scholarly journals Host anemone size as a determinant of social group size and structure in the orange clownfish (Amphiprion percula)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5841 ◽  
Author(s):  
Juliette Chausson ◽  
Maya Srinivasan ◽  
Geoffrey P. Jones
Keyword(s):  
Path Analysis ◽  
Group Size ◽  
Social Group ◽  
Environmental Gradients ◽  
Social Groups ◽  
Ecological Factors ◽  
Habitat Patch ◽  
Behavioral Interactions ◽  
Amphiprion Percula ◽  
Size And Structure

The size and structure of social groups of animals can be governed by a range of ecological factors and behavioral interactions. In small, highly site-attached coral reef fishes, group size is often constrained by the size of the habitat patch they are restricted to. However, group size may also be influenced by changes in abundance along important environmental gradients, such as depth or distance offshore. In addition, the body size and sex structure within social groups can be determined by the size of the habitat patch and the dominance relationships among group members. Here we examined the roles of ecological factors and behavioral interactions in governing group size and structure in the orange clownfish, Amphiprion percula, on inshore reefs in Kimbe Bay, Papua New Guinea. We quantified relationships between ecological variables (anemone size, depth, and distance from shore) and social group variables (group size, and total body length of the three largest individuals (ranks 1, 2, and 3)). Anemone size explained the greatest amount of variation in group variables, with strong, positive relationships between anemone surface area and group size, and total length of individuals ranked 1, 2, and 3. Group structure was also weakly correlated with increasing depth and distance from shore, most likely through the indirect effects of these environmental gradients on anemone size. Variation in group size and the lengths of ranks 2 and 3 were all closely related to the length of rank 1. Path analysis indicated that anemone size has a strong direct effect on the length of rank 1. In turn, the length of rank 1 directly affects the size of the subordinate individuals and indirectly affects the group size through its influence on subordinates. Hence, anemone size directly and indirectly controls social group size and structure in this space-limited fish species. It is also likely that anemonefish have feedback effects on anemone size, although this could not be differentiated in the path analysis.

Habitat patch size and mating system as determinants of social group size in coral-dwelling fishes

Coral Reefs ◽  
2006 ◽  
Vol 26 (1) ◽  
pp. 165-174 ◽  
Author(s):  
V. J. Thompson ◽  
P. L. Munday ◽  
G. P. Jones
Keyword(s):  
Mating System ◽  
Group Size ◽  
Social Group ◽  
Patch Size ◽  
Habitat Patch ◽  
Habitat Patch Size

scholarly journals Fertility as a constraint on group size in African great Apes

2019 ◽  
Author(s):  
R I M Dunbar
Keyword(s):  
Group Size ◽  
Environmental Effects ◽  
Social Groups ◽  
Great Apes ◽  
Adult Females ◽  
African Great Apes ◽  
Cognitive Cost ◽  
Size And Structure ◽  
Do So ◽  
The Way

Abstract Gorillas and chimpanzees live in social groups of very different size and structure. Here I test the hypothesis that this difference might reflect the way fertility maps onto group demography as it does in other Catarrhines. For both genera, birth rates and the number of surviving offspring per female are quadratic (or ∩-shaped) functions of the number of adult females in the group, and this is independent of environmental effects. The rate at which fertility declines ultimately imposes a constraint on the size of social groups that can be maintained in both taxa. The differences in group size between the two genera seem to reflect a contrast in the way females buffer themselves against this cost. Gorillas do this by using males as bodyguards, whereas chimpanzees exploit fission–fusion sociality to do so. The latter allows chimpanzees to live in much larger groups without paying a fertility cost (albeit at a cognitive cost).

scholarly journals Sexual segregation in human conversations

Behaviour ◽  
2016 ◽  
Vol 153 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R.I.M. Dunbar
Keyword(s):  
Sex Differences ◽  
Group Size ◽  
Social Group ◽  
Census Data ◽  
Social Groups ◽  
Characteristic Size ◽  
Sexual Segregation ◽  
Fractal Pattern ◽  
Single Sex ◽  
Conversational Style

Human conversation groups have a characteristic size limit at around four individuals. Although mixed-sex social groups can be significantly larger than this, census data on casual social groups suggest that there is a fractal pattern of fission in conversations when social group size is a multiple of this value. This study suggests that, as social group size increases beyond four, there is a tendency for sexual segregation to occur resulting in an increasing frequency of single-sex conversational subgroups. It is not clear why conversations fragment in this way, but a likely explanation is that sex differences in conversational style result in women (in particular) preferring to join all-female conversations when a social group is large enough to allow this.

Daily Distance Traveled Is Associated with Greater Brain Size in Primates

2020 ◽  
Vol 91 (6) ◽  
pp. 654-668
Author(s):  
Marco Vidal-Cordasco ◽  
Lucía Rodríguez-González ◽  
Olalla Prado-Nóvoa ◽  
Guillermo Zorrilla-Revilla ◽  
Mario Modesto-Mata
Keyword(s):  
Group Size ◽  
Social Group ◽  
Brain Size ◽  
Ecological Factors ◽  
Primate Species ◽  
Brain Mass ◽  
Daily Movement ◽  
Size Evolution ◽  
Movement Distance ◽  
Extant Primate

Explanations for the brain size increments through primate and, particularly, human evolution are numerous. Commonly, these hypotheses rely on the influence that behavioral and ecological variables have on brain size in extant primates, such as diet quality, social group size, or home range (HR) area. However, HR area does not reflect the time spent moving. As such, it has not been properly addressed whether the effort involved in movement could have affected brain size evolution in primates. This study aimed to test the influence of daily movement on primates’ brain sizes, controlling for these other behavioral and ecological factors. We used a large comparative dataset of extant primate species and phylogenetic comparative methods. Our results show a significant correlation between daily movement and brain mass, which is not explained by the influence of diet, social group size, HR, or body mass. Hence, from an evolutionary timescale, a longer daily movement distance is not a constraining factor for the energetic investment in a larger brain. On the contrary, increased mobility could have contributed to brain mass incrementations through evolution.

scholarly journals Social Interactions in Zoo-Housed Elephants: Factors Affecting Social Relationships

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 747 ◽  
Author(s):  
Ellen Williams ◽  
Anne Carter ◽  
Carol Hall ◽  
Samantha Bremner-Harrison
Keyword(s):  
Social Interactions ◽  
Social Relationships ◽  
Social Group ◽  
Social Systems ◽  
Social Groups ◽  
Ecological Factors ◽  
Positive Interactions ◽  
Asian Elephants ◽  
Minimal Impact ◽  
Proactive Management

Elephants have complex social systems that are predominantly driven by ecological factors in situ. Within zoos, elephants are held in relatively static social groups and the factors observed driving social relationships in the wild are largely absent. Little research has investigated the effect of social group factors in zoos on elephant social interactions. The aim of this research was to establish whether there is a relationship between social group factors and social behaviour, in order to identify factors that make elephant herds more or less likely to be compatible. Results will facilitate recommendations for optimum social groupings for zoo elephants. Behavioural data quantifying social interactions were collected between January 2016 and February 2017 at seven UK and Irish zoos and safari parks from 10 African and 22 Asian elephants. Social interactions were split into four categories: positive physical, positive non-physical, negative physical and negative non-physical. Social interactions were related to age (positive physical higher and negative non-physical lower in calves than adults), personality (elephants with higher sociability scores engaged in more positive interactions and less negative interactions), presence of calves in the herd (herds with calves had more positive non-physical), relatedness to other elephants in the herd (positive non-physical were higher when relatives were in the group and negative non-physical were higher between unrelated elephants) and species (Asian elephants engaged in more positive non-physical than African elephants). A greater understanding of factors that may contribute to the success of zoo-elephant social groups is important for individual and herd welfare as it will enable evidence-based decisions which have minimal impact on social structures to be executed. This knowledge will enable proactive management approaches to be undertaken and will thus be paramount in ensuring optimal welfare for elephant herds moving forwards.

scholarly journals Group size and aquatic vegetation modulates male preferences for female shoals in wild zebrafish, Danio rerio

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditya Ghoshal ◽  
Anuradha Bhat
Keyword(s):  
Group Size ◽  
Aquatic Vegetation ◽  
Natural Habitat ◽  
Ecological Factors ◽  
Choice Test ◽  
Female Group ◽  
Aquatic Flora ◽  
In The Wild ◽  
The Individual

AbstractShoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.

Towards a computational theory of social groups: A finite set of cognitive primitives for representing any and all social groups in the context of conflict

2021 ◽  
pp. 1-62
Author(s):  
David Pietraszewski
Keyword(s):  
Social Group ◽  
Group Representation ◽  
Social Groups ◽  
Study Groups ◽  
Human Mind ◽  
Computational Theory ◽  
Mistaken Belief ◽  
Finite Set ◽  
The One ◽  
Definition Of

Abstract We don't yet have adequate theories of what the human mind is representing when it represents a social group. Worse still, many people think we do. This mistaken belief is a consequence of the state of play: Until now, researchers have relied on their own intuitions to link up the concept social group on the one hand, and the results of particular studies or models on the other. While necessary, this reliance on intuition has been purchased at considerable cost. When looked at soberly, existing theories of social groups are either (i) literal, but not remotely adequate (such as models built atop economic games), or (ii) simply metaphorical (typically a subsumption or containment metaphor). Intuition is filling in the gaps of an explicit theory. This paper presents a computational theory of what, literally, a group representation is in the context of conflict: it is the assignment of agents to specific roles within a small number of triadic interaction types. This “mental definition” of a group paves the way for a computational theory of social groups—in that it provides a theory of what exactly the information-processing problem of representing and reasoning about a group is. For psychologists, this paper offers a different way to conceptualize and study groups, and suggests that a non-tautological definition of a social group is possible. For cognitive scientists, this paper provides a computational benchmark against which natural and artificial intelligences can be held.

Time budgets of group-housed pigs in relation to social aggression and production

2021 ◽  
Author(s):  
Carly I O’Malley ◽  
Juan P Steibel ◽  
Ronald O Bates ◽  
Catherine W Ernst ◽  
Janice M Siegford
Keyword(s):  
Social Group ◽  
Social Groups ◽  
Social Aggression ◽  
Growing Pigs ◽  
Least Square ◽  
Time Budgets ◽  
Aggressive Behaviors ◽  
Welfare Benefits ◽  
Production Parameters ◽  
Use Of Resources

Abstract Commercial producers house growing pigs by sex and weight to allow for efficient use of resources and provide pigs the welfare benefits of interacting with their conspecifics and more freedom of movement. However, introduction of unfamiliar pigs can cause increased aggression for 24-48 h as pigs establish social relationships. To address this issue, a better understanding of pig behavior is needed. The objectives of this study were to quantify time budgets of pigs following introduction into a new social group and how these changed over time, and to investigate how social aggression influences overall time budgets and production parameters. A total of 257 grow-finish Yorkshire barrows across 20 pens were introduced into new social groups at 10 wk of age (~23 kg) and observed for aggression and time budgets of behavior at 4 periods: immediately after introduction, 3, 6, and 9 wk later. Pigs were observed for duration of total aggression and initiated aggression (s) for 9 h after introduction and for 4 h at 3, 6, and 9 wk later. Time budgets were created by scan-sampling inactive, movement, ingestion, social, and exploration behaviors every 2 min for 4 h in the afternoon and summarizing proportion of time each behavior was performed by period. Least square means of each behavior were compared across time points. Pigs spent most of their time inactive. In general, the greatest change in pig behavior was observed between introduction and wk 3 (P<0.003), with gradual changes throughout the study period as pigs became more inactive (wk 3 vs. wk 6: P=0.209; wk 6 vs. wk 9: P=0.007) and spent less time on other behaviors. Pigs’ non-aggressive behavior and production parameters were compared to aggression using generalized linear mixed models. The time pigs spent on non-aggressive behaviors were negatively related to aggression (P<0.045) with few exceptions. Initiated aggression after introduction was negatively related to loin muscle area (P=0.003). These results show how finishing pigs spend their time in commercial facilities and indicate that behavior continues to change for up to 9 wk after introduction to a new social group. Efforts to reduce chronic levels of aggression should focus on promoting non-aggressive behaviors, such as exploration and movement, after the initial fighting that occurs immediately after introduction has waned and should be implemented for up at 9 wk after introduction into new social groups.

Effect of social group size on aggressive behaviour between unacquainted domestic pigs

2001 ◽  
Vol 74 (3) ◽  
pp. 203-215 ◽  
Author(s):  
Simon P Turner ◽  
Graham W Horgan ◽  
Sandra A Edwards
Keyword(s):  
Group Size ◽  
Social Group ◽  
Aggressive Behaviour ◽  
Domestic Pigs

Effects of social group size on information transfer and task allocation

1996 ◽  
Vol 10 (2) ◽  
pp. 127-165 ◽  
Author(s):  
Stephen W. Pacala ◽  
Deborah M. Gordon ◽  
H. C. J. Godfray
Keyword(s):  
Group Size ◽  
Task Allocation ◽  
Social Group ◽  
Information Transfer ◽  
And Task
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