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Morris-Drake A, Cobb B, Kern JM, Radford AN. A positive effect of cumulative intergroup threat on reproductive success. Proc Biol Sci 2023; 290:20231853. [PMID: 37964527 PMCID: PMC10646463 DOI: 10.1098/rspb.2023.1853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023] Open
Abstract
Outgroup conflict is a powerful selective force across all social taxa. While it is well documented that individual outgroup contests can have a range of direct and indirect fitness consequences, the cumulative pressure of outgroup threats could also potentially impact reproductive success. Here, we use long-term life-history data from a wild population of dwarf mongooses (Helogale parvula) to investigate how intergroup interaction (IGI) rate might influence breeding and offspring survival. IGI rate did not predict the number of litters produced in a season or the inter-litter interval. Unexpectedly, IGI rate was positively associated with the number of pups alive three months after emergence from the breeding burrow. This was not due to a difference in how many pups emerged but because those in groups experiencing more IGIs had a higher survival likelihood post-emergence. Detailed natural observations revealed that both IGI occurrence and the threat of intergroup conflict led to more sentinel behaviour by adults, probably reducing the predation risk to young. Our results contrast the previously documented negative effects of outgroup interactions on reproductive success and highlight the need to assess cumulative threat, rather than just the impact of physical contests, when considering outgroup conflict as a social driver of fitness.
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Affiliation(s)
- Amy Morris-Drake
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Benjamin Cobb
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Julie M. Kern
- School of Environmental and Rural Science, University of New England, Armidale 2351, New South Wales, Australia
| | - Andrew N. Radford
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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2
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Kern JM, Morris-Drake A, Radford AN. Behavioural, demographic and fitness consequences of social instability in cooperatively breeding dwarf mongoose groups. Proc Biol Sci 2023; 290:20230901. [PMID: 37583317 PMCID: PMC10427820 DOI: 10.1098/rspb.2023.0901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 07/11/2023] [Indexed: 08/17/2023] Open
Abstract
Social instability frequently arises in group-living species, but the potential costs have rarely been investigated in free-living cooperative breeders, especially across different timeframes. Using natural observations, body mass measurements and life-history data from dwarf mongooses (Helogale parvula), we determined the short- and long-term consequences of a change in one of the dominant breeding pairs. We found that a new breeder led to alterations in both collective and individual behaviours (i.e. increases in communal scent-marking, engagement in intergroup interactions, sentinel activity and within-group grooming), as well as reduced body mass gain, further demographic changes and decreased reproductive success (i.e. fewer pups surviving to adulthood). The effects were particularly apparent when it was the female breeder who changed; new female breeders were younger than more experienced counterparts. Our findings support the idea that stability and cooperation are strongly linked and provide potential reasons for previously documented health and fitness benefits of social stability.
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Affiliation(s)
- Julie M. Kern
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- School of Environmental and Rural Science, University of New England, Armidale 2351, NSW, Australia
| | - Amy Morris-Drake
- 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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3
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Morris-Drake A, Linden JF, Kern JM, Radford AN. Extended and cumulative effects of experimentally induced intergroup conflict in a cooperatively breeding mammal. Proc Biol Sci 2021; 288:20211743. [PMID: 34875195 PMCID: PMC8651417 DOI: 10.1098/rspb.2021.1743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/17/2021] [Indexed: 12/05/2022] Open
Abstract
Conflict between rival groups is rife in nature. While recent work has begun exploring the behavioural consequences of this intergroup conflict, studies have primarily considered just the 1-2 h immediately after single interactions with rivals or their cues. Using a habituated population of wild dwarf mongooses (Helogale parvula), we conducted week-long manipulations to investigate longer-term impacts of intergroup conflict. Compared to a single presentation of control herbivore faeces, one rival-group faecal presentation (simulating a territorial intrusion) resulted in more within-group grooming the following day, beyond the likely period of conflict-induced stress. Repeated presentations of outsider cues led to further changes in baseline behaviour by the end of the week: compared to control weeks, mongooses spent less time foraging and foraged closer to their groupmates, even when there had been no recent simulated intrusion. Moreover, there was more baseline territorial scent-marking and a higher likelihood of group fissioning in intrusion weeks. Consequently, individuals gained less body mass at the end of weeks with repeated simulated intrusions. Our experimental findings provide evidence for longer-term, extended and cumulative, effects of an elevated intergroup threat, which may lead to fitness consequences and underpin this powerful selective pressure.
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Affiliation(s)
- Amy Morris-Drake
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Jennifer F. Linden
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Julie M. Kern
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
| | - Andrew N. Radford
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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4
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Strongly bonded individuals prefer to forage together in cooperatively breeding dwarf mongoose groups. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03025-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Romero-González JE, Royka AL, MaBouDi H, Solvi C, Seppänen JT, Loukola OJ. Foraging Bumblebees Selectively Attend to Other Types of Bees Based on Their Reward-Predictive Value. INSECTS 2020; 11:insects11110800. [PMID: 33202846 PMCID: PMC7697648 DOI: 10.3390/insects11110800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 11/16/2022]
Abstract
Using social information can be an efficient strategy for learning in a new environment while reducing the risks associated with trial-and-error learning. Whereas social information from conspecifics has long been assumed to be preferentially attended by animals, heterospecifics can also provide relevant information. Because different species may vary in their informative value, using heterospecific social information indiscriminately can be ineffective and even detrimental. Here, we evaluated how selective use of social information might arise at a proximate level in bumblebees (Bombus terrestris) as a result of experience with demonstrators differing in their visual appearance and in their informative value as reward predictors. Bumblebees were first trained to discriminate rewarding from unrewarding flowers based on which type of "heterospecific" (one of two differently painted model bees) was next to each flower. Subsequently, these bumblebees were exposed to a novel foraging context with two live painted bees. In this novel context, observer bumblebees showed significantly more social information-seeking behavior towards the type of bees that had predicted reward during training. Bumblebees were not attracted by paint-marked small wooden balls (moved via magnets) or paint-marked non-pollinating heterospecifics (woodlice; Porcellio laevis) in the novel context, indicating that bees did not simply respond to conditioned color cues nor to irrelevant social cues, but rather had a "search image" of what previously constituted a valuable, versus invaluable, information provider. The behavior of our bumblebees suggests that their use of social information is governed by learning, is selective, and extends beyond conspecifics.
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Affiliation(s)
- Jose E. Romero-González
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (J.E.R.-G.); (A.L.R.); (H.M.); (C.S.)
| | - Amanda L. Royka
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (J.E.R.-G.); (A.L.R.); (H.M.); (C.S.)
| | - HaDi MaBouDi
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (J.E.R.-G.); (A.L.R.); (H.M.); (C.S.)
- Department of Computer Science, University of Sheffield, Sheffield S1 4DP, UK
| | - Cwyn Solvi
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (J.E.R.-G.); (A.L.R.); (H.M.); (C.S.)
| | - Janne-Tuomas Seppänen
- Open Science Centre, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland;
| | - Olli J. Loukola
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (J.E.R.-G.); (A.L.R.); (H.M.); (C.S.)
- Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
- Correspondence:
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Arbon JJ, Kern JM, Morris-Drake A, Radford AN. Context-dependent contributions to sentinel behaviour: audience, satiation and danger effects. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Eastcott E, Kern JM, Morris-Drake A, Radford AN. Intrapopulation variation in the behavioral responses of dwarf mongooses to anthropogenic noise. Behav Ecol 2020. [DOI: 10.1093/beheco/araa011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Anthropogenic noise is an increasingly widespread pollutant, with a rapidly burgeoning literature demonstrating impacts on humans and other animals. However, most studies have simply considered if there is an effect of noise, examining the overall cohort response. Although substantial evidence exists for intraspecific variation in responses to other anthropogenic disturbances, this possibility has received relatively little experimental attention with respect to noise. Here, we used field-based playbacks with dwarf mongooses (Helogale parvula) to test how traffic noise affects vigilance behavior and to examine potential variation between individuals of different age class, sex, and dominance status. Foragers exhibited a stronger immediate reaction and increased their subsequent vigilance (both that on the ground and as a sentinel) in response to traffic-noise playback compared with ambient-sound playback. Traffic-noise playback also resulted in sentinels conducting longer bouts and being more likely to change post height or location than in ambient-sound playback. Moreover, there was evidence of variation in noise responses with respect to age class and dominance status but not sex. In traffic noise, foraging pups were more likely to flee and were slower to resume foraging than adults; they also tended to increase their vigilance more than adults. Dominants were more likely than subordinates to move post during sentinel bouts conducted in traffic-noise trials. Our findings suggest that the vigilance–foraging trade-off is affected by traffic noise but that individuals differ in how they respond. Future work should, therefore, consider intrapopulation response variation to understand fully the population-wide effects of this global pollutant.
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Affiliation(s)
- Emma Eastcott
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Julie M Kern
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Amy Morris-Drake
- 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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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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Silvestri A, Morgan K, Ridley AR. The association between evidence of a predator threat and responsiveness to alarm calls in Western Australian magpies ( Cracticus tibicen dorsalis). PeerJ 2019; 7:e7572. [PMID: 31523516 PMCID: PMC6714966 DOI: 10.7717/peerj.7572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 07/29/2019] [Indexed: 11/26/2022] Open
Abstract
Alarm calls are a widespread form of antipredator defence and being alerted to the presence of predators by the alarm calls of conspecifics is considered one of the benefits of group living. However, while social information can allow an individual to gain additional information, it can also at times be inaccurate or irrelevant. Such variation in the accuracy of social information is predicted to select for receivers to discriminate between sources of social information. In this study, we used playback experiments to determine whether Western Australian magpies (Cracticus tibicen dorsalis) respond to the predator information associated with alarm calls. Magpies were exposed to the alarm calls of two group members that differed in the threat associated with the alarm call: one call was played in the presence of a predator model while the other was not—in order to establish differences in the predator information provided by each caller. We then played back the alarm calls of the same group members in the absence of the predator model to determine whether magpies responded differently to signallers in response to the previous association between the alarm call and a predator threat. We found that receivers showed significantly greater levels of responsiveness to signallers that previously gave alarm calls in the appropriate context. Thus, the accuracy of threat-based information influenced subsequent receiver response.
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Affiliation(s)
- Annabel Silvestri
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Kate Morgan
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Amanda R Ridley
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
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Rauber R, Manser MB. Experience of the signaller explains the use of social versus personal information in the context of sentinel behaviour in meerkats. Sci Rep 2018; 8:11506. [PMID: 30139953 PMCID: PMC6107524 DOI: 10.1038/s41598-018-29678-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/10/2018] [Indexed: 11/25/2022] Open
Abstract
To maximise foraging opportunities while simultaneously avoiding predation, group-living animals can obtain personal information on food availability and predation risk and/or rely on social information provided by group members. Although mainly associated with low costs of information acquisition, social information has the potential to be irrelevant or inaccurate. In this study we use playbacks of individually distinct sentinel calming calls produced during sentinel behaviour, a form of coordinated vigilance behaviour, to show that meerkats (Suricata suricatta) discriminate between social information provided by different sentinels and adjust their personal vigilance behaviour according to the individual that is played back. We found that foraging group members acquired the lowest amounts of personal information when hearing social information provided by experienced individuals that act as sentinels most often in their group and littermates. Our study shows that social information can be flexibly used in the context of sentinel behaviour in order to optimize the trade-off between foraging and vigilance behaviours dependent on discrimination among signallers. We also provide novel evidence that the experience of sentinels rather than their age or dominance status is the main factor affecting the extent to which individuals use social information.
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Affiliation(s)
- R Rauber
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa.
| | - M B Manser
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
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11
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Abstract
Humans frequently trade goods and can track the amount they owe using memories of past exchanges. While nonhuman animals are also known to be capable of trading cooperative acts immediately for one another, more contentious is the possibility that there can be delayed rewards. We use detailed field observations, social-network analyses, and a playback experiment to demonstrate that wild dwarf mongooses provide more grooming to those groupmates who contribute more to sentinel behavior (acting as a raised guard to look out for danger). We therefore provide experimental evidence of delayed contingent cooperation, and cross-commodity exchange, in a wild nonprimate. Many animals participate in biological markets, with strong evidence existing for immediate cooperative trades. In particular, grooming is often exchanged for itself or other commodities, such as coalitionary support or access to food and mates. More contentious is the possibility that nonhuman animals can rely on memories of recent events, providing contingent cooperation even when there is a temporal delay between two cooperative acts. Here we provide experimental evidence of delayed cross-commodity grooming exchange in wild dwarf mongooses (Helogale parvula). First, we use natural observations and social-network analyses to demonstrate a positive link between grooming and sentinel behavior (acting as a raised guard). Group members who contributed more to sentinel behavior received more grooming and had a better social-network position. We then used a field-based playback experiment to test a causal link between contributions to sentinel behavior and grooming received later in the day. During 3-h trial sessions, the perceived sentinel contributions of a focal individual were either up-regulated (playback of its surveillance calls, which are given naturally during sentinel bouts) or unmanipulated (playback of its foraging close calls as a control). On returning to the sleeping refuge at the end of the day, focal individuals received more grooming following surveillance-call playback than control-call playback and more grooming than a matched individual whose sentinel contributions were not up-regulated. We believe our study therefore provides experimental evidence of delayed contingent cooperation in a wild nonprimate species.
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