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Kersh-Mellor R, Montgomery SH, McLellan CF. Selfish herd effects in aggregated caterpillars and their interaction with warning signals. Biol Lett 2024; 20:20240050. [PMID: 38773926 DOI: 10.1098/rsbl.2024.0050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/03/2024] [Indexed: 05/24/2024] Open
Abstract
Larval Lepidoptera gain survival advantages by aggregating, especially when combined with aposematic warning signals, yet reductions in predation risk may not be experienced equally across all group members. Hamilton's selfish herd theory predicts that larvae that surround themselves with their group mates should be at lower risk of predation, and those on the periphery of aggregations experience the greatest risk, yet this has rarely been tested. Here, we expose aggregations of artificial 'caterpillar' targets to predation from free-flying, wild birds to test for marginal predation when all prey are equally accessible and for an interaction between warning coloration and marginal predation. We find that targets nearer the centre of the aggregation survived better than peripheral targets and nearby targets isolated from the group. However, there was no difference in survival between peripheral and isolated targets. We also find that grouped targets survived better than isolated targets when both are aposematic, but not when they are non-signalling. To our knowledge, our data provide the first evidence to suggest that avian predators preferentially target peripheral larvae from aggregations and that prey warning signals enhance predator avoidance of groups.
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Affiliation(s)
- Rami Kersh-Mellor
- School of Biological Sciences, University of Bristol , Bristol BS8 1TQ, UK
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2
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Hartono AD, Nguyen LTH, Tạ TV. A stochastic differential equation model for predator-avoidance fish schooling. Math Biosci 2024; 367:109112. [PMID: 38043605 DOI: 10.1016/j.mbs.2023.109112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/05/2023] [Accepted: 11/28/2023] [Indexed: 12/05/2023]
Abstract
This paper presents a mathematical model based on stochastic differential equations (SDEs) to depict the dynamics of a predator-prey system in an aquatic environment characterized by schooling behavior among the prey. The model employs a particle-like approach, incorporating attractive and repulsive forces, akin to phenomena observed in molecular physics, to capture the interactions among the constituent units. Two hunting tactics of the predator, center-attacking and nearest-attacking strategies, are integrated into the model. Numerical simulations of this model unveil four distinct predator-avoidance patterns exhibited by schooling prey: Split and Reunion, Split and Separate into Two Groups, Scattered, and Maintain Formation and Distance. Our results also confirm the effectiveness of large groups of schooling prey in mitigating predation risk, consistent with real-life observations in natural aquatic ecosystems. These findings validate the accuracy and applicability of our model.
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Affiliation(s)
- Aditya Dewanto Hartono
- Mathematical Modeling Laboratory, Division of Bioproduction Environmental Sciences, Department of Agro-environmental Sciences, Faculty of Agriculture, Kyushu University, 744 Motooka Nishi Ward, Fukuoka, 819-0395, Japan.
| | - Linh Thi Hoai Nguyen
- International Institute for Carbon-Neutral Energy Research, Kyushu University, 744 Motooka, Nishi Ward, Fukuoka, 819-0395, Japan.
| | - Tôn Việt Tạ
- Mathematical Modeling Laboratory, Division of Bioproduction Environmental Sciences, Department of Agro-environmental Sciences, Faculty of Agriculture, Kyushu University, 744 Motooka Nishi Ward, Fukuoka, 819-0395, Japan; Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, 744 Motooka Nishi Ward, Fukuoka, 819-0395, Japan.
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3
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Hansen MJ, Domenici P, Bartashevich P, Burns A, Krause J. Mechanisms of group-hunting in vertebrates. Biol Rev Camb Philos Soc 2023; 98:1687-1711. [PMID: 37199232 DOI: 10.1111/brv.12973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/19/2023]
Abstract
Group-hunting is ubiquitous across animal taxa and has received considerable attention in the context of its functions. By contrast much less is known about the mechanisms by which grouping predators hunt their prey. This is primarily due to a lack of experimental manipulation alongside logistical difficulties quantifying the behaviour of multiple predators at high spatiotemporal resolution as they search, select, and capture wild prey. However, the use of new remote-sensing technologies and a broadening of the focal taxa beyond apex predators provides researchers with a great opportunity to discern accurately how multiple predators hunt together and not just whether doing so provides hunters with a per capita benefit. We incorporate many ideas from collective behaviour and locomotion throughout this review to make testable predictions for future researchers and pay particular attention to the role that computer simulation can play in a feedback loop with empirical data collection. Our review of the literature showed that the breadth of predator:prey size ratios among the taxa that can be considered to hunt as a group is very large (<100 to >102 ). We therefore synthesised the literature with respect to these predator:prey ratios and found that they promoted different hunting mechanisms. Additionally, these different hunting mechanisms are also related to particular stages of the hunt (search, selection, capture) and thus we structure our review in accordance with these two factors (stage of the hunt and predator:prey size ratio). We identify several novel group-hunting mechanisms which are largely untested, particularly under field conditions, and we also highlight a range of potential study organisms that are amenable to experimental testing of these mechanisms in connection with tracking technology. We believe that a combination of new hypotheses, study systems and methodological approaches should help push the field of group-hunting in new directions.
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Affiliation(s)
- Matthew J Hansen
- Fish Biology, Fisheries and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
| | - Paolo Domenici
- IBF-CNR, Consiglio Nazionale delle Ricerche, Area di Ricerca San Cataldo, Via G. Moruzzi No. 1, Pisa, 56124, Italy
- IAS-CNR, Località Sa Mardini, Torregrande, Oristano, 09170, Italy
| | - Palina Bartashevich
- Faculty of Life Science, Humboldt-Universität zu Berlin, Invalidenstrasse 42, Berlin, 10115, Germany
- Cluster of Excellence "Science of Intelligence," Technical University of Berlin, Marchstr. 23, Berlin, 10587, Germany
| | - Alicia Burns
- Faculty of Life Science, Humboldt-Universität zu Berlin, Invalidenstrasse 42, Berlin, 10115, Germany
- Cluster of Excellence "Science of Intelligence," Technical University of Berlin, Marchstr. 23, Berlin, 10587, Germany
| | - Jens Krause
- Fish Biology, Fisheries and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
- Faculty of Life Science, Humboldt-Universität zu Berlin, Invalidenstrasse 42, Berlin, 10115, Germany
- Cluster of Excellence "Science of Intelligence," Technical University of Berlin, Marchstr. 23, Berlin, 10587, Germany
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4
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Rubin JJ, Kawahara AY. A framework for understanding post-detection deception in predator-prey interactions. PeerJ 2023; 11:e15389. [PMID: 37377786 PMCID: PMC10292197 DOI: 10.7717/peerj.15389] [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: 12/15/2022] [Accepted: 04/19/2023] [Indexed: 06/29/2023] Open
Abstract
Predators and prey exist in persistent conflict that often hinges on deception-the transmission of misleading or manipulative signals-as a means for survival. Deceptive traits are widespread across taxa and sensory systems, representing an evolutionarily successful and common strategy. Moreover, the highly conserved nature of the major sensory systems often extends these traits past single species predator-prey interactions toward a broader set of perceivers. As such, deceptive traits can provide a unique window into the capabilities, constraints and commonalities across divergent and phylogenetically-related perceivers. Researchers have studied deceptive traits for centuries, but a unified framework for categorizing different types of post-detection deception in predator-prey conflict still holds potential to inform future research. We suggest that deceptive traits can be distinguished by their effect on object formation processes. Perceptual objects are composed of physical attributes (what) and spatial (where) information. Deceptive traits that operate after object formation can therefore influence the perception and processing of either or both of these axes. We build upon previous work using a perceiver perspective approach to delineate deceptive traits by whether they closely match the sensory information of another object or create a discrepancy between perception and reality by exploiting the sensory shortcuts and perceptual biases of their perceiver. We then further divide this second category, sensory illusions, into traits that distort object characteristics along either the what or where axes, and those that create the perception of whole novel objects, integrating the what/where axes. Using predator-prey examples, we detail each step in this framework and propose future avenues for research. We suggest that this framework will help organize the many forms of deceptive traits and help generate predictions about selective forces that have driven animal form and behavior across evolutionary time.
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Affiliation(s)
- Juliette J. Rubin
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Akito Y. Kawahara
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
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5
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Burridge SD, Schlupp I, Makowicz AM. Male attention allocation depends on social context. Behav Processes 2023; 209:104878. [PMID: 37116668 DOI: 10.1016/j.beproc.2023.104878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 03/17/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023]
Abstract
Allocation of attention, typically a limited capacity, is a mechanism used to filter large amounts of information and determine what stimuli are most relevant at a particular moment. In dynamic social environments as found in almost all species, including humans, multiple individuals may play a pivotal role in any given interaction where a male's attention may be divided between a rival, a current mate, and/or future potential mates. Although clearly important, the role of the social environment on attention in animals is not well understood. Here, we investigated impacts of the social environment on attention allocation using male sailfin mollies, Poecilia latipinna, which are a part of a sexual-unisexual mating system with the Amazon molly, Poecilia formosa. We asked: 1) Does the species of female influence the amount of attention a male allocates to her? And 2) Is a male's attention towards his mate influenced by different social partners? We show that males perceive a larger male as a more relevant stimulus to pay attention to compared to a smaller male, and a conspecific female (either a partner or audience) as a more relevant stimulus compared to a heterospecific female. Our results show that differential allocation of attention is dependent upon multiple components of the social environment in which an individual interacts. Understanding what qualities of rival males or potential mates provide enough meaning to males to cause a shift in attention away from a mating opportunity is essential to understanding the influence of the social environment in sexual selection.
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Affiliation(s)
- Shelby D Burridge
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Ingo Schlupp
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Amber M Makowicz
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; Department of Biological Sciences, Florida State University, 319 Stadium Drive, Tallahassee, FL 32306.
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6
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Falgueras-Cano J, Falgueras-Cano JA, Moya A. Aggregated Distribution as an Explanation for the Paradox of Plankton and Collective Animal Behavior. BIOLOGY 2022; 11:biology11101477. [PMID: 36290382 PMCID: PMC9598300 DOI: 10.3390/biology11101477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/09/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022]
Abstract
Simple Summary ECA is similar to a cellular automaton that mimics the evolutionary dynamics of species in metapopulations, simulating the underlying mechanisms of natural selection. In this work, we carry out an in-silico study of the effects of different dispersal strategies on the evolutionary balance of interactions between digital organisms. In ECA we see how a specific type of distribution can significantly influence the dynamics, persistence, distribution, and abundance of populations of different species within a particular habitat. In the first place, we show that an aggregate distribution is more inefficient than a uniform distribution. Still, we verify that this aggregate distribution is essential in predator–prey type interactions so that the species involved do not become extinct. We also show that the aggregate distribution does not comply with the competitive exclusion principle and, for this reason, it results in a general and straightforward explanation for the paradox of plankton and the grouping of animals. Many animals and especially some planktonic species group together in specific spaces, although some travel adrift, leaving other areas or patches free where competitors or their prey can prosper, preventing them from becoming extinct. Abstract This work analyzes the evolutionary consequences of different aggregation levels of species distribution with an Evolutionary Cellular Automaton (ECA). We have found that in habitats with the same carrying capacity, aggregated distributions preserve smaller populations than do uniform distributions, i.e., they are less efficient. Nonetheless, we have also found that aggregated distributions, among other factors, can help the evolutionary stability of some biological interactions, such as predator–prey interactions, despite their granting less individual fitness. Besides, the competitive exclusion principle does not usually stand in populations with aggregated distribution. We have applied ECA to study the effects of aggregated distribution in two notorious cases: in the so-called paradox of the plankton and in gregarious animals. In doing so, we intend to ratify long-established ecological knowledge explaining these phenomena from a new perspective. In the first case, due to aggregate distribution, large aggregations of digital organisms mimicking very abundant planktonic species, leave large patches or oceanic areas free for other less competitive organisms, which mimic rare species, to prosper. In this case, we can see how effects, such as ecological drift and the small portion, act simultaneously. In the second case of aggregation, the aggregate distribution of gregarious animals could be explained under specialized predator–prey interactions and interdemic competition. Thus, digital organisms that imitate predators reduce the competitive capacity of their prey, destabilizing their competitiveness against other species. The specialized predator also goes extinct if the prey goes extinct by natural selection. Predators that have an aggregate distribution compensate the prey and thus avoid exclusion. This way there are more predator-free patches in which the prey can prosper. However, by granting greater colonization capacity to its prey, the predator loses competitiveness. Therefore, it is a multilevel selection event in which group adaptation grows to the detriment of the predator as an individual.
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Affiliation(s)
- Javier Falgueras-Cano
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and CSIC, 46980 Valencia, Spain
| | | | - Andrés Moya
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and CSIC, 46980 Valencia, Spain
- Genomics and Health Area, Foundation for the Promotion of Sanitary and Biomedical Research (FISABIO), 46020 Valencia, Spain
- Biomedical Research Center Network of Epidemiology and Public Health (CIBEResp), 28029 Madrid, Spain
- Correspondence:
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7
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Brighton CH, Kloepper LN, Harding CD, Larkman L, McGowan K, Zusi L, Taylor GK. Raptors avoid the confusion effect by targeting fixed points in dense aerial prey aggregations. Nat Commun 2022; 13:4778. [PMID: 35999203 PMCID: PMC9399121 DOI: 10.1038/s41467-022-32354-5] [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: 02/19/2022] [Accepted: 07/26/2022] [Indexed: 11/09/2022] Open
Abstract
Collective behaviours are widely assumed to confuse predators, but empirical support for a confusion effect is often lacking, and its importance must depend on the predator’s targeting mechanism. Here we show that Swainson’s Hawks Buteo swainsoni and other raptors attacking swarming Mexican Free-tailed Bats Tadarida brasiliensis steer by turning towards a fixed point in space within the swarm, rather than by using closed-loop pursuit of any one individual. Any prey with which the predator is on a collision course will appear to remain on a constant bearing, so target selection emerges naturally from the geometry of a collision. Our results show how predators can simplify the demands on their sensory system by decoupling steering from target acquisition when capturing prey from a dense swarm. We anticipate that the same tactic will be used against flocks and schools across a wide range of taxa, in which case a confusion effect is paradoxically more likely to occur in attacks on sparse groups, for which steering and target acquisition cannot be decoupled. Flocking, schooling, and swarming prey are thought to benefit from a confusion effect. However, here the authors show that hawks attacking swarming bats avoid confusion by steering towards a fixed point in the swarm instead of targeting any one individual.
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Affiliation(s)
- Caroline H Brighton
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK.
| | - Laura N Kloepper
- Department of Biological Sciences and Center for Acoustics Research and Education, Spaulding Hall, University of New Hampshire, Durham, NH, 03824, USA.,Department of Biology, Saint Mary's College, 262 Science Hall, Notre Dame, IN, 46556, USA
| | - Christian D Harding
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK.,Department of Physiology, Anatomy, and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Lucy Larkman
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Kathryn McGowan
- Department of Biological Sciences and Center for Acoustics Research and Education, Spaulding Hall, University of New Hampshire, Durham, NH, 03824, USA
| | - Lillias Zusi
- Department of Biological Sciences and Center for Acoustics Research and Education, Spaulding Hall, University of New Hampshire, Durham, NH, 03824, USA
| | - Graham K Taylor
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK.
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8
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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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9
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10
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Nauta J, Khaluf Y, Simoens P. Resource ephemerality influences effectiveness of altruistic behavior in collective foraging. SWARM INTELLIGENCE 2021. [DOI: 10.1007/s11721-021-00205-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Ismail M, Zanolli P, Muratori F, Hance T. Aphids Facing Their Parasitoids: A First Look at How Chemical Signals May Make Higher Densities of the Pea Aphid Acyrthosiphon pisum Less Attractive to the Parasitoid Aphidius ervi. INSECTS 2021; 12:insects12100878. [PMID: 34680647 PMCID: PMC8538517 DOI: 10.3390/insects12100878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Successful foraging behavior of parasitoids depends on specific organic information emitted by host-infested plants. For instance, the emission of volatile compounds increases in infested plants, and these are the first indicator of host presence. Parasitoids are attracted by these volatiles in a quite specific way. By combining behavioral and chemical studies, we showed bottom-up effects in a broad bean Vicia faba (Fabaceae)–pea aphid Acyrthosiphon pisum (Homoptera: Aphididae)–parasitoid Aphidius ervi (Hymenoptera: Braconidae) model system. We found that behavioral selection of parasitoid females toward plants with a high density of aphid infestation was reduced, and this can be linked to reduced emission of volatile compounds. In practice, if parasitoids are less attracted to plants with high-density aphid infestations, there may be potential negative impacts on biological control. Therefore, the common recommendation in biological control is to release parasitoids early in the season when aphid density on crop plants is still low. Abstract Herbivore-induced plant volatiles constitute the first indicators of insect host presence, and these can affect the foraging behavior of their natural enemies. The density of insect hosts may affect the nature and concentration of these plant-induced volatiles. We tested the impact of infestation density (low, intermediate, and high) of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae), feeding on the broad bean Vicia faba, on the attractiveness of the parasitoid Aphidius ervi (Hymenoptera: Braconidae), using a Y-tube olfactometer (infested vs. non-infested plants). The emitted volatile compounds from both infested and non-infested plants were collected and identified. In addition, two series of experiments were carried out to test the impact of the presence of a conspecific female parasitoid within the aphid/plant complex on the attractiveness to other females. Parasitoids were significantly more attracted to the plants with low and intermediate aphid infestation levels. The volatile blend composition of the infested plants changed in relation to aphid density and may explain the low attraction of parasitoids toward high aphid density. The presence of conspecific females on the aphid patch had no apparent impact on the behavioral choices of other parasitoid females. Our study adds a new aspect to understanding plant–aphid–parasitoid interactions, including the possibility that aphids may manipulate chemical cues of host plants affecting the orientation of parasitoids.
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Affiliation(s)
- Mohannad Ismail
- Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium; (P.Z.); (F.M.); (T.H.)
- Correspondence:
| | - Penelope Zanolli
- Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium; (P.Z.); (F.M.); (T.H.)
- Dipartimento di Scienze Agrarie e Ambientali, Università di Udine, Via Delle Scienze 208, 33100 Udine, Italy
| | - Frédéric Muratori
- Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium; (P.Z.); (F.M.); (T.H.)
| | - Thierry Hance
- Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium; (P.Z.); (F.M.); (T.H.)
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12
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Tan EJ, Elgar MA. Motion: enhancing signals and concealing cues. Biol Open 2021; 10:271863. [PMID: 34414408 PMCID: PMC8411570 DOI: 10.1242/bio.058762] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/02/2021] [Indexed: 01/15/2023] Open
Abstract
Animal colour patterns remain a lively focus of evolutionary and behavioural ecology, despite the considerable conceptual and technical developments over the last four decades. Nevertheless, our current understanding of the function and efficacy of animal colour patterns remains largely shaped by a focus on stationary animals, typically in a static background. Yet, this rarely reflects the natural world: most animals are mobile in their search for food and mates, and their surrounding environment is usually dynamic. Thus, visual signalling involves not only animal colour patterns, but also the patterns of animal motion and behaviour, often in the context of a potentially dynamic background. While motion can reveal information about the signaller by attracting attention or revealing signaller attributes, motion can also be a means of concealing cues, by reducing the likelihood of detection (motion camouflage, motion masquerade and flicker-fusion effect) or the likelihood of capture following detection (motion dazzle and confusion effect). The interaction between the colour patterns of the animal and its local environment is further affected by the behaviour of the individual. Our review details how motion is intricately linked to signalling and suggests some avenues for future research. This Review has an associated Future Leader to Watch interview with the first author. Summary: While motion can reveal information about the signaller, motion can also be a means of concealing cues by reducing the likelihood of detection or the likelihood of capture following detection.
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Affiliation(s)
- Eunice J Tan
- Division of Science, Yale-NUS College, Singapore 138527, Singapore
| | - Mark A Elgar
- School of BioSciences, University of Melbourne, Melbourne, Victoria 3010, Australia
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13
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Prakash H, Greif S, Yovel Y, Balakrishnan R. Acoustically eavesdropping bat predators take longer to capture katydid prey signalling in aggregation. J Exp Biol 2021; 224:268371. [PMID: 34047777 DOI: 10.1242/jeb.233262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 04/21/2021] [Indexed: 11/20/2022]
Abstract
Prey that are signalling in aggregation become more conspicuous with increasing numbers and tend to attract more predators. Such grouping may, however, benefit prey by lowering the risk of being captured because of the predator's difficulty in targeting individuals. Previous studies have investigated anti-predatory benefits of prey aggregation using visual predators, but it is unclear whether such benefits are gained in an auditory context. We investigated whether katydids of the genus Mecopoda gain protection from their acoustically eavesdropping bat predator Megaderma spasma when calling in aggregation. In a choice experiment, bats approached calls of prey aggregations more often than those of prey calling alone, indicating that prey calling in aggregation are at higher risk. In prey capture tasks, however, the average time taken and the number of flight passes made by bats before capturing a katydid were significantly higher for prey calling in aggregation than when calling alone, indicating that prey face lower predation risk when calling in aggregation. Another common anti-predatory strategy, calling from within vegetation, increased the time taken by bats to capture katydids calling alone but did not increase the time taken to capture prey calling from aggregations. The increased time taken to capture prey calling in aggregation compared with solitary calling prey offers an escape opportunity, thus providing prey that signal acoustically in aggregations with anti-predatory benefits. For bats, greater detectability of calling prey aggregations is offset by lower foraging efficiency, and this trade-off may shape predator foraging strategies in natural environments.
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Affiliation(s)
- Harish Prakash
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Stefan Greif
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv 69978, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Yossi Yovel
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv 69978, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Rohini Balakrishnan
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India
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14
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Szopa-Comley AW, Donald WG, Ioannou CC. Predator personality and prey detection: inter-individual variation in responses to cryptic and conspicuous prey. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02854-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
Limited attention constrains predators from engaging in cognitively demanding tasks such as searching for cryptic prey at the same time as remaining vigilant towards threats. Since finite attention can result in negative correlations between foraging and vigilance, the tendency of individual predators to focus attention on searching for cryptic prey may be correlated with other behavioural traits which reflect risk-reward trade-offs, such as consistent inter-individual variation in boldness (a personality trait describing risk-taking, defined in this study as the time taken to leave a refuge). We investigated the importance of personality in prey detection by comparing inter-individual variation in the response of three-spined sticklebacks (Gasterosteus aculeatus) to conspicuous and cryptic prey. Fish were slower to attack cryptic prey than conspicuous prey, consistent with cryptic prey being harder to detect. Despite the greater challenge involved in detecting cryptic prey, inter-individual variation in the time taken to detect prey was similar in the cryptic and conspicuous prey treatments, and was uncorrelated with boldness, which was repeatable between individuals. We also observed a positive association between the rate of attack on conspicuous prey and whether individual fish attacked cryptic prey in other trials. Our findings suggest that boldness is not related to prey detection or attention in this context. Instead, consistent differences in motivation once exploration has begun between individual predators may explain inter-individual variation in the time taken to attack both prey cryptic and conspicuous prey.
Significance statement
Using an experimental approach to manipulate the conspicuousness of prey, we show that individual fish consistently differ in their rates of attacking prey. This demonstrates that fish show “personality variation” in predatory behaviour, but these inter-individual differences were not related to the boldness of each fish (their tendency to engage in risky behaviours).
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Pilkiewicz KR, Lemasson BH, Rowland MA, Hein A, Sun J, Berdahl A, Mayo ML, Moehlis J, Porfiri M, Fernández-Juricic E, Garnier S, Bollt EM, Carlson JM, Tarampi MR, Macuga KL, Rossi L, Shen CC. Decoding collective communications using information theory tools. J R Soc Interface 2020; 17:20190563. [PMID: 32183638 PMCID: PMC7115225 DOI: 10.1098/rsif.2019.0563] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 02/28/2020] [Indexed: 02/03/2023] Open
Abstract
Organisms have evolved sensory mechanisms to extract pertinent information from their environment, enabling them to assess their situation and act accordingly. For social organisms travelling in groups, like the fish in a school or the birds in a flock, sharing information can further improve their situational awareness and reaction times. Data on the benefits and costs of social coordination, however, have largely allowed our understanding of why collective behaviours have evolved to outpace our mechanistic knowledge of how they arise. Recent studies have begun to correct this imbalance through fine-scale analyses of group movement data. One approach that has received renewed attention is the use of information theoretic (IT) tools like mutual information, transfer entropy and causation entropy, which can help identify causal interactions in the type of complex, dynamical patterns often on display when organisms act collectively. Yet, there is a communications gap between studies focused on the ecological constraints and solutions of collective action with those demonstrating the promise of IT tools in this arena. We attempt to bridge this divide through a series of ecologically motivated examples designed to illustrate the benefits and challenges of using IT tools to extract deeper insights into the interaction patterns governing group-level dynamics. We summarize some of the approaches taken thus far to circumvent existing challenges in this area and we conclude with an optimistic, yet cautionary perspective.
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Affiliation(s)
- K. R. Pilkiewicz
- Environmental Laboratory, U.S. Army Engineer Research and Development Center (EL-ERDC), Vicksburg, MS, USA
| | | | - M. A. Rowland
- Environmental Laboratory, U.S. Army Engineer Research and Development Center (EL-ERDC), Vicksburg, MS, USA
| | - A. Hein
- National Oceanic and Atmospheric Administration, Santa Cruz, CA, USA
- University of California, Santa Cruz, CA, USA
| | - J. Sun
- Department of Mathematics, Clarkson University, Potsdam, NY, USA
| | - A. Berdahl
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - M. L. Mayo
- Environmental Laboratory, U.S. Army Engineer Research and Development Center (EL-ERDC), Vicksburg, MS, USA
| | - J. Moehlis
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - M. Porfiri
- Department of Mechanical and Aerospace Engineering and Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, NY, USA
| | | | - S. Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, USA
| | - E. M. Bollt
- Department of Mathematics, Clarkson University, Potsdam, NY, USA
| | - J. M. Carlson
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - M. R. Tarampi
- Department of Psychology, University of Hartford, West Hartford, CT, USA
| | - K. L. Macuga
- School of Psychological Science, Oregon State University, Corvallis, OR, USA
| | - L. Rossi
- Department of Mathematical Sciences, University of Delaware, Newark, DE, USA
| | - C.-C. Shen
- Department of Computer and Information Sciences, University of Delaware, Newark, DE, USA
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17
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Lima SL, Lee JK. Is social coordination during escape flights a general phenomenon in birds? Ethology 2020. [DOI: 10.1111/eth.12958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven L. Lima
- Department of Biology Indiana State University Terre Haute IN USA
| | - Jong Koo Lee
- Department of Biology Indiana State University Terre Haute IN USA
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Romenskyy M, Herbert-Read JE, Ioannou CC, Szorkovszky A, Ward AJW, Sumpter DJT. Quantifying the structure and dynamics of fish shoals under predation threat in three dimensions. Behav Ecol 2019. [DOI: 10.1093/beheco/arz197] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Detailed quantifications of how predators and their grouping prey interact in three dimensions (3D) remain rare. Here we record the structure and dynamics of fish shoals (Pseudomugil signifer) in 3D both with and without live predators (Philypnodon grandiceps) under controlled laboratory conditions. Shoals adopted two distinct types of shoal structure: “sphere-like” geometries at depth and flat “carpet-like” structures at the water’s surface, with shoals becoming more compact in both horizontal and vertical planes in the presence of a predator. The predators actively stalked and attacked the prey, with attacks being initiated when the shoals were not in their usual configurations. These attacks caused the shoals to break apart, but shoal reformation was rapid and involved individuals adjusting their positions in both horizontal and vertical dimensions. Our analyses revealed that targeted prey were more isolated from other conspecifics, and were closer in terms of distance and direction to the predator compared to non-targeted prey. Moreover, which prey were targeted could largely be identified based on individuals’ positions from a single plane. This highlights that previously proposed 2D theoretical models and their assumptions appear valid when considering how predators target groups in 3D. Our work provides experimental, and not just anecdotal, support for classic theoretical predictions and also lends new insights into predatory–prey interactions in three-dimensional environments.
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Affiliation(s)
- Maksym Romenskyy
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - James E Herbert-Read
- Department of Zoology, University of Cambridge, Cambridge, UK
- Department of Biology, Aquatic Ecology Unit, Lund University, Lund, Sweden
| | | | | | - Ashley J W Ward
- School of Environmental and Life Sciences, University of Sydney, Sydney, New South Wales, Australia
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Abstract
The selfish herd hypothesis provides an explanation for group aggregation via the selfish avoidance of predators. Conceptually, and as was first proposed, this movement should aim to minimise the danger domain of each individual. Whilst many reasonable proxies have been proposed, none have directly sought to reduce the danger domain. In this work we present a two dimensional stochastic model that actively optimises these domains. The individuals' dynamics are determined by sampling the space surrounding them and moving to achieve the largest possible domain reduction. Two variants of this idea are investigated with sampling occurring either locally or globally. We simulate our models and two of the previously proposed benchmark selfish herd models: k-nearest neighbours (kNN); and local crowded horizon (LCH). The resulting positions are analysed to determine the benefit to the individual and the group's ability to form a compact group. To do this, the group level metric of packing fraction and individual level metric of domain size are observed over time for a range of noise levels. With these measures we show a clear stratification of the four models when noise is not included. kNN never resulted in centrally compacted herd, while the local active selfish model and LCH did so with varying levels of success. The most centralised groups were achieved with our global active selfish herd model. The inclusion of noise improved aggregation in all models. This was particularly so with the local active selfish model with a change to ordering of performance so that it marginally outperformed LCH in aggregation. By more closely following Hamilton's original conception and aligning the individual's goal of a reduced danger domain with the movement it makes increased cohesion is observed, thus confirming his hypothesis, however, these findings are dependent on noise. Moreover, many features originally conjectured by Hamilton are also observed in our simulations.
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Cattelan S, Griggio M. Within-shoal phenotypic homogeneity affects shoaling preference in a killifish. Biol Lett 2019; 14:rsbl.2018.0293. [PMID: 30089660 DOI: 10.1098/rsbl.2018.0293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/19/2018] [Indexed: 12/17/2022] Open
Abstract
Anti-predator benefits associated with living in groups are multiple and taxonomically widespread. In fish shoals, individuals can exploit the confusion effect, whereby predators struggle to target a single individual among several individuals. Theory predicts that the confusion effect could be aided by homogeneity in appearance; thus, individuals should group by phenotypic characteristics, contributing to generating high within-shoal phenotypic homogeneity. While assortments by body size have been extensively documented, almost nothing is known about whether within-shoal homogeneity in body pigmentation affects shoaling preference. To investigate this issue, we used the Mediterranean killifish, Aphanius fasciatus, a shoaling species characterized by conspicuous vertical bars on body sides. Individual females were given a choice between two novel shoals characterized by either a high or low degree of homogeneity in the number of bars. As predicted, individual females preferentially associated with the shoal showing the higher phenotypic homogeneity. Our data demonstrated that fish might associate with the shoal that maximizes phenotypic homogeneity in body pigmentation, irrespective of their own phenotype.
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Affiliation(s)
| | - Matteo Griggio
- Department of Biology, University of Padova, Padova, Italy
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21
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Time to revisit? A predator's previous successes and failures in prey capture determine its return time to patches. Oecologia 2019; 190:387-397. [PMID: 31147778 DOI: 10.1007/s00442-019-04425-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 05/27/2019] [Indexed: 10/26/2022]
Abstract
In a heterogeneous environment containing multiple patches that may deplete and renew, a forager should be able to detect the quality of food resources within and among patches and choose to exploit them to best maximize returns. From the predator's perspective, the behavioral responses of the prey in a patch will be perceived as depletion when they retreat to refuge and renewal when they reemerge. A predator encountering responsive prey should manage predation risk, and thus behavioral resource depression, by optimally timing its return time to the patch based on prey behavior. We evaluated the foraging decisions of a predator that encountered patches differing in size of the refuge and prey density. We used little egrets and goldfish as predators and prey in an environment that contained three patches (pools). We manipulated prey density and refuge size and availability (using covers) and observed predator foraging behavior. When the egret had previously caught a fish it did not discriminate between the pools, and the return time was similar for all cover types. The fish densities also did not affect the egret decisions to return to pools. However, when it failed to catch fish, it returned sooner to the pool containing the small cover than the larger one. Additionally, after failing to catch fish in patches containing the highest prey density, the egrets subsequently preferred to return to such patches sooner. We show experimentally that previous failures influence the foraging decisions of a predator choosing how quickly to return to a previously visited patch.
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22
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Goodale E, Ruxton GD, Beauchamp G. Predator Eavesdropping in a Mixed-Species Environment: How Prey Species May Use Grouping, Confusion, and the Cocktail Party Effect to Reduce Predator Detection. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00141] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Marlin T, Snekser JL, Leese JM. Juvenile convict cichlids shoaling decisions in relation to shoal size and age. Ethology 2019. [DOI: 10.1111/eth.12873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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24
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Evans DA, Stempel AV, Vale R, Branco T. Cognitive Control of Escape Behaviour. Trends Cogn Sci 2019; 23:334-348. [PMID: 30852123 PMCID: PMC6438863 DOI: 10.1016/j.tics.2019.01.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 12/21/2022]
Abstract
When faced with potential predators, animals instinctively decide whether there is a threat they should escape from, and also when, how, and where to take evasive action. While escape is often viewed in classical ethology as an action that is released upon presentation of specific stimuli, successful and adaptive escape behaviour relies on integrating information from sensory systems, stored knowledge, and internal states. From a neuroscience perspective, escape is an incredibly rich model that provides opportunities for investigating processes such as perceptual and value-based decision-making, or action selection, in an ethological setting. We review recent research from laboratory and field studies that explore, at the behavioural and mechanistic levels, how elements from multiple information streams are integrated to generate flexible escape behaviour.
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Affiliation(s)
- Dominic A Evans
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, UCL, London, UK; These authors contributed equally to this work
| | - A Vanessa Stempel
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, UCL, London, UK; These authors contributed equally to this work
| | - Ruben Vale
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, UCL, London, UK; These authors contributed equally to this work
| | - Tiago Branco
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, UCL, London, UK.
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25
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Attaran A, Salahinejad A, Crane AL, Niyogi S, Chivers DP. Chronic exposure to dietary selenomethionine dysregulates the genes involved in serotonergic neurotransmission and alters social and antipredator behaviours in zebrafish (Danio rerio). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:837-844. [PMID: 30623840 DOI: 10.1016/j.envpol.2018.12.090] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
Selenium (Se) is a metalloid of potential interest from both a toxicological and nutritional perspective, having a range of safe intake. The adverse neuro-behavioural effects of Se have been investigated in both humans and fishes, but little is known about its effects on social behaviours or the serotonergic signaling pathway in the brain. In the present study, we investigated the effects of chorionic dietary exposure to Se (as selenomethionine) at different concentrations (control, 2.1, 11.6 or 31.5 μg/g dry wt.) on antipredator avoidance, shoaling behaviour, and social group preferences in adult zebrafish (Danio rerio). In addition, we also measured the expression of important genes in the serotonergic pathway that influence social behaviours. After 60 days of exposure, the highest dose (31.5 μg/g dry wt.) caused the highest level of baseline fear behaviour, with fish swimming lower in the water column and in tighter shoals compared to fish in the other treatments. With high levels of baseline fear, these fish did not significantly intensify fear behaviours in response to predation risk in the form of exposure to chemical alarm cues. When individual fish were given an opportunity to shoal with groups of differing sizes (3 vs. 4 individuals), fish exposed to the high dose spent less time with groups in general, and only control fish showed a significant preference for the larger group. In the zebrafish brain, we found significant upregulation in the mRNA expression of serotonin receptors (htr1aa and htr1b), a transporter (slc6a4a), and tryptophan hydroxylase-2 (tph2), whereas there was a downregulation of the monoamine oxidase (mao) gene. The results of this study suggest that disruption of serotonergic neurotransmission might have been responsible for Se-induced impairment of antipredator and social behaviour in zebrafish.
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Affiliation(s)
- Anoosha Attaran
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada.
| | - Arash Salahinejad
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Adam L Crane
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada; Department of Biology, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | - Som Niyogi
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, Saskatchewan, S7N 5B3, Canada
| | - Douglas P Chivers
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
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26
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Murali G, Kumari K, Kodandaramaiah U. Dynamic colour change and the confusion effect against predation. Sci Rep 2019; 9:274. [PMID: 30670756 PMCID: PMC6342951 DOI: 10.1038/s41598-018-36541-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/22/2018] [Indexed: 11/09/2022] Open
Abstract
The confusion effect - the decreased attack-to-kill ratio of a predator with increase in prey group size - is thought to be one of the main reasons for the evolution of group living in animals. Despite much interest, the influence of prey coloration on the confusion effect is not well understood. We hypothesized that dynamic colour change in motion (due to interference coloration or flash marks), seen widely in many group living animals, enhances the confusion effect. Utilizing a virtual tracking task with humans, we found targets that dynamically changed colour during motion were more difficult to track than targets with background matching patterns, and this effect was stronger at larger group sizes. The current study thus provides the first empirical evidence for the idea that dynamic colour change can benefit animals in a group and may explain the widespread occurrence of dynamic colorations in group-living animals.
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Affiliation(s)
- Gopal Murali
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India.
| | - Kajal Kumari
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India
| | - Ullasa Kodandaramaiah
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India
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27
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Penry-Williams IL, Ioannou CC, Taylor MI. The oddity effect drives prey choice but not necessarily attack time. Ethology 2018. [DOI: 10.1111/eth.12754] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Martin I. Taylor
- School of Biological Sciences; University of East Anglia; Norwich UK
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28
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Hall JR, Baddeley R, Scott-Samuel NE, Shohet AJ, Cuthill IC. Camouflaging moving objects: crypsis and masquerade. Behav Ecol 2018; 28:1248-1255. [PMID: 29622927 PMCID: PMC5873248 DOI: 10.1093/beheco/arx085] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/07/2017] [Accepted: 05/30/2017] [Indexed: 11/14/2022] Open
Abstract
Motion is generally assumed to “break” camouflage. However, although camouflage cannot conceal a group of moving animals, it may impair a predator’s ability to single one out for attack, even if that discrimination is not based on a color difference. Here, we use a computer-based task in which humans had to detect the odd one out among moving objects, with “oddity” based on shape. All objects were either patterned or plain, and either matched the background or not. We show that there are advantages of matching both group-mates and the background. However, when patterned objects are on a plain background (i.e., no background matching), the advantage of being among similarly patterned distractors is only realized when the group size is larger (10 compared to 5). In a second experiment, we present a paradigm for testing how coloration interferes with target-distractor discrimination, based on an adaptive staircase procedure for establishing the threshold. We show that when the predator only has a short time for decision-making, displaying a similar pattern to the distractors and the background affords protection even when the difference in shape between target and distractors is large. We conclude that, even though motion breaks camouflage, being camouflaged could help group-living animals reduce the risk of being singled out for attack by predators.
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Affiliation(s)
- Joanna R Hall
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK.,School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK, and
| | - Roland Baddeley
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK
| | - Nicholas E Scott-Samuel
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK
| | - Adam J Shohet
- Stealth Materials Group, QinetiQ, Cody Technology Park, Farnborough GU14 0LX, UK
| | - Innes C Cuthill
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK, and
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29
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Santos RG, Pinheiro HT, Martins AS, Riul P, Bruno SC, Janzen FJ, Ioannou CC. The anti-predator role of within-nest emergence synchrony in sea turtle hatchlings. Proc Biol Sci 2017; 283:rspb.2016.0697. [PMID: 27383817 PMCID: PMC4947888 DOI: 10.1098/rspb.2016.0697] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/14/2016] [Indexed: 11/16/2022] Open
Abstract
Group formation is a common behaviour among prey species. In egg-laying animals, despite the various factors that promote intra-clutch variation leading to asynchronous hatching and emergence from nests, synchronous hatching and emergence occurs in many taxa. This synchrony may be adaptive by reducing predation risk, but few data are available in any natural system, even for iconic examples of the anti-predator function of group formation. Here, we show for the first time that increased group size (number of hatchlings emerging together from a nest) reduces green turtle (Chelonia mydas) hatchling predation. This effect was only observed earlier in the night when predation pressure was greatest, indicated by the greatest predator abundance and a small proportion of predators preoccupied with consuming captured prey. Further analysis revealed that the effect of time of day was due to the number of hatchlings already killed in an evening; this, along with the apparent lack of other anti-predatory mechanisms for grouping, suggests that synchronous emergence from a nest appears to swamp predators, resulting in an attack abatement effect. Using a system with relatively pristine conditions for turtle hatchlings and their predators provides a more realistic environmental context within which intra-nest synchronous emergence has evolved.
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Affiliation(s)
- Robson G Santos
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Hudson Tercio Pinheiro
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA California Academy of Sciences, San Francisco, CA, USA
| | - Agnaldo Silva Martins
- Departamento de Oceanografia e Ecologia, Universidade Federal do Espírito Santo, Vitória, Espirito Santo, Brazil
| | - Pablo Riul
- Departamento de Engenharia e Meio Ambiente, CCAE, Universidade Federal da Paraíba, Rio Tinto, Paraíba, Brazil
| | | | - Fredric J Janzen
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Christos C Ioannou
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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30
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Ruan WB, Shapiro-Ilan D, Lewis EE, Kaplan F, Alborn H, Gu XH, Schliekelman P. Movement patterns in Entomopathogenic nematodes: Continuous vs. temporal. J Invertebr Pathol 2017; 151:137-143. [PMID: 29158014 DOI: 10.1016/j.jip.2017.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/18/2022]
Abstract
To exploit resources, animals implement various foraging behaviors to increase their fitness. Entomopathogenic nematodes are obligate parasites of insects in nature. In previous studies, entomopathogenic nematodes were reported to exhibit group movement behavior in the presence and absence of insect hosts. However, it was not determined if group movement is continuous or temporal. For example, nematode movement behavior upon emergence from the host might start out in an independent fashion prior to aggregation, or group movement may be exhibited continuously. In the present study, we explored the propensity for innate group movement behavior of two insect parasitic nematodes in two families and genera: Heterorhabditis indica and Steinernema carpocapsae. We hypothesized the nematode populations would initially move independently from their origin and then come together for group movement. Movement patterns were investigated in sand when nematodes were applied in aqueous suspension (via filter paper) to a specific locus or when the nematodes emerged naturally from infected insect hosts. To compare nematode movement behavior over time and space, nematode dispersal was monitored at three distances (2.5, 4.5 and 8.0 cm) from the center (origin) and at two different time periods, 2 days and 3 days after nematode addition. We discovered that nematode dispersal continuously exhibited an aggregative pattern (independent movement was not observed). Results from both nematode species as well as the host-cadaver and filter paper (aqueous nematode suspension) application methods indicated a continuous aggregative pattern. The discovery of continuous aggregative movement patterns in steinernematid and heterorhabditid nematodes elucidates further the complexity of their foraging behavior and may serve as basis for exploring foraging behavior in other host-parasite systems.
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Affiliation(s)
- Wei-Bin Ruan
- College of Life Sciences, Nankai University, Tianjin 30071, China
| | | | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | | | - Hans Alborn
- USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA
| | - Xin-Hui Gu
- Yuxi Tobacco Company, Yuxi 653100, Yunnan, China
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31
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Herbert-Read JE, Kremer L, Bruintjes R, Radford AN, Ioannou CC. Anthropogenic noise pollution from pile-driving disrupts the structure and dynamics of fish shoals. Proc Biol Sci 2017; 284:20171627. [PMID: 28954915 PMCID: PMC5627215 DOI: 10.1098/rspb.2017.1627] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/29/2017] [Indexed: 11/18/2022] Open
Abstract
Noise produced from a variety of human activities can affect the physiology and behaviour of individual animals, but whether noise disrupts the social behaviour of animals is largely unknown. Animal groups such as flocks of birds or shoals of fish use simple interaction rules to coordinate their movements with near neighbours. In turn, this coordination allows individuals to gain the benefits of group living such as reduced predation risk and social information exchange. Noise could change how individuals interact in groups if noise is perceived as a threat, or if it masked, distracted or stressed individuals, and this could have impacts on the benefits of grouping. Here, we recorded trajectories of individual juvenile seabass (Dicentrarchus labrax) in groups under controlled laboratory conditions. Groups were exposed to playbacks of either ambient background sound recorded in their natural habitat, or playbacks of pile-driving, commonly used in marine construction. The pile-driving playback affected the structure and dynamics of the fish shoals significantly more than the ambient-sound playback. Compared to the ambient-sound playback, groups experiencing the pile-driving playback became less cohesive, less directionally ordered, and were less correlated in speed and directional changes. In effect, the additional-noise treatment disrupted the abilities of individuals to coordinate their movements with one another. Our work highlights the potential for noise pollution from pile-driving to disrupt the collective dynamics of fish shoals, which could have implications for the functional benefits of a group's collective behaviour.
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Affiliation(s)
| | - Louise Kremer
- Department of Agronomy, Agroequipments, Farming and Environment, AgroSup Dijon, Dijon, France
| | - Rick Bruintjes
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, Bristol, UK
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Herbert-Read JE, Rosén E, Szorkovszky A, Ioannou CC, Rogell B, Perna A, Ramnarine IW, Kotrschal A, Kolm N, Krause J, Sumpter DJT. How predation shapes the social interaction rules of shoaling fish. Proc Biol Sci 2017; 284:20171126. [PMID: 28855361 PMCID: PMC5577484 DOI: 10.1098/rspb.2017.1126] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/18/2017] [Indexed: 11/21/2022] Open
Abstract
Predation is thought to shape the macroscopic properties of animal groups, making moving groups more cohesive and coordinated. Precisely how predation has shaped individuals' fine-scale social interactions in natural populations, however, is unknown. Using high-resolution tracking data of shoaling fish (Poecilia reticulata) from populations differing in natural predation pressure, we show how predation adapts individuals' social interaction rules. Fish originating from high predation environments formed larger, more cohesive, but not more polarized groups than fish from low predation environments. Using a new approach to detect the discrete points in time when individuals decide to update their movements based on the available social cues, we determine how these collective properties emerge from individuals' microscopic social interactions. We first confirm predictions that predation shapes the attraction-repulsion dynamic of these fish, reducing the critical distance at which neighbours move apart, or come back together. While we find strong evidence that fish align with their near neighbours, we do not find that predation shapes the strength or likelihood of these alignment tendencies. We also find that predation sharpens individuals' acceleration and deceleration responses, implying key perceptual and energetic differences associated with how individuals move in different predation regimes. Our results reveal how predation can shape the social interactions of individuals in groups, ultimately driving differences in groups' collective behaviour.
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Affiliation(s)
- James E Herbert-Read
- Department of Zoology, Stockholm University, Stockholm, Sweden
- Department of Mathematics, Uppsala University, Uppsala, Sweden
| | - Emil Rosén
- Department of Mathematics, Uppsala University, Uppsala, Sweden
| | | | | | - Björn Rogell
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Andrea Perna
- Department of Life Sciences, Roehampton University, London, UK
| | - Indar W Ramnarine
- Department of Life Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago
| | | | - Niclas Kolm
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Jens Krause
- Faculty of Life Sciences, Albrecht Daniel Thaer-Institut, Humboldt-University zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Biology and Ecology of Fishes, Müggelseedamm 310, 12587 Berlin, Germany
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Duffield C, Ioannou CC. Marginal predation: do encounter or confusion effects explain the targeting of prey group edges? Behav Ecol 2017; 28:1283-1292. [PMID: 29622928 PMCID: PMC5873256 DOI: 10.1093/beheco/arx090] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 04/19/2017] [Accepted: 06/29/2017] [Indexed: 11/12/2022] Open
Abstract
Marginal predation, also known as the edge effect, occurs when aggregations of prey are preferentially targeted on their periphery by predators and has long been established in many taxa. Two main processes have been used to explain this phenomenon, the confusion effect and the encounter rate between predators and prey group edges. However, it is unknown at what size a prey group needs to be before marginal predation is detectable and to what extent each mechanism drives the effect. We conducted 2 experiments using groups of virtual prey being preyed upon by 3-spined sticklebacks (Gasterosteus aculeatus) to address these questions. In Experiment 1, we show that group sizes do not need to be large for marginal predation to occur, with this being detectable in groups of 16 or more. In Experiment 2, we find that encounter rate is a more likely explanation for marginal predation than the confusion effect in this system. We find that while confusion does affect predatory behaviors (whether or not predators make an attack), it does not affect marginal predation. Our results suggest that marginal predation is a more common phenomenon than originally thought as it also applies to relatively small groups. Similarly, as marginal predation does not need the confusion effect to occur, it may occur in a wider range of predator–prey species pairings, for example those where the predators search for prey using nonvisual sensory modalities.
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Affiliation(s)
- Callum Duffield
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Christos C Ioannou
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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Gómez-Laplaza LM, Caicoya ÁL, Gerlai R. Quantity discrimination in angelfish (Pterophyllum scalare) is maintained after a 30-s retention interval in the large but not in the small number range. Anim Cogn 2017. [PMID: 28620776 DOI: 10.1007/s10071-017-1104-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The ability to discriminate between sets that differ in the number of elements can be useful in different contexts and may have survival and fitness consequences. As such, numerical/quantity discrimination has been demonstrated in a diversity of animal species. In the laboratory, this ability has been analyzed, for example, using binary choice tests. Furthermore, when the different number of items first presented to the subjects are subsequently obscured, i.e., are not visible at the moment of making a choice, the task requires memory for the size of the sets. In previous work, angelfish (Pterophyllum scalare) have been found to be able to discriminate shoals differing in the number of shoal members both in the small (less than 4) and the large (4 or more) number range, and they were able to perform well even when a short memory retention interval (2-15 s) was imposed. In the current study, we increased the retention interval to 30 s during which the shoals to choose between were obscured, and investigated whether angelfish could show preference for the larger shoal they saw before this interval. Subjects were faced with a discrimination between numerically small shoals (≤4 fish) and also between numerically large (≥4 fish) shoals of conspecifics. We found angelfish not to be able to remember the location of larger versus smaller shoals in the small number range, but to exhibit significant memory for the larger shoal in the large number range as long as the ratio between these shoals was at least 2:1. These results, together with prior findings, suggest the existence of two separate quantity estimation systems, the object file system for small number of items that does not work with the longer retention interval and the analogue magnitude system for larger number of items that does.
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Affiliation(s)
- Luis M Gómez-Laplaza
- Department of Psychology, University of Oviedo, Plaza de Feijoo s/n, 33003, Oviedo, Spain.
| | - Álvaro L Caicoya
- Department of Psychology, University of Oviedo, Plaza de Feijoo s/n, 33003, Oviedo, Spain
| | - Robert Gerlai
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
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Hogan BG, Cuthill IC, Scott-Samuel NE. Dazzle camouflage and the confusion effect: the influence of varying speed on target tracking. Anim Behav 2017; 123:349-353. [PMID: 28123185 PMCID: PMC5226095 DOI: 10.1016/j.anbehav.2016.11.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The formation of groups is a common strategy to avoid predation in animals, and recent research has indicated that there may be interactions between some forms of defensive coloration, notably high-contrast ‘dazzle camouflage’, and one of the proposed benefits of grouping: the confusion effect. However, research into the benefits of dazzle camouflage has largely used targets moving with constant speed. This simplification may not generalize well to real animal systems, where a number of factors influence both within- and between-individual variation in speed. Departure from the speed of your neighbours in a group may be predicted to undermine the confusion effect. This is because individual speed may become a parameter through which the observer can individuate otherwise similar targets: an ‘oddity effect’. However, dazzle camouflage patterns are thought to interfere with predator perception of speed and trajectory. The current experiment investigated the possibility that such patterns could ameliorate the oddity effect caused by within-group differences in prey speed. We found that variation in speed increased the ease with which participants could track targets in all conditions. However, we found no evidence that motion dazzle camouflage patterns reduced oddity effects based on this variation in speed, a result that may be informative about the mechanisms behind this form of defensive coloration. In addition, results from those conditions most similar to those of published studies replicated previous results, indicating that targets with stripes parallel to the direction of motion are harder to track, and that this pattern interacts with the confusion effect to a greater degree than background matching or orthogonal-to-motion striped patterns. Variation in speed in groups induces the oddity effect, reducing predator confusion. Dazzle camouflage does not ameliorate this oddity effect. Parallel striped targets in groups are harder to track than other targets.
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Affiliation(s)
- Benedict G Hogan
- Biological Sciences, University of Bristol, Bristol, U.K.; Experimental Psychology, University of Bristol, Bristol, U.K
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Hogan BG, Hildenbrandt H, Scott-Samuel N, Cuthill IC, Hemelrijk C. The confusion effect when attacking simulated three-dimensional starling flocks. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160564. [PMID: 28280553 PMCID: PMC5319319 DOI: 10.1098/rsos.160564] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 12/09/2016] [Indexed: 05/14/2023]
Abstract
The confusion effect describes the phenomenon of decreasing predator attack success with increasing prey group size. However, there is a paucity of research into the influence of this effect in coherent groups, such as flocks of European starlings (Sturnus vulgaris). Here, for the first time, we use a computer game style experiment to investigate the confusion effect in three dimensions. To date, computerized studies on the confusion effect have used two-dimensional simulations with simplistic prey movement and dynamics. Our experiment is the first investigation of the effects of flock size and density on the ability of a (human) predator to track and capture a target starling in a realistically simulated three-dimensional flock of starlings. In line with the predictions of the confusion effect, modelled starlings appear to be safer from predation in larger and denser flocks. This finding lends credence to previous suggestions that starling flocks have anti-predator benefits and, more generally, it suggests that active increases in density in animal groups in response to predation may increase the effectiveness of the confusion effect.
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Affiliation(s)
- Benedict G. Hogan
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, UK
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TH, UK
- Author for correspondence: Benedict G. Hogan e-mail:
| | - Hanno Hildenbrandt
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, 9747 AG, The Netherlands
| | | | - Innes C. Cuthill
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, UK
| | - Charlotte K. Hemelrijk
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, 9747 AG, The Netherlands
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Olson RS, Knoester DB, Adami C. Evolution of Swarming Behavior Is Shaped by How Predators Attack. ARTIFICIAL LIFE 2016; 22:299-318. [PMID: 27139941 DOI: 10.1162/artl_a_00206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Animal grouping behaviors have been widely studied due to their implications for understanding social intelligence, collective cognition, and potential applications in engineering, artificial intelligence, and robotics. An important biological aspect of these studies is discerning which selection pressures favor the evolution of grouping behavior. In the past decade, researchers have begun using evolutionary computation to study the evolutionary effects of these selection pressures in predator-prey models. The selfish herd hypothesis states that concentrated groups arise because prey selfishly attempt to place their conspecifics between themselves and the predator, thus causing an endless cycle of movement toward the center of the group. Using an evolutionary model of a predator-prey system, we show that how predators attack is critical to the evolution of the selfish herd. Following this discovery, we show that density-dependent predation provides an abstraction of Hamilton's original formulation of domains of danger. Finally, we verify that density-dependent predation provides a sufficient selective advantage for prey to evolve the selfish herd in response to predation by coevolving predators. Thus, our work corroborates Hamilton's selfish herd hypothesis in a digital evolutionary model, refines the assumptions of the selfish herd hypothesis, and generalizes the domain of danger concept to density-dependent predation.
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38
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Reising M, Salmon M, Stapleton S. Hawksbill nest site selection affects hatchling survival at a rookery in Antigua, West Indies. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00708] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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39
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Rieucau G, Sivle LD, Olav Handegard N. Herring perform stronger collective evasive reactions when previously exposed to killer whales calls. Behav Ecol 2015. [DOI: 10.1093/beheco/arv186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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40
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Olson RS, Haley PB, Dyer FC, Adami C. Exploring the evolution of a trade-off between vigilance and foraging in group-living organisms. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150135. [PMID: 26473039 PMCID: PMC4593673 DOI: 10.1098/rsos.150135] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
Even though grouping behaviour has been actively studied for over a century, the relative importance of the numerous proposed fitness benefits of grouping remain unclear. We use a digital model of evolving prey under simulated predation to directly explore the evolution of gregarious foraging behaviour according to one such benefit, the 'many eyes' hypothesis. According to this hypothesis, collective vigilance allows prey in large groups to detect predators more efficiently by making alarm signals or behavioural cues to each other, thereby allowing individuals within the group to spend more time foraging. Here, we find that collective vigilance is sufficient to select for gregarious foraging behaviour as long there is not a direct cost for grouping (e.g. competition for limited food resources), even when controlling for confounding factors such as the dilution effect. Furthermore, we explore the role of the genetic relatedness and reproductive strategy of the prey and find that highly related groups of prey with a semelparous reproductive strategy are the most likely to evolve gregarious foraging behaviour mediated by the benefit of vigilance. These findings, combined with earlier studies with evolving digital organisms, further sharpen our understanding of the factors favouring grouping behaviour.
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Affiliation(s)
- Randal S. Olson
- Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
- BEACON Center for the Study of Evolution in Action, East Lansing, MI 48824, USA
| | - Patrick B. Haley
- Department of Computer Science, The University of Texas at Austin, Austin, TX 78712, USA
- BEACON Center for the Study of Evolution in Action, East Lansing, MI 48824, USA
| | - Fred C. Dyer
- Department of Zoology, Michigan State University, East Lansing, MI 48824, USA
- BEACON Center for the Study of Evolution in Action, East Lansing, MI 48824, USA
| | - Christoph Adami
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- BEACON Center for the Study of Evolution in Action, East Lansing, MI 48824, USA
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41
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Scott-Samuel NE, Holmes G, Baddeley R, Cuthill IC. Moving in groups: how density and unpredictable motion affect predation risk. Behav Ecol Sociobiol 2015; 69:867-872. [PMID: 25983380 PMCID: PMC4425808 DOI: 10.1007/s00265-015-1885-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 11/25/2022]
Abstract
One of the most widely applicable benefits of aggregation is a per capita reduction in predation risk. Many factors can contribute to this but, for moving groups, an increased difficulty in tracking and targeting one individual amongst many has received particular attention. This "confusion effect" has been proposed to result from a bottleneck in information processing, a hypothesis supported by both modelling and experiment. If the competition for limited attention is localised to the particular part of the visual field where the target is located, prey density is likely to be the key factor rather than group numbers per se. Furthermore, unpredictability of prey movement may enhance confusion, but both factors have received insufficient attention from empiricists: undoubtedly because of the difficulty of experimental manipulation in natural systems. We used a computer-based target tracking task with human subjects to manipulate effects of number and density independently, in factorial combination with motion path predictability. Density, rather than number, drove the confusion effect in our experiment and acted synergistically with the unpredictability of the direction of motion. The experimental paradigm we present offers the potential for isolating other factors affecting predation success on group-living prey, and forging links with the psychological literature on object tracking and visual search.
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Affiliation(s)
| | - Gavin Holmes
- School of Psychology, Cardiff University, Cardiff, UK
| | - Roland Baddeley
- School of Experimental Psychology, University of Bristol, Bristol, UK
| | - Innes C. Cuthill
- School of Biological Sciences, University of Bristol, Bristol, UK
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42
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Rieucau G, De Robertis A, Boswell KM, Handegard NO. School density affects the strength of collective avoidance responses in wild-caught Atlantic herring Clupea harengus: a simulated predator encounter experiment. JOURNAL OF FISH BIOLOGY 2014; 85:1650-1664. [PMID: 25243659 DOI: 10.1111/jfb.12520] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 08/01/2014] [Indexed: 06/03/2023]
Abstract
An experimental study in a semi-controlled environment was conducted to examine whether school density in wild-caught Atlantic herring Clupea harengus affects the strength of their collective escape behaviours. Using acoustics, the anti-predator diving responses of C. harengus in two schools that differed in density were quantified by exposing them to a simulated threat. Due to logistical restrictions, the first fish was tested in a low-density school condition (four trials; packing density = 1.5 fish m(-3); c. 6000 fish) followed by fish in a high-density school condition (five trials; packing density = 16 fish m(-3); c. 60 000 fish). The C. harengus in a high-density school exhibited stronger collective diving avoidance responses to the simulated predators than fish in the lower-density school. The findings suggest that the density (and thus the internal organization) of a fish school affects the strength of collective anti-predatory responses, and the extent to which information about predation risk is transferred through the C. harengus school. Therefore, the results challenge the common notion that information transfer within animal groups may not depend on group size and density.
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Affiliation(s)
- G Rieucau
- Institute of Marine Research, P. O. Box 1870 Nordnes, 5817 Bergen, Norway
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43
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Rodgers GM, Downing B, Morrell LJ. Prey body size mediates the predation risk associated with being "odd". Behav Ecol 2014. [DOI: 10.1093/beheco/aru185] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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44
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Niizato T, Murakami H, Gunji YP. Emergence of the scale-invariant proportion in a flock from the metric-topological interaction. Biosystems 2014; 119:62-8. [PMID: 24686118 DOI: 10.1016/j.biosystems.2014.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/04/2014] [Accepted: 03/06/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Takayuki Niizato
- Faculty of Engineering, Information and Systems, Tsukuba University, Japan.
| | | | - Yukio-Pegio Gunji
- Graduate School of Science, Kobe University, Japan; Faculty of Science, Kobe University, Japan
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45
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Muratori FB, Rouyar A, Hance T. Clonal variation in aggregation and defensive behavior in pea aphids. Behav Ecol 2014. [DOI: 10.1093/beheco/aru064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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46
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Rieucau G, Boswell KM, De Robertis A, Macaulay GJ, Handegard NO. Experimental evidence of threat-sensitive collective avoidance responses in a large wild-caught herring school. PLoS One 2014; 9:e86726. [PMID: 24489778 PMCID: PMC3906054 DOI: 10.1371/journal.pone.0086726] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 12/16/2013] [Indexed: 11/19/2022] Open
Abstract
Aggregation is commonly thought to improve animals' security. Within aquatic ecosystems, group-living prey can learn about immediate threats using cues perceived directly from predators, or from collective behaviours, for example, by reacting to the escape behaviours of companions. Combining cues from different modalities may improve the accuracy of prey antipredatory decisions. In this study, we explored the sensory modalities that mediate collective antipredatory responses of herring (Clupea harengus) when in a large school (approximately 60 000 individuals). By conducting a simulated predator encounter experiment in a semi-controlled environment (a sea cage), we tested the hypothesis that the collective responses of herring are threat-sensitive. We investigated whether cues from potential threats obtained visually or from the perception of water displacement, used independently or in an additive way, affected the strength of the collective avoidance reactions. We modified the sensory nature of the simulated threat by exposing the herring to 4 predator models differing in shape and transparency. The collective vertical avoidance response was observed and quantified using active acoustics. The combination of sensory cues elicited the strongest avoidance reactions, suggesting that collective antipredator responses in herring are mediated by the sensory modalities involved during threat detection in an additive fashion. Thus, this study provides evidence for magnitude-graded threat responses in a large school of wild-caught herring which is consistent with the “threat-sensitive hypothesis”.
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Affiliation(s)
| | - Kevin M. Boswell
- Florida International University, Biscayne Bay Campus, Marine Sciences Building, North Miami, Florida, United States of America
| | - Alex De Robertis
- National Marine Fisheries Service, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
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48
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Murray GPD, Stillman RA, Gozlan RE, Britton JR. Experimental Predictions of The Functional Response of A Freshwater Fish. Ethology 2013. [DOI: 10.1111/eth.12117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gregory P. D. Murray
- Centre for Conservation Ecology and Environmental Change School of Applied Sciences Bournemouth University Bournemouth Dorset UK
| | - Richard A. Stillman
- Centre for Conservation Ecology and Environmental Change School of Applied Sciences Bournemouth University Bournemouth Dorset UK
| | - Rodolphe E. Gozlan
- Centre for Conservation Ecology and Environmental Change School of Applied Sciences Bournemouth University Bournemouth Dorset UK
- Unité Mixte de Recherche Biologie des Organismes et Écosystèmes Aquatiques (Institut de Recherche pour le Développement 207, Centre National de la Recherche Scientifique 7208, Muséum National d'Histoire Naturelle, Université Pierre et Marie Curie) Muséum National d'Histoire Naturelle Paris Cedex France
| | - J. Robert Britton
- Centre for Conservation Ecology and Environmental Change School of Applied Sciences Bournemouth University Bournemouth Dorset UK
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Olson RS, Hintze A, Dyer FC, Knoester DB, Adami C. Predator confusion is sufficient to evolve swarming behaviour. J R Soc Interface 2013; 10:20130305. [PMID: 23740485 DOI: 10.1098/rsif.2013.0305] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Swarming behaviours in animals have been extensively studied owing to their implications for the evolution of cooperation, social cognition and predator-prey dynamics. An important goal of these studies is discerning which evolutionary pressures favour the formation of swarms. One hypothesis is that swarms arise because the presence of multiple moving prey in swarms causes confusion for attacking predators, but it remains unclear how important this selective force is. Using an evolutionary model of a predator-prey system, we show that predator confusion provides a sufficient selection pressure to evolve swarming behaviour in prey. Furthermore, we demonstrate that the evolutionary effect of predator confusion on prey could in turn exert pressure on the structure of the predator's visual field, favouring the frontally oriented, high-resolution visual systems commonly observed in predators that feed on swarming animals. Finally, we provide evidence that when prey evolve swarming in response to predator confusion, there is a change in the shape of the functional response curve describing the predator's consumption rate as prey density increases. Thus, we show that a relatively simple perceptual constraint--predator confusion--could have pervasive evolutionary effects on prey behaviour, predator sensory mechanisms and the ecological interactions between predators and prey.
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Affiliation(s)
- Randal S Olson
- Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824, USA.
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50
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Ioannou CC, Guttal V, Couzin ID. Predatory Fish Select for Coordinated Collective Motion in Virtual Prey. Science 2012; 337:1212-5. [PMID: 22903520 DOI: 10.1126/science.1218919] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- C C Ioannou
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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