scholarly journals Mid-sized groups perform best in a collective decision task in sticklebacks

2019 ◽  
Vol 15 (10) ◽  
pp. 20190335
Author(s):  
Ashley J. W. Ward ◽  
Michael M. Webster
Keyword(s):  
Group Size ◽  
Functional Relationship ◽  
Collective Decision ◽  
Collective Behaviour ◽  
Decision Task ◽  
Group Level ◽  
Social Conformity ◽  
Collective Movement

Numerous studies have reported functional improvements in collective behaviour with increasing group size, however, the possibility that such improvements may saturate or even decline as group size continues to grow have seldom been tested experimentally. Here, we tested the ability of solitary three-spined sticklebacks and those in groups, ranging from 2 to 29 fish, to leave an unfavourable patch of habitat. Our results replicate the findings of previous studies at low group sizes, with the fish initially showing a reduction in their latency to leave the unfavourable habitat as group size increased. As group size continued to increase, however, latency to leave the habitat increased, so that the functional relationship between group size and latency to depart was U-shaped. Our results suggest an optimum group size in this context of between 12 and 20 fish. Underlying this group-level trend was a similar U-shaped relationship between group size and the first fish to leave the habitat, suggesting that at larger group sizes, social conformity to the behaviour of the majority can stifle the ability of fish to innovate—in this case, to induce a collective movement from the unfavourable habitat.

scholarly journals Collective turns in jackdaw flocks: kinematics and information transfer

2019 ◽  
Vol 16 (159) ◽  
pp. 20190450 ◽  
Author(s):  
Hangjian Ling ◽  
Guillam E. Mclvor ◽  
Joseph Westley ◽  
Kasper van der Vaart ◽  
Jennifer Yin ◽  
...  
Keyword(s):  
Group Size ◽  
Information Transfer ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Collective Behaviour ◽  
Group Level ◽  
Three Dimensional Imaging ◽  
Individual Interaction ◽  
Social Animals

The rapid, cohesive turns of bird flocks are one of the most vivid examples of collective behaviour in nature, and have attracted much research. Three-dimensional imaging techniques now allow us to characterize the kinematics of turning and their group-level consequences in precise detail. We measured the kinematics of flocks of wild jackdaws executing collective turns in two contexts: during transit to roosts and anti-predator mobbing. All flocks reduced their speed during turns, probably because of constraints on individual flight capability. Turn rates increased with the angle of the turn so that the time to complete turns remained constant. We also find that context may alter where turns are initiated in the flocks: for transit flocks in the absence of predators, initiators were located throughout the flocks, but for mobbing flocks with a fixed ground-based predator, they were always located at the front. Moreover, in some transit flocks, initiators were far apart from each other, potentially because of the existence of subgroups and variation in individual interaction ranges. Finally, we find that as the group size increased the information transfer speed initially increased, but rapidly saturated to a constant value. Our results highlight previously unrecognized complexity in turning kinematics and information transfer in social animals.

scholarly journals The role of individuality in collective group movement

2013 ◽  
Vol 280 (1752) ◽  
pp. 20122564 ◽  
Author(s):  
J. E. Herbert-Read ◽  
S. Krause ◽  
L. J. Morrell ◽  
T. M. Schaerf ◽  
J. Krause ◽  
...  
Keyword(s):  
Group Size ◽  
Group Level ◽  
Biological Organization ◽  
Social Conformity ◽  
Size Dependent ◽  
Movement Characteristics ◽  
Collective Group ◽  
Locomotory Behaviour ◽  
Different Levels

How different levels of biological organization interact to shape each other's function is a central question in biology. One particularly important topic in this context is how individuals' variation in behaviour shapes group-level characteristics. We investigated how fish that express different locomotory behaviour in an asocial context move collectively when in groups. First, we established that individual fish have characteristic, repeatable locomotion behaviours (i.e. median speeds, variance in speeds and median turning speeds) when tested on their own. When tested in groups of two, four or eight fish, we found individuals partly maintained their asocial median speed and median turning speed preferences, while their variance in speed preference was lost. The strength of this individuality decreased as group size increased, with individuals conforming to the speed of the group, while also decreasing the variability in their own speed. Further, individuals adopted movement characteristics that were dependent on what group size they were in. This study therefore shows the influence of social context on individual behaviour. If the results found here can be generalized across species and contexts, then although individuality is not entirely lost in groups, social conformity and group-size-dependent effects drive how individuals will adjust their behaviour in groups.

scholarly journals Group-level patterns emerge from individual speed as revealed by an extremely social robotic fish

2020 ◽  
Author(s):  
Jolle W. Jolles ◽  
Nils Weimar ◽  
Tim Landgraf ◽  
Pawel Romanczuk ◽  
Jens Krause ◽  
...  
Keyword(s):  
Empirical Work ◽  
Feedback System ◽  
Robotic Fish ◽  
Collective Behaviour ◽  
Movement Speed ◽  
Group Level ◽  
Individual Based Models ◽  
Biomimetic Robot ◽  
Induced Changes

AbstractUnderstanding the emergence of collective behaviour has long been a key research focus in the natural sciences. Besides the fundamental role of social interaction rules, a combination of theoretical and empirical work indicates individual speed may be a key process that drives the collective behaviour of animal groups. Socially-induced changes in speed by interacting animals make it difficult to isolate the effects of individual speed on group-level behaviours. Here we tackled this issue by pairing guppies with a biomimetic robot. We used a closed-loop tracking and feedback system to let a robotic fish naturally interact with a live partner in real time, and programmed it to strongly copy and follow its partner’s movements while lacking any preferred movement speed or directionality of its own. We show that individual differences in guppies’ movement speed were highly repeatable and shaped key collective patterns: higher individual speeds resulted in stronger leadership, lower cohesion, higher alignment, and better temporal coordination in the pairs. By combining the strengths of individual-based models and observational work with state-of-the-art robotics, we provide novel evidence that individual speed is a key, fundamental process in the emergence of collective behaviour.

Group Size and Measures of Group-Level Properties: An Examination of Eta-Squared and ICC Values

1998 ◽  
Vol 24 (2) ◽  
pp. 157-172 ◽  
Author(s):  
Paul D. Bliese ◽  
Ronald R. Halverson
Keyword(s):  
Group Size ◽  
Group Level ◽  
Eta Squared

scholarly journals Collective movement in ecology: from emerging technologies to conservation and management

2018 ◽  
Vol 373 (1746) ◽  
pp. 20170004 ◽  
Author(s):  
Peter A. H. Westley ◽  
Andrew M. Berdahl ◽  
Colin J. Torney ◽  
Dora Biro
Keyword(s):  
Quantitative Methods ◽  
Animal Movement ◽  
Movement Ecology ◽  
Theoretical Models ◽  
Collective Behaviour ◽  
Current Status ◽  
Theme Issue ◽  
Ecological Processes ◽  
Collective Movement ◽  
Sensing Technology

Recent advances in technology and quantitative methods have led to the emergence of a new field of study that stands to link insights of researchers from two closely related, but often disconnected disciplines: movement ecology and collective animal behaviour. To date, the field of movement ecology has focused on elucidating the internal and external drivers of animal movement and the influence of movement on broader ecological processes. Typically, tracking and/or remote sensing technology is employed to study individual animals in natural conditions. By contrast, the field of collective behaviour has quantified the significant role social interactions play in the decision-making of animals within groups and, to date, has predominantly relied on controlled laboratory-based studies and theoretical models owing to the constraints of studying interacting animals in the field. This themed issue is intended to formalize the burgeoning field of collective movement ecology which integrates research from both movement ecology and collective behaviour. In this introductory paper, we set the stage for the issue by briefly examining the approaches and current status of research in these areas. Next, we outline the structure of the theme issue and describe the obstacles collective movement researchers face, from data acquisition in the field to analysis and problems of scale, and highlight the key contributions of the assembled papers. We finish by presenting research that links individual and broad-scale ecological and evolutionary processes to collective movement, and finally relate these concepts to emerging challenges for the management and conservation of animals on the move in a world that is increasingly impacted by human activity. This article is part of the theme issue ‘Collective movement ecology’.

scholarly journals Collective behaviour in 480-million-year-old trilobite arthropods from Morocco

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jean Vannier ◽  
Muriel Vidal ◽  
Robin Marchant ◽  
Khadija El Hariri ◽  
Khaoula Kouraiss ◽  
...  
Keyword(s):  
Collective Behaviour ◽  
Seasonal Reproduction ◽  
Organized Activities ◽  
Group Level ◽  
Theoretical Approaches ◽  
Lower Ordovician ◽  
Invertebrate Animals ◽  
Chemical Attraction ◽  
Sexually Mature

Abstract Interactions and coordination between conspecific individuals have produced a remarkable variety of collective behaviours. This co-operation occurs in vertebrate and invertebrate animals and is well expressed in the group flight of birds, fish shoals and highly organized activities of social insects. How individuals interact and why they co-operate to constitute group-level patterns has been extensively studied in extant animals through a variety mechanistic, functional and theoretical approaches. Although collective and social behaviour evolved through natural selection over millions of years, its origin and early history has remained largely unknown. In-situ monospecific linear clusters of trilobite arthropods from the lower Ordovician (ca 480 Ma) of Morocco are interpreted here as resulting either from a collective behaviour triggered by hydrodynamic cues in which mechanical stimulation detected by motion and touch sensors may have played a major role, or from a possible seasonal reproduction behaviour leading to the migration of sexually mature conspecifics to spawning grounds, possibly driven by chemical attraction (e.g. pheromones). This study confirms that collective behaviour has a very ancient origin and probably developed throughout the Cambrian-Ordovician interval, at the same time as the first animal radiation events.

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.

Sign in / Sign up

Export Citation Format

Share Document