1
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Hoetzlein RC. Flock2: A model for orientation-based social flocking. J Theor Biol 2024; 593:111880. [PMID: 38972569 DOI: 10.1016/j.jtbi.2024.111880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 06/14/2024] [Indexed: 07/09/2024]
Abstract
The aerial flocking of birds, or murmurations, has fascinated observers while presenting many challenges to behavioral study and simulation. We examine how the periphery of murmurations remain well bounded and cohesive. We also investigate agitation waves, which occur when a flock is disturbed, developing a plausible model for how they might emerge spontaneously. To understand these behaviors a new model is presented for orientation-based social flocking. Previous methods model inter-bird dynamics by considering the neighborhood around each bird, and introducing forces for avoidance, alignment, and cohesion as three dimensional vectors that alter acceleration. Our method introduces orientation-based social flocking that treats social influences from neighbors more realistically as a desire to turn, indirectly controlling the heading in an aerodynamic model. While our model can be applied to any flocking social bird we simulate flocks of starlings, Sturnus vulgaris, and demonstrate the possibility of orientation waves in the absence of predators. Our model exhibits spherical and ovoidal flock shapes matching observation. Comparisons of our model to Reynolds' on energy consumption and frequency analysis demonstrates more realistic motions, significantly less energy use in turning, and a plausible mechanism for emergent orientation waves.
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2
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Carder HM, Occhialini G, Bistoni G, Riplinger C, Kwan EE, Wendlandt AE. The sugar cube: Network control and emergence in stereoediting reactions. Science 2024; 385:456-463. [PMID: 39052778 DOI: 10.1126/science.adp2447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 06/07/2024] [Indexed: 07/27/2024]
Abstract
Stereochemical editing strategies have recently enabled the transformation of readily accessible substrates into rare and valuable products. Typically, site selectivity is achieved by minimizing kinetic complexity by using protecting groups to suppress reactivity at undesired sites (substrate control) or by using catalysts with tailored shapes to drive reactivity at the desired site (catalyst control). We propose "network control," a contrasting paradigm that exploits hidden interactions between rate constants to greatly amplify modest intrinsic biases and enable precise multisite editing. When network control is applied to the photochemical isomerization of hexoses, six of the eight possible diastereomers can be selectively obtained. The amplification effect can be viewed as a mesoscale phenomenon between the limiting regimes of kinetic control in simple chemical systems and metabolic regulation in complex biological systems.
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Affiliation(s)
- Hayden M Carder
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Gino Occhialini
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Giovanni Bistoni
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | | | | | - Alison E Wendlandt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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3
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Fenton AA. Remapping revisited: how the hippocampus represents different spaces. Nat Rev Neurosci 2024; 25:428-448. [PMID: 38714834 DOI: 10.1038/s41583-024-00817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2024] [Indexed: 05/25/2024]
Abstract
The representation of distinct spaces by hippocampal place cells has been linked to changes in their place fields (the locations in the environment where the place cells discharge strongly), a phenomenon that has been termed 'remapping'. Remapping has been assumed to be accompanied by the reorganization of subsecond cofiring relationships among the place cells, potentially maximizing hippocampal information coding capacity. However, several observations challenge this standard view. For example, place cells exhibit mixed selectivity, encode non-positional variables, can have multiple place fields and exhibit unreliable discharge in fixed environments. Furthermore, recent evidence suggests that, when measured at subsecond timescales, the moment-to-moment cofiring of a pair of cells in one environment is remarkably similar in another environment, despite remapping. Here, I propose that remapping is a misnomer for the changes in place fields across environments and suggest instead that internally organized manifold representations of hippocampal activity are actively registered to different environments to enable navigation, promote memory and organize knowledge.
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Affiliation(s)
- André A Fenton
- Center for Neural Science, New York University, New York, NY, USA.
- Neuroscience Institute at the NYU Langone Medical Center, New York, NY, USA.
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4
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Nguyen D, Ssebunya RN, Hirani K, Mandalakas A, Benjamin J, Ligon BL, Thammasitboon S. Using starling murmuration as a model for creating a global health community of practice to advance equity in scholarship. MEDICAL TEACHER 2024; 46:537-544. [PMID: 37756416 DOI: 10.1080/0142159x.2023.2260083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
BACKGROUND Disparities in scholarship exist between authors in low- or middle-income countries (LMIC) and high-income countries. Recognizing these disparities in our global network providing pediatric, adolescent, and maternal healthcare to vulnerable populations in LMIC, we sought to improve access and provide resources to address educational needs and ultimately impact the broader scholarship disparity. METHODS We created a virtual community of practice (CoP) program underpinned by principles from starling murmuration to promote interdisciplinary scholarship. We developed guiding principles- autonomy, mastery and purpose- to direct the Global Health Scholarship Community of Practice Program. Program components included a continuing professional development (CPD) program, an online platform and resource center, a symposium for scholarship showcase, and peer coaching. RESULTS From February 2021 to October 2022, 277 individuals joined. Eighty-seven percent came from LMIC, with 69% from Africa, 6% from South America, and 13% from other LMIC regions. An average of 30 members attended each of the 21 CPD sessions. Thirty-nine authors submitted nine manuscripts for publication. The symposium increased participation of individuals from LMIC and enhanced scholarly skills and capacity. Early outcomes indicate that members learned, shared, and collaborated as scholars using the online platform. CONCLUSION Sharing of knowledge and collaboration globally are feasible through a virtual CoP and offer a benchmark for future sustainable solutions in healthcare capacity building. We recommend such model and virtual platform to promote healthcare education and mentoring across disciplines.
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Affiliation(s)
- Diane Nguyen
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Department of Education, Innovation, and Technology, Baylor College of Medicine, Houston, TX, USA
- Center for Research, Innovation and Scholarship in Health Professions Education, Texas Children's Hospital, Houston, TX, USA
| | - Rogers N Ssebunya
- Directorate of Research and Knowledge Management, Baylor College of Medicine Children's Foundation-Uganda, Kampala, Uganda
| | - Kajal Hirani
- Baylor International Pediatric AIDS Initiative (BIPAI), Baylor College of Medicine Children's Foundation-Malawi, Lilongwe, Malawi
| | - Anna Mandalakas
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Jennifer Benjamin
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Department of Education, Innovation, and Technology, Baylor College of Medicine, Houston, TX, USA
- Center for Research, Innovation and Scholarship in Health Professions Education, Texas Children's Hospital, Houston, TX, USA
| | - B Lee Ligon
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Center for Research, Innovation and Scholarship in Health Professions Education, Texas Children's Hospital, Houston, TX, USA
| | - Satid Thammasitboon
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Center for Research, Innovation and Scholarship in Health Professions Education, Texas Children's Hospital, Houston, TX, USA
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5
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Levy ERJ, Carrillo-Segura S, Park EH, Redman WT, Hurtado JR, Chung S, Fenton AA. A manifold neural population code for space in hippocampal coactivity dynamics independent of place fields. Cell Rep 2023; 42:113142. [PMID: 37742193 PMCID: PMC10842170 DOI: 10.1016/j.celrep.2023.113142] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/14/2023] [Accepted: 08/30/2023] [Indexed: 09/26/2023] Open
Abstract
Hippocampus place cell discharge is temporally unreliable across seconds and days, and place fields are multimodal, suggesting an "ensemble cofiring" spatial coding hypothesis with manifold dynamics that does not require reliable spatial tuning, in contrast to hypotheses based on place field (spatial tuning) stability. We imaged mouse CA1 (cornu ammonis 1) ensembles in two environments across three weeks to evaluate these coding hypotheses. While place fields "remap," being more distinct between than within environments, coactivity relationships generally change less. Decoding location and environment from 1-s ensemble location-specific activity is effective and improves with experience. Decoding environment from cell-pair coactivity relationships is also effective and improves with experience, even after removing place tuning. Discriminating environments from 1-s ensemble coactivity relies crucially on the cells with the most anti-coactive cell-pair relationships because activity is internally organized on a low-dimensional manifold of non-linear coactivity relationships that intermittently reregisters to environments according to the anti-cofiring subpopulation activity.
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Affiliation(s)
| | - Simón Carrillo-Segura
- Center for Neural Science, New York University, New York, NY 10003, USA; Graduate Program in Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA
| | - Eun Hye Park
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - William Thomas Redman
- Interdepartmental Graduate Program in Dynamical Neuroscience, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | | | - SueYeon Chung
- Center for Neural Science, New York University, New York, NY 10003, USA; Flatiron Institute Center for Computational Neuroscience, New York, NY 10010, USA
| | - André Antonio Fenton
- Center for Neural Science, New York University, New York, NY 10003, USA; Neuroscience Institute at the NYU Langone Medical Center, New York, NY 10016, USA.
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6
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Pertzelan A, Ariel G, Kiflawi M. Schooling of light reflecting fish. PLoS One 2023; 18:e0289026. [PMID: 37478091 PMCID: PMC10361475 DOI: 10.1371/journal.pone.0289026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/09/2023] [Indexed: 07/23/2023] Open
Abstract
One of the hallmarks of the collective movement of large schools of pelagic fish are waves of shimmering flashes that propagate across the school, usually following an attack by a predator. Such flashes arise when sunlight is reflected off the specular (mirror-like) skin that characterizes many pelagic fishes, where it is otherwise thought to offer a means for camouflage in open waters. While it has been suggested that these 'shimmering waves' are a visual manifestation of the synchronized escape response of the fish, the phenomenon has been regarded only as an artifact of esthetic curiosity. In this study we apply agent-based simulations and deep learning techniques to show that, in fact, shimmering waves contain information on the behavioral dynamics of the school. Our analyses are based on a model that combines basic rules of collective motion and the propagation of light beams in the ocean, as they hit and reflect off the moving fish. We use the resulting reflection patterns to infer the essential dynamics and inter-individual interactions which are necessary to generate shimmering waves. Moreover, we show that light flashes observed by the school members themselves may extend the range at which information can be communicated across the school. Assuming that fish pay heed to this information, for example by entering an apprehensive state of reduced response-time, our analysis suggests that it can speed up the propagation of information across the school. Further still, we use an artificial neural network to show that light flashes are, on their own, indicative of the state and dynamics of the school, and are sufficient to infer the direction of attack and the shape of the school with high accuracy.
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Affiliation(s)
- Assaf Pertzelan
- Faculty of Life Sciences, Ben Gurion University, Beer-Sheva, Israel
- The Interuniversity Institute for Marine Sciences at Eilat (IUI), Eilat, Israel
| | - Gil Ariel
- Department of Mathematics, Bar-Ilan University, Ramat-Gan, Israel
| | - Moshe Kiflawi
- Faculty of Life Sciences, Ben Gurion University, Beer-Sheva, Israel
- The Interuniversity Institute for Marine Sciences at Eilat (IUI), Eilat, Israel
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7
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Haluts A, Jordan A, Gov NS. Modelling animal contests based on spatio-temporal dynamics. J R Soc Interface 2023; 20:20220866. [PMID: 37221864 PMCID: PMC10206449 DOI: 10.1098/rsif.2022.0866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/25/2023] [Indexed: 05/25/2023] Open
Abstract
We present a general theoretical model for the spatio-temporal dynamics of animal contests. Inspired by interactions between physical particles, the model is formulated in terms of effective interaction potentials, which map typical elements of contest behaviour into empirically verifiable rules of contestant motion. This allows us to simulate the observable dynamics of contests in various realistic scenarios, notably in dyadic contests over a localized resource. Assessment strategies previously formulated in game-theoretic models, as well as the effects of fighting costs, can be described as variations in our model's parameters. Furthermore, the trends of contest duration associated with these assessment strategies can be derived and understood within the model. Detailed description of the contestants' motion enables the exploration of spatio-temporal properties of asymmetric contests, such as the emergence of chase dynamics. Overall, our framework aims to bridge the growing gap between empirical capabilities and theory in this widespread aspect of animal behaviour.
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Affiliation(s)
- Amir Haluts
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Alex Jordan
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, Konstanz 78315, Germany
| | - Nir S. Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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8
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Devereux HL, Turner MS. Environmental Path-Entropy and Collective Motion. PHYSICAL REVIEW LETTERS 2023; 130:168201. [PMID: 37154632 DOI: 10.1103/physrevlett.130.168201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/18/2023] [Accepted: 03/28/2023] [Indexed: 05/10/2023]
Abstract
Inspired by the swarming or flocking of animal systems we study groups of agents moving in unbounded 2D space. Individual trajectories derive from a "bottom-up" principle: individuals reorient to maximize their future path entropy over environmental states. This can be seen as a proxy for keeping options open, a principle that may confer evolutionary fitness in an uncertain world. We find an ordered (coaligned) state naturally emerges, as well as disordered states or rotating clusters; similar phenotypes are observed in birds, insects, and fish, respectively. The ordered state exhibits an order-disorder transition under two forms of noise: (i) standard additive orientational noise, applied to the postdecision orientations and (ii) "cognitive" noise, overlaid onto each individual's model of the future paths of other agents. Unusually, the order increases at low noise, before later decreasing through the order-disorder transition as the noise increases further.
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Affiliation(s)
- Harvey L Devereux
- Department of Mathematics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Matthew S Turner
- Department of Physics and Centre for Complexity Science, University of Warwick, Coventry CV4 7AL, United Kingdom and Department of Chemical Engineering, Kyoto University, Kyoto 615-8510, Japan
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9
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Papadopoulou M, Fürtbauer I, O'Bryan LR, Garnier S, Georgopoulou DG, Bracken AM, Christensen C, King AJ. Dynamics of collective motion across time and species. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220068. [PMID: 36802781 PMCID: PMC9939269 DOI: 10.1098/rstb.2022.0068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/17/2022] [Indexed: 02/21/2023] Open
Abstract
Most studies of collective animal behaviour rely on short-term observations, and comparisons of collective behaviour across different species and contexts are rare. We therefore have a limited understanding of intra- and interspecific variation in collective behaviour over time, which is crucial if we are to understand the ecological and evolutionary processes that shape collective behaviour. Here, we study the collective motion of four species: shoals of stickleback fish (Gasterosteus aculeatus), flocks of homing pigeons (Columba livia), a herd of goats (Capra aegagrus hircus) and a troop of chacma baboons (Papio ursinus). First, we describe how local patterns (inter-neighbour distances and positions), and group patterns (group shape, speed and polarization) during collective motion differ across each system. Based on these, we place data from each species within a 'swarm space', affording comparisons and generating predictions about the collective motion across species and contexts. We encourage researchers to add their own data to update the 'swarm space' for future comparative work. Second, we investigate intraspecific variation in collective motion over time and provide guidance for researchers on when observations made over different time scales can result in confident inferences regarding species collective motion. This article is part of a discussion meeting issue 'Collective behaviour through time'.
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Affiliation(s)
- Marina Papadopoulou
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
| | - Ines Fürtbauer
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
| | - Lisa R. O'Bryan
- Department of Psychological Sciences, Rice University, Houston, TX 77005, USA
| | - Simon Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Dimitra G. Georgopoulou
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
- Institute of Marine Biology, Biotechnology & Aquaculture, HCMR, 71500 Hersonissos, Crete, Greece
| | - Anna M. Bracken
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
- School of Biodiversity, One Health and Veterinary Medicine, Graham Kerr Building, Glasgow G12 8QQ, UK
| | - Charlotte Christensen
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zürich, Switzerland
| | - Andrew J. King
- Biosciences, School of Biosciences, Geography and Physics, Faculty of Science and Engineering, Swansea University, SA2 8PP Swansea, UK
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10
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Spontaneous vortex formation by microswimmers with retarded attractions. Nat Commun 2023; 14:56. [PMID: 36599830 DOI: 10.1038/s41467-022-35427-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/02/2022] [Indexed: 01/05/2023] Open
Abstract
Collective states of inanimate particles self-assemble through physical interactions and thermal motion. Despite some phenomenological resemblance, including signatures of criticality, the autonomous dynamics that binds motile agents into flocks, herds, or swarms allows for much richer behavior. Low-dimensional models have hinted at the crucial role played in this respect by perceived information, decision-making, and feedback, implying that the corresponding interactions are inevitably retarded. Here we present experiments on spherical Brownian microswimmers with delayed self-propulsion toward a spatially fixed target. We observe a spontaneous symmetry breaking to a transiently chiral dynamical state and concomitant critical behavior that do not rely on many-particle cooperativity. By comparison with the stochastic delay differential equation of motion of a single swimmer, we pinpoint the delay-induced effective synchronization of the swimmers with their own past as the key mechanism. Increasing numbers of swimmers self-organize into layers with pro- and retrograde orbital motion, synchronized and stabilized by steric, phoretic, and hydrodynamic interactions. Our results demonstrate how even most simple retarded interactions can foster emergent complex adaptive behavior in small active-particle ensembles.
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11
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O'Coin D, Mclvor GE, Thornton A, Ouellette NT, Ling H. Velocity correlations in jackdaw flocks in different ecological contexts. Phys Biol 2022; 20. [PMID: 36541516 DOI: 10.1088/1478-3975/aca862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 12/01/2022] [Indexed: 12/03/2022]
Abstract
Velocity correlation is an important feature for animal groups performing collective motions. Previous studies have mostly focused on the velocity correlation in a single ecological context. It is unclear whether correlation characteristics vary in a single species in different contexts. Here, we studied the velocity correlations in jackdaw flocks in two different contexts: transit flocks where birds travel from one location to another, and mobbing flocks where birds respond to an external stimulus. We found that in both contexts, although the interaction rules are different, the velocity correlations remain scale-free, i.e. the correlation length (the distance over which the velocity of two individuals is similar) increases linearly with the group size. Furthermore, we found that the correlation length is independent of the group density for transit flocks, but increases with increasing group density in mobbing flocks. This result confirms a previous observation that birds obey topological interactions in transit flocks, but switch to metric interactions in mobbing flocks. Finally, in both contexts, the impact of group polarization on correlation length is not significant. Our results suggest that wild animals are always able to respond coherently to perturbations regardless of context.
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Affiliation(s)
- Daniel O'Coin
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, North Dartmouth, MA, United States of America
| | - Guillam E Mclvor
- Center for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Alex Thornton
- Center for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Nicholas T Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States of America
| | - Hangjian Ling
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, North Dartmouth, MA, United States of America
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12
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Delfino HC, Carlos CJ. Intra‐annual variation in activity budgets of a wild Chilean Flamingo (
Phoenicopterus chilensis
) population in Southern Brazil. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Henrique Cardoso Delfino
- Laboratório de Ecologia e Sistemática de Aves e Mamíferos Marinhos (LABSMAR), Departamento de Zoologia, Programa de Pós‐Graduação em Biologia Animal, Instituto de Biociências Universidade Federal do Rio Grande do Sul 9500 CEP: 91509‐900, Av. Bento Gonçalves Porto Alegre RS Brazil
| | - Caio José Carlos
- Laboratório de Ecologia e Sistemática de Aves e Mamíferos Marinhos (LABSMAR), Departamento de Zoologia, Programa de Pós‐Graduação em Biologia Animal, Instituto de Biociências Universidade Federal do Rio Grande do Sul 9500 CEP: 91509‐900, Av. Bento Gonçalves Porto Alegre RS Brazil
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13
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Papadopoulou M, Hildenbrandt H, Sankey DWE, Portugal SJ, Hemelrijk CK. Emergence of splits and collective turns in pigeon flocks under predation. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211898. [PMID: 35223068 PMCID: PMC8864349 DOI: 10.1098/rsos.211898] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/25/2022] [Indexed: 05/03/2023]
Abstract
Complex patterns of collective behaviour may emerge through self-organization, from local interactions among individuals in a group. To understand what behavioural rules underlie these patterns, computational models are often necessary. These rules have not yet been systematically studied for bird flocks under predation. Here, we study airborne flocks of homing pigeons attacked by a robotic falcon, combining empirical data with a species-specific computational model of collective escape. By analysing GPS trajectories of flocking individuals, we identify two new patterns of collective escape: early splits and collective turns, occurring even at large distances from the predator. To examine their formation, we extend an agent-based model of pigeons with a 'discrete' escape manoeuvre by a single initiator, namely a sudden turn interrupting the continuous coordinated motion of the group. Both splits and collective turns emerge from this rule. Their relative frequency depends on the angular velocity and position of the initiator in the flock: sharp turns by individuals at the periphery lead to more splits than collective turns. We confirm this association in the empirical data. Our study highlights the importance of discrete and uncoordinated manoeuvres in the collective escape of bird flocks and advocates the systematic study of their patterns across species.
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Affiliation(s)
- Marina Papadopoulou
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Hanno Hildenbrandt
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | | | - Steven J. Portugal
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, UK
| | - Charlotte K. Hemelrijk
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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14
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Causes of variation of darkness in flocks of starlings, a computational model. SWARM INTELLIGENCE 2021. [DOI: 10.1007/s11721-021-00207-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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An all-leader agent-based model for turning and flocking birds. J Math Biol 2021; 83:45. [PMID: 34596763 DOI: 10.1007/s00285-021-01675-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 08/27/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
Starting from recent experimental observations of starlings and jackdaws, we propose a minimal agent-based mathematical model for bird flocks based on a system of second-order delayed stochastic differential equations with discontinuous (both in space and time) right-hand side. The model is specifically designed to reproduce self-organized spontaneous sudden changes of direction, not caused by external stimuli like predator's attacks. The main novelty of the model is that every bird is a potential turn initiator, thus leadership is formed in a group of indistinguishable agents. We investigate some theoretical properties of the model and we show the numerical results. Biological insights are also discussed.
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16
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Unraveling hidden interactions in complex systems with deep learning. Sci Rep 2021; 11:12804. [PMID: 34140551 PMCID: PMC8211832 DOI: 10.1038/s41598-021-91878-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 05/26/2021] [Indexed: 11/08/2022] Open
Abstract
Rich phenomena from complex systems have long intrigued researchers, and yet modeling system micro-dynamics and inferring the forms of interaction remain challenging for conventional data-driven approaches, being generally established by scientists with human ingenuity. In this study, we propose AgentNet, a model-free data-driven framework consisting of deep neural networks to reveal and analyze the hidden interactions in complex systems from observed data alone. AgentNet utilizes a graph attention network with novel variable-wise attention to model the interaction between individual agents, and employs various encoders and decoders that can be selectively applied to any desired system. Our model successfully captured a wide variety of simulated complex systems, namely cellular automata (discrete), the Vicsek model (continuous), and active Ornstein-Uhlenbeck particles (non-Markovian) in which, notably, AgentNet's visualized attention values coincided with the true variable-wise interaction strengths and exhibited collective behavior that was absent in the training data. A demonstration with empirical data from a flock of birds showed that AgentNet could identify hidden interaction ranges exhibited by real birds, which cannot be detected by conventional velocity correlation analysis. We expect our framework to open a novel path to investigating complex systems and to provide insight into general process-driven modeling.
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Mercado E. Song Morphing by Humpback Whales: Cultural or Epiphenomenal? Front Psychol 2021; 11:574403. [PMID: 33519588 PMCID: PMC7844363 DOI: 10.3389/fpsyg.2020.574403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Singing humpback whales (Megaptera noavaengliae) collectively and progressively change the sounds and patterns they produce within their songs throughout their lives. The dynamic modifications that humpback whales make to their songs are often cited as an impressive example of cultural transmission through vocal learning in a non-human. Some elements of song change challenge this interpretation, however, including: (1) singers often incrementally and progressively morph phrases within and across songs as time passes, with trajectories of change being comparable across multiple time scales; (2) acoustically isolated subpopulations singing similar songs morph the acoustic properties of songs in similar ways; and (3) complex sound patterns, including phrases, themes, and whole songs, recur across years and populations. These properties of song dynamics suggest that singing humpback whales may be modulating song features in response to local conditions and genetic predispositions rather than socially learning novel sound patterns by copying other singers. Experimental and observational tests of key predictions of these alternative hypotheses are critical to identifying how and why singing humpback whales constantly change their songs.
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Affiliation(s)
- Eduardo Mercado
- Neural and Cognitive Plasticity Laboratory, Department of Psychology, University at Buffalo, Buffalo, NY, United States
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Gompper G, Winkler RG, Speck T, Solon A, Nardini C, Peruani F, Löwen H, Golestanian R, Kaupp UB, Alvarez L, Kiørboe T, Lauga E, Poon WCK, DeSimone A, Muiños-Landin S, Fischer A, Söker NA, Cichos F, Kapral R, Gaspard P, Ripoll M, Sagues F, Doostmohammadi A, Yeomans JM, Aranson IS, Bechinger C, Stark H, Hemelrijk CK, Nedelec FJ, Sarkar T, Aryaksama T, Lacroix M, Duclos G, Yashunsky V, Silberzan P, Arroyo M, Kale S. The 2020 motile active matter roadmap. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:193001. [PMID: 32058979 DOI: 10.1088/1361-648x/ab6348] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Activity and autonomous motion are fundamental in living and engineering systems. This has stimulated the new field of 'active matter' in recent years, which focuses on the physical aspects of propulsion mechanisms, and on motility-induced emergent collective behavior of a larger number of identical agents. The scale of agents ranges from nanomotors and microswimmers, to cells, fish, birds, and people. Inspired by biological microswimmers, various designs of autonomous synthetic nano- and micromachines have been proposed. Such machines provide the basis for multifunctional, highly responsive, intelligent (artificial) active materials, which exhibit emergent behavior and the ability to perform tasks in response to external stimuli. A major challenge for understanding and designing active matter is their inherent nonequilibrium nature due to persistent energy consumption, which invalidates equilibrium concepts such as free energy, detailed balance, and time-reversal symmetry. Unraveling, predicting, and controlling the behavior of active matter is a truly interdisciplinary endeavor at the interface of biology, chemistry, ecology, engineering, mathematics, and physics. The vast complexity of phenomena and mechanisms involved in the self-organization and dynamics of motile active matter comprises a major challenge. Hence, to advance, and eventually reach a comprehensive understanding, this important research area requires a concerted, synergetic approach of the various disciplines. The 2020 motile active matter roadmap of Journal of Physics: Condensed Matter addresses the current state of the art of the field and provides guidance for both students as well as established scientists in their efforts to advance this fascinating area.
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Affiliation(s)
- Gerhard Gompper
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
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Lima SL, Lee JK. Is social coordination during escape flights a general phenomenon in birds? Ethology 2020. [DOI: 10.1111/eth.12958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven L. Lima
- Department of Biology Indiana State University Terre Haute IN USA
| | - Jong Koo Lee
- Department of Biology Indiana State University Terre Haute IN USA
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Behavioural plasticity and the transition to order in jackdaw flocks. Nat Commun 2019; 10:5174. [PMID: 31729384 PMCID: PMC6858344 DOI: 10.1038/s41467-019-13281-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/25/2019] [Indexed: 12/04/2022] Open
Abstract
Collective behaviour is typically thought to arise from individuals following fixed interaction rules. The possibility that interaction rules may change under different circumstances has thus only rarely been investigated. Here we show that local interactions in flocks of wild jackdaws (Corvus monedula) vary drastically in different contexts, leading to distinct group-level properties. Jackdaws interact with a fixed number of neighbours (topological interactions) when traveling to roosts, but coordinate with neighbours based on spatial distance (metric interactions) during collective anti-predator mobbing events. Consequently, mobbing flocks exhibit a dramatic transition from disordered aggregations to ordered motion as group density increases, unlike transit flocks where order is independent of density. The relationship between group density and group order during this transition agrees well with a generic self-propelled particle model. Our results demonstrate plasticity in local interaction rules and have implications for both natural and artificial collective systems. Modelling collective behaviour in different circumstances remains a challenge because of uncertainty related to interaction rule changes. Here, the authors report plasticity in local interaction rules in flocks of wild jackdaws with implications for both natural and artificial collective systems.
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Ling H, Mclvor GE, Westley J, van der Vaart K, Yin J, Vaughan RT, Thornton A, Ouellette NT. Collective turns in jackdaw flocks: kinematics and information transfer. J R Soc Interface 2019; 16:20190450. [PMID: 31640502 PMCID: PMC6833319 DOI: 10.1098/rsif.2019.0450] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/01/2019] [Indexed: 11/12/2022] Open
Abstract
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.
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Affiliation(s)
- Hangjian Ling
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, North Dartmouth, MA, USA
| | - Guillam E. Mclvor
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Joseph Westley
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Kasper van der Vaart
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Jennifer Yin
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Richard T. Vaughan
- School of Computing Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Alex Thornton
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Nicholas T. Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
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22
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Propagating wave based on transition of interaction within animal group. Biosystems 2019; 185:104019. [PMID: 31445065 DOI: 10.1016/j.biosystems.2019.104019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 11/20/2022]
Abstract
Propagating waves, information transfers of direction of travel in collective groups, have been observed in animal groups of insects, birds, fish, and mammals. Nevertheless, although many previously proposed models of group behaviors have elucidated various aspects of collective motion, none has directly shown the propagating wave constructively. These models consisted of flocking algorithms in which individuals modify their positions or velocities through average responses to their neighbors. The algorithms involve the function of diluting local fluctuations, individual motions, or social cues that initiate coherent decision-making of where to travel and which spread through a group in the form of a wave. The present study challenged physics-inspired models based solely on average interaction and instead proposed a combination with pair interaction: the 'copy' mechanism. By the mechanism, individuals specially attend and mimic the motion of the largest turning neighbor. The model comprises three modes (base, copy, and align modes) that sequentially switch among themselves, depending on the degree of variance in direction. The model therefore involves propagating waves that produce rapid collective responses and quick turning motions of a group. This proposal is an attempt to uncover the mechanisms of self-organized waves in simulation studies of coordinated groups, without explicit signals such as alarm calls. Understanding such mechanisms is expected to contribute to the 'collective mind' metaphor, answering the question of how animal groups obtain higher-order computational capabilities from local inter-individual interactions.
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Bastien R, Porat A, Meroz Y. Towards a framework for collective behavior in growth-driven systems, based on plant-inspired allotropic pairwise interactions. BIOINSPIRATION & BIOMIMETICS 2019; 14:055004. [PMID: 31292284 DOI: 10.1088/1748-3190/ab30d3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A variety of biological systems are not motile, but sessile in nature, relying on growth as the main driver of their movement. Groups of such growing organisms can form complex structures, such as the functional architecture of growing axons, or the adaptive structure of plant root systems. These processes are not yet understood, however the decentralized growth dynamics bear similarities to the collective behavior observed in groups of motile organisms, such as flocks of birds or schools of fish. Equivalent growth mechanisms make these systems amenable to a theoretical framework inspired by tropic responses of plants, where growth is considered implicitly as the driver of the observed bending towards a stimulus. We introduce two new concepts related to plant tropisms: point tropism, the response of a plant to a nearby point signal source, and allotropism, the growth-driven response of plant organs to neighboring plants. We first analytically and numerically investigate the 2D dynamics of single organs responding to point signals fixed in space. Building on this we study pairs of organs interacting via allotropism, i.e. each organ senses signals emitted at the tip of their neighbor and responds accordingly. In the case of local sensing we find a rich state-space. We describe the different states, as well as the sharp transitions between them. We also find that the form of the state-space depends on initial conditions. This work sets the stage towards a theoretical framework for the investigation and understanding of systems of interacting growth-driven individuals.
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Affiliation(s)
- Renaud Bastien
- Department of Collective Behaviour, Max Planck Institute for Ornithology and Department of Biology, University of Konstanz, 78464 Konstanz, Germany. These two authors contributed equally
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26
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Ling H, Mclvor GE, van der Vaart K, Vaughan RT, Thornton A, Ouellette NT. Local interactions and their group-level consequences in flocking jackdaws. Proc Biol Sci 2019; 286:20190865. [PMID: 31266425 PMCID: PMC6650722 DOI: 10.1098/rspb.2019.0865] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/07/2019] [Indexed: 11/12/2022] Open
Abstract
As one of nature's most striking examples of collective behaviour, bird flocks have attracted extensive research. However, we still lack an understanding of the attractive and repulsive forces that govern interactions between individuals within flocks and how these forces influence neighbours' relative positions and ultimately determine the shape of flocks. We address these issues by analysing the three-dimensional movements of wild jackdaws ( Corvus monedula) in flocks containing 2-338 individuals. We quantify the social interaction forces in large, airborne flocks and find that these forces are highly anisotropic. The long-range attraction in the direction perpendicular to the movement direction is stronger than that along it, and the short-range repulsion is generated mainly by turning rather than changing speed. We explain this phenomenon by considering wingbeat frequency and the change in kinetic and gravitational potential energy during flight, and find that changing the direction of movement is less energetically costly than adjusting speed for birds. Furthermore, our data show that collision avoidance by turning can alter local neighbour distributions and ultimately change the group shape. Our results illustrate the macroscopic consequences of anisotropic interaction forces in bird flocks, and help to draw links between group structure, local interactions and the biophysics of animal locomotion.
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Affiliation(s)
- Hangjian Ling
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Guillam E. Mclvor
- Center for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Kasper van der Vaart
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | | | - Alex Thornton
- Center for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Nicholas T. Ouellette
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
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27
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Ling H, Mclvor GE, van der Vaart K, Vaughan RT, Thornton A, Ouellette NT. Costs and benefits of social relationships in the collective motion of bird flocks. Nat Ecol Evol 2019; 3:943-948. [DOI: 10.1038/s41559-019-0891-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/28/2019] [Indexed: 11/10/2022]
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Storms RF, Carere C, Zoratto F, Hemelrijk CK. Complex patterns of collective escape in starling flocks under predation. Behav Ecol Sociobiol 2019; 73:10. [PMID: 30930523 PMCID: PMC6404399 DOI: 10.1007/s00265-018-2609-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/13/2018] [Accepted: 11/12/2018] [Indexed: 11/04/2022]
Abstract
ABSTRACT Collective behaviour of animals has been a main focus of recent research, yet few empirical studies deal with this issue in the context of predation, a major driver of social complexity in many animal species. When starling (Sturnus vulgaris) flocks are under attack by a raptor, such as a peregrine falcon (Falco peregrinus), they show a great diversity of patterns of collective escape. The corresponding structural complexity concerns rapid variation in density and shape of the flock over time. Here, we present a first step towards unravelling this complexity. We apply a time series analysis to video footage of 182 sequences of hunting by falcons on flocks of thousands of starlings close to two urban roosts during winter. We distinguish several types of collective escape by determining the position and movement of individuals relative to each other (which determines darkness and shape of the flock over time) as well as relative to the predator, namely 'flash expansion', 'blackening', 'wave event', 'vacuole', 'cordon' and 'split'. We show that the specific type of collective escape depends on the collective pattern that precedes it and on the level of threat posed by the raptor. A wave event was most likely to occur when the predator attacked at medium speed. Flash expansion occurred more frequently when the predator approached the flock at faster rather than slower speed and attacked from above rather than from the side or below. Flash expansion was often followed by split, but in many cases, the flock showed resilience by remaining intact. During a hunting sequence, the frequencies of different patterns of collective escape increased when the frequency of attack by the raptor was higher. Despite their complexity, we show that patterns of collective escape depend on the predatory threat, which resembles findings in fish. SIGNIFICANCE STATEMENT Patterns of collective escape in flocks of starlings have always intrigued laymen and scientists. A detailed analysis of their complex dynamics has been lacking so far, and is the focus of our present study: we analysed video footage of hunting by falcons on flocks of thousands of starlings and show how patterns of collective escape (namely flash expansion, blackening, wave event, vacuole, cordon and split) depend on the preceding pattern and on details of attack. A higher frequency of attack during a hunting sequence resulted in a higher frequency of collective escape events. Flash expansion happened most often when the predator attacks at greater speed. A wave event was most likely when the raptor attacks at medium (rather than high or low) speed. These results provide a first quantitative approach to social complexity in collective avoidance of a predator.
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Affiliation(s)
- R. F. Storms
- Theoretical Research in Evolutionary Life Sciences (TRÊS), Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - C. Carere
- Department of Ecological and Biological Sciences, University of Tuscia, viale dell‘Università s.n.c., 01100 Viterbo, Italy
| | - F. Zoratto
- Centre for Behavioural Sciences and Mental Health, Istituto Superiore di Sanità, viale Regina Elena 299, I-00161 Rome, Italy
| | - C. K. Hemelrijk
- Theoretical Research in Evolutionary Life Sciences (TRÊS), Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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Cavagna A, Giardina I, Mora T, Walczak AM. Physical constraints in biological collective behaviour. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.coisb.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Niizato T, Murakami H. Entangled time in flocking: Multi-time-scale interaction reveals emergence of inherent noise. PLoS One 2018; 13:e0195988. [PMID: 29689074 PMCID: PMC5915279 DOI: 10.1371/journal.pone.0195988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/04/2018] [Indexed: 11/24/2022] Open
Abstract
Collective behaviors that seem highly ordered and result in collective alignment, such as schooling by fish and flocking by birds, arise from seamless shuffling (such as super-diffusion) and bustling inside groups (such as Lévy walks). However, such noisy behavior inside groups appears to preclude the collective behavior: intuitively, we expect that noisy behavior would lead to the group being destabilized and broken into small sub groups, and high alignment seems to preclude shuffling of neighbors. Although statistical modeling approaches with extrinsic noise, such as the maximum entropy approach, have provided some reasonable descriptions, they ignore the cognitive perspective of the individuals. In this paper, we try to explain how the group tendency, that is, high alignment, and highly noisy individual behavior can coexist in a single framework. The key aspect of our approach is multi-time-scale interaction emerging from the existence of an interaction radius that reflects short-term and long-term predictions. This multi-time-scale interaction is a natural extension of the attraction and alignment concept in many flocking models. When we apply this method in a two-dimensional model, various flocking behaviors, such as swarming, milling, and schooling, emerge. The approach also explains the appearance of super-diffusion, the Lévy walk in groups, and local equilibria. At the end of this paper, we discuss future developments, including extending our model to three dimensions.
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Affiliation(s)
- Takayuki Niizato
- Tsukuba University, Faculty of Engineering, Information and Systems, Tsukuba, Ibaraki, Japan
- * E-mail:
| | - Hisashi Murakami
- University of Tokyo, Research Center for Advanced Science and Technology, Megro, Tokyo, Japan
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Blanchet A, Degond P. Kinetic Models for Topological Nearest-Neighbor Interactions. JOURNAL OF STATISTICAL PHYSICS 2017; 169:929-950. [PMID: 32009675 PMCID: PMC6959382 DOI: 10.1007/s10955-017-1882-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 09/18/2017] [Indexed: 06/10/2023]
Abstract
We consider systems of agents interacting through topological interactions. These have been shown to play an important part in animal and human behavior. Precisely, the system consists of a finite number of particles characterized by their positions and velocities. At random times a randomly chosen particle, the follower, adopts the velocity of its closest neighbor, the leader. We study the limit of a system size going to infinity and, under the assumption of propagation of chaos, show that the limit kinetic equation is a non-standard spatial diffusion equation for the particle distribution function. We also study the case wherein the particles interact with their K closest neighbors and show that the corresponding kinetic equation is the same. Finally, we prove that these models can be seen as a singular limit of the smooth rank-based model previously studied in Blanchet and Degond (J Stat Phys 163:41-60, 2016). The proofs are based on a combinatorial interpretation of the rank as well as some concentration of measure arguments.
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Affiliation(s)
- Adrien Blanchet
- IAST/TSE, Université Toulouse Capitole, 21 Allée de Brienne, 31000 Toulouse, France
| | - Pierre Degond
- Department of Mathematics, Imperial College London, London, SW7 2AZ UK
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Ward AJW, Schaerf TM, Herbert-Read JE, Morrell L, Sumpter DJT, Webster MM. Local interactions and global properties of wild, free-ranging stickleback shoals. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170043. [PMID: 28791135 PMCID: PMC5541530 DOI: 10.1098/rsos.170043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 06/07/2017] [Indexed: 05/27/2023]
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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Affiliation(s)
- Ashley J. W. Ward
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Timothy M. Schaerf
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
- School of Science and Technology, University of New England, Armidale, Australia
| | - James E. Herbert-Read
- Department of Mathematics, Uppsala University, Uppsala, Sweden
- Department of Biology, Stockholm University, Stockholm, Sweden
| | - Lesley Morrell
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, UK
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33
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Goodenough AE, Little N, Carpenter WS, Hart AG. Birds of a feather flock together: Insights into starling murmuration behaviour revealed using citizen science. PLoS One 2017. [PMID: 28628640 PMCID: PMC5476259 DOI: 10.1371/journal.pone.0179277] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Pre-roost murmuration displays by European starlings Sturnus vulgaris are a spectacular example of collective animal behaviour. To date, empirical research has focussed largely on flock movement and biomechanics whereas research on possible causal mechanisms that affect flock size and murmuration duration has been limited and restricted to a small number of sites. Possible explanations for this behaviour include reducing predation through the dilution, detection or predator confusion effects (the “safer together” hypotheses) or recruiting more birds to create larger (warmer) roosts (the “warmer together” hypothesis). We collected data on size, duration, habitat, temperature and predators from >3,000 murmurations using citizen science. Sightings were submitted from 23 countries but UK records predominated. Murmurations occurred across a range of habitats but there was no association between habitat and size/duration. Size increased significantly from October to early February, followed by a decrease until the end of the season in March (overall mean 30,082 birds; maximum 750,000 birds). Mean duration was 26 minutes (± 44 seconds SEM). Displays were longest at the start/end of the season, probably due to a significant positive relationship with day length. Birds of prey were recorded at 29.6% of murmurations. The presence of predators including harrier Circus, peregrine Falco peregrinus, and sparrowhawk Accipiter nisus was positively correlated with murmuration size (R2 = 0.401) and duration (R2 = 0.258), especially when these species were flying near to, or actively engaging with, starlings. Temperature was negatively correlated with duration but the effect was much weaker than that of day length. When predators were present, murmurations were statistically more likely to end with all birds going down en masse to roost rather than dispersing from the site. Our findings suggest that starling murmurations are primarily an anti-predator adaptation rather than being undertaken to attract larger numbers of individuals to increase roost warmth.
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Affiliation(s)
- Anne E Goodenough
- School of Natural & Social Sciences, Francis Close Hall, University of Gloucestershire, Cheltenham, Gloucestershire, United Kingdom
| | - Natasha Little
- Royal Society of Biology, Charles Darwin House, London, United Kingdom
| | - William S Carpenter
- School of Natural & Social Sciences, Francis Close Hall, University of Gloucestershire, Cheltenham, Gloucestershire, United Kingdom
| | - Adam G Hart
- School of Natural & Social Sciences, Francis Close Hall, University of Gloucestershire, Cheltenham, Gloucestershire, United Kingdom
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Ioannou CC, Ramnarine IW, Torney CJ. High-predation habitats affect the social dynamics of collective exploration in a shoaling fish. SCIENCE ADVANCES 2017; 3:e1602682. [PMID: 28508069 PMCID: PMC5415332 DOI: 10.1126/sciadv.1602682] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/08/2017] [Indexed: 06/07/2023]
Abstract
Collective decisions play a major role in the benefits that animals gain from living in groups. Although the mechanisms of how groups collectively make decisions have been extensively researched, the response of within-group dynamics to ecological conditions is virtually unknown, despite adaptation to the environment being a cornerstone in biology. We investigate how within-group interactions during exploration of a novel environment are shaped by predation, a major influence on the behavior of prey species. We tested guppies (Poecilia reticulata) from rivers varying in predation risk under controlled laboratory conditions and find the first evidence of differences in group interactions between animals adapted to different levels of predation. Fish from high-predation habitats showed the strongest negative relationship between initiating movements and following others, which resulted in less variability in the total number of movements made between individuals. This relationship between initiating movements and following others was associated with differentiation into initiators and followers, which was only observed in fish from high-predation rivers. The differentiation occurred rapidly, as trials lasted 5 min, and was related to shoal cohesion, where more diverse groups from high-predation habitats were more cohesive. Our results show that even within a single species over a small geographical range, decision-making in a social context can vary with local ecological factors.
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Affiliation(s)
| | - Indar W. Ramnarine
- Department of Life Sciences, University of the West Indies at St. Augustine, St. Augustine, Trinidad and Tobago
| | - Colin J. Torney
- School of Mathematics and Statistics, University of Glasgow, Glasgow G12 8QW, U.K
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35
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Hogan BG, Hildenbrandt H, Scott-Samuel N, Cuthill IC, Hemelrijk C. The confusion effect when attacking simulated three-dimensional starling flocks. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160564. [PMID: 28280553 PMCID: PMC5319319 DOI: 10.1098/rsos.160564] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 12/09/2016] [Indexed: 05/14/2023]
Abstract
The confusion effect describes the phenomenon of decreasing predator attack success with increasing prey group size. However, there is a paucity of research into the influence of this effect in coherent groups, such as flocks of European starlings (Sturnus vulgaris). Here, for the first time, we use a computer game style experiment to investigate the confusion effect in three dimensions. To date, computerized studies on the confusion effect have used two-dimensional simulations with simplistic prey movement and dynamics. Our experiment is the first investigation of the effects of flock size and density on the ability of a (human) predator to track and capture a target starling in a realistically simulated three-dimensional flock of starlings. In line with the predictions of the confusion effect, modelled starlings appear to be safer from predation in larger and denser flocks. This finding lends credence to previous suggestions that starling flocks have anti-predator benefits and, more generally, it suggests that active increases in density in animal groups in response to predation may increase the effectiveness of the confusion effect.
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Affiliation(s)
- Benedict G. Hogan
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, UK
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TH, UK
- Author for correspondence: Benedict G. Hogan e-mail:
| | - Hanno Hildenbrandt
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, 9747 AG, The Netherlands
| | | | - Innes C. Cuthill
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, UK
| | - Charlotte K. Hemelrijk
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, 9747 AG, The Netherlands
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Pita D, Collignon B, Halloy J, Fernández-Juricic E. Collective behaviour in vertebrates: a sensory perspective. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160377. [PMID: 28018616 PMCID: PMC5180114 DOI: 10.1098/rsos.160377] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/19/2016] [Indexed: 05/06/2023]
Abstract
Collective behaviour models can predict behaviours of schools, flocks, and herds. However, in many cases, these models make biologically unrealistic assumptions in terms of the sensory capabilities of the organism, which are applied across different species. We explored how sensitive collective behaviour models are to these sensory assumptions. Specifically, we used parameters reflecting the visual coverage and visual acuity that determine the spatial range over which an individual can detect and interact with conspecifics. Using metric and topological collective behaviour models, we compared the classic sensory parameters, typically used to model birds and fish, with a set of realistic sensory parameters obtained through physiological measurements. Compared with the classic sensory assumptions, the realistic assumptions increased perceptual ranges, which led to fewer groups and larger group sizes in all species, and higher polarity values and slightly shorter neighbour distances in the fish species. Overall, classic visual sensory assumptions are not representative of many species showing collective behaviour and constrain unrealistically their perceptual ranges. More importantly, caution must be exercised when empirically testing the predictions of these models in terms of choosing the model species, making realistic predictions, and interpreting the results.
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Affiliation(s)
- Diana Pita
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Bertrand Collignon
- Université Paris Diderot, Sorbonne Paris Cité, LIED, UMR 8236, 75013 Paris, France
| | - José Halloy
- Université Paris Diderot, Sorbonne Paris Cité, LIED, UMR 8236, 75013 Paris, France
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Olson RS, Knoester DB, Adami C. Evolution of Swarming Behavior Is Shaped by How Predators Attack. ARTIFICIAL LIFE 2016; 22:299-318. [PMID: 27139941 DOI: 10.1162/artl_a_00206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Animal grouping behaviors have been widely studied due to their implications for understanding social intelligence, collective cognition, and potential applications in engineering, artificial intelligence, and robotics. An important biological aspect of these studies is discerning which selection pressures favor the evolution of grouping behavior. In the past decade, researchers have begun using evolutionary computation to study the evolutionary effects of these selection pressures in predator-prey models. The selfish herd hypothesis states that concentrated groups arise because prey selfishly attempt to place their conspecifics between themselves and the predator, thus causing an endless cycle of movement toward the center of the group. Using an evolutionary model of a predator-prey system, we show that how predators attack is critical to the evolution of the selfish herd. Following this discovery, we show that density-dependent predation provides an abstraction of Hamilton's original formulation of domains of danger. Finally, we verify that density-dependent predation provides a sufficient selective advantage for prey to evolve the selfish herd in response to predation by coevolving predators. Thus, our work corroborates Hamilton's selfish herd hypothesis in a digital evolutionary model, refines the assumptions of the selfish herd hypothesis, and generalizes the domain of danger concept to density-dependent predation.
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38
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Attanasi A, Cavagna A, Del Castello L, Giardina I, Jelic A, Melillo S, Parisi L, Pohl O, Shen E, Viale M. Emergence of collective changes in travel direction of starling flocks from individual birds' fluctuations. J R Soc Interface 2016; 12:20150319. [PMID: 26236825 DOI: 10.1098/rsif.2015.0319] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
One of the most impressive features of moving animal groups is their ability to perform sudden coherent changes in travel direction. While this collective decision can be a response to an external alarm cue, directional switching can also emerge from the intrinsic fluctuations in individual behaviour. However, the cause and the mechanism by which such collective changes of direction occur are not fully understood yet. Here, we present an experimental study of spontaneous collective turns in natural flocks of starlings. We employ a recently developed tracking algorithm to reconstruct three-dimensional trajectories of each individual bird in the flock for the whole duration of a turning event. Our approach enables us to analyse changes in the individual behaviour of every group member and reveal the emergent dynamics of turning. We show that spontaneous turns start from individuals located at the elongated tips of the flocks, and then propagate through the group. We find that birds on the tips deviate from the mean direction of motion much more frequently than other individuals, indicating that persistent localized fluctuations are the crucial ingredient for triggering a collective directional change. Finally, we quantitatively verify that birds follow equal-radius paths during turning, the effects of which are a change of the flock's orientation and a redistribution of individual locations in the group.
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39
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Phase diagram of a multiple forces model for animal group formation: marches versus circles determined by the relative strength of alignment and cohesion. POPUL ECOL 2016. [DOI: 10.1007/s10144-016-0544-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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How memory and motivation modulate the responses to trail pheromones in three ant species. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2059-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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41
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Birds of a feather flock--and sing--together. Lab Anim (NY) 2015; 45:11. [PMID: 26684947 DOI: 10.1038/laban.913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Abstract
We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns.
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43
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Cavagna A, Giardina I, Grigera TS, Jelic A, Levine D, Ramaswamy S, Viale M. Silent flocks: constraints on signal propagation across biological groups. PHYSICAL REVIEW LETTERS 2015; 114:218101. [PMID: 26066459 DOI: 10.1103/physrevlett.114.218101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Experiments find coherent information transfer through biological groups on length and time scales distinctly below those on which asymptotically correct hydrodynamic theories apply. We present here a new continuum theory of collective motion coupling the velocity and density fields of Toner and Tu to the inertial spin field recently introduced to describe information propagation in natural flocks of birds. The long-wavelength limit of the new equations reproduces the Toner-Tu theory, while at shorter wavelengths (or, equivalently, smaller damping), spin fluctuations dominate over density fluctuations, and second-sound propagation of the kind observed in real flocks emerges. We study the dispersion relation of the new theory and find that when the speed of second sound is large, a gap in momentum space sharply separates first- from second-sound modes. This gap implies the existence of silent flocks, namely, of medium-sized systems across which information cannot propagate in a linear and underdamped way, either under the form of orientational fluctuations or under that of density fluctuations, making it hard for the group to achieve coordination.
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Affiliation(s)
| | - Irene Giardina
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Università Sapienza, 00185 Rome, Italy
- Initiative for the Theoretical Sciences, The Graduate Center, CUNY, New York, New York 10016 USA
| | - Tomas S Grigera
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) and Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina CONICET La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
| | - Asja Jelic
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Università Sapienza, 00185 Rome, Italy
| | - Dov Levine
- Initiative for the Theoretical Sciences, The Graduate Center, CUNY, New York, New York 10016 USA
- Department of Physics, Technion-IIT, 32000 Haifa, Israel
| | - Sriram Ramaswamy
- TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Osman Sagar Road, Narsingi, Hyderabad 500 075, India
| | - Massimiliano Viale
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Università Sapienza, 00185 Rome, Italy
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44
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The evolution of spatial ordering of oil drops fast spreading on a water surface. Nat Commun 2015; 6:7189. [PMID: 25998157 PMCID: PMC4455131 DOI: 10.1038/ncomms8189] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/15/2015] [Indexed: 12/19/2022] Open
Abstract
The design of dynamically self-assembled systems is of high interest in science and technology. Here, we report a unique cascade in the self-ordering of droplets accompanied by a dewetting transition. The dynamic self-emergent droplets are observed when a thin liquid layer of an immiscible fluorocarbon oil (perfluorooctyl bromide, PFOB) is placed on a water surface. Due to the gradual evaporation of PFOB, a circular PFOB-free domain appears as a result of a local dewetting transition. A circular pearling structure is generated at the rim with the growth of the dewetting hole. As the next stage, linear arrays of droplets are generated in a radial manner from the centre of the hole. These one-dimensional arrangements then evolve into two-dimensional hexagonal arrays of microdroplets through collective rhythmical shrinking/expanding motions. The emergence of such dynamic patterns is discussed in terms of the nonlinear kinetics of the dewetting transition under thermodynamically dissipative conditions. The spreading of liquids on water can lead to complex drop assemblies, but none of them so far exhibits coordinated dynamics. Here, Yamamoto et al. observe a dance of insoluble oil drops on a water surface evolving from linear to hexagonal arrays, due to dewetting transition and evaporation of oil.
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45
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Hemelrijk CK, Hildenbrandt H. Diffusion and topological neighbours in flocks of starlings: relating a model to empirical data. PLoS One 2015; 10:e0126913. [PMID: 25993474 PMCID: PMC4436282 DOI: 10.1371/journal.pone.0126913] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/01/2015] [Indexed: 11/21/2022] Open
Abstract
Moving in a group while avoiding collisions with group members causes internal dynamics in the group. Although these dynamics have recently been measured quantitatively in starling flocks (Sturnus vulgaris), it is unknown what causes them. Computational models have shown that collective motion in groups is likely due to attraction, avoidance and, possibly, alignment among group members. Empirical studies show that starlings adjust their movement to a fixed number of closest neighbours or topological range, namely 6 or 7 and assume that each of the three activities is done with the same number of neighbours (topological range). Here, we start from the hypothesis that escape behavior is more effective at preventing collisions in a flock when avoiding the single closest neighbor than compromising by avoiding 6 or 7 of them. For alignment and attraction, we keep to the empirical topological range. We investigate how avoiding one or several neighbours affects the internal dynamics of flocks of starlings in our computational model StarDisplay. By comparing to empirical data, we confirm that internal dynamics resemble empirical data more closely if flock members avoid merely their single, closest neighbor. Our model shows that considering a different number of interaction partners per activity represents a useful perspective and that changing a single parameter, namely the number of interaction partners that are avoided, has several effects through selforganisation.
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Affiliation(s)
- Charlotte K. Hemelrijk
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Hanno Hildenbrandt
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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46
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Hemelrijk CK, van Zuidam L, Hildenbrandt H. What underlies waves of agitation in starling flocks. Behav Ecol Sociobiol 2015; 69:755-764. [PMID: 26380537 PMCID: PMC4564680 DOI: 10.1007/s00265-015-1891-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 11/28/2022]
Abstract
Fast transfer of information in groups can have survival value. An example is the so-called wave of agitation observed in groups of animals of several taxa under attack. It has been shown to reduce predator success. It usually involves the repetition of a manoeuvre throughout the group, transmitting the information of the attack quickly, faster than the group moves itself. The specific manoeuvre underlying a wave is typically known, but not so in starlings (Sturnus vulgaris). Although waves of agitation in starling flocks have been suggested to reflect density waves, exact escape manoeuvres cannot be distinguished because flocks are spatially too far away. Therefore, waves may also reflect orientation waves (due to escape by rolling). In the present study, we investigate this issue in a computational model, StarDisplay. We use this model because its flocks have been shown to resemble starling flocks in many traits. In the model, we show that agitation waves result from changes in orientation rather than in density. They resemble empirical data both qualitatively in visual appearance and quantitatively in wave speed. In the model, local interactions with only two to seven closest neighbours suffice to generate empirical wave speed. Wave speed increases with the number of neighbours mimicked or repeated from and the distance to them. It decreases with reaction time and with time to identify the escape manoeuvre of others and is not affected by flock size. Our findings can be used as predictions for empirical studies.
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Affiliation(s)
- Charlotte K Hemelrijk
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Lars van Zuidam
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Hanno Hildenbrandt
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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47
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Attanasi A, Cavagna A, Del Castello L, Giardina I, Grigera TS, Jelić A, Melillo S, Parisi L, Pohl O, Shen E, Viale M. Information transfer and behavioural inertia in starling flocks. NATURE PHYSICS 2014; 10:615-698. [PMID: 25264452 PMCID: PMC4173114 DOI: 10.1038/nphys3035] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Collective decision-making in biological systems requires all individuals in the group to go through a behavioural change of state. During this transition fast and robust transfer of information is essential to prevent cohesion loss. The mechanism by which natural groups achieve such robustness, though, is not clear. Here we present an experimental study of starling flocks performing collective turns. We find that information about direction changes propagates across the flock with a linear dispersion law and negligible attenuation, hence minimizing group decoherence. These results contrast starkly with current models of collective motion, which predict diffusive transport of information. Building on spontaneous symmetry breaking and conservation laws arguments, we formulate a new theory that correctly reproduces linear and undamped propagation. Essential to the new framework is the inclusion of the birds' behavioural inertia. The new theory not only explains the data, but also predicts that information transfer must be faster the stronger the group's orientational order, a prediction accurately verified by the data. Our results suggest that swift decision-making may be the adaptive drive for the strong behavioural polarization observed in many living groups.
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Affiliation(s)
- Alessandro Attanasi
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
| | - Andrea Cavagna
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
- Initiative for the Theoretical Sciences, The Graduate Center, City University of New York, 10016 New York, USA
- Correspondence and requests for materials should be addressed to A.J. () or A.C. ()
| | - Lorenzo Del Castello
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
| | - Irene Giardina
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
- Initiative for the Theoretical Sciences, The Graduate Center, City University of New York, 10016 New York, USA
| | - Tomas S. Grigera
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) and Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, c.c. 16, suc. 4, 1900 La Plata, Argentina CONICET La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
| | - Asja Jelić
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
- Correspondence and requests for materials should be addressed to A.J. () or A.C. ()
| | - Stefania Melillo
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
| | - Leonardo Parisi
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Informatica, Universitá Sapienza, 00198 Rome, Italy
| | - Oliver Pohl
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
| | - Edward Shen
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
| | - Massimiliano Viale
- Istituto Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, 00185 Rome, Italy
- Dipartimento di Fisica, Universit a Sapienza, 00185 Rome, Italy
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48
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Niizato T, Murakami H, Gunji YP. Emergence of the scale-invariant proportion in a flock from the metric-topological interaction. Biosystems 2014; 119:62-8. [PMID: 24686118 DOI: 10.1016/j.biosystems.2014.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/04/2014] [Accepted: 03/06/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Takayuki Niizato
- Faculty of Engineering, Information and Systems, Tsukuba University, Japan.
| | | | - Yukio-Pegio Gunji
- Graduate School of Science, Kobe University, Japan; Faculty of Science, Kobe University, Japan
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49
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Demšar J, Lebar Bajec I. Simulated predator attacks on flocks: a comparison of tactics. ARTIFICIAL LIFE 2014; 20:343-359. [PMID: 24730766 DOI: 10.1162/artl_a_00135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
It is not exactly known why birds aggregate in coordinated flocks. The most common hypothesis proposes that the reason is protection from predators. Most of the currently developed examples of individual-based predator-prey models assume predators are attracted to the center of a highly coordinated flock. This proposed attraction of a predator to a flock would appear to be contradictory to an alternate hypothesis that flocks evolved as a protection against predation. In an attempt to resolve this apparent conflict, in this article we use a fuzzy individual-based model to study three attack tactics (attack center, attack nearest, attack isolated) and analyze the success of predation on two types of prey (social and individualistic). Our simulations revealed that social flocking (as opposed to individualistic behavior) is the optimal anti-predatory response to predators attacking mainly isolated individuals.
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50
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Lukeman R. Ordering dynamics in collectively swimming Surf Scoters. J Theor Biol 2014; 355:151-9. [PMID: 24675619 DOI: 10.1016/j.jtbi.2014.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 03/02/2014] [Accepted: 03/07/2014] [Indexed: 10/25/2022]
Abstract
One striking feature of collective motion in animal groups is a high degree of alignment among individuals, generating polarized motion. When order is lost, the dynamic process of reorganization, directly resulting from the individual interaction rules, provides significant information about both the nature of the rules, and how these rules affect the functioning of the collective. By analyzing trajectories of collectively swimming Surf Scoters (Melanitta perspicillata) during transitions between order and disorder, I find that individual speed and polarization are positively correlated in time, such that individuals move more slowly in groups exhibiting lower alignment. A previously validated zone-based model framework is used to specify interactions that permit repolarization while maintaining group cohesion and avoiding collisions. Polarization efficiency is optimized under the constraints of cohesion and collision-avoidance for alignment-dominated propulsion (versus autonomous propulsion), and for repulsion an order of magnitude larger than attraction and alignment. The relative strengths of interactions that optimize polarization also quantitatively recover the speed-polarization dependence observed in the data. Parameters determined here through optimizing polarization efficiency are essentially the same as those determined previously from a different approach: a best-fit model for polarized Surf Scoter movement data. The rules governing these flocks are therefore robust, accounting for behavior across a range of order and structure, and also highly responsive to perturbation. Flexibility and efficient repolarization offers an adaptive explanation for why specific interactions in such animal groups are used.
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Affiliation(s)
- Ryan Lukeman
- Department of Mathematics, Statistics, and Computer Science, St. Francis Xavier University, Antigonish, NS, Canada.
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