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Kerr NZ, Morris WF, Walters JR. Inclusive Fitness May Explain Some but Not All Benefits Derived from Helping Behavior in a Cooperatively Breeding Bird. Am Nat 2024; 203:393-410. [PMID: 38358814 DOI: 10.1086/728670] [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] [Indexed: 02/17/2024]
Abstract
AbstractIn cooperative breeding systems, inclusive fitness theory predicts that nonbreeding helpers more closely related to the breeders should be more willing to provide costly alloparental care and thus have more impact on breeder fitness. In the red-cockaded woodpecker (Dryobates borealis), most helpers are the breeders' earlier offspring, but helpers do vary within groups in both relatedness to the breeders (some even being unrelated) and sex, and it can be difficult to parse their separate impacts on breeder fitness. Moreover, most support for inclusive fitness theory has been positive associations between relatedness and behavior rather than actual fitness consequences. We used functional linear models to evaluate the per capita effects of helpers of different relatedness on eight breeder fitness components measured for up to 41 years at three sites. In support of inclusive fitness theory, helpers more related to the breeding pair made greater contributions to six fitness components. However, male helpers made equal contributions to increasing prefledging survival regardless of relatedness. These findings suggest that both inclusive fitness benefits and other direct benefits may underlie helping behaviors in the red-cockaded woodpecker. Our results also demonstrate the application of an underused statistical approach to disentangle a complex ecological phenomenon.
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2
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Bourne AR, Ridley AR, Cunningham SJ. Helpers don't help when it's hot in a cooperatively breeding bird, the Southern Pied Babbler. Behav Ecol 2023; 34:562-570. [PMID: 37434640 PMCID: PMC10332451 DOI: 10.1093/beheco/arad023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 02/25/2023] [Accepted: 04/04/2023] [Indexed: 07/13/2023] Open
Abstract
Cooperative breeding, where more than two individuals invest in rearing a single brood, occurs in many bird species globally and often contributes to improved breeding outcomes. However, high temperatures are associated with poor breeding outcomes in many species, including cooperative species. We used data collected over three austral summer breeding seasons to investigate the contribution that helpers make to daytime incubation in a cooperatively breeding species, the Southern Pied Babbler Turdoides bicolor, and the ways in which their contribution is influenced by temperature. Helpers spent a significantly higher percentage of their time foraging (41.8 ± 13.7%) and a significantly lower percentage of their time incubating (18.5 ± 18.8%) than members of the breeding pair (31.3 ± 11% foraging and 37.4 ± 15.7% incubating). In groups with only one helper, the helper's contribution to incubation was similar to that of breeders. However, helpers in larger groups contributed less to incubation, individually, with some individuals investing no time in incubation on a given observation day. Helpers significantly decrease their investment in incubation on hot days (>35.5°C), while breeders tend to maintain incubation effort as temperatures increase. Our results demonstrate that pied babblers share the workload of incubation unequally between breeders and helpers, and this inequity is more pronounced during hot weather. These results may help to explain why recent studies have found that larger group size does not buffer against the impacts of high temperatures in this and other cooperatively breeding species.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Australian Wildlife Conservancy, 322 Hay Street, Subiaco 6008, Western Australia
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley 6009, Australia
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
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3
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Ridley AR, Nelson-Flower MJ, Wiley EM, Humphries DJ, Kokko H. Kidnapping intergroup young: an alternative strategy to maintain group size in the group-living pied babbler ( Turdoides bicolor). Philos Trans R Soc Lond B Biol Sci 2022; 377:20210153. [PMID: 35369755 PMCID: PMC8977656 DOI: 10.1098/rstb.2021.0153] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Both inter- and intragroup interactions can be important influences on behaviour, yet to date most research focuses on intragroup interactions. Here, we describe a hitherto relatively unknown behaviour that results from intergroup interaction in the cooperative breeding pied babbler: kidnapping. Kidnapping can result in the permanent removal of young from their natal group. Since raising young requires energetic investment and abductees are usually unrelated to their kidnappers, there appears no apparent evolutionary advantage to kidnapping. However, kidnapping may be beneficial in species where group size is a critically limiting factor (e.g. for reproductive success or territory defence). We found kidnapping was a highly predictable event in pied babblers: primarily groups that fail to raise their own young kidnap the young of others, and we show this to be the theoretical expectation in a model that predicts kidnapping to be facultative, only occurring in those cases where an additional group member has sufficient positive impact on group survival to compensate for the increase in reproductive competition. In babblers, groups that failed to raise young were also more likely to accept extragroup adults (hereafter rovers). Groups that fail to breed may either (i) kidnap intergroup young or (ii) accept rovers as an alternative strategy to maintain or increase group size. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
- Amanda R Ridley
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, Australia.,Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Martha J Nelson-Flower
- Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town, Western Cape, South Africa.,Department of Biology, Langara College, Vancouver, BC, Canada
| | - Elizabeth M Wiley
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, Australia
| | - David J Humphries
- Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Hanna Kokko
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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4
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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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/02/2021] [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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5
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King SL. The evolutionary roots of cooperation. Curr Biol 2022. [DOI: 10.1016/j.cub.2022.02.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Bourne AR, Ridley AR, Spottiswoode CN, Cunningham SJ. Direct and indirect effects of high temperatures on fledging in a cooperatively breeding bird. Behav Ecol 2021. [DOI: 10.1093/beheco/arab087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Abstract
High temperatures and low rainfall consistently constrain reproduction in arid-zone bird species. Understanding the mechanisms underlying this pattern is critical for predicting how climate change will influence population persistence and to inform conservation and management. In this study, we analyzed Southern Pied Babbler Turdoides bicolor nestling survival, daily growth rate and adult investment behavior during the nestling period over three austral summer breeding seasons. High temperatures were associated with lower body mass, shorter tarsi, and reduced daily growth rates of nestlings. Our piecewise structural equation models suggested that direct impacts of temperature had the strongest influence on nestling size and daily growth rates for both 5-day-old and 11-day-old nestlings, followed by temperature-related adjustments to provisioning rates by adults. Rainfall and group size influenced the behavior of provisioning adults but did not influence nestling growth or survival. Adjustments to adult provisioning strategies did not compensate for direct negative effects of high air temperatures on nestling size or daily growth rates. Detailed mechanistic data like these allow us to model the pathways by which high temperature causes nest failure. In turn, this could allow us to design targeted conservation action to effectively mitigate climate effects.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Hackett Drive, Crawley, Perth WA, Australia
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
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7
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Moss JB, Moore AJ. Constrained flexibility of parental cooperation limits adaptive responses to harsh conditions. Evolution 2021; 75:1835-1849. [PMID: 34153114 PMCID: PMC8362138 DOI: 10.1111/evo.14285] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/20/2021] [Accepted: 06/01/2021] [Indexed: 12/15/2022]
Abstract
Parental care is predicted to evolve to mitigate harsh environments, thus adaptive plasticity of care may be an important response to our climate crisis. In biparental species, fitness costs may be reduced by resolving conflict and enhancing cooperation among partners. We investigated this prediction with the burying beetle, Nicrophorus orbicollis, by exposing them to contrasting benign and harsh thermal environments. Despite measurable fitness costs under the harsh environment, sexual conflict persisted in the form of sex-specific social plasticity. That is, females provided equivalent care with or without males, whereas males with partners deserted earlier and reduced provisioning effort. The interaction of social condition and thermal environment did not explain variation in individual behavior, failing to support a temperature-mediated shift from conflict to cooperation. Examining selection gradients and splines on cumulative care revealed a likely explanation for these patterns. Contrary to predictions, increased care did not enhance offspring performance under stress. Rather, different components of care were under different selection regimes, with optimization constrained due to lack of coordination between parents. We suggest that the potential for parenting to ameliorate the effects of our climate crisis may depend on the sex-specific evolutionary drivers of parental care, and that this may be best reflected in components of care.
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Affiliation(s)
- Jeanette B Moss
- Department of Entomology, University of Georgia, Athens, Georgia, 30602, USA.,Current Address: Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana Champaign, Urbana, Illinois, 61801, USA
| | - Allen J Moore
- Department of Entomology, University of Georgia, Athens, Georgia, 30602, USA
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8
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Bourne AR, Ridley AR, McKechnie AE, Spottiswoode CN, Cunningham SJ. Dehydration risk is associated with reduced nest attendance and hatching success in a cooperatively breeding bird, the southern pied babbler Turdoides bicolor. CONSERVATION PHYSIOLOGY 2021; 9:coab043. [PMID: 34150211 PMCID: PMC8208672 DOI: 10.1093/conphys/coab043] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/26/2021] [Accepted: 06/09/2021] [Indexed: 05/12/2023]
Abstract
High air temperatures have measurable negative impacts on reproduction in wild animal populations, including during incubation in birds. Understanding the mechanisms driving these impacts requires comprehensive knowledge of animal physiology and behaviour under natural conditions. We used a novel combination of a non-invasive doubly labelled water (DLW) technique, nest temperature data and field-based behaviour observations to test effects of temperature, rainfall and group size on physiology and behaviour during incubation in southern pied babblers Turdoides bicolor, a cooperatively breeding passerine endemic to the arid savanna regions of southern Africa. The proportion of time that clutches were incubated declined as air temperatures increased, a behavioural pattern traditionally interpreted as a benefit of ambient incubation. However, we show that (i) clutches had a <50% chance of hatching when exposed to daily maximum air temperatures of >35.3°C; (ii) pied babbler groups incubated their nests almost constantly (99% of daylight hours) except on hot days; (iii) operative temperatures in unattended nests frequently exceeded 40.5°C, above which bird embryos are at risk of death; (iv) pied babblers incubating for long periods of time failed to maintain water balance on hot days; and (v) pied babblers from incubating groups lost mass on hot days. These results suggest that pied babblers might leave their nests during hot periods to lower the risk of dehydration associated with prolonged incubation at high operative temperatures. As mean air temperatures increase and extreme heat events become more frequent under climate change, birds will likely incur ever greater thermoregulatory costs of incubation, leading to compromised nest attendance and increased potential for eggs to overheat, with implications for nest success and, ultimately, population persistence.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Corresponding author: FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley 6009, Australia
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, Pretoria 0184, South Africa
- DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0002, South Africa
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
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9
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Ridley AR, Wiley EM, Bourne AR, Cunningham SJ, Nelson-Flower MJ. Understanding the potential impact of climate change on the behavior and demography of social species: The pied babbler (Turdoides bicolor) as a case study. ADVANCES IN THE STUDY OF BEHAVIOR 2021. [DOI: 10.1016/bs.asb.2021.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Josi D, Freudiger A, Taborsky M, Frommen JG. Experimental predator intrusions in a cooperative breeder reveal threat-dependent task partitioning. Behav Ecol 2020. [DOI: 10.1093/beheco/araa094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
In cooperatively breeding species, nonbreeding individuals provide alloparental care and help in territory maintenance and defense. Antipredator behaviors of subordinates can enhance offspring survival, which may provide direct and indirect fitness benefits to all group members. Helping abilities and involved costs and benefits, risks, and outside options (e.g., breeding independently) usually diverge between group members, which calls for status-specific differentiated behavioral responses. Such role differentiation within groups may generate task-specific division of labor, as exemplified by eusocial animals. In vertebrates, little is known about such task differentiation among group members. We show how breeders and helpers of the cooperatively breeding cichlid Neolamprologus savoryi partition predator defense depending on intruder type and the presence of dependent young. In the field, we experimentally simulated intrusions by different fish species posing a risk either specifically to eggs, young, or adults. We used intrusions by harmless algae eaters as a control. Breeders defended most when dependent young were present, while helper investment hinged mainly on their body size and on the potential threat posed by the respective intruders. Breeders and helpers partitioned defense tasks primarily when dependent young were exposed to immediate risk, with breeders investing most in antipredator defense, while helpers increased guarding and care in the breeding chamber. Breeders’ defense likely benefits helpers as well, as it was especially enhanced in the treatment where helpers were also at risk. These findings illustrate that in a highly social fish different group members exhibit fine-tuned behavioral responses in dependence of ecological and reproductive parameter variation.
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Affiliation(s)
- Dario Josi
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, Hinterkappelen, Switzerland
- Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Annika Freudiger
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, Hinterkappelen, Switzerland
- Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Michael Taborsky
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, Hinterkappelen, Switzerland
| | - Joachim G Frommen
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, Hinterkappelen, Switzerland
- Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
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11
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Bourne AR, Cunningham SJ, Spottiswoode CN, Ridley AR. Hot droughts compromise interannual survival across all group sizes in a cooperatively breeding bird. Ecol Lett 2020; 23:1776-1788. [PMID: 32945068 DOI: 10.1111/ele.13604] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/03/2020] [Accepted: 08/13/2020] [Indexed: 12/20/2022]
Abstract
Climate change is affecting animal populations around the world and one relatively unexplored aspect of species vulnerability is whether and to what extent responses to environmental stressors might be mitigated by variation in group size in social species. We used a 15-year data set for a cooperatively breeding bird, the southern pied babbler Turdoides bicolor, to determine the impact of temperature, rainfall and group size on body mass change and interannual survival in both juveniles and adults. Hot and dry conditions were associated with reduced juvenile growth, mass loss in adults and compromised survival between years in both juveniles (86% reduction in interannual survival) and adults (60% reduction in interannual survival). Individuals across all group sizes experienced similar effects of climatic conditions. Larger group sizes may not buffer individual group members against the impacts of hot and dry conditions, which are expected to increase in frequency and severity in future.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.,Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.,Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
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12
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Bourne AR, Cunningham SJ, Spottiswoode CN, Ridley AR. High temperatures drive offspring mortality in a cooperatively breeding bird. Proc Biol Sci 2020; 287:20201140. [PMID: 33043866 DOI: 10.1101/2020.05.31.126862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
An improved understanding of life-history responses to current environmental variability is required to predict species-specific responses to anthopogenic climate change. Previous research has suggested that cooperation in social groups may buffer individuals against some of the negative effects of unpredictable climates. We use a 15-year dataset on a cooperative breeding arid zone bird, the southern pied babbler Turdoides bicolor, to test (i) whether environmental conditions and group size correlate with survival of young during three development stages (egg, nestling, fledgling) and (ii) whether group size mitigates the impacts of adverse environmental conditions on survival of young. Exposure to high mean daily maximum temperatures (mean Tmax) during early development was associated with reduced survival probabilities of young in all three development stages. No young survived when mean Tmax > 38°C, across all group sizes. Low survival of young at high temperatures has broad implications for recruitment and population persistence in avian communities given the rapid pace of advancing climate change. Impacts of high temperatures on survival of young were not moderated by group size, suggesting that the availability of more helpers in a group is unlikely to buffer against compromised offspring survival as average and maximum temperatures increase with rapid anthropogenic climate change.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley 6009, Australia
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13
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Bourne AR, Cunningham SJ, Spottiswoode CN, Ridley AR. High temperatures drive offspring mortality in a cooperatively breeding bird. Proc Biol Sci 2020; 287:20201140. [PMID: 33043866 DOI: 10.1098/rspb.2020.1140] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
An improved understanding of life-history responses to current environmental variability is required to predict species-specific responses to anthopogenic climate change. Previous research has suggested that cooperation in social groups may buffer individuals against some of the negative effects of unpredictable climates. We use a 15-year dataset on a cooperative breeding arid zone bird, the southern pied babbler Turdoides bicolor, to test (i) whether environmental conditions and group size correlate with survival of young during three development stages (egg, nestling, fledgling) and (ii) whether group size mitigates the impacts of adverse environmental conditions on survival of young. Exposure to high mean daily maximum temperatures (mean Tmax) during early development was associated with reduced survival probabilities of young in all three development stages. No young survived when mean Tmax > 38°C, across all group sizes. Low survival of young at high temperatures has broad implications for recruitment and population persistence in avian communities given the rapid pace of advancing climate change. Impacts of high temperatures on survival of young were not moderated by group size, suggesting that the availability of more helpers in a group is unlikely to buffer against compromised offspring survival as average and maximum temperatures increase with rapid anthropogenic climate change.
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Affiliation(s)
- Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Claire N Spottiswoode
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.,Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Amanda R Ridley
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.,Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley 6009, Australia
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14
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Bourne AR, Cunningham SJ, Spottiswoode CN, Ridley AR. Compensatory Breeding in Years Following Drought in a Desert-Dwelling Cooperative Breeder. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00190] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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15
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Smith MG, Riehl C. Intermittent breeding is associated with breeding group turnover in a cooperatively breeding bird. Oecologia 2020; 192:953-963. [PMID: 32285196 DOI: 10.1007/s00442-020-04635-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/12/2020] [Indexed: 11/29/2022]
Abstract
Intermittent breeding, in which an adult skips a breeding opportunity, can represent a non-adaptive constraint or an adaptive response to the tradeoff between current and future reproduction. In group-living animals, the social group may also affect the frequency of reproduction, but this possibility has received little attention. Here we use an 11-year data set to investigate intermittent breeding in the greater ani (Crotophaga major), a tropical bird that nests in stable breeding groups containing several unrelated co-breeding females. Population-wide, an average of 62% of females laid eggs in a given year (range 35-84%), and the average female failed to lay eggs once every 3.2 years. We found little support for the hypothesis that intermittent breeding reflects a tradeoff between current and future reproduction: breeding in year t did not affect a female's likelihood of breeding in year t + 1, and clutch size in year t did not affect clutch size in year t + 1. Increases in clutch size were associated with decreases in egg mass for eggs laid at the end of that clutch, but this did not affect subsequent nesting attempts. However, reproductive skipping was associated with changes in group membership. Females whose groups changed in composition after year t were significantly less likely to breed in year t + 1 than females whose groups remained stable. These results indicate that breeding group stability influences the frequency of reproduction, suggesting that transitions between groups may be costly to females and their mates.
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Affiliation(s)
- Maria G Smith
- Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Christina Riehl
- Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA.
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Pike KN, Ashton BJ, Morgan KV, Ridley AR. Social and Individual Factors Influence Variation in Offspring Care in the Cooperatively Breeding Western Australian Magpie. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Liu M, Rubenstein DR, Cheong S, Shen S. Multitasking and the evolution of optimal clutch size in fluctuating environments. Ecol Evol 2018; 8:8803-8817. [PMID: 30271547 PMCID: PMC6157677 DOI: 10.1002/ece3.4364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 11/09/2022] Open
Abstract
Adaptive studies of avian clutch size variation across environmental gradients have resulted in what has become known as the fecundity gradient paradox, the observation that clutch size typically decreases with increasing breeding season length along latitudinal gradients, but increases with increasing breeding season length along elevational gradients. These puzzling findings challenge the common belief that organisms should reduce their clutch size in favor of additional nesting attempts as the length of the breeding season increases, an approach typically described as a bet-hedging strategy. Here, we propose an alternative hypothesis-the multitasking hypothesis-and show that laying smaller clutches represents a multitasking strategy of switching between breeding and recovery from breeding. Both our individual-based and analytical models demonstrate that a small clutch size strategy is favored during shorter breeding seasons because less time and energy are wasted under the severe time constraints associated with breeding multiply within a season. Our model also shows that a within-generation bet-hedging strategy is not favored by natural selection, even under a high risk of predation and in long breeding seasons. Thus, saving time-wasting less time as a result of an inability to complete a breeding cycle at the end of breeding season-is likely to be the primary benefit favoring the evolution of small avian clutch sizes during short breeding seasons. We also synthesize the seasonality hypothesis (pronounced seasonality leads to larger clutch size) and clutch size-dependent predation hypothesis (larger clutch size causes higher predation risks) within our multitasking hypothesis to develop an integrative model to help resolve the paradox of contrasting patterns of clutch size along elevational and latitudinal gradients. Ultimately, our models provide a new perspective for understanding life-history evolution under fluctuating environments.
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Affiliation(s)
- Ming Liu
- Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
- Department of EntomologyNational Taiwan UniversityTaipeiTaiwan
| | - Dustin R. Rubenstein
- Department of Ecology, Evolution and Environmental BiologyColumbia UniversityNew YorkNew York
- Center for Integrative Animal BehaviorColumbia UniversityNew YorkNew York
| | - Siew‐Ann Cheong
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological UniversitySingaporeSingapore
- Complexity InstituteNanyang Technological UniversitySingaporeSingapore
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Wiley EM, Ridley AR. The effects of temperature on offspring provisioning in a cooperative breeder. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.05.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Male-male competition is not costly to dominant males in a cooperatively breeding bird. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-2011-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Affiliation(s)
- Amanda R. Ridley
- Percy FitzPatrick Institute of African Ornithology; University of Cape Town; Rondebosch 7701 South Africa
- School of Animal Biology; University of Western Australia; Perth 6009 Western Australia Australia
| | - Elizabeth M. Wiley
- Percy FitzPatrick Institute of African Ornithology; University of Cape Town; Rondebosch 7701 South Africa
- School of Animal Biology; University of Western Australia; Perth 6009 Western Australia Australia
| | - Alex M. Thompson
- Percy FitzPatrick Institute of African Ornithology; University of Cape Town; Rondebosch 7701 South Africa
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Nelson-Flower MJ, Hockey PAR, O'Ryan C, English S, Thompson AM, Bradley K, Rose R, Ridley AR. Costly reproductive competition between females in a monogamous cooperatively breeding bird. Proc Biol Sci 2013; 280:20130728. [PMID: 23677348 DOI: 10.1098/rspb.2013.0728] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In many cooperatively breeding societies, only a few socially dominant individuals in a group breed, reproductive skew is high, and reproductive conflict is common. Surprisingly, the effects of this conflict on dominant reproductive success in vertebrate societies have rarely been investigated, especially in high-skew societies. We examine how subordinate female competition for breeding opportunities affects the reproductive success of dominant females in a monogamous cooperatively breeding bird, the Southern pied babbler (Turdoides bicolor). In this species, successful subordinate reproduction is very rare, despite the fact that groups commonly contain sexually mature female subordinates that could mate with unrelated group males. However, we show that subordinate females compete with dominant females to breed, and do so far more often than expected, based on the infrequency of their success. Attempts by subordinates to obtain a share of breeding impose significant costs on dominant females: chicks fledge from fewer nests, more nests are abandoned before incubation begins, and more eggs are lost. Dominant females appear to attempt to reduce these costs by aggressively suppressing potentially competitive subordinate females. This empirical evidence provides rare insight into the nature of the conflicts between females and the resultant costs to reproductive success in cooperatively breeding societies.
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Affiliation(s)
- Martha J Nelson-Flower
- Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa.
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Settepani V, Grinsted L, Granfeldt J, Jensen JL, Bilde T. Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae). J Evol Biol 2012; 26:51-62. [PMID: 23163349 DOI: 10.1111/jeb.12024] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/19/2012] [Indexed: 11/28/2022]
Abstract
Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task specialization, but in distinctly different ways: Stegodyphus sarasinorum showed behavioural asymmetries at the individual level, that is, individual spiders that had attacked prey once were more likely to attack prey again, independent of their body size or hunger level. In contrast, Anelosimus eximius showed no individual specialization, but showed differentiation according to instar, where adult and subadult females were more likely to engage in prey attack than were juveniles. We found no evidence for division of labour between prey attack and web maintenance. Different solutions to achieve task differentiation in prey attack for the two species studied here suggest an adaptive value of task specialization in foraging for social spiders.
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Affiliation(s)
- V Settepani
- Ecology and Genetics, Department of Bioscience, Aarhus University, Aarhus, Denmark.
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Do fledglings choose wisely? An experimental investigation into social foraging behaviour. Behav Ecol Sociobiol 2012. [DOI: 10.1007/s00265-012-1426-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Nelson-Flower MJ, Hockey PAR, O’Ryan C, Ridley AR. Inbreeding avoidance mechanisms: dispersal dynamics in cooperatively breeding southern pied babblers. J Anim Ecol 2012; 81:876-83. [DOI: 10.1111/j.1365-2656.2012.01983.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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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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Townsend SW, Zöttl M, Manser MB. All clear? Meerkats attend to contextual information in close calls to coordinate vigilance. Behav Ecol Sociobiol 2011. [DOI: 10.1007/s00265-011-1202-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Holbrook CT, Barden PM, Fewell JH. Division of labor increases with colony size in the harvester ant Pogonomyrmex californicus. Behav Ecol 2011. [DOI: 10.1093/beheco/arr075] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Nelson-Flower MJ, Hockey PA, O'Ryan C, Raihani NJ, du Plessis MA, Ridley AR. Monogamous dominant pairs monopolize reproduction in the cooperatively breeding pied babbler. Behav Ecol 2011. [DOI: 10.1093/beheco/arr018] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Bruintjes R, Taborsky M. Size-dependent task specialization in a cooperative cichlid in response to experimental variation of demand. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2010.10.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Bergmüller R, Schürch R, Hamilton IM. Evolutionary causes and consequences of consistent individual variation in cooperative behaviour. Philos Trans R Soc Lond B Biol Sci 2010; 365:2751-64. [PMID: 20679117 PMCID: PMC2936170 DOI: 10.1098/rstb.2010.0124] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behaviour is typically regarded as among the most flexible of animal phenotypic traits. In particular, expression of cooperative behaviour is often assumed to be conditional upon the behaviours of others. This flexibility is a key component of many hypothesized mechanisms favouring the evolution of cooperative behaviour. However, evidence shows that cooperative behaviours are often less flexible than expected and that, in many species, individuals show consistent differences in the amount and type of cooperative and non-cooperative behaviours displayed. This phenomenon is known as 'animal personality' or a 'behavioural syndrome'. Animal personality is evolutionarily relevant, as it typically shows heritable variation and can entail fitness consequences, and hence, is subject to evolutionary change. Here, we review the empirical evidence for individual variation in cooperative behaviour across taxa, we examine the evolutionary processes that have been invoked to explain the existence of individual variation in cooperative behaviour and we discuss the consequences of consistent individual differences on the evolutionary stability of cooperation. We highlight that consistent individual variation in cooperativeness can both stabilize or disrupt cooperation in populations. We conclude that recognizing the existence of consistent individual differences in cooperativeness is essential for an understanding of the evolution and prevalence of cooperation.
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Affiliation(s)
- Ralph Bergmüller
- Department of Biology, University of Neuchâtel, 2009 Neuchâtel, Switzerland.
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Grüebler MU, Naef-Daenzer B. Brood overlap and male ornamentation in the double-brooded barn swallow. Behav Ecol 2010. [DOI: 10.1093/beheco/arq017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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