scholarly journals Discrete but variable structure of animal societies leads to the false perception of a social continuum

2016 ◽  
Vol 3 (5) ◽  
pp. 160147 ◽  
Author(s):  
Dustin R. Rubenstein ◽  
Carlos A. Botero ◽  
Eileen A. Lacey
Keyword(s):  
Social Structure ◽  
Variable Structure ◽  
Single Female ◽  
Reproductive Conflict ◽  
Reproductive Structures ◽  
Taxonomic Groups ◽  
Proportional Decrease ◽  
Range Of Values ◽  
Plural Breeding ◽  
Animal Societies

Animal societies are typically divided into those in which reproduction within a group is monopolized by a single female versus those in which it is shared among multiple females. It remains controversial, however, whether these two forms of social structure represent distinct evolutionary outcomes or endpoints along a continuum of reproductive options. To address this issue and to determine whether vertebrates and insects exhibit the same patterns of variation in social structure, we examined the demographic and reproductive structures of 293 species of wasps, ants, birds and mammals. Using phylogenetically informed comparative analyses, we found strong evidence indicating that not all reproductive arrangements within social groups are viable in nature and that in societies with multiple reproductives, selection favours instead taxon-specific patterns of decrease in the proportion of breeders as a function of group size. These outcomes suggest that the selective routes to sociality differ depending upon whether monopolization of reproduction by one individual is possible and that variation within and among taxonomic groups may lead to the false perception of a continuum of social structures. Thus, the occurrence of very large societies may require either complete reproductive monopolization (monogyny/singular breeding) or the maintenance of a taxon-specific range of values for the proportional decrease in the number of breeders within a group (polygyny/plural breeding), both of which may reduce reproductive conflict among females.

scholarly journals A long post-reproductive lifespan is a shared trait among genetically distinct killer whale populations

2021 ◽  
Author(s):  
Mia Nielsen ◽  
Samuel Ellis ◽  
Jared Towers ◽  
Thomas Doniol-Valcroze ◽  
Daniel Franks ◽  
...  
Keyword(s):  
Social Structure ◽  
Killer Whale ◽  
Demographic Data ◽  
Reproductive Period ◽  
Substantial Variation ◽  
Killer Whales ◽  
Reproductive Conflict ◽  
Demographic Patterns ◽  
General Prediction

The extended female post-reproductive lifespan found in humans and some toothed whales remains an evolutionary puzzle. Theory predicts demographic patterns resulting in increased female relatedness with age (kinship dynamics) can select for a prolonged post-reproductive lifespan due to the combined costs of inter-generational reproductive conflict and benefits of late-life helping. Here we test this prediction using >40 years of longitudinal demographic data from the sympatric yet genetically distinct killer whale ecotypes: resident and Bigg’s killer whales. The female relatedness with age is predicted to increase in both ecotypes, but with a less steep increase in Bigg’s due to their different social structure. Here, we show that there is a significant post-reproductive lifespan in both ecotypes with >30% of adult female years being lived as post-reproductive, supporting the general prediction that an increase in local relatedness with age predisposes the evolution of a post-reproductive lifespan. Differences in the magnitude of kinship dynamics however, did not influence the timing or duration of the post-reproductive lifespan with females in both ecotypes terminating reproduction before their mid-40s followed by an expected post-reproductive period of ~20 years. Our results highlight the important role of kinship dynamics in the evolution of a long post-reproductive lifespan in long-lived mammals, while further implying that the timing of menopause may be a robust trait that is persistent despite substantial variation in demographic patterns among population.

THEORY FROM CHAOS

Episteme ◽  
2013 ◽  
Vol 10 (4) ◽  
pp. 465-478 ◽  
Author(s):  
Michael Dickson
Keyword(s):  
Social Structure ◽  
Scientific Theory ◽  
Agent Based Model ◽  
Agent Based ◽  
The Face ◽  
New Evidence ◽  
Range Of Values

AbstractI explore an agent-based model of the development and dissemination of scientific theory that makes very little use of any pre-defined “social structure” (such as partnerships or collaborations). In these models, under a broad range of values of the parameters, widespread (but not universal) “agreement” about scientific theory emerges. Moreover, the residual disagreement turns out to be important to developing new theories in the face of new evidence.

scholarly journals Family feuds: social competition and sexual conflict in complex societies

2012 ◽  
Vol 367 (1600) ◽  
pp. 2304-2313 ◽  
Author(s):  
Dustin R. Rubenstein
Keyword(s):  
Sexual Conflict ◽  
Kin Selection ◽  
Social Groups ◽  
Sexual Partners ◽  
Complex Societies ◽  
Social Competition ◽  
Reproductive Conflict ◽  
Sexual Competition ◽  
Kin Structure ◽  
Animal Societies

Darwin was initially puzzled by the processes that led to ornamentation in males—what he termed sexual selection—and those that led to extreme cooperation and altruism in complex animal societies—what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities—particularly in females—and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females.

scholarly journals Resolving social conflict among females without overt aggression

2013 ◽  
Vol 368 (1631) ◽  
pp. 20130076 ◽  
Author(s):  
Michael A. Cant ◽  
Andrew J. Young
Keyword(s):  
Social Conflict ◽  
Conflicts Of Interest ◽  
Empirical Work ◽  
Overt Aggression ◽  
Reproductive Conflict ◽  
Biological Reality ◽  
Social Partners ◽  
Behavioural Conflict ◽  
Time Changes ◽  
Animal Societies

Members of animal societies compete over resources and reproduction, but the extent to which such conflicts of interest are resolved peacefully (without recourse to costly or wasteful acts of aggression) varies widely. Here, we describe two theoretical mechanisms that can help to understand variation in the incidence of overt behavioural conflict: (i) destruction competition and (ii) the use of threats. The two mechanisms make different assumptions about the degree to which competitors are socially sensitive (responsive to real-time changes in the behaviour of their social partners). In each case, we discuss how the model assumptions relate to biological reality and highlight the genetic, ecological and informational factors that are likely to promote peaceful conflict resolution, drawing on empirical examples. We suggest that, relative to males, reproductive conflict among females may be more frequently resolved peacefully through threats of punishment, rather than overt acts of punishment, because (i) offspring are more costly to produce for females and (ii) reproduction is more difficult to conceal. The main need now is for empirical work to test whether the mechanisms described here can indeed explain how social conflict can be resolved without overt aggression.

scholarly journals Reproductive conflict resolution in cooperative breeders

2019 ◽  
Vol 30 (6) ◽  
pp. 1743-1750
Author(s):  
Dominic L Cram ◽  
Arne Jungwirth ◽  
Helen Spence-Jones ◽  
Tim Clutton-Brock
Keyword(s):  
Conflict Resolution ◽  
Related Species ◽  
Theoretical Models ◽  
Female Group ◽  
Reproductive Conflict ◽  
General Hypothesis ◽  
Suricata Suricatta ◽  
Conflict Resolution Strategies ◽  
Animal Societies ◽  
Resolution Strategies

Abstract Female infanticide is common in animal societies where groups comprise multiple co-breeding females. To reduce the risk that their offspring are killed, mothers can synchronize breeding and pool offspring, making it hard for females to avoid killing their own young. However, female reproductive conflict does not invariably result in reproductive synchrony, and we lack a general hypothesis explaining the variation in conflict resolution strategies seen across species. Here, we investigate the fitness consequences of birth timing relative to other females and the prevalence of birth synchrony in cooperatively breeding Kalahari meerkats (Suricata suricatta). We show that, although there would be substantial benefits to females in synchronizing births and reducing their risk of infanticide, birth synchrony is rare. Since precise breeding synchrony has evolved in a related species with similar infanticidal female reproductive conflict, its absence in meerkats requires an evolutionary explanation. We therefore explore the costs and benefits of synchronizing breeding in two theoretical models, each of which contrasts synchrony with an alternative reproductive strategy: (i) breeding opportunistically and accepting fitness losses to infanticide or (ii) suppressing the reproduction of others to prevent infanticide. Our models show that the costs of synchrony constrain its development if subordinates breed infrequently, and that selection instead favors the suppression of subordinate reproduction by the dominant and opportunistic reproduction by subordinates. Together, our results suggest that the resolution of reproductive conflict in animal societies is shaped by differential breeding propensities among female group members, leading to divergent conflict resolution strategies even in closely related species.

On the Implementation of a Continuous Controller Via a Discrete Valued Controller

1992 ◽  
Vol 114 (3) ◽  
pp. 352-358 ◽  
Author(s):  
R. M. DeSantis
Keyword(s):  
Experimental Study ◽  
Systems Approach ◽  
Variable Structure ◽  
Feedback System ◽  
Operating Conditions ◽  
Theoretical Development ◽  
Variable Structure Systems ◽  
Range Of Values ◽  
Discrete Controller ◽  
Continuous Range

A procedure for implementing a continuous controller, the output of which may vary within a continuous range of values, by means of a discrete controller, of which the output may only be given a discrete set of values, is presented. The theoretical development is based on the variable structure systems approach and is complemented with an analytical and experimental study of a position servomechanism with an elastic transmission. Relevant properties of the ensuing feedback system are discussed under both nominal and perturbed operating conditions. Preliminary simulation and experimental results suggest the procedure to be reliable, easy to implement and practically feasible.

scholarly journals The trade-off between information and pathogen transmission in animal societies

2020 ◽  
Author(s):  
Valeria Romano ◽  
Cédric Sueur ◽  
Andrew J.J. MacIntosh
Keyword(s):  
Social Structure ◽  
Social Relationships ◽  
Feedback Loop ◽  
Social Contact ◽  
Pathogen Transmission ◽  
Evolutionary Mechanisms ◽  
Trade Off ◽  
Individual Fitness ◽  
Network Properties ◽  
Animal Societies

Social structure can regulate information and pathogen transmission via social contact or proximity, which ultimately affects individual fitness. In theory, the same network properties that favor social information transmission also favor the spread of socially-transmitted pathogens, creating a trade-off between them. The mechanisms underlying the development and stability of individual relationships considering this trade-off remain underexplored. Here, we outline the evolutionary mechanisms of social transmission and hypothesize that network topology can be optimized in a way that balances the costs and benefits of social relationships. In this context, emergent network properties might reflect a trade-off between information and pathogen transmission in animal societies. We then propose an implementation of Hinde’s classical framework by incorporating the costs of socializing in a negative feedback loop in the emergence of social structure. We hope this manuscript encourages research into this underxplored social trade-off and the evolutionary processes underlying it.

scholarly journals Differential female sociality is linked with the fine-scale structure of sexual interactions in replicate groups of red junglefowl, Gallus gallus

2019 ◽  
Vol 286 (1913) ◽  
pp. 20191734 ◽  
Author(s):  
Grant C. McDonald ◽  
Lewis G. Spurgin ◽  
Eleanor A. Fairfield ◽  
David S. Richardson ◽  
Tommaso Pizzari
Keyword(s):  
Sexual Selection ◽  
Social Structure ◽  
Gallus Gallus ◽  
Fine Scale ◽  
Core Group ◽  
Red Junglefowl ◽  
Emergent Structure ◽  
The Individual ◽  
Animal Societies ◽  
Social Behaviours

Recent work indicates that social structure has extensive implications for patterns of sexual selection and sexual conflict. However, little is known about the individual variation in social behaviours linking social structure to sexual interactions. Here, we use network analysis of replicate polygynandrous groups of red junglefowl ( Gallus gallus ) to show that the association between social structure and sexual interactions is underpinned by differential female sociality. Sexual dynamics are largely explained by a core group of highly social, younger females, which are more fecund and more polyandrous, and thus associated with more intense postcopulatory competition for males. By contrast, less fecund females from older cohorts, which tend to be socially dominant, avoid male sexual attention by clustering together and perching on branches, and preferentially reproduce with dominant males by more exclusively associating and mating with them. Collectively, these results indicate that individual females occupy subtly different social niches and demonstrate that female sociality can be an important factor underpinning the landscape of intrasexual competition and the emergent structure of animal societies.

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