1
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Feist F, Terranova F, Petersen GS, Tourtigues E, Friard O, Gamba M, Ludynia K, Gridley T, Pichegru L, Mathevon N, Reby D, Favaro L. Effect of Environmental Variables on African Penguin Vocal Activity: Implications for Acoustic Censusing. BIOLOGY 2023; 12:1191. [PMID: 37759590 PMCID: PMC10525562 DOI: 10.3390/biology12091191] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/26/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023]
Abstract
Global biodiversity is in rapid decline, and many seabird species have disproportionally poorer conservation statuses than terrestrial birds. A good understanding of population dynamics is necessary for successful conservation efforts, making noninvasive, cost-effective monitoring tools essential. Here, we set out to investigate whether passive acoustic monitoring (PAM) could be used to estimate the number of animals within a set area of an African penguin (Spheniscus demersus) colony in South Africa. We were able to automate the detection of ecstatic display songs (EDSs) in our recordings, thus facilitating the handling of large datasets. This allowed us to show that calling rate increased with wind speed and humidity but decreased with temperature, and to highlight apparent abundance variations between nesting habitat types. We then showed that the number of EDSs in our recordings positively correlated with the number of callers counted during visual observations, indicating that the density could be estimated based on calling rate. Our observations suggest that increasing temperatures may adversely impact penguin calling behaviour, with potential negative consequences for population dynamics, suggesting the importance of effective conservation measures. Crucially, this study shows that PAM could be successfully used to monitor this endangered species' populations with minimal disturbance.
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Affiliation(s)
- Franziska Feist
- ENES Bioacoustics Research Team, University of Saint-Etienne, 42100 Saint-Etienne, France
| | - Francesca Terranova
- Department of Life Sciences and Systems Biology, University of Turin, 10124 Turin, Italy
| | - Gavin Sean Petersen
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town 7441, South Africa
| | - Emma Tourtigues
- ENES Bioacoustics Research Team, University of Saint-Etienne, 42100 Saint-Etienne, France
| | - Olivier Friard
- Department of Life Sciences and Systems Biology, University of Turin, 10124 Turin, Italy
| | - Marco Gamba
- Department of Life Sciences and Systems Biology, University of Turin, 10124 Turin, Italy
| | - Katrin Ludynia
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town 7441, South Africa
- Department of Biodiversity and Conservation Biology, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa
| | - Tess Gridley
- Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Lorien Pichegru
- Institute for Coastal and Marine Research, Nelson Mandela Metropolitan University, Port Elisabeth 6031, South Africa
| | - Nicolas Mathevon
- ENES Bioacoustics Research Team, University of Saint-Etienne, 42100 Saint-Etienne, France
- Institut Universitaire de France, Ministry of Higher Education, Research and Innovation, 1 rue Descartes, CEDEX 05, 75231 Paris, France
| | - David Reby
- ENES Bioacoustics Research Team, University of Saint-Etienne, 42100 Saint-Etienne, France
- Institut Universitaire de France, Ministry of Higher Education, Research and Innovation, 1 rue Descartes, CEDEX 05, 75231 Paris, France
| | - Livio Favaro
- Department of Life Sciences and Systems Biology, University of Turin, 10124 Turin, Italy
- CAPE Department, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
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2
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Group resource-holding potential: worker size, colony size and the outcome of contests in ants. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2023.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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3
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Lee JH, Sung HC. Morphological characteristics convey social status signals in captive tree sparrows (Passer montanus). PLoS One 2023; 18:e0283625. [PMID: 36989332 PMCID: PMC10057748 DOI: 10.1371/journal.pone.0283625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
In social animals that form flocks, individuals compete or cooperate to gain access to shared resources. In particular, group-foraging individuals frequently engage in aggressive interactions with conspecifics, including threat displays and physical attacks, in order to acquire food resources. Here, we investigated social interactions in flocks of captive tree sparrows (Passer montanus) to observe the formation of dominance hierarchies. We also examined correlations between social status and morphological traits to identify which physical traits act as indicators of dominance. To do so, we recorded aggressive behaviours (attacks and threats) of tree sparrows caught in two distinct regions in the Republic of Korea (Gwangju and Gurye). After merging the two groups, we examined dominance structures using David's scores for one month, and we recorded 1,051 aggressive interactions at a feeder in a group of 19 individuals. Using the number of aggressions and attack and threat behaviours, we tested whether morphological traits and sex influenced dominance structures. Aggressions were significantly more frequent in males than in females. However, no significant difference was observed the frequency of between- and within-sex aggression. In addition, differences in the frequency of aggression behaviours were observed between capture-site groups. Dominance structure was significantly correlated with certain morphological traits; specifically, the frequency of attacking behaviours was correlated with bill-nose length, and the frequency of threat displays was correlated with sex and badge size. These results suggest that social signals are closely related to morphological traits that are used to form dominance hierarchies in tree sparrow flocks.
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Affiliation(s)
- Ju-Hyun Lee
- Department of Biological Science, Chonnam National University, Gwangju, The Republic of Korea
| | - Ha-Cheol Sung
- Department of Biological Science, Chonnam National University, Gwangju, The Republic of Korea
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4
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Braga Goncalves I, Morris-Drake A, Kennedy P, Radford AN. Fitness consequences of outgroup conflict. eLife 2022; 11:e74550. [PMID: 35833830 PMCID: PMC9282852 DOI: 10.7554/elife.74550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 06/27/2022] [Indexed: 12/13/2022] Open
Abstract
In social species across the animal kingdom, conspecific outsiders threaten the valuable resources of groups and their members. This outgroup conflict is recognised as a powerful selection pressure, but we argue that studies explicitly quantifying the fitness consequences need to be broader in scope: more attention should be paid to delayed, cumulative, and third-party fitness consequences, not just those arising immediately to group members involved in physical contests. In the first part of this review, we begin by documenting how single contests can have survival and reproductive consequences either immediately or with a delay. Then, we step beyond contests to describe fitness consequences that can also result from interactions with cues of rival presence and the general landscape of outgroup threat, and beyond single interactions to describe cumulative effects of territorial pressure and elevated outgroup-induced stress. Using examples from a range of taxa, we discuss which individuals are affected negatively and positively, considering both interaction participants and third-party group members of the same or the next generation. In the second part of the review, we provide suggestions about how to move forward. We highlight the importance of considering how different types of outgroup conflict can generate different selection pressures and of investigating variation in fitness consequences within and between species. We finish by discussing the value of theoretical modelling and long-term studies of natural populations, experimental manipulations, and meta-analyses to develop further our understanding of this crucial aspect of sociality.
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Affiliation(s)
| | - Amy Morris-Drake
- School of Biological Sciences, University of BristolBristolUnited Kingdom
| | - Patrick Kennedy
- School of Biological Sciences, University of BristolBristolUnited Kingdom
| | - Andrew N Radford
- School of Biological Sciences, University of BristolBristolUnited Kingdom
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5
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Morris-Drake A, Kennedy P, Braga Goncalves I, Radford AN. Variation between species, populations, groups and individuals in the fitness consequences of out-group conflict. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210148. [PMID: 35369741 PMCID: PMC8977661 DOI: 10.1098/rstb.2021.0148] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Out-group conflict is rife in the natural world, occurring from primates to ants. Traditionally, research on this aspect of sociality has focused on the interactions between groups and their conspecific rivals, investigating contest function and characteristics, which group members participate and what determines who wins. In recent years, however, there has been increasing interest in the consequences of out-group conflict. In this review, we first set the scene by outlining the fitness consequences that can arise immediately to contest participants, as well as a broader range of delayed, cumulative and third-party effects of out-group conflict on survival and reproductive success. For the majority of the review, we then focus on variation in these fitness consequences of out-group conflict, describing known examples both between species and between populations, groups and individuals of the same species. Throughout, we suggest possible reasons for the variation, provide examples from a diverse array of taxa, and suggest what is needed to advance this burgeoning area of social evolution. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
- Amy Morris-Drake
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Patrick Kennedy
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Ines Braga Goncalves
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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6
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Sobroza TV, Gordo M, Barnett AP, Boubli JP, Spironello WR. Parapatric pied and red-handed tamarin responses to congeneric and conspecific calls. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2021. [DOI: 10.1016/j.actao.2020.103688] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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7
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Preston EFR, Thompson FJ, Ellis S, Kyambulima S, Croft DP, Cant MA. Network-level consequences of outgroup threats in banded mongooses: Grooming and aggression between the sexes. J Anim Ecol 2021; 90:153-167. [PMID: 33428240 DOI: 10.1111/1365-2656.13323] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/17/2020] [Indexed: 01/10/2023]
Abstract
Animal groups are heterogeneous assemblages of individuals with differing fitness interests, which may lead to internal conflict over investment in group territorial defence. Differences between individuals may lead to different behavioural responses to intergroup conflict, particularly between the sexes. These potential impacts have been little studied. We used social network analysis to investigate the impact of simulated intergroup conflicts on social relationships in groups of wild banded mongooses Mungos mungo, in which intergroup fights are more costly for males than females. We predicted that social cohesion (specifically male-to-male and female-to-male grooming) would increase after conflict, and aggression would decrease, to minimize conflict between the sexes. Simulated intergroup conflicts were performed by exposing banded mongoose groups to scents, 'war cry' playbacks, and live intruders from a rival group. All grooming and aggression interactions between individuals were recorded, and grooming and aggression social networks were created for the 2 days preceding a simulated intergroup conflict (pre-conflict network) and the 2 days after (post-conflict network). We found no evidence of an increase in social cohesion after simulated conflicts, measured as grooming eigenvector centrality. Male-to-male, male-to-female and female-to-male grooming strength decreased after simulated intrusions compared to female-to-female grooming strength. However, male-female aggression decreased in intrusion trials compared to other interaction types, consistent with the hypothesis that intergroup encounters reduce the level of intragroup conflict between males and females. Males were more affected socially by intergroup encounters than females, which may be because they are investing in defence rather than internal relationships. Focusing on individual relationship changes, using social network analysis, can reveal changes in the directionality of behaviour in response to intergroup encounters, and highlight how individual responses to conflict may scale up to affect social networks and, potentially, group performance. This study highlights the importance of studying both group-level behaviours and individual relationships to more fully understand responses to intergroup encounters.
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Affiliation(s)
- Elizabeth F R Preston
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
| | - Faye J Thompson
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
| | - Samuel Ellis
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Darren P Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Michael A Cant
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
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8
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Green PA, Briffa M, Cant MA. Assessment during Intergroup Contests. Trends Ecol Evol 2020; 36:139-150. [PMID: 33187729 DOI: 10.1016/j.tree.2020.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 12/11/2022]
Abstract
Research on how competitors assess (i.e., gather information on) fighting ability and contested resources, as well as how assessment impacts on contest processes and outcomes, has been fundamental to the field of dyadic (one-on-one) contests. Despite recent growth in studies of contests between social-living groups, there is limited understanding of assessment during these intergroup contests. We adapt current knowledge of dyadic contest assessment to the intergroup case, describing what traits of groups, group members, and resources are assessed, and how assessment is manifested in contest processes (e.g., behaviors) and outcomes. This synthesis helps to explain the role of individual heterogeneity in assessment and how groups are shaped by the selective pressure of contests.
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Affiliation(s)
- P A Green
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK.
| | - M Briffa
- School of Biological and Marine Sciences, Plymouth University, Drake Circus, Plymouth PL3 8AA, UK
| | - M A Cant
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK
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9
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Interactions with conspecific outsiders as drivers of cognitive evolution. Nat Commun 2020; 11:4937. [PMID: 33024110 PMCID: PMC7538913 DOI: 10.1038/s41467-020-18780-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 09/14/2020] [Indexed: 11/23/2022] Open
Abstract
The social intelligence hypothesis (SIH) posits that within-group interactions drive cognitive evolution, but it has received equivocal support. We argue the SIH overlooks a major component of social life: interactions with conspecific outsiders. Competition for vital resources means conspecific outsiders present myriad threats and opportunities in all animal taxa across the social spectrum (from individuals to groups). We detail cognitive challenges generated by conspecific outsiders, arguing these select for ‘Napoleonic’ intelligence; explain potential influences on the SIH; and highlight important considerations when empirically testing these ideas. Including interactions with conspecific outsiders may substantially improve our understanding of cognitive evolution. The social intelligence hypothesis predicts that social organisms tend to be more intelligent because within-group interactions drive cognitive evolution. Here, authors propose that conspecific outsiders can be just as important in selecting for sophisticated cognitive adaptations.
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10
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Lucchesi S, Cheng L, Janmaat K, Mundry R, Pisor A, Surbeck M. Beyond the group: how food, mates, and group size influence intergroup encounters in wild bonobos. Behav Ecol 2020. [DOI: 10.1093/beheco/arz214] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract
In social-living animals, interactions between groups are frequently agonistic, but they can also be tolerant and even cooperative. Intergroup tolerance and cooperation are regarded as a crucial step in the formation of highly structured multilevel societies. Behavioral ecological theory suggests that intergroup tolerance and cooperation can emerge either when the costs of hostility outweigh the benefits of exclusive resource access or when both groups gain fitness benefits through their interactions. However, the factors promoting intergroup tolerance are still unclear due to the paucity of data on intergroup interactions in tolerant species. Here, we examine how social and ecological factors affect the onset and termination of intercommunity encounters in two neighboring communities of wild bonobos, a species exhibiting flexible patterns of intergroup interactions, at Kokolopori Bonobo Reserve, Democratic Republic of the Congo. We recorded the timing and location of intercommunity encounters and measured fruit abundance and distribution, groups’ social characteristics, and space-use dynamics over a 19-month period. We found that intercommunity tolerance was facilitated by a decrease in feeding competition, with high fruit abundance increasing the likelihood of communities to encounter, and high clumpiness of fruit patches increasing the probability to terminate encounters likely due to increased contest. In addition, the possibility for extra-community mating, as well as the potential benefits of more efficient foraging in less familiar areas, reduced the probability that the communities terminated encounters. By investigating the factors involved in shaping relationships across groups, this study contributes to our understanding of how animal sociality can extend beyond the group level.
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Affiliation(s)
- Stefano Lucchesi
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Leveda Cheng
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Karline Janmaat
- Institute for Biodiversity and Ecosystem Dynamics, Faculty of Science, University of Amsterdam, Amsterdam, The Netherlands
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Universitätsstrasse 10, Konstanz, Germany
| | - Roger Mundry
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Anne Pisor
- Department of Anthropology, Washington State University, Pullman, WA, USA
| | - Martin Surbeck
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
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11
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Morris-Drake A, Christensen C, Kern JM, Radford AN. Experimental field evidence that out-group threats influence within-group behavior. Behav Ecol 2019; 30:1425-1435. [PMID: 31579132 PMCID: PMC6765380 DOI: 10.1093/beheco/arz095] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 11/13/2022] Open
Abstract
In social species, conspecific outsiders present various threats to groups and their members. These out-group threats are predicted to affect subsequent within-group interactions (e.g., affiliation and aggression) and individual behavior (e.g., foraging and vigilance decisions). However, experimental investigations of such consequences are rare, especially in natural conditions. We used field-based call playbacks and fecal presentations on habituated wild dwarf mongooses (Helogale parvula)-a cooperatively breeding, territorial species-to examine postinteraction responses to the simulated threat of a rival group. Dwarf mongooses invested more in grooming of groupmates, foraged closer together, and more regularly acted as sentinels (a raised guard) after encountering indicators of rival-group presence compared to control conditions. These behavioral changes likely arise from greater anxiety and, in the case of increased vigilance, the need to seek additional information about the threat. The influence of an out-group threat lasted at least 1 h but individuals of different dominance status and sex responded similarly, potentially because all group members suffer costs if a contest with rivals is lost. Our results provide field-based experimental evidence from wild animals that out-group threats can influence within-group behavior and decision making, and suggest the need for greater consideration of the lasting impacts of social conflict.
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Affiliation(s)
- Amy Morris-Drake
- School of Biological Sciences, University of Bristol, Bristol, UK
| | | | - Julie M Kern
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, Bristol, UK
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12
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Between-group attack and defence in an ecological setting: Insights from nonhuman animals. Behav Brain Sci 2019; 42:e137. [PMID: 31407982 DOI: 10.1017/s0140525x19000773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Attempts to understand the fundamental forces shaping conflict between attacking and defending groups can be hampered by a narrow focus on humans and reductionist, oversimplified modelling. Further progress depends on recognising the striking parallels in between-group conflict across the animal kingdom, harnessing the power of experimental tests in nonhuman species and modelling the eco-evolutionary feedbacks that drive attack and defence.
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13
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Mirville MO, Ridley AR, Samedi JPM, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Low familiarity and similar ‘group strength’ between opponents increase the intensity of intergroup interactions in mountain gorillas (Gorilla beringei beringei). Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2592-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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14
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Mirville MO, Ridley AR, Samedi J, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Factors influencing individual participation during intergroup interactions in mountain gorillas. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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15
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Strong MJ, Sherman BL, Riehl C. Home field advantage, not group size, predicts outcomes of intergroup conflicts in a social bird. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2017.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Pal A, Kumara HN, Mishra PS, Velankar AD, Singh M. Between-group encounters in Nicobar long-tailed macaque (Macaca fascicularis umbrosus). ETHOL ECOL EVOL 2018. [DOI: 10.1080/03949370.2018.1459866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Arijit Pal
- Conservation Biology Department, Sálim Ali Centre for Ornithology and Natural History, Coimbatore 641108, India
- Manipal University, Manipal 576104, India
| | - Honnavalli N. Kumara
- Conservation Biology Department, Sálim Ali Centre for Ornithology and Natural History, Coimbatore 641108, India
| | - Partha Sarathi Mishra
- Conservation Biology Department, Sálim Ali Centre for Ornithology and Natural History, Coimbatore 641108, India
- Bharathiar University, Coimbatore 641046, India
| | - Avadhoot D. Velankar
- Conservation Biology Department, Sálim Ali Centre for Ornithology and Natural History, Coimbatore 641108, India
- Manipal University, Manipal 576104, India
| | - Mewa Singh
- Biopsychology Laboratory and Institution of Excellence, University of Mysore, Mysore 570006, India
- Organismal Biology Unit, Jawaharlal Nehru Centre for Advance Scientific Research, Bangalore 560064, India
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17
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Christensen C, Radford AN. Dear enemies or nasty neighbors? Causes and consequences of variation in the responses of group-living species to territorial intrusions. Behav Ecol 2018. [DOI: 10.1093/beheco/ary010] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, Bristol, UK
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18
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Thompson NA, Cords M. Stronger social bonds do not always predict greater longevity in a gregarious primate. Ecol Evol 2018; 8:1604-1614. [PMID: 29435236 PMCID: PMC5792528 DOI: 10.1002/ece3.3781] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/02/2017] [Accepted: 12/11/2017] [Indexed: 01/21/2023] Open
Abstract
In group-living species, individuals often have preferred affiliative social partners, with whom ties or bonds can confer advantages that correspond with greater fitness. For example, in adult female baboons and juvenile horses, individuals with stronger or more social ties experience greater survival. We used detailed behavioral and life history records to explore the relationship between tie quality and survival in a gregarious monkey (Cercopithecus mitis stuhlmanni), while controlling for dominance rank, group size, and life history strategy. We used Cox proportional hazards regressions to model the cumulative (multi-year) and current (single-year) relationships of social ties and the hazard of mortality in 83 wild adult females of known age, observed 2-8 years each (437 subject-years) in eight social groups. The strength of bonds with close partners was associated with increased mortality risk under certain conditions: Females that had strong bonds with close partners that were inconsistent over multiple years had a higher risk of mortality than females adopting any other social strategy. Within a given year, females had a higher risk of death if they were strongly bonded with partners that changed from the previous year versus with partners that remained consistent. Dominance rank, number of adult female groupmates, and age at first reproduction did not predict the risk of death. This study demonstrates that costs and benefits of strong social bonds can be context-dependent, relating to the consistency of social partners over time.
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Affiliation(s)
- Nicole A. Thompson
- Department of Ecology, Evolution, and Environmental BiologyColumbia UniversityNew YorkNYUSA
- New York Consortium in Evolutionary PrimatologyNew YorkNYUSA
| | - Marina Cords
- Department of Ecology, Evolution, and Environmental BiologyColumbia UniversityNew YorkNYUSA
- New York Consortium in Evolutionary PrimatologyNew YorkNYUSA
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19
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Radford AN, Majolo B, Aureli F. Within-group behavioural consequences of between-group conflict: a prospective review. Proc Biol Sci 2017; 283:rspb.2016.1567. [PMID: 27903869 PMCID: PMC5136580 DOI: 10.1098/rspb.2016.1567] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/31/2016] [Indexed: 02/04/2023] Open
Abstract
Conflict is rife in group-living species and exerts a powerful selective force. Group members face a variety of threats from extra-group conspecifics, from individuals looking for reproductive opportunities to rival groups seeking resources. Theory predicts that such between-group conflict should influence within-group behaviour. However, compared with the extensive literature on the consequences of within-group conflict, relatively little research has considered the behavioural impacts of between-group conflict. We give an overview of why between-group conflict is expected to influence subsequent behaviour among group members. We then use what is known about the consequences of within-group conflict to generate testable predictions about how between-group conflict might affect within-group behaviour in the aftermath. We consider the types of behaviour that could change and how the role of different group members in the conflict can exert an influence. Furthermore, we discuss how conflict characteristics and outcome, group size, social structure and within-group relationship quality might modulate post-conflict behavioural changes. Finally, we propose the need for consistent definitions, a broader range of examined behaviours and taxa, individual-focused data collection, complementary observational and experimental approaches, and a consideration of lasting effects if we are to understand fully the significant influence of between-group conflict on social behaviour.
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Affiliation(s)
- Andrew N Radford
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Bonaventura Majolo
- School of Psychology, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK
| | - Filippo Aureli
- Instituto de Neuroetologia, Universidad Veracruzana, Xalapa 91000 Veracruz, Mexico.,Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moore University, Liverpool L3 3AF, UK
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Jordan NR, Buse C, Wilson AM, Golabek KA, Apps PJ, Lowe JC, Van der Weyde LK, Weldon McNutt J. Dynamics of direct inter-pack encounters in endangered African wild dogs. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2338-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Radford AN, Bruintjes R. Expanding the Link between Out-Group Threats and In-Group Behavior: (A Reply to Kavaliers and Choleris). Am Nat 2017; 189:459-462. [PMID: 28350494 DOI: 10.1086/690837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In social species, groups and their members face a variety of threats from conspecific outsiders. Such out-group conflict is predicted to influence within-group behavior, with empirical work demonstrating this link in humans, primates, and birds. In our note "Out-Group Threat Promotes Within-Group Affiliation in a Cooperative Fish," appearing in The American Naturalist in February 2016, we provided experimental evidence that simulated territorial intrusions result in subsequent increases in affiliation among groupmates in a cichlid fish (Neolamprologus pulcher). Martin Kavaliers and Elena Choleris, in their comment "Out-Group Threat Responses, In-Group Bias, and Nonapeptide Involvement Are Conserved Across Vertebrates," appearing in this issue, commented on our cichlid-fish article; they consider the conserved nature of the link between out-group threat and in-group behavior and bias in vertebrates, the influence of pathogens in the process, and the potential underpinning hormonal mechanisms. Here, we provide clarification and expansion of some of the core points that are discussed in the comment by Kavaliers and Choleris.
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Galanter N, Silva D, Rowell JT, Rychtář J. Resource competition amid overlapping territories: The territorial raider model applied to multi-group interactions. J Theor Biol 2017; 412:100-106. [DOI: 10.1016/j.jtbi.2016.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/04/2016] [Accepted: 10/17/2016] [Indexed: 12/01/2022]
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24
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Van Belle S, Scarry CJ. Individual participation in intergroup contests is mediated by numerical assessment strategies in black howler and tufted capuchin monkeys. Philos Trans R Soc Lond B Biol Sci 2016; 370:20150007. [PMID: 26503680 DOI: 10.1098/rstb.2015.0007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Asymmetries in resource-holding potential between opposing groups frequently determine outcomes of intergroup contests. Since both numerical superiority and high intergroup dominance rank may confer competitive advantages, group members should benefit from assessing the relative strength of rivals prior to engaging in defensive displays. However, differences in individual assessment may emerge when cost-benefit trade-offs differ among group members. We examine the influence of numerical superiority and intergroup dominance relationships on individual participation in intergroup encounters in black howler monkeys (Alouatta pigra) and tufted capuchin monkeys (Sapajus nigritus). Black howlers responded with longer vocal displays during encounters with neighbours with an equal number of resident males, while tufted capuchins increased their participation with increasing relative male group size. Within each species, males and females responded similarly to varying numerical odds, suggesting that despite pay-off asymmetries between males and females, both sexes were similarly influenced by numerical asymmetries in deciding to participate in collective group defence. Whereas the outcome of contests among tufted capuchins was determined by relative male group size, reflected in a pronounced intergroup dominance hierarchy, the absence of dominance relationships among black howler groups may have provoked prolonged vocal displays in order to assess rival groups with matching competitive abilities.
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Affiliation(s)
- Sarie Van Belle
- Department of Anthropology, University of Texas at Austin, 2201 Speedway C3200, Austin, TX 78712, USA
| | - Clara J Scarry
- Department of Anthropology, University of Texas at Austin, 2201 Speedway C3200, Austin, TX 78712, USA Department of Anthropology, Stony Brook University, Social and Behavioral Sciences Building S-501, Stony Brook, NY 11794-4364, USA
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25
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Tobias JA, Sheard C, Seddon N, Meade A, Cotton AJ, Nakagawa S. Territoriality, Social Bonds, and the Evolution of Communal Signaling in Birds. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00074] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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26
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Christensen C, Kern JM, Bennitt E, Radford AN. Rival group scent induces changes in dwarf mongoose immediate behavior and subsequent movement. Behav Ecol 2016. [DOI: 10.1093/beheco/arw092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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Effects of group size and contest location on the outcome and intensity of intergroup contests in wild blue monkeys. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.11.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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28
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Bruintjes R, Lynton-Jenkins J, Jones JW, Radford AN. Out-Group Threat Promotes Within-Group Affiliation in a Cooperative Fish. Am Nat 2016; 187:274-82. [DOI: 10.1086/684411] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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29
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Plastic territoriality in group-living chestnut-crowned babblers: roles of resource value, holding potential and predation risk. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2014.12.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Conflict between Groups Promotes Later Defense of a Critical Resource in a Cooperatively Breeding Bird. Curr Biol 2014; 24:2935-9. [DOI: 10.1016/j.cub.2014.10.036] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/23/2014] [Accepted: 10/13/2014] [Indexed: 11/18/2022]
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31
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Call of duty? Variation in use of the watchman's song by sentinel dwarf mongooses, Helogale parvula. Anim Behav 2013. [DOI: 10.1016/j.anbehav.2013.02.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Golabek K, Ridley A, Radford A. Food availability affects strength of seasonal territorial behaviour in a cooperatively breeding bird. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2011.11.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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33
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Abstract
In many social animals, group-mates cooperate to defend their range against intrusion by neighboring groups. Because group size tends to be highly variable, such conflicts are often asymmetric. Although numerical superiority is assumed to provide a competitive advantage, small groups can generally defend their ranges, even when greatly outnumbered. The prevailing explanation for this puzzling phenomenon is that individuals in relatively large groups experience a greater temptation to flee from conflicts, in effect leveling the balance of power. Using playback experiments simulating territorial intrusions by wild capuchin monkey (Cebus capucinus) groups, we show that such a collective action problem does indeed undermine the competitive ability of large groups. Focal capuchins were more likely to run away from territorial intrusions when their group had a numeric advantage; each one-individual increase in relative group size raised the odds of flight by 25%. However, interaction location had a more important impact on individuals' reactions, creating a strong home-field advantage. After controlling for relative group size, the odds that a focal animal fled were 91% lower in experiments that occurred in the center compared with on the edge of its group's range, whereas the odds that it rushed toward the speaker were more than sixfold higher. These location-dependent patterns of defection and cooperation create a competitive advantage for residents over intruders across a wide range of relative group sizes, which may stabilize range boundaries and provide a general explanation for how groups of widely divergent sizes can coexist, even in the face of intense intergroup competition.
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Crofoot MC, Rubenstein DI, Maiya AS, Berger-Wolf TY. Aggression, grooming and group-level cooperation in white-faced capuchins (Cebus capucinus): insights from social networks. Am J Primatol 2011; 73:821-33. [PMID: 21590698 DOI: 10.1002/ajp.20959] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 03/26/2011] [Accepted: 03/27/2011] [Indexed: 11/06/2022]
Abstract
The form of animal social systems depends on the nature of agonistic and affiliative interactions. Social network theory provides tools for characterizing social structure that go beyond simple dyadic interactions and consider the group as a whole. We show three groups of capuchin monkeys from Barro Colorado Island, Panama, where there are strong connections between key aspects of aggression, grooming, and proximity networks, and, at least among females, those who incur risk to defend their group have particular "social personalities." Although there is no significant correlation for any of the network measures between giving and receiving aggression, suggesting that dominance relationships do not follow a simple hierarchy, strong correlations emerge for many measures between the aggression and grooming networks. At the local, but not global, scale, receiving aggression and giving grooming are strongly linked in all groups. Proximity shows no correlation with aggression at either the local or the global scale, suggesting that individuals neither seek out nor avoid aggressors. Yet, grooming has a global but not local connection to proximity. Extensive groomers who tend to direct their efforts at other extensive groomers also spend time in close proximity to many other individuals. These results indicate the important role that prosociality plays in shaping female social relationships. We also show that females who receive the least aggression, and thus pay low costs for group living, are most likely to participate in group defense. No consistent "social personality" traits characterize the males who invest in group defense.
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Affiliation(s)
- Margaret C Crofoot
- Division of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany
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36
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Batchelor TP, Briffa M. Fight tactics in wood ants: individuals in smaller groups fight harder but die faster. Proc Biol Sci 2011; 278:3243-50. [PMID: 21389029 DOI: 10.1098/rspb.2011.0062] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
When social animals engage in inter-group contests, the outcome is determined by group sizes and individual masses, which together determine group resource-holding potential ('group RHP'). Individuals that perceive themselves as being in a group with high RHP may receive a motivational increase and increase their aggression levels. Alternatively, individuals in lower RHP groups may increase their aggression levels in an attempt to overcome the RHP deficit. We investigate how 'group RHP' influences agonistic tactics in red wood ants Formica rufa. Larger groups had higher total agonistic indices, but per capita agonistic indices were highest in the smallest groups, indicating that individuals in smaller groups fought harder. Agonistic indices were influenced by relative mean mass, focal group size, opponent group size and opponent group agonistic index. Focal group attrition rates decreased as focal group relative agonistic indices increased and there was a strong negative influence of relative mean mass. The highest focal attrition rates were received when opponent groups were numerically large and composed of large individuals. Thus, fight tactics in F. rufa seem to vary with both aspects of group RHP, group size and the individual attributes of group members, indicating that information on these are available to fighting ants.
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Affiliation(s)
- Tim P Batchelor
- Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
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37
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Radford AN. Preparing for battle? Potential intergroup conflict promotes current intragroup affiliation. Biol Lett 2010; 7:26-9. [PMID: 20610419 DOI: 10.1098/rsbl.2010.0507] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Groups of human soldiers increase their affiliative behaviour when moving into combat zones. Despite numerous other species also competing as groups, little is known about how potential intergroup conflict might influence current intragroup affiliative behaviour in non-human animals. Here, I show that allopreening (when one individual preens another) increases in groups of cooperatively breeding green woodhoopoes (Phoeniculus purpureus) when they enter areas where conflicts with neighbours are more likely. Self-preening, which is an indicator of stress in other species, did not increase in conflict areas, suggesting that the change in affiliative behaviour is not the simple consequence of greater stress. Instead, because it is the dominant breeding pair that increase their preening of subordinate helpers, it is possible that current affiliative behaviour is being exchanged for agonistic support in any intergroup conflicts that might ensue. These results are important for our understanding of group dynamics, cooperation and the evolution of sociality, but also bring to mind the intriguing possibilities of social contracts and future planning in birds.
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Affiliation(s)
- Andrew N Radford
- School of Biological Sciences, University of Bristol, , Woodland Road, Bristol BS8 1UG, UK.
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38
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Radford AN. Selective Prey Delivery to Incubating Females by Dominant Males, but not Helpers, in the Cooperatively Breeding Green Woodhoopoe. Ethology 2009. [DOI: 10.1111/j.1439-0310.2009.01696.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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39
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Zhao Z, Bohorquez JC, Dixon A, Johnson NF. Anomalously slow attrition times for asymmetric populations with internal group dynamics. PHYSICAL REVIEW LETTERS 2009; 103:148701. [PMID: 19905607 DOI: 10.1103/physrevlett.103.148701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Indexed: 05/28/2023]
Abstract
The many-body dynamics exhibited by living objects include group formation within a population and the nonequilibrium process of attrition between two opposing populations due to competition or conflict. We show analytically and numerically that the combination of these two dynamical processes generates an attrition duration T whose nonlinear dependence on population asymmetry x is in stark contrast to standard mass-action theories. A minority population experiences a longer survival time than two equally balanced populations, irrespective of whether or not the majority population adopts such an internal grouping. Adding a third population with predefined group sizes allows T(x) to be tailored. Our findings compare favorably to real-world observations.
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Affiliation(s)
- Zhenyuan Zhao
- Department of Physics, University of Miami, Coral Gables, Florida 33126, USA
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40
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Furrer RD, Manser MB. Banded mongoose recruitment calls convey information about risk and not stimulus type. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2009.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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41
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Drewe JA, Madden JR, Pearce GP. The social network structure of a wild meerkat population: 1. Inter-group interactions. Behav Ecol Sociobiol 2009. [DOI: 10.1007/s00265-009-0782-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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42
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Radford AN. Duration and outcome of intergroup conflict influences intragroup affiliative behaviour. Proc Biol Sci 2009; 275:2787-91. [PMID: 18765344 DOI: 10.1098/rspb.2008.0787] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theoreticians have long suggested that the amount of intergroup conflict in which a group is involved could influence the level of cooperation or affiliation displayed by its members. Despite the prevalence of intergroup conflicts in many social animal species, however, few empirical studies have investigated this potential link. Here, I show that intragroup allopreening rates are highest in green woodhoopoe (Phoeniculus purpureus) groups that have the greatest involvement in intergroup conflict. One reason for this relationship is a post-conflict increase in allopreening, and I demonstrate for the first time that both conflict duration and outcome influence subsequent allopreening rates: group members allopreened more following long conflicts and those they lost compared with short conflicts and those they won, perhaps because the former are more stressful. The increase in affiliative behaviour was the result of more allopreening of subordinate helpers by the dominant breeding pair, which may be because the breeders are trying to encourage helpers to participate in future conflicts; relative group size influences conflict outcome and helpers contribute more to conflicts than do the breeding pair. These results emphasize that our understanding of cooperation and group dynamics can be enhanced by investigations of how intergroup interactions affect intragroup processes.
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Affiliation(s)
- Andrew N Radford
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
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43
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Hollén LI, Bell MB, Radford AN. Cooperative Sentinel Calling? Foragers Gain Increased Biomass Intake. Curr Biol 2008; 18:576-9. [DOI: 10.1016/j.cub.2008.02.078] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/27/2008] [Accepted: 02/27/2008] [Indexed: 11/26/2022]
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44
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45
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Crofoot MC, Gilby IC, Wikelski MC, Kays RW. Interaction location outweighs the competitive advantage of numerical superiority in Cebus capucinus intergroup contests. Proc Natl Acad Sci U S A 2008; 105:577-81. [PMID: 18184811 PMCID: PMC2206578 DOI: 10.1073/pnas.0707749105] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Indexed: 11/18/2022] Open
Abstract
Numerical superiority confers a competitive advantage during contests among animal groups, shaping patterns of resource access, and, by extension, fitness. However, relative group size does not always determine the winner of intergroup contests. Smaller, presumably weaker social groups often defeat their larger neighbors, but how and when they are able to do so remains poorly understood. Models of competition between individuals suggest that location may influence contest outcome. However, because of the logistical difficulties of studying intergroup interactions, previous studies have been unable to determine how contest location and group size interact to shape relationships among groups. We address this question by using an automated radio telemetry system to study intergroup interactions among six capuchin monkey (Cebus capucinus) social groups of varying sizes. We find that the odds of winning increase with relative group size; one additional group member increases the odds of winning an interaction by 10%. However, this effect is not uniform across space; with each 100 m that a group moves away from the center of its home range, its odds of winning an interaction decrease by 31%. We demonstrate that contest outcome depends on an interaction between group size and location, such that small groups can defeat much larger groups near the center of their home range. The tendency of resident groups to win contests may help explain how small groups persist in areas with intense intergroup competition.
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Affiliation(s)
- Margaret C Crofoot
- Department of Anthropology, Harvard University, Cambridge, MA 02138, USA.
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46
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Radford AN, Ridley AR. Recruitment Calling: A Novel Form of Extended Parental Care in an Altricial Species. Curr Biol 2006; 16:1700-4. [PMID: 16950106 DOI: 10.1016/j.cub.2006.06.053] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
In many altricial birds, fledglings disperse when they are no longer fed, and this dispersal marks the end of parental care. In some species, however, young remain in close association with their parents after nutritional independence. Because juveniles are still inferior foragers at this stage, they might benefit from parental assistance in locating good feeding sites, but this possibility remains largely unexplored. Here, we show that parents and helpers in pied babbler (Turdoides bicolor) societies use a recruitment call to direct nutritionally independent, but inexperienced, foragers to particular food patches. Observations and a playback experiment indicated that adult babblers use a "purr" call to recruit group members to a foraging patch. Creation of experimental foraging patches supported observations that individuals tend to give the call when they are foraging on abundant, divisible food sources and when their group contains independent fledglings (youngsters who are no longer fed directly). Fledglings responded to calls more often than adults, who frequently encountered aggression from the caller if they did, and the fledglings gained significant foraging benefits. This is the first study to demonstrate that altricial birds may use recruitment calls to extend parental care past the period of direct provisioning.
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Affiliation(s)
- Andrew N Radford
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom.
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47
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Radford A. Group-specific vocal signatures and neighbour–stranger discrimination in the cooperatively breeding green woodhoopoe. Anim Behav 2005. [DOI: 10.1016/j.anbehav.2005.04.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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