Shoals of sticklebacks differ in their collective personalities

cjb250 — Wed, 07 Feb 2018 01:34:32 +0000

For centuries, scientists and non-scientists alike have been fascinated by the beautiful and often complex collective behaviour of animal groups, such as the highly synchronised movements of flocks of birds and schools of fish. Often, those spectacular collective patterns emerge from individual group members using simple rules in their interactions, without requiring global knowledge of their group.

In recent years it has also become apparent that, across the animal kingdom, individual animals often differ considerably and consistently in their behaviour, with some individuals being bolder, more active, or more social than others.

New research conducted at the ̽��ֱ�� of Cambridge’s Department of Zoology suggests that observations of different groups of schooling fish could provide important insights into how the make-up of groups can drive collective behaviour and performance.

In the study, published today in the journal Proceedings of the Royal Society B, the researchers created random groups of wild-caught stickleback fish and subjected them repeatedly to a range of environments that included open spaces, plant cover, and patches of food.

Dr Jolle Jolles, lead author of the study, now based at the Max Planck Institute for Ornithology, said: “By filming the schooling fish from above and tracking the groups’ movements in detail, we found that the randomly composed shoals showed profound differences in their collective behaviour that persisted across different ecological contexts. Some groups were consistently faster, better coordinated, more cohesive, and showed clearer leadership structure than others.

“That such differences existed among the groups is remarkable as individuals were randomly grouped with others that were of similar age and size and with which they had very limited previous social contact.”

This research shows for the first time that, even among animals where group membership changes frequently over time and individuals are not very strongly related to each other, such as schooling fish or flocking birds, stable differences can emerge in the collective performance of animal groups.

Such behavioural variability among groups may directly affect the survival and reproductive success of the individuals within them and influence how they associate with one another. Ultimately these findings may therefore help understand the selective pressures that have shaped social behaviour.

Dr Andrea Manica, co-author of the paper from the ̽��ֱ�� of Cambridge, added: “Our research reveals that the collective performance of groups is strongly driven by their composition, suggesting that consistent behavioural differences among groups could be a widespread phenomenon in animal societies.”

These research findings provide important new insights that may help explain and predict the performance of social groups, which could be beneficial in building human teams or constructing automated robot swarms.

̽��ֱ��research was supported by the Biotechnology and Biological Sciences Research Council.

Reference
Jolles, JW et al. Repeatable group differences in the collective behaviour of stickleback shoals across ecological contexts. Proceedings of the Royal Society B; 7 Feb 2018; DOI: 10.1098/rspb.2017.2629

Research from the ̽��ֱ�� of Cambridge has revealed that, among schooling fish, groups can have different collective personalities, with some shoals sticking closer together, being better coordinated, and showing clearer leadership than others.

Jolle Jolles

Stickleback

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How birds of different feathers flock together

gm349 — Wed, 06 Mar 2013 11:41:51 +0000

New research from the Universities of Cambridge and Exeter reveals for the first time that, contrary to current models used to explain the movement of flocks, the differences between bird species and social relationships between individuals play a critical role in determining the dynamics of mixed-species flocks.

̽��ֱ��unified behaviour of bird flocks has puzzled scientists for hundreds of years. One naturalist from the turn of the century even suggested telepathy may be involved. There have since been more logical explanations, including mathematical models that show that repeated interactions among individuals following simple rules can generate coordinated group movements. However, these models usually rely on the assumption that individuals within groups are identical and interact independently, which may not reflect reality.

Jolle Jolles, a PhD student at the ̽��ֱ�� of Cambridge’s Department of Zoology and author of the paper, said: “Spectacular collective behaviour can be found in a large range of animal species, and we now know that often these complex coordinated group movements may be the result of individuals following simple rules. However, rarely are the individual characteristics and social relationships within them taken into account. Our research highlights that these striking displays of group behaviour are much more complex.”

By analysing high-resolution photographs of mixed flocks of rooks and jackdaws (both from the corvid family), the researchers found that rather than individuals interacting in a consistent fashion throughout the flock, interactions depended on social dynamics between the different species as well as relationships within a species.

̽��ֱ��researchers discovered that birds prefer to fly close to members of their own species, and that the larger and more dominant rooks take the lead by flying near the front of flocks. Additionally, the lifelong, monogamous pair bonds that are characteristic of both species seem to be reflected in flight, as birds often fly particularly close to a single, same-species partner.

Dr Alex Thornton, principal investigator of the Cambridge Jackdaw Project, now at the ̽��ֱ�� of Exeter and author of the paper, said: “Together, our findings demonstrate that to understand the structure of groups – such as bird flocks – we need to consider the characteristics and relationships of the individuals within them.”

̽��ֱ��research, which was funded by the British Ecological Society and the BBSRC, was published in the journal Animal Behaviour.

For more information about this story, please contact: Genevieve Maul, Office of Communications, ̽��ֱ�� of Cambridge. Email: Genevieve.Maul@admin.cam.ac.uk; Tel: 01223 765542.

When different species of birds flock together, their flight formations are determined by social dynamics both between and within species.

Together, our findings demonstrate that to understand the structure of groups – such as bird flocks – we need to consider the characteristics and relationships of the individuals within them.

Alex Thornton

Jolle Jolles

Circles indicate paired flight of jackdaws

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̽��ֱ�� of Cambridge - Jolle Jolles

Shoals of sticklebacks differ in their collective personalities

How birds of different feathers flock together