1
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Di Pietro V, Menezes C, de Britto Frediani MG, Pereira DJ, Fajgenblat M, Ferreira HM, Wenseleers T, Oliveira RC. The inheritance of alternative nest architectural traditions in stingless bees. Curr Biol 2024:S0960-9822(24)00255-0. [PMID: 38508185 DOI: 10.1016/j.cub.2024.02.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/29/2024] [Indexed: 03/22/2024]
Abstract
The transmission of complex behavior and culture in humans has long been attributed to advanced forms of social learning,1,2 which play a crucial role in our technological advancement.3 While similar phenomena of behavioral traditions and cultural inheritance have been observed in animals,1,2,4,5,6 including in primates,7 whales,8 birds,9 and even insects,10 the underlying mechanisms enabling the persistence of such animal traditions, particularly in insects, are less well understood. This study introduces pioneering evidence of enduring architectural traditions in the stingless bee Scaptotrigona depilis, which are maintained without any evidence for social learning. We demonstrate that S. depilis exhibits two distinct nest architectures, comprising either helicoidal or flat, stacked horizontal combs, which are transmitted across generations through stigmergy11,12,13,14,15,16,17-an environmental feedback mechanism whereby the presence of the existing comb structures guides subsequent construction behaviors-thereby leading to a form of environmental inheritance.18,19,20 Cross-fostering experiments further show that genetic factors or prior experience does not drive the observed variation in nest architecture. Moreover, the experimental introduction of corkscrew dislocations within the combs prompted helicoidal building, confirming the use of stigmergic building rules. At a theoretical level, we establish that the long-term equilibrium of building in the helicoidal pattern fits with the expectations of a two-state Markov chain model. Overall, our findings provide compelling evidence for the persistence of behavioral traditions in an insect, based on a simple mechanism of environmental inheritance and stigmergic interactions, without requiring any sophisticated learning mechanism, thereby expanding our understanding of how traditions can be maintained in non-human species.
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Affiliation(s)
- Viviana Di Pietro
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Cristiano Menezes
- Embrapa Environment, Laboratory of Entomology and Phytopathology, SP-340 Road, 13918-110 Jaguariúna, Brazil
| | | | - David José Pereira
- Embrapa Environment, Laboratory of Entomology and Phytopathology, SP-340 Road, 13918-110 Jaguariúna, Brazil
| | - Maxime Fajgenblat
- Laboratory of Freshwater Ecology, Evolution and Conservation, Department of Biology, KU Leuven, Charles Deberiotstraat 32, Leuven 3000, Belgium; I-BioStat, Data Science Institute, Hasselt University, Agoralaan 1, Diepenbeek 3590, Belgium
| | - Helena Mendes Ferreira
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium
| | - Tom Wenseleers
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Ricardo Caliari Oliveira
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium; Universitat Autònoma de Barcelona, Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Av. de l'Eix Central, edifici C, 08193 Bellaterra (Barcelona), Spain.
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2
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Bassanetti T, Cezera S, Delacroix M, Escobedo R, Blanchet A, Sire C, Theraulaz G. Cooperation and deception through stigmergic interactions in human groups. Proc Natl Acad Sci U S A 2023; 120:e2307880120. [PMID: 37816053 PMCID: PMC10589714 DOI: 10.1073/pnas.2307880120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/30/2023] [Indexed: 10/12/2023] Open
Abstract
Stigmergy is a generic coordination mechanism widely used by animal societies, in which traces left by individuals in a medium guide and stimulate their subsequent actions. In humans, new forms of stigmergic processes have emerged through the development of online services that extensively use the digital traces left by their users. Here, we combine interactive experiments with faithful data-based modeling to investigate how groups of individuals exploit a simple rating system and the resulting traces in an information search task in competitive or noncompetitive conditions. We find that stigmergic interactions can help groups to collectively find the cells with the highest values in a table of hidden numbers. We show that individuals can be classified into three behavioral profiles that differ in their degree of cooperation. Moreover, the competitive situation prompts individuals to give deceptive ratings and reinforces the weight of private information versus social information in their decisions.
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Affiliation(s)
- Thomas Bassanetti
- Laboratoire de Physique Théorique, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
| | | | - Maxime Delacroix
- Laboratoire de Physique Théorique, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
| | - Ramón Escobedo
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
| | - Adrien Blanchet
- Toulouse School of Economics, CNRS, 31080Toulouse, France
- Institute for Advanced Study in Toulouse, 31080Toulouse, France
| | - Clément Sire
- Laboratoire de Physique Théorique, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
| | - Guy Theraulaz
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, CNRS, Université Toulouse III-Paul Sabatier, 31062Toulouse, France
- Institute for Advanced Study in Toulouse, 31080Toulouse, France
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3
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Tonello L, Vallortigara G. Evolutionary models of lateralization: Steps toward stigmergy? Front Behav Neurosci 2023; 17:1121335. [PMID: 36818605 PMCID: PMC9931731 DOI: 10.3389/fnbeh.2023.1121335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 01/11/2023] [Indexed: 02/05/2023] Open
Affiliation(s)
- Lucio Tonello
- Center for Nonlinear Science, University of North Texas, Denton, TX, United States,GIOYA HEI, E305, The Hub Workspace, San Gwann, Malta,*Correspondence: Lucio Tonello ✉
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4
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Friedman DA, Tschantz A, Ramstead MJD, Friston K, Constant A. Active Inferants: An Active Inference Framework for Ant Colony Behavior. Front Behav Neurosci 2021; 15:647732. [PMID: 34248515 PMCID: PMC8264549 DOI: 10.3389/fnbeh.2021.647732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 05/18/2021] [Indexed: 11/13/2022] Open
Abstract
In this paper, we introduce an active inference model of ant colony foraging behavior, and implement the model in a series of in silico experiments. Active inference is a multiscale approach to behavioral modeling that is being applied across settings in theoretical biology and ethology. The ant colony is a classic case system in the function of distributed systems in terms of stigmergic decision-making and information sharing. Here we specify and simulate a Markov decision process (MDP) model for ant colony foraging. We investigate a well-known paradigm from laboratory ant colony behavioral experiments, the alternating T-maze paradigm, to illustrate the ability of the model to recover basic colony phenomena such as trail formation after food location discovery. We conclude by outlining how the active inference ant colony foraging behavioral model can be extended and situated within a nested multiscale framework and systems approaches to biology more generally.
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Affiliation(s)
- Daniel Ari Friedman
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, United States
- Active Inference Lab, University of California, Davis, Davis, CA, United States
| | - Alec Tschantz
- Sackler Centre for Consciousness Science, University of Sussex, Brighton, United Kingdom
- Department of Informatics, University of Sussex, Brighton, United Kingdom
| | - Maxwell J. D. Ramstead
- Division of Social and Transcultural Psychiatry, Department of Psychiatry, McGill University, Montreal, QC, Canada
- Culture, Mind, and Brain Program, McGill University, Montreal, QC, Canada
- Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom
- Spatial Web Foundation, Los Angeles, CA, United States
| | - Karl Friston
- Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom
| | - Axel Constant
- Theory and Method in Biosciences, The University of Sydney, Sydney, NSW, Australia
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5
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Carey NE, Bardunias P, Nagpal R, Werfel J. Validating a Termite-Inspired Construction Coordination Mechanism Using an Autonomous Robot. Front Robot AI 2021; 8:645728. [PMID: 33969004 PMCID: PMC8098689 DOI: 10.3389/frobt.2021.645728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Many species of termites build large, structurally complex mounds, and the mechanisms behind this coordinated construction have been a longstanding topic of investigation. Recent work has suggested that humidity may play a key role in the mound expansion of savannah-dwelling Macrotermes species: termites preferentially deposit soil on the mound surface at the boundary of the high-humidity region characteristic of the mound interior, implying a coordination mechanism through environmental feedback where addition of wet soil influences the humidity profile and vice versa. Here we test this potential mechanism physically using a robotic system. Local humidity measurements provide a cue for material deposition. As the analogue of the termite's deposition of wet soil and corresponding local increase in humidity, the robot drips water onto an absorbent substrate as it moves. Results show that the robot extends a semi-enclosed area outward when air is undisturbed, but closes it off when air is disturbed by an external fan, consistent with termite building activity in still vs. windy conditions. This result demonstrates an example of adaptive construction patterns arising from the proposed coordination mechanism, and supports the hypothesis that such a mechanism operates in termites.
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Affiliation(s)
- Nicole E Carey
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
| | - Paul Bardunias
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, United States.,Department of Civil and Environmental Engineering, South Dakota School of Mines, Rapid City, SD, United States
| | - Radhika Nagpal
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
| | - Justin Werfel
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
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6
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Abstract
The termite nest is one of the architectural wonders of the living world, built by the collective action of workers in a colony. Each nest has several characteristic structural motifs that allow for efficient ventilation, cooling, and traversal. We use tomography to quantify the nest architecture of the African termite Apicotermes lamani, consisting of regularly spaced floors connected by scattered linear and helicoidal ramps. To understand how these elaborate structures are built and arranged, we formulate a minimal model for the spatiotemporal evolution of three hydrodynamic fields-mud, termites, and pheromones-linking environmental physics to collective building behavior using simple local rules based on experimental observations. We find that floors and ramps emerge as solutions of the governing equations, with statistics consistent with observations of A. lamani nests. Our study demonstrates how a local self-reinforcing biotectonic scheme is capable of generating an architecture that is simultaneously adaptable and functional, and likely to be relevant for a range of other animal-built structures.
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7
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Salman M, Garzón Ramos D, Hasselmann K, Birattari M. Phormica: Photochromic Pheromone Release and Detection System for Stigmergic Coordination in Robot Swarms. Front Robot AI 2020; 7:591402. [PMID: 33501350 PMCID: PMC7805914 DOI: 10.3389/frobt.2020.591402] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/17/2020] [Indexed: 12/01/2022] Open
Abstract
Stigmergy is a form of indirect communication and coordination in which agents modify the environment to pass information to their peers. In nature, animals use stigmergy by, for example, releasing pheromone that conveys information to other members of their species. A few systems in swarm robotics research have replicated this process by introducing the concept of artificial pheromone. In this paper, we present Phormica, a system to conduct experiments in swarm robotics that enables a swarm of e-puck robots to release and detect artificial pheromone. Phormica emulates pheromone-based stigmergy thanks to the ability of robots to project UV light on the ground, which has been previously covered with a photochromic material. As a proof of concept, we test Phormica on three collective missions in which robots act collectively guided by the artificial pheromone they release and detect. Experimental results indicate that a robot swarm can effectively self-organize and act collectively by using stigmergic coordination based on the artificial pheromone provided by Phormica.
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Affiliation(s)
| | | | | | - Mauro Birattari
- IRIDIA, CoDE, Université libre de Bruxelles, Brussels, Belgium
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8
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Abstract
In soft robotics, bio-inspiration ranges from hard- to software. Orb web spiders provide excellent examples for both. Adapted sensors on their legs may use morphological computing to fine-tune feedback loops that supervise the handling and accurate placement of silk threads. The spider's webs embody the decision rules of a complex behaviour that relies on navigation and piloting laid down in silk by behaviour charting inherited rules. Analytical studies of real spiders allow the modelling of path-finding construction rules optimized in evolutionary algorithms. We propose that deconstructing spiders and unravelling webs may lead to adaptable robots able to invent and construct complex novel structures using relatively simple rules of thumb.
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Affiliation(s)
- Fritz Vollrath
- Department of Zoology, University of Oxford, Mansfield Road, Oxford OX1 3ZS, UK
| | - Thiemo Krink
- Department of Computer Science, Aarhus Universitet, Åbogade 34, 8200 Aarhus, Denmark
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9
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Abstract
We present a simple three-dimensional model to describe the autonomous expansion of a substrate whose growth is driven by the local mean curvature of its surface. The model aims to reproduce the nest construction process in arboreal Nasutitermes termites, whose cooperation may similarly be mediated by the shape of the structure they are walking on, for example focusing the building activity of termites where local mean curvature is high. We adopt a phase-field model where the nest is described by one continuous scalar field and its growth is governed by a single nonlinear equation with one adjustable parameter d. When d is large enough the equation is linearly unstable and fairly reproduces a growth process in which the initial walls expand, branch and merge, while progressively invading all the available space, which is consistent with the intricate structures of real nests. Interestingly, the linear problem associated with our growth equation is analogous to the buckling of a thin elastic plate under symmetric in-plane compression, which is also known to produce rich patterns through nonlinear and secondary instabilities. We validated our model by collecting nests of two species of arboreal Nasutitermes from the field and imaging their structure with a micro-computed tomography scanner. We found a strong resemblance between real and simulated nests, characterized by the emergence of a characteristic length scale and by the abundance of saddle-shaped surfaces with zero-mean curvature, which validates the choice of the driving mechanism of our growth model.
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Affiliation(s)
- G Facchini
- Life Sciences Department, University of Roehampton, London, UK
| | - A Lazarescu
- Institut de Recherche en Mathématique et Physique, UCLouvain, Louvain-la-Neuve, Belgium
| | - A Perna
- Life Sciences Department, University of Roehampton, London, UK
| | - S Douady
- Laboratoire Matière et Systèmes Complexes, Université Paris Diderot, Paris, France
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10
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Calovi DS, Bardunias P, Carey N, Scott Turner J, Nagpal R, Werfel J. Surface curvature guides early construction activity in mound-building termites. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180374. [PMID: 31006366 DOI: 10.1098/rstb.2018.0374] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Termite colonies construct towering, complex mounds, in a classic example of distributed agents coordinating their activity via interaction with a shared environment. The traditional explanation for how this coordination occurs focuses on the idea of a 'cement pheromone', a chemical signal left with deposited soil that triggers further deposition. Recent research has called this idea into question, pointing to a more complicated behavioural response to cues perceived with multiple senses. In this work, we explored the role of topological cues in affecting early construction activity in Macrotermes. We created artificial surfaces with a known range of curvatures, coated them with nest soil, placed groups of major workers on them and evaluated soil displacement as a function of location at the end of 1 h. Each point on the surface has a given curvature, inclination and absolute height; to disambiguate these factors, we conducted experiments with the surface in different orientations. Soil displacement activity is consistently correlated with surface curvature, and not with inclination nor height. Early exploration activity is also correlated with curvature, to a lesser degree. Topographical cues provide a long-term physical memory of building activity in a manner that ephemeral pheromone labelling cannot. Elucidating the roles of these and other cues for group coordination may help provide organizing principles for swarm robotics and other artificial systems. This article is part of the theme issue 'Liquid brains, solid brains: How distributed cognitive architectures process information'.
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Affiliation(s)
- Daniel S Calovi
- 1 Harvard School of Engineering and Applied Sciences , 33 Oxford Street, Cambridge, MA 02138 , USA.,2 Wyss Institute for Biologically Inspired Engineering , Cambridge, MA 02138 , USA
| | - Paul Bardunias
- 3 Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry Syracuse , Syracuse, NY 13210 , USA
| | - Nicole Carey
- 1 Harvard School of Engineering and Applied Sciences , 33 Oxford Street, Cambridge, MA 02138 , USA.,2 Wyss Institute for Biologically Inspired Engineering , Cambridge, MA 02138 , USA
| | - J Scott Turner
- 3 Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry Syracuse , Syracuse, NY 13210 , USA
| | - Radhika Nagpal
- 1 Harvard School of Engineering and Applied Sciences , 33 Oxford Street, Cambridge, MA 02138 , USA
| | - Justin Werfel
- 2 Wyss Institute for Biologically Inspired Engineering , Cambridge, MA 02138 , USA
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11
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Hunt ER, Jones S, Hauert S. Testing the limits of pheromone stigmergy in high-density robot swarms. R Soc Open Sci 2019; 6:190225. [PMID: 31827817 PMCID: PMC6894587 DOI: 10.1098/rsos.190225] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 09/20/2019] [Indexed: 06/10/2023]
Abstract
Area coverage and collective exploration are key challenges for swarm robotics. Previous research in this field has drawn inspiration from ant colonies, with real, or more commonly virtual, pheromones deposited into a shared environment to coordinate behaviour through stigmergy. Repellent pheromones can facilitate rapid dispersal of robotic agents, yet this has been demonstrated only for relatively small swarm sizes (N < 30). Here, we report findings from swarms of real robots (Kilobots) an order of magnitude larger (N > 300) and from realistic simulation experiments up to N = 400. We identify limitations to stigmergy in a spatially constrained, high-density environment-a free but bounded two-dimensional workspace-using repellent binary pheromone. At larger N and higher densities, a simple stigmergic avoidance algorithm becomes first no better, then inferior to, the area coverage of non-interacting random walkers. Thus, the assumption of robustness and scalability for such approaches may need to be re-examined when they are working at a high density caused by ever-increasing swarm sizes. Instead, subcellular biology, and diffusive processes, may prove a better source of inspiration at large N in high agent density environments.
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Affiliation(s)
- Edmund R. Hunt
- Department of Engineering Mathematics, University of Bristol, Merchant Venturers Building, Bristol BS8 1UB, UK
- Bristol Robotics Laboratory, University of the West of England, Frenchay Campus, Coldharbour Lane, Stoke Gifford, Bristol BS16 1QY, UK
| | - Simon Jones
- Bristol Robotics Laboratory, University of the West of England, Frenchay Campus, Coldharbour Lane, Stoke Gifford, Bristol BS16 1QY, UK
| | - Sabine Hauert
- Department of Engineering Mathematics, University of Bristol, Merchant Venturers Building, Bristol BS8 1UB, UK
- Bristol Robotics Laboratory, University of the West of England, Frenchay Campus, Coldharbour Lane, Stoke Gifford, Bristol BS16 1QY, UK
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12
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Penn A, Turner JS. Can we identify general architectural principles that impact the collective behaviour of both human and animal systems? Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2018.0253. [PMID: 29967308 PMCID: PMC6030581 DOI: 10.1098/rstb.2018.0253] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2018] [Indexed: 11/26/2022] Open
Abstract
The search for general common principles that unify disciplines is a longstanding challenge for interdisciplinary research. Architecture has always been an interdisciplinary pursuit, combining engineering, art and culture. The rise of biomimetic architecture adds to the interdisciplinary span. We discuss the similarities and differences among human and animal societies in how architecture influences their collective behaviour. We argue that the emergence of a fully biomimetic architecture involves breaking down what we call ‘pernicious dualities’ that have permeated our discourse for decades, artificial divisions between species, between organism and environment, between genotype and phenotype, and in the case of architecture, the supposed duality between the built environment and its builders. We suggest that niche construction theory may serve as a starting point for unifying our thinking across disciplines, taxa and spatial scales. This article is part of the theme issue ‘Interdisciplinary approaches for uncovering the impacts of architecture on collective behaviour’.
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Affiliation(s)
- Alan Penn
- The Bartlett School of Architecture, Faculty of the Built Environment, University College of London, London, UK
| | - J Scott Turner
- Department of Environmental and Forest Biology, SUNY College of Environmental Science & Forestry, Syracuse, NY, USA.,Stellenbosch Institute for Advanced Study, Stellenbosch, South Africa
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13
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Cimino MGCA, Lazzeri A, Pedrycz W, Vaglini G. Using Stigmergy to Distinguish Event-Specific Topics in Social Discussions. Sensors (Basel) 2018; 18:s18072117. [PMID: 30004417 PMCID: PMC6068524 DOI: 10.3390/s18072117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/13/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
In settings wherein discussion topics are not statically assigned, such as in microblogs, a need exists for identifying and separating topics of a given event. We approach the problem by using a novel type of similarity, calculated between the major terms used in posts. The occurrences of such terms are periodically sampled from the posts stream. The generated temporal series are processed by using marker-based stigmergy, i.e., a biologically-inspired mechanism performing scalar and temporal information aggregation. More precisely, each sample of the series generates a functional structure, called mark, associated with some concentration. The concentrations disperse in a scalar space and evaporate over time. Multiple deposits, when samples are close in terms of instants of time and values, aggregate in a trail and then persist longer than an isolated mark. To measure similarity between time series, the Jaccard's similarity coefficient between trails is calculated. Discussion topics are generated by such similarity measure in a clustering process using Self-Organizing Maps, and are represented via a colored term cloud. Structural parameters are correctly tuned via an adaptation mechanism based on Differential Evolution. Experiments are completed for a real-world scenario, and the resulting similarity is compared with Dynamic Time Warping (DTW) similarity.
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Affiliation(s)
- Mario G C A Cimino
- Department of Information Engineering, University of Pisa, 56122 Pisa, Italy.
| | - Alessandro Lazzeri
- Department of Information Engineering, University of Pisa, 56122 Pisa, Italy.
| | - Witold Pedrycz
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2G7, Canada.
| | - Gigliola Vaglini
- Department of Information Engineering, University of Pisa, 56122 Pisa, Italy.
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14
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Badhe RV, Kumar P, Choonara YE, Marimuthu T, du Toit LC, Bijukumar D, Chejara DR, Mabrouk M, Pillay V. Customized Peptide Biomaterial Synthesis via an Environment-Reliant Auto-Programmer Stigmergic Approach. Materials (Basel) 2018; 11:E609. [PMID: 29659507 DOI: 10.3390/ma11040609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 11/28/2022]
Abstract
Stigmergy, a form of self-organization, was employed here to engineer a self-organizing peptide capable of forming a nano- or micro-structure and that can potentially be used in various drug delivery and biomedical applications. These self-assembling peptides exhibit several desirable qualities for drug delivery, tissue engineering, cosmetics, antibiotics, food science, and biomedical surface engineering. In this study, peptide biomaterial synthesis was carried out using an environment-reliant auto-programmer stigmergic approach. A model protein, α-gliadin (31, 36, and 38 kD), was forced to attain a primary structure with free –SH groups and broken down enzymatically into smaller fragments using chymotrypsin. This breakdown was carried out at different environment conditions (37 and 50 °C), and the fragments were allowed to self-organize at these temperatures. The new peptides so formed diverged according to the environmental conditions. Interestingly, two peptides (with molecular weights of 13.8 and 11.8 kD) were isolated when the reaction temperature was maintained at 50 °C, while four peptides with molecular weights of 54, 51, 13.8, and 12.8 kD were obtained when the reaction was conducted at 37 °C. Thus, at a higher temperature (50 °C), the peptides formed, compared to the original protein, had lower molecular weights, whereas, at a lower temperature (37 °C), two peptides had higher molecular weights and two had lower molecular weights.
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15
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Green B, Bardunias P, Turner JS, Nagpal R, Werfel J. Excavation and aggregation as organizing factors in de novo construction by mound-building termites. Proc Biol Sci 2018; 284:rspb.2016.2730. [PMID: 28615497 DOI: 10.1098/rspb.2016.2730] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 05/12/2017] [Indexed: 11/12/2022] Open
Abstract
Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in which actions that change the environment provide cues that influence future work. Termite construction has long been thought to be organized via a putative 'cement pheromone': a chemical added to deposited soil that stimulates further deposition in the same area, thus creating a positive feedback loop whereby coherent structures are built up. To investigate the detailed mechanisms and behaviours through which termites self-organize the early stages of mound construction, we tracked the motion and behaviour of major workers from two Macrotermes species in experimental arenas. Rather than a construction process focused on accumulation of depositions, as models based on cement pheromone would suggest, our results indicated that the primary organizing mechanisms were based on excavation. Digging activity was focused on a small number of excavation sites, which in turn provided templates for soil deposition. This behaviour was mediated by a mechanism of aggregation, with termites being more likely to join in the work at an excavation site as the number of termites presently working at that site increased. Statistical analyses showed that this aggregation mechanism was a response to active digging, distinct from and unrelated to putative chemical cues that stimulate deposition. Agent-based simulations quantitatively supported the interpretation that the early stage of de novo construction is primarily organized by excavation and aggregation activity rather than by stigmergic deposition.
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Affiliation(s)
- Ben Green
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Paul Bardunias
- Department of Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - J Scott Turner
- Department of Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Radhika Nagpal
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Justin Werfel
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
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16
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Khuong A, Gautrais J, Perna A, Sbaï C, Combe M, Kuntz P, Jost C, Theraulaz G. Stigmergic construction and topochemical information shape ant nest architecture. Proc Natl Acad Sci U S A 2016; 113:1303-8. [PMID: 26787857 DOI: 10.1073/pnas.1509829113] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.
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Mizumoto N, Kobayashi K, Matsuura K. Emergence of intercolonial variation in termite shelter tube patterns and prediction of its underlying mechanism. R Soc Open Sci 2015; 2:150360. [PMID: 26715997 PMCID: PMC4680612 DOI: 10.1098/rsos.150360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Building behaviours occur in various organisms from bacteria to humans. Social insects build various structures such as large nests and underground galleries, achieved by self-organization. Structures built by social insects have recently been demonstrated to vary widely in size and shape within a species, even under the same environmental conditions. However, little is known about how intraspecific variation in structures emerges from collective behaviours. Here we show that the colony variation of structures can be generated by simply changing two behavioural parameters of group members, even with the same building algorithm. Our laboratory experiment of termite shelter tube construction demonstrated clear intercolonial variation, and a two-dimensional lattice model showed that it can be attributed to the extent of positive feedback and the number of individuals engaged in building. This study contributes to explaining the great diversity of structures emerging from collective building in social insects.
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Affiliation(s)
- Nobuaki Mizumoto
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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