| 1. |
- Ward, Ashley J. W., et al.
(författare)
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Local interactions and global properties of wild, free-ranging stickleback shoals
- 2017
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 4:7
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Tidskriftsartikel (refereegranskat)abstract
- Collective motion describes the global properties of moving groups of animals and the self-organized, coordinated patterns of individual behaviour that produce them. We examined the group-level patterns and local interactions between individuals in wild, free-ranging shoals of three-spine sticklebacks, Gasterosteus aculeatus. Our data reveal that the highest frequencies of near-neighbour encounters occur at between one and two body lengths from a focal fish, with the peak frequency alongside a focal individual. Fish also show the highest alignment with these laterally placed individuals, and generally with animals in front of themselves. Furthermore, fish are more closely matched in size, speed and orientation to their near neighbours than to more distant neighbours, indicating local organization within groups. Among the group-level properties reported here, we find that polarization is strongly influenced by group speed, but also the variation in speed among individuals and the nearest neighbour distances of group members. While we find no relationship between group order and group size, we do find that larger groups tend to have lower nearest neighbour distances, which in turn may be important in maintaining group order.
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| 2. |
- Herbert-Read, James E., et al.
(författare)
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Inferring the rules of interaction of shoaling fish
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:46, s. 18726-18731
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Tidskriftsartikel (refereegranskat)abstract
- Collective motion, where large numbers of individuals move synchronously together, is achieved when individuals adopt interaction rules that determine how they respond to their neighbors' movements and positions. These rules determine how group-living animals move, make decisions, and transmit information between individuals. Nonetheless, few studies have explicitly determined these interaction rules in moving groups, and very little is known about the interaction rules of fish. Here, we identify three key rules for the social interactions of mosquitofish (Gambusia holbrooki): (i) Attraction forces are important in maintaining group cohesion, while we find only weak evidence that fish align with their neighbor's orientation; (ii) repulsion is mediated principally by changes in speed; (iii) although the positions and directions of all shoal members are highly correlated, individuals only respond to their single nearest neighbor. The last two of these rules are different from the classical models of collective animal motion, raising new questions about how fish and other animals self-organize on the move.
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| 3. |
- Herbert-Read, James E., et al.
(författare)
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The role of individuality in collective group movement
- 2013
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 280:1752, s. 20122564-
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Schaerf, T. M., et al.
(författare)
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A statistical method for identifying different rules of interaction between individuals in moving animal groups
- 2021
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Ingår i: Journal of the Royal Society, Interface. - : The Royal Society. - 1742-5662. ; 18:176
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Tidskriftsartikel (refereegranskat)abstract
- The emergent patterns of collective motion are thought to arise from application of individual-level rules that govern how individuals adjust their velocity as a function of the relative position and behaviours of their neighbours. Empirical studies have sought to determine such rules of interaction applied by 'average' individuals by aggregating data from multiple individuals across multiple trajectory sets. In reality, some individuals within a group may interact differently from others, and such individual differences can have an effect on overall group movement. However, comparisons of rules of interaction used by individuals in different contexts have been largely qualitative. Here we introduce a set of randomization methods designed to determine statistical differences in the rules of interaction between individuals. We apply these methods to a case study of leaders and followers in pairs of freely exploring eastern mosquitofish (Gambusia holbrooki). We find that each of the randomization methods is reliable in terms of: repeatability of p-values, consistency in identification of significant differences and similarity between distributions of randomization-based test statistics. We observe convergence of the distributions of randomization-based test statistics across repeat calculations, and resolution of any ambiguities regarding significant differences as the number of randomization iterations increases.
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| 5. |
- Ward, A. J. W., et al.
(författare)
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The physiology of leadership in fish shoals : leaders have lower maximal metabolic rates and lower aerobic scope
- 2018
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Ingår i: Journal of Zoology. - : Wiley. - 0952-8369 .- 1469-7998. ; 305:2, s. 73-81
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Tidskriftsartikel (refereegranskat)abstract
- The question of who leads and who follows is crucial to our understanding of the collective movements of group-living animals. Various characteristics associated with leadership have been documented across a range of social taxa, including hunger, motivation, dominance and personality. Comparatively little is known about the physiological mechanisms that underlie leadership. Here, we tested whether the metabolic phenotype of individual fish (x-ray tetras, Pristella maxillaris) determined their relative position within a moving shoal and their tendency to act as leaders. In contrast to previous work, we found that individuals with low maximal metabolic rates and low aerobic scope tended to be more likely to be found at the front of shoals and were more likely to act as leaders. We suggest that leadership by low-performing individuals leads to greater group cohesion. However, in more challenging environmental contexts, such as flowing water, higher performing animals may be more likely to become leaders while low-performing individuals seek the more favourable hydrodynamic conditions at the rear of the group. Hence, the travelling speed of the group may mediate the relationship between metabolic phenotype and leadership.
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