scholarly journals Reproductive competition triggers mass eviction in cooperative banded mongooses

2016 ◽  
Vol 283 (1826) ◽  
pp. 20152607 ◽  
Author(s):  
Faye J. Thompson ◽  
Harry H. Marshall ◽  
Jennifer L. Sanderson ◽  
Emma I. K. Vitikainen ◽  
Hazel J. Nichols ◽  
...  
Keyword(s):  
Population Structure ◽  
Social Evolution ◽  
Important Determinant ◽  
Adaptive Strategy ◽  
Reproductive Competition ◽  
Structured Population ◽  
Competition Hypothesis ◽  
Cooperatively Breeding ◽  
Group Members ◽  
Species Groups

In many vertebrate societies, forced eviction of group members is an important determinant of population structure, but little is known about what triggers eviction. Three main explanations are: (i) the reproductive competition hypothesis, (ii) the coercion of cooperation hypothesis, and (iii) the adaptive forced dispersal hypothesis. The last hypothesis proposes that dominant individuals use eviction as an adaptive strategy to propagate copies of their alleles through a highly structured population. We tested these hypotheses as explanations for eviction in cooperatively breeding banded mongooses ( Mungos mungo ), using a 16-year dataset on life history, behaviour and relatedness. In this species, groups of females, or mixed-sex groups, are periodically evicted en masse . Our evidence suggests that reproductive competition is the main ultimate trigger for eviction for both sexes. We find little evidence that mass eviction is used to coerce helping, or as a mechanism to force dispersal of relatives into the population. Eviction of females changes the landscape of reproductive competition for remaining males, which may explain why males are evicted alongside females. Our results show that the consequences of resolving within-group conflict resonate through groups and populations to affect population structure, with important implications for social evolution.

scholarly journals Occurrence and Evolution of Cooperative Breeding Among the Diurnal Raptors (Accipitridae and Falconidae)

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 717-729
Author(s):  
Rebecca T. Kimball ◽  
Patricia G. Parker ◽  
James C. Bednarz
Keyword(s):  
Cooperative Breeding ◽  
Group Living ◽  
Adult Males ◽  
Delayed Dispersal ◽  
Nest Sites ◽  
Cooperatively Breeding ◽  
Group Members ◽  
Species Groups ◽  
Related Individuals ◽  
Single Nest

Abstract Cooperative breeding, in which more than two individuals live in a group and raise offspring, usually in a single nest, is found in only 3% of avian species. On the basis of a review of the literature, we found reports of groups (usually trios) at nest sites in 42 species of diurnal raptors. At least one example of cooperative breeding was found in 29% of genera and 14% of species, distributed in both Accipitridae and Falconidae. Given the difficulty of obtaining behavioral observations necessary to detect cooperative breeding in most raptor species, combined with the large number of species that have been poorly studied, cooperative breeding in diurnal raptors may be more common than our data indicate. However, when data on the sex of the extra bird(s) or relationships among group members were available, patterns were quite varied. For 7 of 13 species, groups primarily contained multiple adult males, though three of those species also had groups formed from offspring that had delayed dispersal; three species had a low, but regular, occurrence of multiple females (females of groups laid eggs in the same nest); and the remaining three species were characterized by having extra birds that were yearlings or subadults. In over half of species, groups did not appear to be composed of related individuals, contrary to many cooperatively breeding passerine species where groups are primarily composed of offspring that have delayed dispersal. Our review suggests that the evolution of group living in many raptors may be independent of delayed dispersal, and that the factors important in explaining the evolution of that behavior depend upon the benefits of group living.

scholarly journals Proactive prosociality in a cooperatively breeding corvid, the azure-winged magpie ( Cyanopica cyana )

2016 ◽  
Vol 12 (10) ◽  
pp. 20160649 ◽  
Author(s):  
Lisa Horn ◽  
Clara Scheer ◽  
Thomas Bugnyar ◽  
Jorg J. M. Massen
Keyword(s):  
Cooperative Breeding ◽  
Cooperatively Breeding ◽  
Group Members ◽  
Over Time

One of the contemporary hypotheses concerning the evolution of human altruism is the cooperative breeding hypothesis (CBH) which has recently been tested in non-human primates. Using a similar paradigm, we investigated prosociality in a cooperatively breeding corvid, the azure-winged magpie. We found that the magpies delivered food to their group members at high rates, and unlike other corvids, they did so without any cues provided by others. In two control conditions, the magpies stopped participating over time, indicating that they learned to discriminate prosocial tests from controls. Azure-winged magpies are thus the first birds that experimentally show proactive prosociality. Our findings are in line with the CBH; however, additional corvid species need to be tested in this promising paradigm.

Dream-Sharing and Human Self-Domestication

2021 ◽  
Author(s):  
Mark Blagrove ◽  
Julia Lockheart
Keyword(s):  
Emotional Reactivity ◽  
Social Evolution ◽  
Cultural Practices ◽  
Neural Mechanisms ◽  
The Social ◽  
Primary Driver ◽  
Group Members ◽  
Human Social Evolution ◽  
Dream Sharing ◽  
Experimental Findings

There are many theories of the function of dreams, such as memory consolidation, emotion processing, threat simulation and social simulation. In general, such theories hold that the function of dreams occurs within sleep; occurs for unrecalled dreams as well as for dream that are recalled on awakening; and that conscious recall of dreams is not necessary for their function to occur. In contrast, we propose that dreams have an effect of enhancing empathy and group bonding when dreams are shared and discussed with others. We propose also that this effect would have occurred in history and pre-history and, as it would have enhanced the cohesiveness and mutual understanding of group members, the fictional and engaging characteristics of dream content would have been selected for during human social evolution, interacting with cultural practices of dream-sharing. Such dream-sharing may have taken advantage of the long REM periods that occur for biological reasons near the end of the night. Dream-production and dream-sharing may have developed alongside story-telling, utilising common neural mechanisms. Dream-sharing hence would have contributed to Human Self-Domestication, held by many researchers to be the primary driver of the evolution of human prosociality, tolerance and reduced intragroup emotional reactivity. We note that within-sleep theories of dream function rely on correlational rather than experimental findings, and have as yet untested and speculative mechanisms, whereas post-sleep effects of dream-sharing are easily testable and have mechanisms congruent with the social processes proposed by the theory of Human Self-Domestication.

Fledgling sex-ratio is biased towards the helping sex in a Neotropical cooperative breeder, the brown-and-yellow marshbird (Pseudoleistes virescens)

Behaviour ◽  
2021 ◽  
pp. 1-26
Author(s):  
Myriam E. Mermoz ◽  
Cecilia Villarruel ◽  
Alicia de la Colina ◽  
Bettina Mahler
Keyword(s):  
Sex Ratio ◽  
Breeding Success ◽  
Population Level ◽  
Adaptive Strategy ◽  
Individual Level ◽  
Cooperatively Breeding ◽  
Nestling Survival ◽  
Biased Sex Ratio ◽  
Communal Areas ◽  
Breeding Seasons

Abstract In many cooperatively breeding species, helpers increase the breeding success of their parents. The repayment hypothesis predicts a skewed sex-ratio towards the helping sex at population level; at individual level bias would increase in broods attended by a smaller number of helpers. We studied a brown-and-yellow marshbird (Pseudoleistes virescens) population during 11 breeding seasons. We found that 90% of helpers were males and that they increased nestling survival, although this effect disappeared in presence of parasitic shiny cowbirds. Helpers sometimes helped at nests of adults other than their parents. Population sex-ratio of fledglings was highly skewed towards males (1.4:1). At individual level, male-biased sex-ratio of fledglings was more pronounced early in the season and increased with brood losses but was not affected by number of helpers. Marshbirds feed at communal areas so retaining helpers would not be costly. Therefore, a general skew towards males might be the best adaptive strategy.

Experimental predator intrusions in a cooperative breeder reveal threat-dependent task partitioning

2020 ◽  
Vol 31 (6) ◽  
pp. 1369-1378 ◽  
Author(s):  
Dario Josi ◽  
Annika Freudiger ◽  
Michael Taborsky ◽  
Joachim G Frommen
Keyword(s):  
Behavioral Responses ◽  
Alloparental Care ◽  
Potential Threat ◽  
Antipredator Defense ◽  
Outside Options ◽  
Cooperatively Breeding ◽  
Indirect Fitness ◽  
Antipredator Behaviors ◽  
Group Members ◽  
Eusocial Animals

Abstract In cooperatively breeding species, nonbreeding individuals provide alloparental care and help in territory maintenance and defense. Antipredator behaviors of subordinates can enhance offspring survival, which may provide direct and indirect fitness benefits to all group members. Helping abilities and involved costs and benefits, risks, and outside options (e.g., breeding independently) usually diverge between group members, which calls for status-specific differentiated behavioral responses. Such role differentiation within groups may generate task-specific division of labor, as exemplified by eusocial animals. In vertebrates, little is known about such task differentiation among group members. We show how breeders and helpers of the cooperatively breeding cichlid Neolamprologus savoryi partition predator defense depending on intruder type and the presence of dependent young. In the field, we experimentally simulated intrusions by different fish species posing a risk either specifically to eggs, young, or adults. We used intrusions by harmless algae eaters as a control. Breeders defended most when dependent young were present, while helper investment hinged mainly on their body size and on the potential threat posed by the respective intruders. Breeders and helpers partitioned defense tasks primarily when dependent young were exposed to immediate risk, with breeders investing most in antipredator defense, while helpers increased guarding and care in the breeding chamber. Breeders’ defense likely benefits helpers as well, as it was especially enhanced in the treatment where helpers were also at risk. These findings illustrate that in a highly social fish different group members exhibit fine-tuned behavioral responses in dependence of ecological and reproductive parameter variation.

scholarly journals Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130565 ◽  
Author(s):  
Ben J. Hatchwell ◽  
Philippa R. Gullett ◽  
Mark J. Adams
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Alloparental Care ◽  
Hamilton’S Rule ◽  
Long Term Study ◽  
Inclusive Fitness Theory ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Hamilton's Rule

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist ( c ) are outweighed by the benefit to the recipient ( b ), weighted by the relatedness of altruist to recipient ( r ), i.e. Hamilton's rule rb > c . Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.

scholarly journals Fine-Scale Population Structure but Limited Genetic Differentiation in a Cooperatively Breeding Paper Wasp

2020 ◽  
Vol 12 (5) ◽  
pp. 701-714 ◽  
Author(s):  
Sarah E Bluher ◽  
Sara E Miller ◽  
Michael J Sheehan
Keyword(s):  
Population Structure ◽  
Genetic Differentiation ◽  
Cooperative Breeding ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Paper Wasp ◽  
Paper Wasps ◽  
Natal Philopatry ◽  
Continental Scale ◽  
Cooperatively Breeding

Abstract Relatively little is known about the processes shaping population structure in cooperatively breeding insect species, despite the long-hypothesized importance of population structure in shaping patterns of cooperative breeding. Polistes paper wasps are primitively eusocial insects, with a cooperative breeding system in which females often found nests in cooperative associations. Prior mark-recapture studies of Polistes have documented extreme female philopatry, although genetic studies frequently fail to detect the strong population structure expected for highly philopatric species. Together these findings have led to lack of consensus on the degree of dispersal and population structure in these species. This study assessed population structure of female Polistes fuscatus wasps at three scales: within a single site, throughout Central New York, and across the Northeastern United States. Patterns of spatial genetic clustering and isolation by distance were observed in nuclear and mitochondrial genomes at the continental scale. Remarkably, population structure was evident even at fine spatial scales within a single collection site. However, P. fuscatus had low levels of genetic differentiation across long distances. These results suggest that P. fuscatus wasps may employ multiple dispersal strategies, including extreme natal philopatry as well as longer-distance dispersal. We observed greater genetic differentiation in mitochondrial genes than in the nuclear genome, indicative of increased dispersal distances in males. Our findings support the hypothesis that limited female dispersal contributes toward population structure in paper wasps.

scholarly journals Adaptation and the genetics of social behaviour

2009 ◽  
Vol 364 (1533) ◽  
pp. 3209-3216 ◽  
Author(s):  
Laurent Keller
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Division Of Labour ◽  
Chemical Signalling ◽  
Insect Societies ◽  
Genetic Mechanisms ◽  
Selective Forces ◽  
Group Members ◽  
Reproductive Division Of Labour ◽  
Reproductive Division

In recent years much progress has been made towards understanding the selective forces involved in the evolution of social behaviour including conflicts over reproduction among group members. Here, I argue that an important additional step necessary for advancing our understanding of the resolution of potential conflicts within insect societies is to consider the genetics of the behaviours involved. First, I discuss how epigenetic modifications of behaviour may affect conflict resolution within groups. Second, I review known natural polymorphisms of social organization to demonstrate that a lack of consideration of the genetic mechanisms involved may lead to erroneous explanations of the adaptive significance of behaviour. Third, I suggest that, on the basis of recent genetic studies of sexual conflict in Drosophila , it is necessary to reconsider the possibility of within-group manipulation by means of chemical substances (i.e. pheromones). Fourth, I address the issue of direct versus indirect genetic effects, which is of particular importance for the study of behaviour in social groups. Fifth, I discuss the issue of how a genetic influence on dominance hierarchies and reproductive division of labour can have secondary effects, for example in the evolution of promiscuity. Finally, because the same sets of genes (e.g. those implicated in chemical signalling and the responses that are triggered) may be used even in species as divergent as ants, cooperative breeding birds and primates, an integration of genetic mechanisms into the field of social evolution may also provide unifying ideas.

scholarly journals The determinants of dominance relationships among subordinate females in the cooperatively breeding meerkat

Behaviour ◽  
2014 ◽  
Vol 151 (1) ◽  
pp. 89-102 ◽  
Author(s):  
N.K. Thavarajah ◽  
M. Fenkes ◽  
T.H. Clutton-Brock
Keyword(s):  
Reproductive Success ◽  
Competitive Advantage ◽  
Reproductive Skew ◽  
Breeding Female ◽  
Suricata Suricatta ◽  
Dominance Relationships ◽  
Dominance Structure ◽  
Starting Point ◽  
Cooperatively Breeding ◽  
Group Members

In cooperatively breeding species with high reproductive skew, a single breeding female is dominant to all other group members, but it is not yet known if there are consistent dominance relationships among subordinates. In this study on meerkats (Suricata suricatta), we used naturally observed dominance assertions and submissive interactions within dyads of subordinate females to investigate: (i) whether or not a dominance structure exists among them and what factors influence dominance relationships; and (ii) how dominance may influence the future reproductive success of subordinate females. Our study indicates that superiority in age and weight provide a competitive advantage during conflicts among subordinate females and that females who consistently dominate in these contests are subsequently more likely to attain a dominant breeding position. This provides a starting point for further investigations into dominance structure among subordinates in meerkat societies and other cooperative breeders.

scholarly journals Submission signals in animal groups

Behaviour ◽  
2021 ◽  
pp. 1-20
Author(s):  
Adam R. Reddon ◽  
Tommaso Ruberto ◽  
Simon M. Reader
Keyword(s):  
Social Interactions ◽  
Social Evolution ◽  
Group Living ◽  
Conflict Avoidance ◽  
Crucial Aspect ◽  
Social Animals ◽  
Mutual Interest ◽  
Living Species ◽  
Group Members ◽  
Animal Societies

Abstract Aggression is costly, and animals have evolved tactics to mitigate these costs. Submission signals are an underappreciated example of such adaptations. Here we review submissive behaviour, with an emphasis on non-primates. We highlight the design of submission signals and how such signals can reduce costs. Animal societies necessitate frequent social interactions, which can increase the probability of conflict. Where maintaining group proximity is essential, animals cannot avoid aggression by fleeing. Mutual interest between group members may also select for efficient conflict avoidance and resolution mechanisms. As a result, submission signals may be especially well developed among group living species, helping social animals to overcome potential costs of recurring conflict that could otherwise counter the benefits of group living. Therefore, submission signalling can be a crucial aspect of social living and is deserving of specific attention within the broader context of social evolution and communication.

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