Costs and benefits of group living in primates: group size effects on behaviour and demography

2008 ◽  
Vol 76 (4) ◽  
pp. 1235-1247 ◽  
Author(s):  
Bonaventura Majolo ◽  
Aurora de Bortoli Vizioli ◽  
Gabriele Schino
Keyword(s):  
Group Size ◽  
Size Effects ◽  
Group Living ◽  
Costs And Benefits

scholarly journals Costs and benefits of group living in primates: an energetic perspective

2017 ◽  
Vol 372 (1727) ◽  
pp. 20160239 ◽  
Author(s):  
A. Catherine Markham ◽  
Laurence R. Gesquiere
Keyword(s):  
Group Size ◽  
Group Living ◽  
Field Studies ◽  
Adaptive Significance ◽  
Physiological Measures ◽  
Costs And Benefits ◽  
Energetic Stress ◽  
Metabolic States ◽  
Spatial And Temporal Changes ◽  
Energetic Balance

Group size is a fundamental component of sociality, and has important consequences for an individual's fitness as well as the collective and cooperative behaviours of the group as a whole. This review focuses on how the costs and benefits of group living vary in female primates as a function of group size, with a particular emphasis on how competition within and between groups affects an individual's energetic balance. Because the repercussions of chronic energetic stress can lower an animal's fitness, identifying the predictors of energetic stress has important implications for understanding variation in survivorship and reproductive success within and between populations. Notably, we extend previous literature on this topic by discussing three physiological measures of energetic balance—glucocorticoids, c-peptides and thyroid hormones. Because these hormones can provide clear signals of metabolic states and processes, they present an important complement to field studies of spatial and temporal changes in food availability. We anticipate that their further application will play a crucial role in elucidating the adaptive significance of group size in different social and ecological contexts. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals'.

scholarly journals Skew in ovarian activation depends on domicile size in a facultatively social thrips

2016 ◽  
Author(s):  
James DJ Gilbert ◽  
Alice Wells ◽  
Stephen J Simpson
Keyword(s):  
Group Size ◽  
Group Formation ◽  
Group Living ◽  
Reproductive Skew ◽  
Behavioural Ecology ◽  
Costs And Benefits ◽  
Reproductive Competition ◽  
Ovarian Activation ◽  
Per Capita ◽  
Breeding Resources

Costs and benefits of group living are a fundamental topic in behavioural ecology. Resource availability affects individuals' breeding prospects alone and in groups, as well as how reproduction is distributed within groups ("reproductive skew"). Here, we provide correlational evidence in facultatively social thrips that breeding resources are associated with (1) whether solitary or social living is favoured, and (2) the degree of ovarian skew.Dunatothrips aneurae(Thysanoptera, Phlaeothripidae) cooperatively build silk "domiciles" on Australian acacias, feeding exclusively from internal phyllode surfaces. Per capita productivity scaled differently with group size depending on domicile volume - females in small domiciles did better alone than in groups, whereas in large domiciles single and group-nesting females did equally well. Ovarian dissections revealed that in small domiciles some females were nonreproductive, indicating ovarian (i.e. reproductive) skew. Skew increased as domicile size decreased and group size increased. Breeders had smaller oocyte volume in smaller domiciles, especially those containing nonreproductives. These findings suggest group formation and reproductive skew inD. aneuraemay be influenced by reproductive competition for breeding resources. Nonreproductive females in small domiciles may be reproductively suppressed, subfertile, or waiting to reproduce. We speculate they may avoid eviction by contributing as "helpers" to domicile maintenance.

How Much Does Social Group Size Influence Golden Marmot Vigilance?

Behaviour ◽  
1996 ◽  
Vol 133 (15-16) ◽  
pp. 1133-1151 ◽  
Author(s):  
Daniel T. Blumstein
Keyword(s):  
Size Effect ◽  
Group Size ◽  
Size Effects ◽  
Social Group ◽  
Group Living ◽  
Relative Importance ◽  
Net Benefit ◽  
Significant Group ◽  
Group Size Effect ◽  
Variation Explained

AbstractA commonly cited benefit of group living is the ability for individuals to reduce the time devoted to scanning for predators with increasing group size - the 'group size effect'. Interestingly, most studies reporting a group size effect have focused on documenting a significant group size effect and did not discuss the relative 'importance' of group size. One way to study the relative importance of group size is to calculate the amount of variation in vigilance explained by group size. I studied effects of social group size on golden marmot (Marmota caudata aurea) vigilance in two ways. First, I estimated the overall amount of time marmots were vigilant during their morning active periods. Second, I estimated the amount of time marmots were vigilant specifically while foraging. Analyses statistically controlled for several factors that have been suggested to confound the study of group size effects. While marmots were active, only 14% of the variation in vigilance was explained by social group size. For foraging marmots, even less variation (about 6%) was explained by social group size. The amount of variation explained by social group size in golden marmots is considerably less that reported in several studies of other species where explained variation was reported or could be estimated from data. Some of the discrepancy between variation explained in this and other studies may stem from my focus on social group size which appears to explain less variation than the more commonly studied foraging aggregation size. However, species differ in the amount of time they devote to foraging and therefore vary in the magnitude of net benefit from group size effects. Future comparative work will be required to rigorously study the relationship between amount of time foraging and the magnitude of group size effects.

Subjective Fear Dilutes as Group Size Increases

2020 ◽  
Author(s):  
dean mobbs ◽  
Ellen Tedeschi ◽  
Anastasia Buyalskaya ◽  
Brian Silston
Keyword(s):  
Group Size ◽  
Real World ◽  
Survival Benefit ◽  
Group Living ◽  
External Factors ◽  
Threat Perception ◽  
Perception Of Threat ◽  
Threat Level ◽  
Internal States ◽  
Risk Dilution

According to Hamilton’s Selfish Herd Theory, a crucial survival benefit of group living is that it provides a ‘risk dilution’ function against predation. Despite a large literature on group living benefits in animals, few studies have been conducted on how group size alters subjective fear or threat perception in humans, and on what factors drive preferences for being in groups when facing threats. We conducted seven experiments (N=3,838) to test (A) if the presence of others decreases perception of threat under a variety of conditions. In studies 1 to 3, we experimentally manipulated group size in hypothetical and real-world situations, to show that fear responses decreased as group size increased. In studies 4 to 7 we again used a combination of hypothetical, virtual and real-world decisions to test (B) how internal states (e.g. anxiety) and external factors (e.g. threat level, availability of help) affected participants’ preference for groups. Participants consistently chose larger groups when threat and anxiety were high. Overall, our findings show that group size provides a salient signal of protection and safety.

Yellow-Footed Rock-Wallaby Group Size Effects Reflect A Trade-Off

Ethology ◽  
2001 ◽  
Vol 107 (7) ◽  
pp. 655-664 ◽  
Author(s):  
Daniel T. Blumstein ◽  
Janice C. Daniel ◽  
Christopher S. Evans
Keyword(s):  
Group Size ◽  
Size Effects ◽  
Trade Off

scholarly journals Fitness of breeders in social Damaraland mole-rats is independent of group size

2021 ◽  
Author(s):  
Jack Thorley ◽  
Hanna Bensch ◽  
Kyle Finn ◽  
Tim Clutton-Brock ◽  
Markus Zöttl
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Survival Rates ◽  
Group Living ◽  
Adult Survival ◽  
High Survival ◽  
Successful Reproduction ◽  
Related Group ◽  
Group Members ◽  
Using Data

Damaraland mole-rats (Fukomys damarensis) are usually viewed as an obligatorily group living eusocial species in which successful reproduction is dependent on reproductive altruism of closely related group members. However, the reproductive ecology of social mole-rats in their natural environment remains poorly understood and it is unclear to what extent successful reproduction is dependent on assistance from other group members. Using data from a 7-year field study of marked individuals, we show that, after dispersal from their natal group, individuals typically settled alone in new burrow systems where they enjoyed high survival rates, and often remained in good body condition for several years before finding a mate. Unlike most other eusocial or singular cooperative breeders, we found that Damaraland mole-rats reproduced successfully in pairs without helpers and experimentally formed pairs had the same reproductive success as larger established groups. Overall there was only a weak increase in reproductive success with increasing group size and no effect of group size on adult survival rates across the population. Juveniles in large groups grew faster early in life but their growth rates declined subsequently so that they eventually plateaued at a lower maximum body mass than juveniles from small groups. Taken together, our data suggest that the fitness benefits of group living to breeders are small and we suggest that extended philopatry in Damaraland mole-rats has evolved because of the high costs and constraints of dispersal rather than because of strong indirect benefits accrued through cooperative behaviour.

Goal Relevance and Desirability of Virtuous Behavior in Satisfying Affiliative and Pathogen Avoidance Needs

2021 ◽  
Author(s):  
Mitch Brown
Keyword(s):  
Group Living ◽  
Self Control ◽  
Evolutionary Perspective ◽  
Costs And Benefits ◽  
Behavioral Repertoire ◽  
Fundamental Nature ◽  
Virtuous Behavior ◽  
Goal Relevance ◽  
Effective Group ◽  
Pathogen Avoidance

Recent findings suggest that behavioral repertoires frequently conceptualized as virtuous possess a fundamental nature that implicates virtues as highly desirable in facilitating group living through factors of caring, self-control, and inquisitiveness. Although much of this desirability has previously demonstrated in mating domains, it could be possible their benefits extend to affiliative and pathogen-avoidant domains. Two studies (N=285) sought to determine the potential costs and benefits of associating with virtuous individuals (Study 1) and how these affordances could shape subsequent interpersonal preferences (Study 2). In Study 1, participants inferred a caring behavioral repertoire as particularly effective at facilitating both affiliative and pathogen-avoidant goals, whereas inquisitiveness was perceived as threatening to pathogen-avoidant goals. Study 2 provides evidence dispositionally heightened affiliative interests heightened preferences for caring, but pathogen-avoidant motives did not influence preferences. I frame results from an evolutionary perspective and synthesize it with recent findings demonstrating how virtue shapes effective group living.

Group Size Effects in Electronic Brainstorming

2011 ◽  
pp. 330-336
Author(s):  
Alan R. Dennis ◽  
Michael L. Williams
Keyword(s):  
Group Size ◽  
Size Effects ◽  
Meta Analysis ◽  
Idea Generation ◽  
Communication Process ◽  
Future Research ◽  
Research And Practice ◽  
Electronic Brainstorming

The goal of this article is to analyze the effect of group size on idea generation in both verbal and electronic brainstorming (EBS) groups. Group size effects were analyzed by a meta-analysis of 21 previously published articles. Section one reviews how group size impacts the communication process in group idea generation. Section two and three present the methods and results of our meta-analysis. Section four is a discussion of the results and implications for future research and practice.

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