scholarly journals Personality composition is more important than group size in determining collective foraging behaviour in the wild

2014 ◽  
Vol 281 (1796) ◽  
pp. 20141424 ◽  
Author(s):  
Carl N. Keiser ◽  
Jonathan N. Pruitt
Keyword(s):  
Group Size ◽  
Foraging Behaviour ◽  
Collective Behaviour ◽  
Nest Architecture ◽  
Social Spider ◽  
The Social ◽  
In The Wild ◽  
Behavioural Phenotypes ◽  
Collective Foraging ◽  
Animal Societies

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.

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
Keyword(s):  
Foraging Behaviour ◽  
Social Dynamics ◽  
Prey Capture ◽  
Social Groups ◽  
Collective Behaviour ◽  
Legacy Effects ◽  
Social Spider ◽  
The Social ◽  
Collective Foraging ◽  
The Individual

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.

scholarly journals Collective behaviour is not robust to disturbance, yet parent and offspring colonies resemble each other in social spiders

2019 ◽  
Author(s):  
David N. Fisher ◽  
James L.L. Lichtenstein ◽  
Raul Costa-Pereira ◽  
Justin Yeager ◽  
Jonathan N. Pruitt
Keyword(s):  
Initial Conditions ◽  
Collective Behaviour ◽  
Group Level ◽  
Natural Conditions ◽  
Social Spider ◽  
The Social ◽  
Parent Colony ◽  
Group Members ◽  
Collective Foraging ◽  
The Stability

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.

scholarly journals Trait overdispersion and the role of sociality in the assembly of social spider communities across the Americas

2018 ◽  
Vol 115 (23) ◽  
pp. 6010-6015 ◽  
Author(s):  
Philippe Fernandez-Fournier ◽  
Jennifer Guevara ◽  
Catherine Hoffman ◽  
Leticia Avilés
Keyword(s):  
Body Size ◽  
Group Size ◽  
Abiotic Factors ◽  
Social Systems ◽  
Null Model ◽  
Niche Space ◽  
Social Spider ◽  
The Social ◽  
Size And Morphology

Among the factors that may lead to differences in resource use among closely related species, body size and morphology have been traditionally considered to play a role in community assembly. Here we argue that for animals that live and forage in groups, level of sociality, reflecting differences in group size and cooperative tendencies, can be an additional and powerful dimension separating species in niche space. We compare 50+ communities of the social spider genus Anelosimus across the Americas against a null model that accounts for known effects of biotic and abiotic factors on the distribution of social systems in the genus. We show that these communities are more overdispersed than expected by chance in either or both body size and level of sociality, traits we have previously shown to be associated with differences in resource utilization (prey size, microhabitat, and phenology). We further show that the contribution of sociality to differences in the size of the prey captured is two to three times greater than that of body size, suggesting that changes in group size and cooperative tendencies may be more effective than changes in body size at separating species in niche space.

scholarly journals Social Preferences of Translocated Giraffes (Giraffa Camelopardalis Giraffa) in Senegal: Evidence for Friendship Among Females?

2014 ◽  
Vol 47 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Lenka Malyjurkova ◽  
Marketa Hejzlarova ◽  
Pavla Junkova Vymyslicka ◽  
Karolina Brandlova
Keyword(s):  
Social Relationships ◽  
Group Size ◽  
Social Preferences ◽  
Native Range ◽  
Association Index ◽  
Giraffa Camelopardalis ◽  
The Social ◽  
In Captivity ◽  
In The Wild ◽  
The Relationship

Abstract Giraffe social behaviour and relationships are currently in the period of scientific renaissance, changing the former ideas of nonexisting social bonds into understanding of complex social structures of giraffe herds. Different giraffe subspecies have been studied in the wild and only one was subject of detailed study in captivity. Our study focused on the neglected Cape giraffe (Giraffa camelopardalis giraffa). We investigated the social preferences of 28 introduced giraffes in semi-captivity in Bandia reserve, Senegal. Our aim was to assess the group size of Cape giraffes outside their native range and describe their social relationships. Mean group size in Bandia was 7.22 ± 4.06 (range 2-17). The dyads were classified according to strength of relationship (weak, medium, strong) using the association index. We reported weak and medium relationships in all types of dyads except female-juvenile. The strongest bond was found in mother-calf dyads. Three of 21 possible female dyads also demonstrated strong relationships. Those three dyads included six of seven adult females, which we labelled as friends. Females associated more frequently with calves of their friends then with calves of non-friend females. The strength of the relationship between calves depended on the strength of relationship between their mothers. We concluded that Cape giraffes in new environment have shown similar group size and nonrandom preference for conspecifics as shown in wild and captive studies. The research was supported by CIGA 20135010, CIGA 2134217, IGA FTZ 20135123, ESF/MŠMT CZ.1.07/2.3.00/30.0040.

Conflict and Cooperation in the Group Feeding of the Social Spider Stegodyphus Mimosarum

Behaviour ◽  
1985 ◽  
Vol 94 (1-2) ◽  
pp. 167-182 ◽  
Author(s):  
Margit M. Enders ◽  
Paul I. Ward
Keyword(s):  
Group Size ◽  
Feeding Behaviour ◽  
Prey Size ◽  
The Body ◽  
Large Prey ◽  
Social Spider ◽  
Small Prey ◽  
Conflict And Cooperation ◽  
The Social ◽  
Group Feeding

Abstract1. Stegodyphus mimosarum, a social spider, lives in colonies which may contain hundreds of individuals. Feeding behaviour was examined with respect to feeding group size and prey size. 2. Prey were less likely to escape and were subdued more quickly when attacked by more than one spider. 3. During capture small prey were frequently bitten directly on the body whereas large prey were almost always bitten on an appendage. 4. Pulling struggles for subdued prey occurred. They lasted longest over medium sized prey. Small prey were easier to transport to the nest than medium prey and large prey were pulled by more spiders from a single retreat. 5. Spiders which had participated in a capture initially bit preferentially on the prey's head or thorax but others which joined later to feed bit at random. 6. Feeding became less efficient as group size increased and an experiment suggests that individuals injected less poison and digestive enzymes when feeding in groups.

scholarly journals Social interactions shape individual and collective personality in social spiders

2018 ◽  
Vol 285 (1886) ◽  
pp. 20181366 ◽  
Author(s):  
Edmund R. Hunt ◽  
Brian Mi ◽  
Camila Fernandez ◽  
Brandyn M. Wong ◽  
Jonathan N. Pruitt ◽  
...  
Keyword(s):  
Social Interactions ◽  
Group Composition ◽  
Feedback Mechanism ◽  
Collective Behaviour ◽  
Social Spider ◽  
The Social ◽  
Potential Impact ◽  
Positive Feedback Mechanism ◽  
The Relationship ◽  
Over Time

The behavioural composition of a group and the dynamics of social interactions can both influence how social animals work collectively. For example, individuals exhibiting certain behavioural tendencies may have a disproportionately large impact on the group, and so are referred to as keystone individuals, while interactions between individuals can facilitate information transmission about resources. Despite the potential impact of both behavioural composition and interactions on collective behaviour, the relationship between consistent behaviours (also known as personalities) and social interactions remains poorly understood. Here, we use stochastic actor-oriented models to uncover the interdependencies between boldness and social interactions in the social spider Stegodyphus dumicola . We find that boldness has no effect on the likelihood of forming social interactions, but interactions do affect boldness, and lead to an increase in the boldness of the shyer individual. Furthermore, spiders tend to interact with the same individuals as their neighbours. In general, boldness decreases over time, but once an individual's boldness begins to increase, this increase accelerates, suggesting a positive feedback mechanism. These dynamics of interactions and boldness result in skewed boldness distributions of a few bold individuals and many shy individuals, as observed in nature. This group behavioural composition facilitates efficient collective behaviours, such as rapid collective prey attack. Thus, by examining the relationship between behaviour and interactions, we reveal the mechanisms that underlie the emergence of adaptive group composition and collective behaviour.

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