which provides comfortable (for data of socio-cultural area and social time) conditions of operation and development.The article gives attention to the relation between the concepts of «social needs» and «educational needs» and shows where they overlap. The existence of educational needs is an essential feature of students. Educational need is a need arising from the contradiction between the existing and necessary (desired) level of education and encourages the person to eliminate this contradiction.Educational needs were defined as the needs for the formation of the education means of those personal qualities that contribute to personal self-realization and the formation of personal qualities in the field of education that will enable them to obtain the desired social benefits and improve the social well-being of the individual. Such qualities are: high level of intellectual development; theoretical knowledge and practical skills necessary for professional activity; communicative skills and a high level of culture; personal qualities (integrity, workability, creativity, etc.). Education itself is a factor that allows the formation and accumulation of socially significant qualities in an individual’s arsenal that enable them to receive the benefits, satisfy the urgent needs and be realized as an active and active-oriented member of society.It was emphasized that in today’s conditions, students according to their characteristics are quite different from all other sections of the population, first of all ideological formation, influence mobility and their kinds of needs, which to a great extent determine its social well-being.Social needs of students are considered in connection with the functions of education, primarily with the functions of intelligence reproduction of society, vocational, economic and social. The article used data from nationwide surveys of students «Higher Education in Ukraine: Students’ Public Opinion» and «Higher Education in Reform Conditions: Changes in Public Opinion» conducted by Ilko Kucheriv Democratic Initiatives Foundation in 2015 and 2017 respectively; the data of a sociological survey «Values of Ukrainian Youth», conducted in 2016 by the Center for Independent Sociological Research «OMEGA», by request of Ministry of Youth and Sport of Ukraine.Based on the data of sociological research, we concluded that the level of social needs satisfaction of students in the field of higher education is not high. We need more detailed analysis of students who are studying at various educational institutions, as well as to identify the trends that are characteristic for education sections in different areas of study.


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