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MacLeod CD, Luong LT. Navigating the landscape of fear: Fruit flies exhibit distinct antipredator and antiparasite defensive behaviors. Ecology 2024:e4397. [PMID: 39223438 DOI: 10.1002/ecy.4397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/19/2024] [Accepted: 05/24/2024] [Indexed: 09/04/2024]
Abstract
Most organisms are at risk of being consumed by a predator or getting infected by a parasite at some point in their life. Theoretical constructs such as the landscape of fear (perception of risk) and nonconsumptive effects (NCEs, costly responses sans predation or infection) have been proposed to describe and quantify antipredator and antiparasite responses. How prey/host species identify and respond to these risks determines their survival, reproductive success and, ultimately, fitness. Most studies to date have focused on either predator-prey or parasite-host interactions, yet habitats and ecosystems contain both parasitic and/or predatory species that represent a complex and heterogenous mosaic of risk factors. Here, we experimentally investigated the behavioral responses of a cactophilic fruit fly, Drosophila nigrospiracula, exposed to a range of species that include parasites (ectoparasitic mite), predators (jumping spiders), as well as harmless heterospecifics (nonparasitic mites, ants, and weevils). We demonstrate that D. nigrospiracula can differentiate between threat and non-threat species, increase erratic movements and decrease velocity in the presence of parasites, but decrease erratic movements and time spent grooming in the presence of predators. Of particular importance, flies could distinguish between parasitic female mites and nonparasitic male mites of the same species, and respond accordingly. We also show that the direction of these NCEs differs when exposed to parasitic mites (i.e., risk of infection) versus spiders (i.e., risk of predation). Given the opposing effects of predation versus infection risk on fly behavior, we discuss potential trade-offs between parasite and predator avoidance behaviors. Our findings illustrate the complexity of risk assessment in a landscape of fear and the fine-tuned NCEs that arise in response. Moreover, this study is the first to examine these behavioral NCEs in a terrestrial system.
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Affiliation(s)
- Colin D MacLeod
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Lien T Luong
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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2
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Horváth G, Sos T, Bóné G, Lőrincz CE, Pap PL, Herczeg G. Integrating behavioural thermoregulatory strategy into the animal personality framework using the common lizard, Zootoca vivipara as a model. Sci Rep 2024; 14:14200. [PMID: 38902323 PMCID: PMC11189939 DOI: 10.1038/s41598-024-64305-z] [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: 01/30/2024] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
The study of consistent between-individual behavioural variation in single (animal personality) and across two or more behavioural traits (behavioural syndrome) is a central topic of behavioural ecology. Besides behavioural type (individual mean behaviour), behavioural predictability (environment-independent within-individual behavioural variation) is now also seen as an important component of individual behavioural strategy. Research focus is still on the 'Big Five' traits (activity, exploration, risk-taking, sociability and aggression), but another prime candidate to integrate to the personality framework is behavioural thermoregulation in small-bodied poikilotherms. Here, we found animal personality in thermoregulatory strategy (selected body temperature, voluntary thermal maximum, setpoint range) and 'classic' behavioural traits (activity, sheltering, risk-taking) in common lizards (Zootoca vivipara). Individual state did not explain the between-individual variation. There was a positive behavioural type-behavioural predictability correlation in selected body temperature. Besides an activity-risk-taking syndrome, we also found a risk-taking-selected body temperature syndrome. Our results suggest that animal personality and behavioural syndrome are present in common lizards, both including thermoregulatory and 'classic' behavioural traits, and selecting high body temperature with high predictability is part of the risk-prone behavioural strategy. We propose that thermoregulatory behaviour should be considered with equal weight to the 'classic' traits in animal personality studies of poikilotherms employing active behavioural thermoregulation.
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Affiliation(s)
- Gergely Horváth
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117, Budapest, Hungary.
- HUN-REN-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117, Budapest, Hungary.
| | - Tibor Sos
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Centre for Systems Biology, Biodiversity and Bioresources, Babeş-Bolyai University, Clinicilor street 5-7, Cluj-Napoca, Romania
- "Milvus Group" Bird and Nature Protection Association, B-dul 1 Decembrie 1918 121, 540445, Tîrgu Mureș, Romania
| | - Gábor Bóné
- "Milvus Group" Bird and Nature Protection Association, B-dul 1 Decembrie 1918 121, 540445, Tîrgu Mureș, Romania
| | - Csanád Endre Lőrincz
- Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6726, Szeged, Hungary
| | - Péter László Pap
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Centre for Systems Biology, Biodiversity and Bioresources, Babeş-Bolyai University, Clinicilor street 5-7, Cluj-Napoca, Romania
| | - Gábor Herczeg
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117, Budapest, Hungary
- HUN-REN-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117, Budapest, Hungary
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Tan M, Zhang S, Stevens M, Li D, Tan EJ. Antipredator defences in motion: animals reduce predation risks by concealing or misleading motion signals. Biol Rev Camb Philos Soc 2024; 99:778-796. [PMID: 38174819 DOI: 10.1111/brv.13044] [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: 12/06/2022] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024]
Abstract
Motion is a crucial part of the natural world, yet our understanding of how animals avoid predation whilst moving remains rather limited. Although several theories have been proposed for how antipredator defence may be facilitated during motion, there is often a lack of supporting empirical evidence, or conflicting findings. Furthermore, many studies have shown that motion often 'breaks' camouflage, as sudden movement can be detected even before an individual is recognised. Whilst some static camouflage strategies may conceal moving animals to a certain extent, more emphasis should be given to other modes of camouflage and related defences in the context of motion (e.g. flicker fusion camouflage, active motion camouflage, motion dazzle, and protean motion). Furthermore, when motion is involved, defence strategies are not necessarily limited to concealment. An animal can also rely on motion to mislead predators with regards to its trajectory, location, size, colour pattern, or even identity. In this review, we discuss the various underlying antipredator strategies and the mechanisms through which they may be linked to motion, conceptualising existing empirical and theoretical studies from two perspectives - concealing and misleading effects. We also highlight gaps in our understanding of these antipredator strategies, and suggest possible methodologies for experimental designs/test subjects (i.e. prey and/or predators) and future research directions.
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Affiliation(s)
- Min Tan
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Shichang Zhang
- Centre for Behavioural Ecology & Evolution, State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, Hubei, China
| | - Martin Stevens
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, TR10 9FE, UK
| | - Daiqin Li
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
- Centre for Behavioural Ecology & Evolution, State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, Hubei, China
| | - Eunice J Tan
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
- Division of Science, Yale-NUS College, 16 College Avenue West, Singapore, 138527, Singapore
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Scharf I, Hanna K, Gottlieb D. Experimental arena settings might lead to misinterpretation of movement properties. INSECT SCIENCE 2024; 31:271-284. [PMID: 37231528 DOI: 10.1111/1744-7917.13213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/07/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023]
Abstract
Movement is an important animal behavior contributing to reproduction and survival. Animal movement is often examined in arenas or enclosures under laboratory conditions. We used the red flour beetle (Tribolium castaneum) to examine here the effect of the arena size, shape, number of barriers, access to the arena's center, and illumination on six movement properties. We demonstrate great differences among arenas. For example, the beetles moved over longer distances in clear arenas than in obstructed ones. Movement along the arena's perimeter was greater in smaller arenas than in larger ones. Movement was more directional in round arenas than in rectangular ones. In general, the beetles stopped moving closer to the perimeter and closer to corners (in the square and rectangular arenas) than expected by chance. In some cases, the arena properties interacted with the beetle sex to affect several movement properties. All these suggest that arena properties might also interact with experimental manipulations to affect the outcome of studies and lead to results specific to the arena used. In other words, instead of examining animal movement, we in fact examine the animal interaction with the arena structure. Caution is therefore advised in interpreting the results of studies on movement in arenas under laboratory conditions and we recommend paying attention also to barriers or obstacles in field experiments. For instance, movement along the arena's perimeter is often interpreted as centrophobism or thigmotaxis but the results here show that such movement is arena dependent.
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Affiliation(s)
- Inon Scharf
- The George S. Wise Faculty of Life Sciences, School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Kimberley Hanna
- The George S. Wise Faculty of Life Sciences, School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Daphna Gottlieb
- Department of Food Science, Institute of Post-Harvest and Food Science, Volcani Center, ARO, Rishon LeZion, Israel
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Horváth G, Garamszegi LZ, Herczeg G. Phylogenetic meta-analysis reveals system-specific behavioural type-behavioural predictability correlations. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230303. [PMID: 37680498 PMCID: PMC10480700 DOI: 10.1098/rsos.230303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/24/2023] [Indexed: 09/09/2023]
Abstract
The biological significance of behavioural predictability (environment-independent within-individual behavioural variation) became accepted recently as an important part of an individual's behavioural strategy besides behavioural type (individual mean behaviour). However, we do not know how behavioural type and predictability evolve. Here, we tested different evolutionary scenarios: (i) the two traits evolve independently (lack of correlations) and (ii) the two traits' evolution is constrained (abundant correlations) due to either (ii/a) proximate constraints (direction of correlations is similar) or (ii/b) local adaptations (direction of correlations is variable). We applied a set of phylogenetic meta-analyses based on 93 effect sizes across 44 vertebrate and invertebrate species, focusing on activity and risk-taking. The general correlation between behavioural type and predictability did not differ from zero. Effect sizes for correlations showed considerable heterogeneity, with both negative and positive correlations occurring. The overall absolute (unsigned) effect size was high (Zr = 0.58), and significantly exceeded the null expectation based on randomized data. Our results support the adaptive scenario: correlations between behavioural type and predictability are abundant in nature, but their direction is variable. We suggest that the evolution of these behavioural components might be constrained in a system-specific way.
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Affiliation(s)
- Gergely Horváth
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
- ELKH-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
| | - László Zsolt Garamszegi
- Centre for Ecological Research, Institute of Ecology and Botany, Alkotmány u. 2-4, 2163 Vácrátót, Hungary
- National Laboratory for Health Security, Centre for Ecological Research, Budapest, Hungary
| | - Gábor Herczeg
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
- ELKH-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
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Ioannou CC, Carvalho LAB, Budleigh C, Ruxton GD. Virtual prey with Lévy motion are preferentially attacked by predatory fish. Behav Ecol 2023; 34:695-699. [PMID: 37434636 PMCID: PMC10332449 DOI: 10.1093/beheco/arad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 04/13/2023] [Accepted: 04/26/2023] [Indexed: 07/13/2023] Open
Abstract
Of widespread interest in animal behavior and ecology is how animals search their environment for resources, and whether these search strategies are optimal. However, movement also affects predation risk through effects on encounter rates, the conspicuousness of prey, and the success of attacks. Here, we use predatory fish attacking a simulation of virtual prey to test whether predation risk is associated with movement behavior. Despite often being demonstrated to be a more efficient strategy for finding resources such as food, we find that prey displaying Lévy motion are twice as likely to be targeted by predators than prey utilizing Brownian motion. This can be explained by the predators, at the moment of the attack, preferentially targeting prey that were moving with straighter trajectories rather than prey that were turning more. Our results emphasize that costs of predation risk need to be considered alongside the foraging benefits when comparing different movement strategies.
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Affiliation(s)
| | - Luis Arrochela Braga Carvalho
- School of Biological Sciences, Life Sciences Building, 24 Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Chessy Budleigh
- School of Biological Sciences, Life Sciences Building, 24 Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, Sir Harold Mitchell Building, Greenside Place, St Andrews KY16 9TH, UK
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Cliffe RN, Haupt RJ, Kennedy S, Felton C, Williams HJ, Avey-Arroyo J, Wilson R. The behaviour and activity budgets of two sympatric sloths; Bradypus variegatus and Choloepus hoffmanni. PeerJ 2023; 11:e15430. [PMID: 37273542 PMCID: PMC10234273 DOI: 10.7717/peerj.15430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 04/26/2023] [Indexed: 06/06/2023] Open
Abstract
It is usually beneficial for species to restrict activity to a particular phase of the 24-hour cycle as this enables the development of morphological and behavioural adaptations to enhance survival under specific biotic and abiotic conditions. Sloth activity patterns are thought to be strongly related to the environmental conditions due to the metabolic consequences of having a low and highly variable core body temperature. Understanding the drivers of sloth activity and their ability to withstand environmental fluctuations is of growing importance for the development of effective conservation measures, particularly when we consider the vulnerability of tropical ecosystems to climate change and the escalating impacts of anthropogenic activities in South and Central America. Unfortunately, the cryptic nature of sloths makes long term observational research difficult and so there is very little existing literature examining the behavioural ecology of wild sloths. Here, we used micro data loggers to continuously record, for the first time, the behaviour of both Bradypus and Choloepus sloths over periods of days to weeks. We investigate how fluctuations in the environmental conditions affect the activity of sloths inhabiting a lowland rainforest on the Caribbean coast of Costa Rica and examined how this might relate to their low power lifestyle. Both Bradypus and Choloepus sloths were found to be cathemeral in their activity, with high levels of between-individual and within-individual variation in the amounts of time spent active, and in the temporal distribution of activity over the 24-hour cycle. Daily temperature did not affect activity, although Bradypus sloths were found to show increased nocturnal activity on colder nights, and on nights following colder days. Our results demonstrate a distinct lack of synchronicity within the same population, and we suggest that this pattern provides sloths with the flexibility to exploit favourable environmental conditions whilst reducing the threat of predation.
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Affiliation(s)
- Rebecca N. Cliffe
- The Sloth Conservation Foundation, Hayfield, Derbyshire, United Kingdom
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea, United Kingdom
- The Sloth Sanctuary of Costa Rica, Limon, Costa Rica
| | - Ryan J. Haupt
- Department of Geology and Geophysics, University of Wyoming, Laramie, WY, United States of America
| | - Sarah Kennedy
- The Sloth Conservation Foundation, Hayfield, Derbyshire, United Kingdom
| | - Cerys Felton
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea, United Kingdom
| | - Hannah J. Williams
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea, United Kingdom
- Migration Department, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | | | - Rory Wilson
- Swansea Lab for Animal Movement, Biosciences, College of Science, Swansea University, Swansea, United Kingdom
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Krama T, Munkevics M, Krams R, Grigorjeva T, Trakimas G, Jõers P, Popovs S, Zants K, Elferts D, Rantala MJ, Sledevskis E, Contreras-Garduño J, de Bivort BL, Krams IA. Development under predation risk increases serotonin-signaling, variability of turning behavior and survival in adult fruit flies Drosophila melanogaster. Front Behav Neurosci 2023; 17:1189301. [PMID: 37304760 PMCID: PMC10248140 DOI: 10.3389/fnbeh.2023.1189301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/09/2023] [Indexed: 06/13/2023] Open
Abstract
The development of high-throughput behavioral assays, where numerous individual animals can be analyzed in various experimental conditions, has facilitated the study of animal personality. Previous research showed that isogenic Drosophila melanogaster flies exhibit striking individual non-heritable locomotor handedness. The variability of this trait, i.e., the predictability of left-right turn biases, varies across genotypes and under the influence of neural activity in specific circuits. This suggests that the brain can dynamically regulate the extent of animal personality. It has been recently shown that predators can induce changes in prey phenotypes via lethal or non-lethal effects affecting the serotonergic signaling system. In this study, we tested whether fruit flies grown with predators exhibit higher variability/lower predictability in their turning behavior and higher survival than those grown with no predators in their environment. We confirmed these predictions and found that both effects were blocked when flies were fed an inhibitor (αMW) of serotonin synthesis. The results of this study demonstrate a negative association between the unpredictability of turning behavior of fruit flies and the hunting success of their predators. We also show that the neurotransmitter serotonin controls predator-induced changes in the turning variability of fruit flies, regulating the dynamic control of behavioral predictability.
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Affiliation(s)
- Tatjana Krama
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
- Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia
| | - Māris Munkevics
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, Latvia
| | - Ronalds Krams
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
- Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia
| | - Tatjana Grigorjeva
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
| | - Giedrius Trakimas
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
- Institute of Biosciences, Vilnius University, Vilnius, Lithuania
| | - Priit Jõers
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Sergejs Popovs
- Department of Biotechnology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
| | - Krists Zants
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, Latvia
| | - Didzis Elferts
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, Latvia
| | - Markus J. Rantala
- Department of Biology, Turku Brain and Mind Center, University of Turku, Turku, Finland
| | - Eriks Sledevskis
- Department of Technology, Institute of Life Sciences and Technologies, Daugavpils University, Daugavpils, Latvia
| | - Jorge Contreras-Garduño
- Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, Morelia, Mexico
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Benjamin L. de Bivort
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | - Indrikis A. Krams
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, Latvia
- Latvian Biomedical Research and Study Centre, Riga, Latvia
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
- Department of Psychology, University of Tennessee, Knoxville, Knoxville, TN, United States
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Lancer BH, Evans BJE, Fabian JM, O'Carroll DC, Wiederman SD. Preattentive facilitation of target trajectories in a dragonfly visual neuron. Commun Biol 2022; 5:829. [PMID: 35982305 PMCID: PMC9388622 DOI: 10.1038/s42003-022-03798-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 08/04/2022] [Indexed: 12/03/2022] Open
Abstract
The ability to pursue targets in visually cluttered and distraction-rich environments is critical for predators such as dragonflies. Previously, we identified Centrifugal Small-Target Motion Detector 1 (CSTMD1), a dragonfly visual neuron likely involved in such target-tracking behaviour. CSTMD1 exhibits facilitated responses to targets moving along a continuous trajectory. Moreover, CSTMD1 competitively selects a single target out of a pair. Here, we conducted in vivo, intracellular recordings from CSTMD1 to examine the interplay between facilitation and selection, in response to the presentation of paired targets. We find that neuronal responses to both individual trajectories of simultaneous, paired targets are facilitated, rather than being constrained to the single, selected target. Additionally, switches in selection elicit suppression which is likely an important attribute underlying target pursuit. However, binocular experiments reveal these results are constrained to paired targets within the same visual hemifield, while selection of a target in one visual hemifield establishes ocular dominance that prevents facilitation or response to contralaterally presented targets. These results reveal that the dragonfly brain preattentively represents more than one target trajectory, to balance between attentional flexibility and resistance against distraction. A dragonfly visual neuron independently facilitates responses to rival targets within the same visual field, mediating selective attention.
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Affiliation(s)
- Benjamin H Lancer
- School of Biomedicine, The University of Adelaide, Adelaide, Australia.
| | - Bernard J E Evans
- School of Biomedicine, The University of Adelaide, Adelaide, Australia
| | - Joseph M Fabian
- School of Biomedicine, The University of Adelaide, Adelaide, Australia
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Sanmartín-Villar I, Yu X, Cordero-Rivera A. Direct and cross-generational effects of reproduction on fitness and behavioral variability in male-biased environments. Curr Zool 2022. [DOI: 10.1093/cz/zoac045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Population structure determines individuals’ interactions and trade-offs with evolutionary consequences. Male-biased populations increase intrasexual competition and intersexual harassment, reducing female resource acquisition, and thus, resources availability for the following generation. We analyzed direct and cross-generational effects of male harassment in two generations of damselflies (Odonata). We exposed adult females to treatments with different sex-ratio and density (balanced and male-biased) to modify the male harassment level. We analyzed female fecundity, fertility, and number of faecal deposits as an indirect measure of resources acquisition. We studied female flight performance after repeated exposures to males. We analyzed survivorship, development, exploration, thigmotaxis, and feeding latency of larvae produced by the experimental females. In both generations, we analyzed four metrics of behavior: mean value, interindividual differences in plasticity, intra-individual unpredictability, and repeatability. Mating duration increased in male-biased treatment, whereas female resources acquisition and fertility decreased. Females that mated longer showed higher fecundity when they were exposed to balanced treatment, but not if they were exposed to male-biased treatment. Females from the male-biased treatment showed interindividual differences in plasticity and no repeatability in flight performance. Offspring showed balanced sex-ratio and similar survivorship, development, and feeding latency independently of the parental treatment; however, females exposed to male-biased treatment produced offspring with higher differences in exploration plasticity and daughters less explorative and with higher unpredictable thigmotaxis. We propose prolonged copulation as courtship at balanced sex-ratio but a cost to females under male-biased sex-ratio. Cross-generational effects in behavioral variability may be a mechanism to cope with predicted future environments.
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Affiliation(s)
- Iago Sanmartín-Villar
- Universidade de Vigo, ECOEVO Lab, Escola de Enxeñaría Forestal, Campus Universitario A Xunqueira , 36005 Pontevedra, Galiza , Spain
| | - Xin Yu
- Universidade de Vigo, ECOEVO Lab, Escola de Enxeñaría Forestal, Campus Universitario A Xunqueira , 36005 Pontevedra, Galiza , Spain
- College of Life Sciences, Chongqing Normal University , Daxuecheng Middle Rd, Shapingba District, Chongqing 401333 , China
| | - Adolfo Cordero-Rivera
- Universidade de Vigo, ECOEVO Lab, Escola de Enxeñaría Forestal, Campus Universitario A Xunqueira , 36005 Pontevedra, Galiza , Spain
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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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12
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Maskrey DK, Sneddon LU, Arnold KE, Wolfenden DC, Thomson JS. Temperature-driven changes in behavioural unpredictability and personality in the beadlet sea anemone, Actinia equina. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Pagès JF, Bartumeus F, Romero J, Alcoverro T. The scent of fear makes sea urchins go ballistic. MOVEMENT ECOLOGY 2021; 9:50. [PMID: 34627405 PMCID: PMC8502380 DOI: 10.1186/s40462-021-00287-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Classic ecological formulations of predator-prey interactions often assume that predators and prey interact randomly in an information-limited environment. In the field, however, most prey can accurately assess predation risk by sensing predator chemical cues, which typically trigger some form of escape response to reduce the probability of capture. Here, we explore under laboratory-controlled conditions the long-term (minutes to hours) escaping response of the sea urchin Paracentrotus lividus, a key species in Mediterranean subtidal macrophyte communities. METHODS Behavioural experiments involved exposing a random sample of P. lividus to either one of two treatments: (i) control water (filtered seawater) or (ii) predator-conditioned water (with cues from the main P. lividus benthic predator-the gastropod Hexaplex trunculus). We analysed individual sea urchin trajectories, computed their heading angles, speed, path straightness, diffusive properties, and directional entropy (as a measure of path unpredictability). To account for the full picture of escaping strategies, we followed not only the first instants post-predator exposure, but also the entire escape trajectory. We then used linear models to compare the observed results from control and predators treatments. RESULTS The trajectories from sea urchins subjected to predator cues were, on average, straighter and faster than those coming from controls, which translated into differences in the diffusive properties and unpredictability of their movement patterns. Sea urchins in control trials showed complex diffusive properties in an information-limited environment, with highly variable trajectories, ranging from Brownian motion to superdiffusion, and even marginal ballistic motion. In predator cue treatments, variability reduced, and trajectories became more homogeneous and predictable at the edge of ballistic motion. CONCLUSIONS Despite their old evolutionary origin, lack of cephalization, and homogenous external appearance, the trajectories that sea urchins displayed in information-limited environments were complex and ranged widely between individuals. Such variable behavioural repertoire appeared to be intrinsic to the species and emerged when the animals were left unconstrained. Our results highlight that fear from predators can be an important driver of sea urchin movement patterns. All in all, the observation of anomalous diffusion, highly variable trajectories and the behavioural shift induced by predator cues, further highlight that the functional forms currently used in classical predator-prey models are far from realistic.
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Affiliation(s)
- Jordi F Pagès
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Blanes, Spain.
| | - Frederic Bartumeus
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Blanes, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Cerdanyola del Vallès, Spain
| | - Javier Romero
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Teresa Alcoverro
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Blanes, Spain
- Nature Conservation Foundation, Amritha, 1311, 12th Cross, Vijayanagar 1st Stage, Mysore, 570017, India
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14
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Garde B, Wilson RP, Lempidakis E, Börger L, Portugal SJ, Hedenström A, Dell'Omo G, Quetting M, Wikelski M, Shepard ELC. Fine-scale changes in speed and altitude suggest protean movements in homing pigeon flights. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210130. [PMID: 34017602 PMCID: PMC8131938 DOI: 10.1098/rsos.210130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/12/2021] [Indexed: 05/14/2023]
Abstract
The power curve provides a basis for predicting adjustments that animals make in flight speed, for example in relation to wind, distance, habitat foraging quality and objective. However, relatively few studies have examined how animals respond to the landscape below them, which could affect speed and power allocation through modifications in climb rate and perceived predation risk. We equipped homing pigeons (Columba livia) with high-frequency loggers to examine how flight speed, and hence effort, varies in relation to topography and land cover. Pigeons showed mixed evidence for an energy-saving strategy, as they minimized climb rates by starting their ascent ahead of hills, but selected rapid speeds in their ascents. Birds did not modify their speed substantially in relation to land cover, but used higher speeds during descending flight, highlighting the importance of considering the rate of change in altitude before estimating power use from speed. Finally, we document an unexpected variability in speed and altitude over fine scales; a source of substantial energetic inefficiency. We suggest this may be a form of protean behaviour adopted to reduce predation risk when flocking is not an option, and that such a strategy could be widespread.
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Affiliation(s)
- Baptiste Garde
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Rory P. Wilson
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Emmanouil Lempidakis
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Luca Börger
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Steven J. Portugal
- Department of Biological Sciences, Royal Holloway University of London, Egham, UK
| | - Anders Hedenström
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden
| | | | - Michael Quetting
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
| | - Martin Wikelski
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
- Department of Migration and Immuno-Ecology, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | - Emily L. C. Shepard
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
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15
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Gazzola A, Balestrieri A, Scribano G, Fontana A, Pellitteri-Rosa D. Contextual behavioural plasticity in Italian agile frog (Rana latastei) tadpoles exposed to native and alien predator cues. J Exp Biol 2021; 224:238115. [PMID: 33795420 DOI: 10.1242/jeb.240465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/24/2021] [Indexed: 11/20/2022]
Abstract
Predation is a strong driver for the evolution of prey behaviour. To properly assess the actual risk of predation, anuran tadpoles mostly rely on water-borne chemical cues, and their ability to evaluate environmental information is even more crucial when potential predators consist of unknown alien species. Behavioural plasticity - that is, the capacity to express changes in behaviour in response to different environmental stimuli - is crucial to cope with predation risk. We explored the defensive behaviour of Italian agile frog (Rana latastei) tadpoles when exposed to the chemical cues of two predator species, one native (dragonfly larvae) and one alien (red swamp crayfish). Firstly, we observed whether a plastic life history trait (i.e. hatching time) might be affected by native predatory cues. Secondly, we recorded a suite of behavioural responses (activity level, lateralization and sinuosity) to each cue. For assessing lateralization and sinuosity, we developed a C++ code for the automatic analysis of digitally recorded tadpole tracks. Hatching time seemed not to be affected by the potential risk of predation, while both predator species and diet affected tadpoles' defensive behaviour. Tadpoles responded to a predator threat by two main defensive strategies: freezing and 'zig-zagging'. While the first behaviour had previously been reported, the analysis of individual trajectories indicated that tadpoles can also increase path complexity, probably to prevent predators from anticipating their location. We also recorded a decrease in lateralization intensity, which suggests that under predation risk, tadpoles tend to scrutinize the surrounding environment equally on both sides.
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Affiliation(s)
- Andrea Gazzola
- Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, I-27100 Pavia, Italy
| | - Alessandro Balestrieri
- Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, I-27100 Pavia, Italy
| | - Giovanni Scribano
- Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, I-27100 Pavia, Italy
| | - Andrea Fontana
- Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, I-27100 Pavia, Italy
| | - Daniele Pellitteri-Rosa
- Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, I-27100 Pavia, Italy
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16
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Tay NE, Fleming PA, Warburton NM, Moseby KE. Predator exposure enhances the escape behaviour of a small marsupial, the burrowing bettong. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Hertel AG, Royauté R, Zedrosser A, Mueller T. Biologging reveals individual variation in behavioural predictability in the wild. J Anim Ecol 2020; 90:723-737. [PMID: 33301175 DOI: 10.1111/1365-2656.13406] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022]
Abstract
Recent research highlights the ecological importance of individual variation in behavioural predictability. Individuals may not only differ in their average expression of a behavioural trait (their behavioural type) and in their ability to adjust behaviour to changing environmental conditions (individual plasticity), but also in their variability around their average behaviour (predictability). However, quantifying behavioural predictability in the wild has been challenging due to limitations of acquiring sufficient repeated behavioural measures. We here demonstrate how common biologging data can be used to detect individual variation in behavioural predictability in the wild and reveal the coexistence of highly predictable individuals along with unpredictable individuals within the same population. We repeatedly quantified two behaviours-daily movement distance and diurnal activity-in 62 female brown bears Ursus arctos tracked across 187 monitoring years. We calculated behavioural predictability over the short term (50 consecutive monitoring days within 1 year) and long term (across monitoring years) as the residual intra-individual variability (rIIV) of behaviour around the behavioural reaction norm. We tested whether predictability varies systematically across average behavioural types and whether it is correlated across functionally distinct behaviours, that is, daily movement distance and amount of diurnal activity. Brown bears showed individual variation in behavioural predictability from predictable to unpredictable individuals. For example, the standard deviation around the average daily movement distance within one monitoring year varied up to fivefold from 1.1 to 5.5 km across individuals. Individual predictability for both daily movement distance and diurnality was conserved across monitoring years. Individual predictability was correlated with behavioural type where individuals which were on average more diurnal and mobile were also more unpredictable in their behaviour. In contrast, more nocturnal individuals moved less and were more predictable in their behaviour. Finally, individual predictability in daily movement distance and diurnality was positively correlated, suggesting that individual predictability may be a quantitative trait in its own regard that could evolve and is underpinned by genetic variation. Unpredictable individuals may cope better with stochastic events and unpredictability may hence be an adaptive behavioural response to increased predation risk. Coexistence of predictable and unpredictable individuals may therefore ensure adaptable and resilient populations.
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Affiliation(s)
- Anne G Hertel
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt (Main), Germany.,Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
| | - Raphaël Royauté
- Behavioural Ecology, Department of Biology, Ludwig-Maximilian University of Munich, Planegg-Martinsried, Germany
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway.,Institute of Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Thomas Mueller
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt (Main), Germany.,Department of Biological Sciences, Goethe University, Frankfurt (Main), Germany
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18
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López-Incera A, Ried K, Müller T, Briegel HJ. Development of swarm behavior in artificial learning agents that adapt to different foraging environments. PLoS One 2020; 15:e0243628. [PMID: 33338066 PMCID: PMC7748156 DOI: 10.1371/journal.pone.0243628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/24/2020] [Indexed: 11/25/2022] Open
Abstract
Collective behavior, and swarm formation in particular, has been studied from several perspectives within a large variety of fields, ranging from biology to physics. In this work, we apply Projective Simulation to model each individual as an artificial learning agent that interacts with its neighbors and surroundings in order to make decisions and learn from them. Within a reinforcement learning framework, we discuss one-dimensional learning scenarios where agents need to get to food resources to be rewarded. We observe how different types of collective motion emerge depending on the distance the agents need to travel to reach the resources. For instance, strongly aligned swarms emerge when the food source is placed far away from the region where agents are situated initially. In addition, we study the properties of the individual trajectories that occur within the different types of emergent collective dynamics. Agents trained to find distant resources exhibit individual trajectories that are in most cases best fit by composite correlated random walks with features that resemble Lévy walks. This composite motion emerges from the collective behavior developed under the specific foraging selection pressures. On the other hand, agents trained to reach nearby resources predominantly exhibit Brownian trajectories.
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Affiliation(s)
- Andrea López-Incera
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria
| | - Katja Ried
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria
| | - Thomas Müller
- Fachbereich Philosophie, Universität Konstanz, Konstanz, Germany
| | - Hans J. Briegel
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria
- Fachbereich Philosophie, Universität Konstanz, Konstanz, Germany
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19
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Papageorgiou D, Farine DR. Group size and composition influence collective movement in a highly social terrestrial bird. eLife 2020; 9:59902. [PMID: 33168135 PMCID: PMC7655099 DOI: 10.7554/elife.59902] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/07/2020] [Indexed: 12/17/2022] Open
Abstract
A challenge of group-living is to maintain cohesion while navigating through heterogeneous landscapes. Larger groups benefit from information pooling, translating to greater ‘collective intelligence’, but face increased coordination challenges. If these facets interact, we should observe a non-linear relationship between group size and collective movement. We deployed high-resolution GPS tags to vulturine guineafowl from 21 distinct social groups and used continuous-time movement models to characterize group movements across five seasons. Our data revealed a quadratic relationship between group size and movement characteristics, with intermediate-sized groups exhibiting the largest home-range size and greater variation in space use. Intermediate-sized groups also had higher reproductive success, but having more young in the group reduced home-range size. Our study suggests the presence of an optimal group size, and composition, for collective movement. Many social animals live in stable groups that stay together for years, or even lifetimes. Being in a group offers a range of benefits, such as safety from predators, information on where to find food or water, and more accurate navigation. But these benefits come at a cost. The larger the group, the harder it is to make decisions that balance the needs of each individual. So, while members of a large group should be better at locating resources and finding their way, they may take longer to decide where to go next. In nature, groups of the same species can vary greatly in size and can have large or small numbers of offspring. This raises the question of whether there is an optimal group size where the benefits of living together are maximized relative to the costs? To help answer this question, Papageorgiou and Farine studied the group behaviour of vulturine guineafowl, a social, ground-dwelling bird found in the savannahs of East Africa. A lightweight GPS tracker was fitted to the members of 21 different groups of vulturine guineafowl to see how group size affects the movement of these birds. The tags collected data every five minutes from dawn until dusk each day, and remained active over five two-month spans of similar weather conditions. This revealed that groups of intermediate size, which contain 33 to 37 birds, ranged over larger areas allowing them to access more diverse resources, and used less energy by travelling shorter distances. Birds in these groups also explored more new areas, decreasing their chances of encountering a predator, and produced more chicks, suggesting that their collective behaviour gave them a reproductive advantage. These findings suggest that intermediate sized groups display an optimal level of movement compared to larger or smaller groups. Understanding how social groups of different sizes interact with their environment can aid conservation planning. Future work should focus on how this relationship changes with the seasons. This could reveal more about the effects of group size during challenging conditions, like drought.
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Affiliation(s)
- Danai Papageorgiou
- Max Planck Institute of Animal Behavior, Department of Collective Behavior, Universitätsstraße, Konstanz, Germany.,University of Konstanz, Department of Biology, Universitätsstraße, Konstanz, Germany.,University of Konstanz, Center for the Advanced Study of Collective Behaviour, Universitätsstraße, Konstanz, Germany.,Kenya Wildlife Service, Nairobi, Kenya
| | - Damien Roger Farine
- Max Planck Institute of Animal Behavior, Department of Collective Behavior, Universitätsstraße, Konstanz, Germany.,University of Konstanz, Department of Biology, Universitätsstraße, Konstanz, Germany.,University of Konstanz, Center for the Advanced Study of Collective Behaviour, Universitätsstraße, Konstanz, Germany.,Department of Ornithology, National Museums of Kenya, Nairobi, Kenya
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20
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Reed EJ, Uddenberg S, Suthaharan P, Mathys CD, Taylor JR, Groman SM, Corlett PR. Paranoia as a deficit in non-social belief updating. eLife 2020; 9:56345. [PMID: 32452769 PMCID: PMC7326495 DOI: 10.7554/elife.56345] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
Paranoia is the belief that harm is intended by others. It may arise from selective pressures to infer and avoid social threats, particularly in ambiguous or changing circumstances. We propose that uncertainty may be sufficient to elicit learning differences in paranoid individuals, without social threat. We used reversal learning behavior and computational modeling to estimate belief updating across individuals with and without mental illness, online participants, and rats chronically exposed to methamphetamine, an elicitor of paranoia in humans. Paranoia is associated with a stronger prior on volatility, accompanied by elevated sensitivity to perceived changes in the task environment. Methamphetamine exposure in rats recapitulates this impaired uncertainty-driven belief updating and rigid anticipation of a volatile environment. Our work provides evidence of fundamental, domain-general learning differences in paranoid individuals. This paradigm enables further assessment of the interplay between uncertainty and belief-updating across individuals and species. Everyone has had fleeting concerns that others might be against them at some point in their lives. Sometimes these concerns can escalate into paranoia and become debilitating. Paranoia is a common symptom in serious mental illnesses like schizophrenia. It can cause extreme distress and is linked with an increased risk of violence towards oneself or others. Understanding what happens in the brains of people experiencing paranoia might lead to better ways to treat or manage it. Some experts argue that paranoia is caused by errors in the way people assess social situations. An alternative idea is that paranoia stems from the way the brain forms and updates beliefs about the world. Now, Reed et al. show that both people with paranoia and rats exposed to a paranoia-inducing substance expect the world will change frequently, change their minds often, and have a harder time learning in response to changing circumstances. In the experiments, human volunteers with and without psychiatric disorders played a game where the best choices change. Then, the participants completed a survey to assess their level of paranoia. People with higher levels of paranoia predicted more changes would occur and made less predictable choices. In a second set of experiments, rats were put in a cage with three holes where they sometimes received sugar rewards. Some of the rats received methamphetamine, a drug that causes paranoia in humans. Rats given the drug also expected the location of the sugar reward would change often. The drugged animals had harder time learning and adapting to changing circumstances. The experiments suggest that brain processes found in both rats, which are less social than humans, and humans contribute to paranoia. This suggests paranoia may make it harder to update beliefs. This may help scientists understand what causes paranoia and develop therapies or drugs that can reduce paranoia. This information may also help scientists understand why during societal crises like wars or natural disasters humans are prone to believing conspiracies. This is particularly important now as the world grapples with climate change and a global pandemic. Reed et al. note paranoia may impede the coordination of collaborative solutions to these challenging situations.
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Affiliation(s)
- Erin J Reed
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, United States.,Yale MD-PhD Program, Yale School of Medicine, New Haven, United States
| | - Stefan Uddenberg
- Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Praveen Suthaharan
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Have, United States
| | - Christoph D Mathys
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.,Translational Neuromodeling Unit (TNU), Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Jane R Taylor
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Have, United States
| | - Stephanie Mary Groman
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Have, United States
| | - Philip R Corlett
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Have, United States
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21
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Behavioral anatomy of a hunt : Using dynamic real-world paradigm and computer vision to compare human user-generated strategies with prey movement varying in predictability. Atten Percept Psychophys 2020; 82:3112-3123. [PMID: 32406004 PMCID: PMC7381454 DOI: 10.3758/s13414-020-02016-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is commonly thought that the mind constructs predictive models of the environment to plan an appropriate behavioral response. Therefore a more predictable environment should entail better performance, and prey should move in an unpredictable (random) manner to evade capture, known as protean motion. To test this, we created a novel experimental design and analysis in which human participants took the role of predator or prey. The predator was set the task of capturing the prey, while the prey was set the task of escaping. Participants performed this task standing on separate sides of a board and controlling a marker representing them. In three conditions, the prey followed a pattern of movement with varying predictability (predictable, semi-random, and random) and in one condition moved autonomously (user generated). The user-generated condition illustrated a naturalistic, dynamic environment involving a purposeful agent whose degree of predictability was not known in advance. The average distance between participants was measured through a video analysis custom-built in MATLAB. The user-generated condition had the largest average distance. This indicated that, rather than moving randomly (protean motion), humans may naturally employ a cybernetic escape strategy that dynamically maximizes perceived distance, regardless of the predictability of this strategy.
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22
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Murali G, Kodandaramaiah U. Size and unpredictable movement together affect the effectiveness of dynamic flash coloration. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Prentice PM, Houslay TM, Martin JGA, Wilson AJ. Genetic variance for behavioural 'predictability' of stress response. J Evol Biol 2020; 33:642-652. [PMID: 32022966 DOI: 10.1111/jeb.13601] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/07/2020] [Accepted: 01/30/2020] [Indexed: 02/02/2023]
Abstract
Genetic factors underpinning phenotypic variation are required if natural selection is to result in adaptive evolution. However, evolutionary and behavioural ecologists typically focus on variation among individuals in their average trait values and seek to characterize genetic contributions to this. As a result, less attention has been paid to if and how genes could contribute towards within-individual variance or trait 'predictability'. In fact, phenotypic 'predictability' can vary among individuals, and emerging evidence from livestock genetics suggests this can be due to genetic factors. Here, we test this empirically using repeated measures of a behavioural stress response trait in a pedigreed population of wild-type guppies. We ask (a) whether individuals differ in behavioural predictability and (b) whether this variation is heritable and so evolvable under selection. Using statistical methodology from the field of quantitative genetics, we find support for both hypotheses and also show evidence of a genetic correlation structure between the behavioural trait mean and individual predictability. We show that investigating sources of variability in trait predictability is statistically tractable and can yield useful biological interpretation. We conclude that, if widespread, genetic variance for 'predictability' will have major implications for the evolutionary causes and consequences of phenotypic variation.
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Affiliation(s)
- Pamela M Prentice
- Centre for Ecology and Conservation, University of Exeter, Cornwall, UK
| | | | | | - Alastair J Wilson
- Centre for Ecology and Conservation, University of Exeter, Cornwall, UK
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24
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Horváth G, Rodríguez‐Ruiz G, Martín J, López P, Herczeg G. Maternal diet affects juvenile Carpetan rock lizard performance and personality. Ecol Evol 2019; 9:14476-14488. [PMID: 31938534 PMCID: PMC6953655 DOI: 10.1002/ece3.5882] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/14/2019] [Accepted: 11/03/2019] [Indexed: 11/07/2022] Open
Abstract
Differences in both stable and labile state variables are known to affect the emergence and maintenance of consistent interindividual behavioral variation (animal personality or behavioral syndrome), especially when experienced early in life. Variation in environmental conditions experienced by gestating mothers (viz. nongenetic maternal effects) is known to have significant impact on offspring condition and behavior; yet, their effect on behavioral consistency is not clear. Here, by applying an orthogonal experimental design, we aimed to study whether increased vitamin D3 content in maternal diet during gestation (vitamin-supplemented vs. vitamin control treatments) combined with corticosterone treatment (corticosterone-treated vs. corticosterone control treatments) applied on freshly hatched juveniles had an effect on individual state and behavioral consistency of juvenile Carpetan rock lizards (Iberolacerta cyreni). We tested the effect of our treatments on (a) climbing speed and the following levels of behavioral variation, (b) strength of animal personality (behavioral repeatability), (c) behavioral type (individual mean behavior), and (d) behavioral predictability (within-individual behavioral variation unrelated to environmental change). We found higher locomotor performance of juveniles from the vitamin-supplemented group (42.4% increase), irrespective of corticosterone treatment. While activity personality was present in all treatments, shelter use personality was present only in the vitamin-supplemented × corticosterone-treated treatment and risk-taking personality was present in corticosterone control treatments. Contrary to our expectations, behavioral type was not affected by our treatments, indicating that individual quality can affect behavioral strategies without affecting group-level mean behavior. Behavioral predictability decreased in individuals with low climbing speed, which could be interpreted as a form of antipredator strategy. Our results clearly demonstrate that maternal diet and corticosterone treatment have the potential to induce or hamper between-individual variation in different components of boldness, often in interactions.
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Affiliation(s)
- Gergely Horváth
- Behavioural Ecology GroupDepartment of Systematic Zoology and EcologyEötvös Loránd UniversityBudapestHungary
| | | | - José Martín
- Department of Evolutionary EcologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - Pilar López
- Department of Evolutionary EcologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - Gábor Herczeg
- Behavioural Ecology GroupDepartment of Systematic Zoology and EcologyEötvös Loránd UniversityBudapestHungary
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25
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26
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Hügel T, Goerlitz HR. Species‐specific strategies increase unpredictability of escape flight in eared moths. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Theresa Hügel
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology Group Max Planck Institute for Ornithology Seewiesen Germany
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Horváth G, Garamszegi LZ, Bereczki J, Urszán TJ, Balázs G, Herczeg G. Roll with the fear: environment and state dependence of pill bug (Armadillidium vulgare) personalities. Naturwissenschaften 2019; 106:7. [PMID: 30729319 DOI: 10.1007/s00114-019-1602-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 12/12/2022]
Abstract
Most studies on animal personality evaluate individual mean behaviour to describe individual behavioural strategy, while often neglecting behavioural variability on the within-individual level. However, within-individual behavioural plasticity (variation induced by environment) and within-individual residual variation (regulatory behavioural precision) are recognized as biologically valid components of individual behaviour, but the evolutionary ecology of these components is still less understood. Here, we tested whether behaviour of common pill bugs (Armadillidium vulgare) differs on the among- and within-individual level and whether it is affected by various individual specific state-related traits (sex, size and Wolbachia infection). To this aim, we assayed risk-taking in familiar vs. unfamiliar environments 30 times along 38 days and applied double modelling statistical technique to handle the complex hierarchical structure for both individual-specific trait means and variances. We found that there are significant among-individual differences not only in mean risk-taking behaviour but also in environment- and time-induced behavioural plasticity and residual variation. Wolbachia-infected individuals took less risk than healthy conspecifics; in addition, individuals became more risk-averse with time. Residual variation decreased with time, and individuals expressed higher residual variation in the unfamiliar environment. Further, sensitization was stronger in females and in larger individuals in general. Our results suggest that among-individual variation, behavioural plasticity and residual variation are all (i) biologically relevant components of an individual's behavioural strategy and (ii) responsive to changes in environment or labile state variables. We propose pill bugs as promising models for personality research due to the relative ease of getting repeated behavioural measurements.
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Affiliation(s)
- Gergely Horváth
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary.
| | - László Zsolt Garamszegi
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary.,Department of Evolutionary Ecology, Estación Biológica de Donaña-CSIC, c/ Americo Vespucio, 26, 41092, Seville, Spain.,MTA-ELTE, Theoretical Biology and Evolutionary Ecology Research Group, Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary
| | - Judit Bereczki
- Department of Evolutionary Zoology and Human Biology, Institute of Biology and Ecology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary
| | - Tamás János Urszán
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary
| | - Gergely Balázs
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary
| | - Gábor Herczeg
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter Sétány 1/c, Budapest, H-1117, Hungary
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Richardson G, Dickinson P, Burman OHP, Pike TW. Unpredictable movement as an anti-predator strategy. Proc Biol Sci 2018; 285:20181112. [PMID: 30135159 PMCID: PMC6125907 DOI: 10.1098/rspb.2018.1112] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/20/2018] [Indexed: 11/12/2022] Open
Abstract
Prey animals have evolved a wide variety of behaviours to combat the threat of predation, and these have been generally well studied. However, one of the most common and taxonomically widespread antipredator behaviours of all has, remarkably, received almost no experimental attention: so-called 'protean' behaviour. This is behaviour that is sufficiently unpredictable to prevent a predator anticipating in detail the future position or actions of its prey. In this study, we used human 'predators' participating in 3D virtual reality simulations to test how protean (i.e. unpredictable) variation in prey movement affects participants' ability to visually target them as they move (a key determinant of successful predation). We found that targeting accuracy was significantly predicted by prey movement path complexity, although, surprisingly, there was little evidence that high levels of unpredictability in the underlying movement rules equated directly to decreased predator performance. Instead, the specific movement rules differed in how they impacted on targeting accuracy, with the efficacy of protean variation in one element depending on the values of the remaining elements. These findings provide important insights into the understudied phenomenon of protean antipredator behaviour, which are directly applicable to predator-prey dynamics within a broad range of taxa.
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Affiliation(s)
- Graham Richardson
- School of Life Sciences, University of Lincoln, Lincoln LN6 7DL, UK
- School of Computer Science, University of Lincoln, Lincoln LN6 7TS, UK
| | - Patrick Dickinson
- School of Computer Science, University of Lincoln, Lincoln LN6 7TS, UK
| | | | - Thomas W Pike
- School of Life Sciences, University of Lincoln, Lincoln LN6 7DL, UK
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