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Ben Mocha Y, Scemama de Gialluly S, Griesser M, Markman S. What is cooperative breeding in mammals and birds? Removing definitional barriers for comparative research. Biol Rev Camb Philos Soc 2023; 98:1845-1861. [PMID: 37332253 DOI: 10.1111/brv.12986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 06/20/2023]
Abstract
Cooperative breeding (i.e. when alloparents care for the offspring of other group members) has been studied for nearly a century. Yet, inconsistent definitions of this breeding system still hamper comparative research. Here, we identify two major inconsistencies, discuss their consequences and propose a way forward. First, some researchers restrict the term 'cooperative breeding' to species with non-breeding alloparents. We show that such restrictive definitions lack distinct quantitative criteria to define non-breeding alloparents. This ambiguity, we argue, reflects the reproductive-sharing continuum among cooperatively breeding species. We therefore suggest that cooperative breeding should not be restricted to the few species with extreme reproductive skew and should be defined independent of the reproductive status of alloparents. Second, definitions rarely specify the type, extent and prevalence of alloparental care required to classify species as cooperative breeders. We thus analysed published data to propose qualitative and quantitative criteria for alloparental care. We conclude by proposing the following operational definition: cooperative breeding is a reproductive system where >5% of broods/litters in at least one population receive species-typical parental care and conspecifics provide proactive alloparental care that fulfils >5% of at least one type of the offspring's needs. This operational definition is designed to increase comparability across species and disciplines while allowing to study the intriguing phenomenon of cooperative breeding as a behaviour with multiple dimensions.
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Affiliation(s)
- Yitzchak Ben Mocha
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, 3498838, Israel
- Department of Biology and Environment, University of Haifa at Oranim, Tivon, 36006, Israel
- Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
| | | | - Michael Griesser
- Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Department of Collective Behaviour, Max Planck Institute of Animal Behaviour, Universitätsstrasse 10, Konstanz, 78457, Germany
| | - Shai Markman
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, 3498838, Israel
- Department of Biology and Environment, University of Haifa at Oranim, Tivon, 36006, Israel
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2
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Benvenuto C, Lorenzi MC. Social regulation of reproduction: control or signal? Trends Ecol Evol 2023; 38:1028-1040. [PMID: 37385846 DOI: 10.1016/j.tree.2023.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 07/01/2023]
Abstract
Traditionally, dominant breeders have been considered to be able to control the reproduction of other individuals in multimember groups that have high variance in reproductive success/reproductive skew (e.g., forced sterility/coercion of conspecifics in eusocial animals; sex-change suppression in sequential hermaphrodites). These actions are typically presented as active impositions by reproductively dominant individuals. However, how can individuals regulate the reproductive physiology of others? Alternatively, all contestants make reproductive decisions, and less successful individuals self-downregulate reproduction in the presence of dominant breeders. Shifting perspective from a top-down manipulation to a broader view, which includes all contenders, and using a multitaxon approach, we propose a unifying framework for the resolution of reproductive skew conflicts based on signalling rather than control, along a continuum of levels of strategic regulation of reproduction.
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Affiliation(s)
- Chiara Benvenuto
- School of Science, Engineering, and Environment, University of Salford, Salford, UK.
| | - Maria Cristina Lorenzi
- Laboratoire d'Ethologie Expérimentale et Comparée (LEEC), Université Sorbonne Paris Nord, Villetaneuse, France
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3
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Amorim PS, Dias RI. Social attributes shape antipredator behavior strategies in the ruddy ground-dove. Behav Processes 2023; 213:104964. [PMID: 37925060 DOI: 10.1016/j.beproc.2023.104964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/27/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023]
Abstract
The cost-benefit of social behavior depends on group size and the social interaction. As group size increases, competition for resources increases, while individual vigilance may decrease due to the lower probability of individual predation or increased competition for resources. To test predictions of the "many eyes hypothesis" and the "competition hypothesis", we investigated the effects of social attributes on the vigilance, foraging, direct conflict and sex on social groups of ruddy ground-doves (Columbina talpacoti) in an urban area. We observed that the number of conspecifics did not influence individual foraging behavior, instead, the vigilance decreased as flock size increased. Moreover, the number of conflicts within the flock negatively affected individual vigilance. However, larger flocks exhibited more direct conflicts, and males were more frequently involved in social conflicts, regardless of the sex ratio of the flock. Finally, the investment in both vigilance and foraging was not influenced by the sex of the focal individual or the sex ratio of the flock. Our findings indicate that conspecific numbers and flock social organization significantly influence the cost-benefit dynamics of flocking behavior. Larger flocks enhance vigilance for predator detection but come at an individual cost due to increased resource competition and conflicts.
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Affiliation(s)
- Paulo Sérgio Amorim
- Universidade Federal de Juiz de Fora, Instituto de Ciências Biológicas, Programa de Pós-graduação em Biodiversidade e Conservação da Natureza, Juiz de Fora, MG 36036-900, Brazil.
| | - Raphael Igor Dias
- Centro Universitário de Brasília, Faculdade de Ciências da Educação e Saúde, Brasília, DF 70790-075, Brazil.
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4
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Teunissen N, Fan M, Roast MJ, Hidalgo Aranzamendi N, Kingma SA, Peters A. Best of both worlds? Helpers in a cooperative fairy-wren assist most to breeding pairs that comprise a potential mate and a relative. ROYAL SOCIETY OPEN SCIENCE 2023; 10:231342. [PMID: 38026024 PMCID: PMC10646452 DOI: 10.1098/rsos.231342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
In cooperative breeders, individuals forego independent reproduction and help others raise offspring. Helping is proposed to be driven by indirect benefits from raising relatives, and/or direct benefits from raising additional recruits or helping itself. We propose that consideration of social context is also important, in particular the characteristics of the breeding pair: helping may also serve to lighten the workload of-or maintain social bonds with-breeders (e.g. kin, potential mates) who in turn can offer benefits to helpers (e.g. prolonged nepotism, future mating, future production of relatives). Here, we test this hypothesis, while controlling for potential direct and indirect benefits from raising offspring, in purple-crowned fairy-wrens (Malurus coronatus) exhibiting variation in social group composition, and thus, breeder value. We show that helper provisioning rates to the nest were explained by characteristics of breeders that helpers assisted, rather than benefits from raising offspring. The presence of at least one related breeder was a prerequisite to help, but helpers provisioned most if assisting a relative and potential mate. Neglecting to take group composition into account would have led to misinterpretation of our results. A comprehensive understanding of the evolution of cooperative breeding hence requires nuanced consideration of social context.
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Affiliation(s)
- Niki Teunissen
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Behavioural Ecology Group, Department of Animal Sciences, Wageningen University and Research, Wageningen, The Netherlands
| | - Marie Fan
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Michael J. Roast
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | | | - Sjouke A. Kingma
- Behavioural Ecology Group, Department of Animal Sciences, Wageningen University and Research, Wageningen, The Netherlands
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
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5
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Ben Mocha Y, Dahan T, Zou Y, Griesser M, Markman S. Evidence for a reproductive sharing continuum in cooperatively breeding mammals and birds: consequences for comparative research. Proc Biol Sci 2023; 290:20230607. [PMID: 37700641 PMCID: PMC10498043 DOI: 10.1098/rspb.2023.0607] [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: 03/13/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
Extreme reproductive skew occurs when a dominant female/male almost monopolizes reproduction within a group of multiple sexually mature females/males, respectively. It is sometimes considered an additional, restrictive criterion to define cooperative breeding. However, datasets that use this restrictive definition to classify species as cooperative breeders systematically overestimate reproductive skew by including groups in which reproduction cannot be shared by definition (e.g. groups with a single female/male). Here, we review the extent of reproductive sharing in 41 mammal and 37 bird species previously classified as exhibiting alloparental care and extreme reproductive skew, while only considering multi-female or multi-male groups. We demonstrate that in groups where unequal reproduction sharing is possible, extreme reproductive skew occurs in a few species only (11/41 mammal species and 12/37 bird species). These results call for significant changes in datasets that classify species' caring and mating system. To facilitate these changes, we provide an updated dataset on reproductive sharing in 63 cooperatively breeding species. At the conceptual level, our findings suggest that reproductive skew should not be a defining criterion of cooperative breeding and support the definition of cooperative breeding as a care system in which alloparents provide systematic care to other group members' offspring.
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Affiliation(s)
- Yitzchak Ben Mocha
- Department of Evolutionary and Environmental Biology, University of Haifa, 3498838 Haifa, Israel
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Tal Dahan
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
| | - Yuqi Zou
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Michael Griesser
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Department of Collective Behaviour, Max Planck Institute of Animal Behaviour, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Shai Markman
- Department of Evolutionary and Environmental Biology, University of Haifa, 3498838 Haifa, Israel
- Department of Biology and Environment, University of Haifa at Oranim, 36006 Tivon, Israel
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6
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Culbert BM, Ligocki IY, Salena MG, Wong MYL, Hamilton IM, Bernier NJ, Balshine S. Galanin expression varies with parental care and social status in a wild cooperatively breeding fish. Horm Behav 2022; 146:105275. [PMID: 36272180 DOI: 10.1016/j.yhbeh.2022.105275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/27/2022] [Accepted: 10/04/2022] [Indexed: 11/04/2022]
Abstract
As many busy parents will attest, caring for young often comes at the expense of having time to feed and care for oneself. Galanin is a neuropeptide that regulates food intake and modulates parental care; however, the relative importance of galanin in the regulation of feeding versus caring by parents has never been evaluated before under naturalistic settings. Here, we assessed how expression of the galanin system varied in two brain regions, the hypothalamus (which regulates feeding) and the preoptic area (which modulates social behaviours including care) in a wild cichlid fish, Neolamprologus pulcher. Females with young had higher hypothalamic expression of galanin receptor 1a, and the highest expression of galanin and galanin receptor 1a was observed in females that foraged the least. However, expression of five other feeding-related neuropeptides did not change while females were caring for young suggesting that changes in the hypothalamic galanin system may not have been directly related to changes in food intake. The preoptic galanin system was unaffected by the presence of young, but preoptic galanin expression was higher in dominant females (which are aggressive, regularly reproduce and care for young) compared to subordinate females (which are submissive, rarely reproduce but often help care for young). Additionally, preoptic galanin expression was higher in fish that performed more territory defense. Overall, our results indicate that galanin has brain-region-specific roles in modulating both parental care and social status in wild animals.
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Affiliation(s)
- Brett M Culbert
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada.
| | - Isaac Y Ligocki
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA; Department of Biology, Millersville University, Millersville, PA, USA
| | - Matthew G Salena
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Marian Y L Wong
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ian M Hamilton
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA; Department of Mathematics, The Ohio State University, Columbus, OH, USA
| | - Nicholas J Bernier
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
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7
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Guo X, Zhao Q, Meng L, Hardy IC, Li B. Reproductive skew in quasisocial parasitoids: how egalitarian is cooperative brooding? Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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8
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Bose APH, Dabernig-Heinz J, Koch L, Grimm J, Lang S, Hegedűs B, Banda T, Makasa L, Jordan A, Sefc KM. Parentage analysis across age cohorts reveals sex differences in reproductive skew in a group-living cichlid fish, Neolamprologus multifasciatus. Mol Ecol 2022; 31:2418-2434. [PMID: 35170123 DOI: 10.1111/mec.16401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 11/30/2022]
Abstract
Group-living animals are often faced with complex reproductive decisions, namely how to partition within-group reproduction, how to obtain extra-group reproduction, and how these two means of reproduction should be balanced. The solutions to these questions can be difficult to predict because ecological conditions can affect the scopes for within-group and extra-group reproduction in complex ways. For example, individuals that are restricted from moving freely around their habitats may have limited extra-group reproductive opportunities, but at the same time, groups may live in close proximities to one another, which could potentially have the opposite effect. The group-living cichlid fish, Neolamprologus multifasciatus, experiences such ecological conditions, and we conducted an intensive genetic parentage analysis to investigate how reproduction is distributed within and among groups for both males and females. We found that cohabiting males live in 'high-skew' societies, where dominant males monopolize the majority of within-group reproduction, while females live in 'low-skew' societies, where multiple females can produce offspring concurrently. Despite extremely short distances separating groups, we inferred only very low levels of extra-group reproduction suggesting that subordinate males have very limited reproductive opportunities. A strength of our parentage analysis lies in its inclusion of individuals that spanned a wide age range, from young fry to adults. We outline the logistical circumstances when very young offspring may not always be accessible to parentage researchers, and present strategies to overcome the challenges of inferring mating patterns from a wide age range of offspring.
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Affiliation(s)
- Aneesh P H Bose
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Lukas Koch
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | | | | | - Taylor Banda
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, Mpulungu, Zambia
| | - Lawrence Makasa
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, Mpulungu, Zambia
| | - Alex Jordan
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
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9
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Impact of genetic relatedness and food competition on female dominance hierarchies in a cichlid fish. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Josi D, Heg D, Takeyama T, Bonfils D, Konovalov DA, Frommen JG, Kohda M, Taborsky M. Age- and sex-dependent variation in relatedness corresponds to reproductive skew, territory inheritance, and workload in cooperatively breeding cichlids. Evolution 2021; 75:2881-2897. [PMID: 34555177 PMCID: PMC9298395 DOI: 10.1111/evo.14348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/27/2021] [Accepted: 08/18/2021] [Indexed: 11/28/2022]
Abstract
Kin selection plays a major role in the evolution of cooperative systems. However, many social species exhibit complex within-group relatedness structures, where kin selection alone cannot explain the occurrence of cooperative behavior. Understanding such social structures is crucial to elucidate the evolution and maintenance of multi-layered cooperative societies. In lamprologine cichlids, intragroup relatedness seems to correlate positively with reproductive skew, suggesting that in this clade dominants tend to provide reproductive concessions to unrelated subordinates to secure their participation in brood care. We investigate how patterns of within-group relatedness covary with direct and indirect fitness benefits of cooperation in a highly social vertebrate, the cooperatively breeding, polygynous lamprologine cichlid Neolamprologus savoryi. Behavioral and genetic data from 43 groups containing 578 individuals show that groups are socially and genetically structured into subgroups. About 17% of group members were unrelated immigrants, and average relatedness between breeders and brood care helpers declined with helper age due to group membership dynamics. Hence the relative importance of direct and indirect fitness benefits of cooperation depends on helper age. Our findings highlight how both direct and indirect fitness benefits of cooperation and group membership can select for cooperative behavior in societies comprising complex social and relatedness structures.
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Affiliation(s)
- Dario Josi
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland.,Conservation, Ecology, Evolution and Behaviour Research Group, Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Dik Heg
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland.,CTU Bern, University of Bern, Bern, Switzerland
| | - Tomohiro Takeyama
- Department of Biosphere-Geosphere Science, Okayama University of Science, Okayama, Japan.,Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Danielle Bonfils
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland
| | - Dmitry A Konovalov
- College of Science and Engineering, James Cook University, Townsville, Australia
| | - Joachim G Frommen
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland.,Conservation, Ecology, Evolution and Behaviour Research Group, Ecology and Environment Research Centre, Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Masanori Kohda
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Michael Taborsky
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland
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11
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Riehl C. Evolutionary origins of cooperative and communal breeding: Lessons from the crotophagine cuckoos. Ethology 2021. [DOI: 10.1111/eth.13149] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Christina Riehl
- Department of Ecology and Evolutionary Biology Princeton University Princeton NJ USA
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12
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Undin M, Lockhart PJ, Hills SFK, Armstrong DP, Castro I. Mixed Mating in a Multi-Origin Population Suggests High Potential for Genetic Rescue in North Island Brown Kiwi, Apteryx mantelli. FRONTIERS IN CONSERVATION SCIENCE 2021. [DOI: 10.3389/fcosc.2021.702128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reinforcement translocations are increasingly utilised in conservation with the goal of achieving genetic rescue. However, concerns regarding undesirable results, such as genetic homogenisation or replacement, are widespread. One factor influencing translocation outcomes is the rate at which the resident and the introduced individuals interbreed. Consequently, post-release mate choice is a key behaviour to consider in conservation planning. Here we studied mating, and its consequences for genomic admixture, in the North Island brown kiwi Apteryx mantelli population on Ponui Island which was founded by two translocation events over 50 years ago. The two source populations used are now recognised as belonging to two separate management units between which birds differ in size and are genetically differentiated. We examined the correlation between male and female morphometrics for 17 known pairs and quantified the relatedness of 20 pairs from this admixed population. In addition, we compared the genetic similarity and makeup of 106 Ponui Island birds, including 23 known pairs, to birds representing the source populations for the original translocations. We found no evidence for size-assortative mating. On the contrary, genomic SNP data suggested that kiwi of one feather did not flock together, meaning that mate choice resulted in pairing between individuals that were less related than expected by random chance. Furthermore, the birds in the current Ponui Island population were found to fall along a gradient of genomic composition consistent with non-clustered representation of the two parental genomes. These findings indicate potential for successful genetic rescue in future Apteryx reinforcement translocations, a potential that is currently under utilised due to restrictive translocation policies. In light of our findings, we suggest that reconsideration of these policies could render great benefits for the future diversity of this iconic genus in New Zealand.
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13
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Cost, risk, and avoidance of inbreeding in a cooperatively breeding bird. Proc Natl Acad Sci U S A 2020; 117:15724-15730. [PMID: 32571952 DOI: 10.1073/pnas.1918726117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inbreeding is often avoided in natural populations by passive processes such as sex-biased dispersal. But, in many social animals, opposite-sexed adult relatives are spatially clustered, generating a risk of incest and hence selection for active inbreeding avoidance. Here we show that, in long-tailed tits (Aegithalos caudatus), a cooperative breeder that risks inbreeding by living alongside opposite-sex relatives, inbreeding carries fitness costs and is avoided by active kin discrimination during mate choice. First, we identified a positive association between heterozygosity and fitness, indicating that inbreeding is costly. We then compared relatedness within breeding pairs to that expected under multiple mate-choice models, finding that pair relatedness is consistent with avoidance of first-order kin as partners. Finally, we show that the similarity of vocal cues offers a plausible mechanism for discrimination against first-order kin during mate choice. Long-tailed tits are known to discriminate between the calls of close kin and nonkin, and they favor first-order kin in cooperative contexts, so we conclude that long-tailed tits use the same kin discrimination rule to avoid inbreeding as they do to direct help toward kin.
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14
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Group formation and the evolutionary pathway to complex sociality in birds. Nat Ecol Evol 2020; 4:479-486. [PMID: 32094543 DOI: 10.1038/s41559-020-1113-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 01/14/2020] [Indexed: 11/08/2022]
Abstract
Group-living species show a diversity of social organization, from simple mated pairs to complex communities of interdependent individuals performing specialized tasks. The advantages of living in cooperative groups are well understood, but why some species breed in small aggregations while others evolve large, complex groups with clearly divided roles is unclear. We address this problem by reconstructing the evolutionary pathways to cooperative breeding across 4,730 bird species. We show that differences in the way groups form at the origin of cooperative breeding predicts the level of group complexity that emerges. Groups that originate through the retention of offspring have a clear reproductive divide with distinct breeder and helper roles. This is associated with reproductive specialization, where breeders invest more in fecundity and less in care. In contrast, groups formed through the aggregation of unrelated adults are smaller and lack specialization. These results help explain why some species have not transitioned beyond simple groups while others have taken the pathway to increased group complexity.
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15
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Kaiser SA, Martin TE, Oteyza JC, Danner JE, Armstad CE, Fleischer RC. Within-group relatedness and patterns of reproductive sharing and cooperation in the tropical chestnut-crested yuhina. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Nonacs P. Hamilton's rule is essential but insufficient for understanding monogamy's role in social evolution. ROYAL SOCIETY OPEN SCIENCE 2019; 6:180913. [PMID: 30800348 PMCID: PMC6366207 DOI: 10.1098/rsos.180913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
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17
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Downing PA, Griffin AS, Cornwallis CK. Sex differences in helping effort reveal the effect of future reproduction on cooperative behaviour in birds. Proc Biol Sci 2018; 285:20181164. [PMID: 30135160 PMCID: PMC6125912 DOI: 10.1098/rspb.2018.1164] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 07/25/2018] [Indexed: 01/06/2023] Open
Abstract
The evolution of helping behaviour in species that breed cooperatively in family groups is typically attributed to kin selection alone. However, in many species, helpers go on to inherit breeding positions in their natal groups, but the extent to which this contributes to selection for helping is unclear as the future reproductive success of helpers is often unknown. To quantify the role of future reproduction in the evolution of helping, we compared the helping effort of female and male retained offspring across cooperative birds. The kin selected benefits of helping are equivalent between female and male helpers-they are equally related to the younger siblings they help raise-but the future reproductive benefits of helping differ because of sex differences in the likelihood of breeding in the natal group. We found that the sex which is more likely to breed in its natal group invests more in helping, suggesting that in addition to kin selection, helping in family groups is shaped by future reproduction.
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Theuerkauf J, Kuehn R, Rouys S, Bloc H, Gula R. Fraternal Polyandry and Clannish Spatial Organization in a Flightless Island Bird. Curr Biol 2018; 28:1482-1488.e3. [PMID: 29706518 DOI: 10.1016/j.cub.2018.03.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/11/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
Polyandry has been studied in many species, especially birds [1]. Exclusively fraternal polyandry (several full or half-brothers with one unrelated female) is only known in human societies [2, 3], in which it is an important mechanism for limiting reproductive output [3] in association with scarce environmental resources [2]. However, the social organization of the Kagu Rhynochetos jubatus, a bird species endemic to New Caledonia, has the characteristics of this mating system. Kagu are cooperative breeders and evolved in the absence of predators [4, 5]. Breeding birds and their helpers contributes to the care and defense of the chick [6]. Kagu populations occur in both poor and rich habitats [7] and differ substantially in food supply and associated reproduction rates [8]. This enabled us to verify whether fraternal polyandry increased reproductive output in low-density situations but limited reproduction in high-density populations. Our 15-year study revealed that, regardless of resource availability, Kagu were organized in facultative fraternal polyandrous families grouped in clans. Within a clan, all breeding females were unrelated, whereas all males were related. There was no extra-clan paternity. An average family size of four to five adults was optimal for breeding success. Males that have long-established families in their own territory regularly visited their parents. We conclude that fraternal polyandry in Kagu increases reproductive output under poor environmental conditions but limits population growth when the population is near carrying capacity because the clannish spatial organization prevents new families from establishing territories.
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Affiliation(s)
- Jörn Theuerkauf
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679 Warsaw, Poland.
| | - Ralph Kuehn
- Unit of Molecular Zoology, Chair of Zoology, Department of Animal Science, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany; Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Box 30003, MSC 4901, Las Cruces, NM 88003, USA
| | - Sophie Rouys
- Conservation Research New Caledonia, 98800 Nouméa, New Caledonia
| | - Henri Bloc
- Conservation Research New Caledonia, 98800 Nouméa, New Caledonia; Syndicat Mixte des Grandes Fougères, BP 10, 98881 Farino, New Caledonia
| | - Roman Gula
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679 Warsaw, Poland.
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Nelson-Flower MJ, Flower TP, Ridley AR. Sex differences in the drivers of reproductive skew in a cooperative breeder. Mol Ecol 2018; 27:2435-2446. [PMID: 29663552 DOI: 10.1111/mec.14587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/25/2018] [Accepted: 03/26/2018] [Indexed: 01/08/2023]
Abstract
Many cooperatively breeding societies are characterized by high reproductive skew, such that some socially dominant individuals breed, while socially subordinate individuals provide help. Inbreeding avoidance serves as a source of reproductive skew in many high-skew societies, but few empirical studies have examined sources of skew operating alongside inbreeding avoidance or compared individual attempts to reproduce (reproductive competition) with individual reproductive success. Here, we use long-term genetic and observational data to examine factors affecting reproductive skew in the high-skew cooperatively breeding southern pied babbler (Turdoides bicolor). When subordinates can breed, skew remains high, suggesting factors additional to inbreeding avoidance drive skew. Subordinate females are more likely to compete to breed when older or when ecological constraints on dispersal are high, but heavy subordinate females are more likely to successfully breed. Subordinate males are more likely to compete when they are older, during high ecological constraints, or when they are related to the dominant male, but only the presence of within-group unrelated subordinate females predicts subordinate male breeding success. Reproductive skew is not driven by reproductive effort, but by forces such as intrinsic physical limitations and intrasexual conflict (for females) or female mate choice, male mate-guarding and potentially reproductive restraint (for males). Ecological conditions or "outside options" affect the occurrence of reproductive conflict, supporting predictions of recent synthetic skew models. Inbreeding avoidance together with competition for access to reproduction may generate high skew in animal societies, and disparate processes may be operating to maintain male vs. female reproductive skew in the same species.
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Affiliation(s)
- Martha J Nelson-Flower
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Tom P Flower
- Department of Biology, Capilano University, North Vancouver, BC, Canada.,Percy FitzPatrick Institute of African Ornithology, DST NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | - Amanda R Ridley
- Percy FitzPatrick Institute of African Ornithology, DST NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa.,Centre for Evolutionary Biology, University of Western Australia, Crawley, WA, Australia
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