1
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Dorsey OC, Rosenthal GG. A taste for the familiar: explaining the inbreeding paradox. Trends Ecol Evol 2023; 38:132-142. [PMID: 36241551 DOI: 10.1016/j.tree.2022.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 09/04/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022]
Abstract
The negative consequences of inbreeding have led animal biologists to assume that mate choice is generally biased against relatives. However, inbreeding avoidance is highly variable and by no means the rule across animal taxa. Even when inbreeding is costly, there are numerous examples of animals failing to avoid inbreeding or even preferring to mate with close kin. We argue that selective and mechanistic constraints interact to limit the evolution of inbreeding avoidance, notably when there is a risk of mating with heterospecifics and losing fitness through hybridization. Further, balancing inbreeding avoidance with conspecific mate preference may drive the evolution of multivariate sexual communication. Studying different social and sexual decisions within the same species can illuminate trade-offs among mate-choice mechanisms.
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Affiliation(s)
- Owen C Dorsey
- Program in Ecology and Evolutionary Biology and Department of Biology, Texas A&M University, TX, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico.
| | - Gil G Rosenthal
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico; Department of Biology, University of Padua, Padua, Italy
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2
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Pemberton JM, Kruuk LE, Clutton-Brock T. The Unusual Value of Long-Term Studies of Individuals: The Example of the Isle of Rum Red Deer Project. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2022. [DOI: 10.1146/annurev-ecolsys-012722-024041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Long-term studies of individuals enable incisive investigations of questions across ecology and evolution. Here, we illustrate this claim by reference to our long-term study of red deer on the Isle of Rum, Scotland. This project has established many of the characteristics of social organization, selection, and population ecology typical of large, polygynous, seasonally breeding mammals, with wider implications for our understanding of sexual selection and the evolution of sex differences, as well as for their population dynamics and population management. As molecular genetic techniques have developed, the project has pivoted to investigate evolutionary genetic questions, also breaking new ground in this field. With ongoing advances in genomics and statistical approaches and the development of increasingly sophisticated ways to assay new phenotypic traits, the questions that long-term studies such as the red deer study can answer become both broader and ever more sophisticated. They also offer powerful means of understanding the effects of ongoing climate change on wild populations.
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Affiliation(s)
- Josephine M. Pemberton
- Institute of Ecology and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Loeske E.B. Kruuk
- Institute of Ecology and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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3
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Nomano FY, Matsui S, Senda M, Tsuchiya Y, Takagi M. Random mating and the lack of sex-biased kin clustering in an island population of the bull-headed shrike, Lanius bucephalus. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2022.2069159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Fumiaki Y. Nomano
- Graduate School of Environmental Earth Science, Hokkaido University, Kita 10, Nishi 5, Kita-ku, Sapporo 060-0810, Japan
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, Sokendai, The Graduate University for Advanced Studies, Hayama, Miura, Kanagawa 240-0193, Japan
| | - Shin Matsui
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan
- Department of Biology, School of Biological Sciences, Tokai University, Minamisawa 5-1-1-1, Minami-ku Hokkaido, Sapporo 005-8601, Japan
| | - Mariko Senda
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan
- Yamashina Institute for Ornithology, Konoyama 115, Abiko, Chiba 270-1145, Japan
| | - Yuko Tsuchiya
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan
| | - Masaoki Takagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan
- Department of Natural History Science, Graduate School of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan
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4
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Hooper AK, Bonduriansky R. Effects of genetic vs. environmental quality on condition-dependent morphological and life history traits in a neriid fly. J Evol Biol 2022; 35:803-816. [PMID: 35514040 PMCID: PMC9325454 DOI: 10.1111/jeb.14014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 03/14/2022] [Indexed: 12/02/2022]
Abstract
Condition is assumed to reflect both genes and environment, enabling condition‐dependent signals to reveal genetic quality. However, because the phenotypic effects of variation in genetic quality could be masked by environmental heterogeneity, the contribution of genetic quality to phenotypic variation in fitness‐related traits and condition‐dependent signals remains unclear. We compared effects of ecologically relevant manipulations of environmental quality (nutrient dilution in the larval diet) and genetic quality (one generation of inbreeding) on male and female morphology, life history and reproductive performance in the neriid fly Telostylinus angusticollis. We found that larval diet quality had strong, positive effects on male and female body size, male secondary sexual traits, and aspects of male and female reproductive performance. By contrast, inbreeding had weak effects on most traits, and no trait showed clear and consistent effects of both environmental and genetic quality. Indeed, inbreeding effects on body size and male competitive performance were of opposite sign in rich vs. poor larval diet treatment groups. Our results suggest that environmental quality strongly affects condition, but the effects of genetic quality are subtle and environment‐dependent in this species. These findings raise questions about the genetic architecture of condition and the potential for condition‐dependent traits to function as signals of genetic quality.
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Affiliation(s)
- Amy K Hooper
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Russell Bonduriansky
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
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5
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Pike VL, Cornwallis CK, Griffin AS. Why don't all animals avoid inbreeding? Proc Biol Sci 2021; 288:20211045. [PMID: 34344184 PMCID: PMC8334842 DOI: 10.1098/rspb.2021.1045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/12/2021] [Indexed: 01/22/2023] Open
Abstract
Individuals are expected to avoid mating with relatives as inbreeding can reduce offspring fitness, a phenomenon known as inbreeding depression. This has led to the widespread assumption that selection will favour individuals that avoid mating with relatives. However, the strength of inbreeding avoidance is variable across species and there are numerous cases where related mates are not avoided. Here we test if the frequency that related males and females encounter each other explains variation in inbreeding avoidance using phylogenetic meta-analysis of 41 different species from six classes across the animal kingdom. In species reported to mate randomly with respect to relatedness, individuals were either unlikely to encounter relatives, or inbreeding had negligible effects on offspring fitness. Mechanisms for avoiding inbreeding, including active mate choice, post-copulatory processes and sex-biased dispersal, were only found in species with inbreeding depression. These results help explain why some species seem to care more about inbreeding than others: inbreeding avoidance through mate choice only evolves when there is both a risk of inbreeding depression and related sexual partners frequently encounter each other.
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6
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Wells DA, Cant MA, Thompson FJ, Marshall HH, Vitikainen EIK, Hoffman JI, Nichols HJ. Extra-group paternity varies with proxies of relatedness in a social mammal with high inbreeding risk. Behav Ecol 2020. [DOI: 10.1093/beheco/araa105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Behavioral mechanisms for avoiding inbreeding are common in the natural world and are believed to have evolved as a response to the negative consequences of inbreeding. However, despite a fundamental role in fitness, we have a limited understanding of the cues that individuals use to assess inbreeding risk, as well as the extent to which individual inbreeding behavior is repeatable. We used piecewise structural equation modeling of 24 years of data to investigate the causes and consequences of within- versus extra-group paternity in banded mongooses. This cooperatively breeding mammal lives in tight-knit social groups that often contain closely related opposite-sex breeders, so inbreeding can be avoided through extra-group mating. We used molecular parentage assignments to show that, despite extra-group paternity resulting in outbred offspring, within-group inbreeding occurs frequently, with around 16% litters being moderately or highly inbred. Additionally, extra-group paternity appears to be plastic, with females mating outside of their social group according to individual proxies (age and immigration status) and societal proxies (group size and age) of within-group inbreeding risk but not in direct response to levels of within-group relatedness. While individual repeatability in extra-group paternity was relatively low, female cobreeders showed high repeatability, suggesting a strong constraint arising from the opportunities for extra-group mating. The use of extra-group paternity as an inbreeding avoidance strategy is, therefore, limited by high costs, opportunity constraints, and the limited reliability of proxies of inbreeding risk.
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Affiliation(s)
- David A Wells
- Department of Animal Behaviour, University of Bielefeld, Postfach, Bielefeld, Germany
- School of Natural Science and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Michael A Cant
- College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Faye J Thompson
- College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Harry H Marshall
- Centre for Research in Ecology, Evolution and Behaviour, Department of Life Sciences, University of Roehampton, London, UK
| | - Emma I K Vitikainen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Joseph I Hoffman
- Department of Animal Behaviour, University of Bielefeld, Postfach, Bielefeld, Germany
- British Antarctic Survey, Cambridge, Cambridgeshire, UK
| | - Hazel J Nichols
- Department of Animal Behaviour, University of Bielefeld, Postfach, Bielefeld, Germany
- Department of Biosciences, Swansea University, Swansea, UK
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7
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Gow EA, Arcese P, Dagenais D, Sardell RJ, Wilson S, Reid JM. Testing predictions of inclusive fitness theory in inbreeding relatives with biparental care. Proc Biol Sci 2019; 286:20191933. [PMID: 31795864 PMCID: PMC6939262 DOI: 10.1098/rspb.2019.1933] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Inclusive fitness theory predicts that parental care will vary with relatedness between potentially caring parents and offspring, potentially shaping mating system evolution. Systems with extra-pair paternity (EPP), and hence variable parent–brood relatedness, provide valuable opportunities to test this prediction. However, existing theoretical and empirical studies assume that a focal male is either an offspring's father with no inbreeding, or is completely unrelated. We highlight that this simple dichotomy does not hold given reproductive interactions among relatives, complicating the effect of EPP on parent–brood relatedness yet providing new opportunities to test inclusive fitness theory. Accordingly, we tested hierarchical hypotheses relating parental feeding rate to parent–brood relatedness, parent kinship and inbreeding, using song sparrows (Melospiza melodia) experiencing natural variation in relatedness. As predicted, male and female feeding rates increased with relatedness to a dependent brood, even controlling for brood size. Male feeding rate tended to decrease as paternity loss increased, and increased with increasing kinship and hence inbreeding between socially paired mates. We thereby demonstrate that variation in a key component of parental care concurs with subtle predictions from inclusive fitness theory. We additionally highlight that such effects can depend on the underlying social mating system, potentially generating status-specific costs of extra-pair reproduction.
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Affiliation(s)
- Elizabeth A Gow
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter Arcese
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Danielle Dagenais
- Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Rebecca J Sardell
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland
| | - Scott Wilson
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.,National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Jane M Reid
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland.,Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
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8
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McLean EM, Archie EA, Alberts SC. Lifetime Fitness in Wild Female Baboons: Trade-Offs and Individual Heterogeneity in Quality. Am Nat 2019; 194:745-759. [PMID: 31738100 DOI: 10.1086/705810] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Understanding the evolution of life histories requires information on how life histories vary among individuals and how such variation predicts individual fitness. Using complete life histories for females in a well-studied population of wild baboons, we tested two nonexclusive hypotheses about the relationships among survival, reproduction, and fitness: the quality hypothesis, which predicts positive correlations between life-history traits, mediated by variation in resource acquisition, and the trade-off hypothesis, which predicts negative correlations between life-history traits, mediated by trade-offs in resource allocation. In support of the quality hypothesis, we found that females with higher rates of offspring survival were themselves better at surviving. Further, after statistically controlling for variation in female quality, we found evidence for two types of trade-offs: females who produced surviving offspring at a slower rate had longer life spans than those who produced surviving offspring at a faster rate, and females who produced surviving offspring at a slower rate had a higher overall proportion of offspring survive infancy than females who produced surviving offspring at a faster rate. Importantly, these trade-offs were evident even when accounting for (i) the influence of offspring survival on maternal birth rate, (ii) the dependence of offspring survival on maternal survival, and (iii) potential age-related changes in birth rate and/or offspring survival. Our results shed light on why trade-offs are evident in some populations while variation in individual quality masks trade-offs in others.
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9
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Burgess SC, Sander L, Bueno M. How relatedness between mates influences reproductive success: An experimental analysis of self-fertilization and biparental inbreeding in a marine bryozoan. Ecol Evol 2019; 9:11353-11366. [PMID: 31641478 PMCID: PMC6802076 DOI: 10.1002/ece3.5636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/18/2019] [Accepted: 08/06/2019] [Indexed: 11/21/2022] Open
Abstract
Kin associations increase the potential for inbreeding. The potential for inbreeding does not, however, make inbreeding inevitable. Numerous factors influence whether inbreeding preference, avoidance, or tolerance evolves, and, in hermaphrodites where both self-fertilization and biparental inbreeding are possible, it remains particularly difficult to predict how selection acts on the overall inbreeding strategy, and to distinguish the type of inbreeding when making inferences from genetic markers. Therefore, we undertook an empirical analysis on an understudied type of mating system (spermcast mating in the marine bryozoan, Bugula neritina) that provides numerous opportunities for inbreeding preference, avoidance, and tolerance. We created experimental crosses, containing three generations from two populations to estimate how parental reproductive success varies across parental relatedness, ranging from self, siblings, and nonsiblings from within the same population. We found that the production of viable selfed offspring was extremely rare (only one colony produced three selfed offspring) and biparental inbreeding more common. Paternity analysis using 16 microsatellite markers confirmed outcrossing. The production of juveniles was lower for sib mating compared with nonsib mating. We found little evidence for consistent inbreeding, in terms of nonrandom mating, in adult samples collected from three populations, using multiple population genetic inferences. Our results suggest several testable hypotheses that potentially explain the overall mating and dispersal strategy in this species, including early inbreeding depression, inbreeding avoidance through cryptic mate choice, and differential dispersal distances of sperm and larvae.
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Affiliation(s)
- Scott C. Burgess
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
| | - Lisa Sander
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
| | - Marília Bueno
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
- Present address:
Departamento de Biologia AnimalInstituto de BiologiaUniversidade Estadual de Campinas – UNICAMPCampinasBrazil
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10
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Lifetime Fitness Costs of Inbreeding and Being Inbred in a Critically Endangered Bird. Curr Biol 2019; 29:2711-2717.e4. [DOI: 10.1016/j.cub.2019.06.064] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/31/2019] [Accepted: 06/21/2019] [Indexed: 11/20/2022]
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11
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Fisher DN, Pruitt JN. Opposite responses to selection and where to find them. J Evol Biol 2019; 32:505-518. [PMID: 30807674 DOI: 10.1111/jeb.13432] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/17/2019] [Accepted: 02/22/2019] [Indexed: 01/22/2023]
Abstract
We generally expect traits to evolve in the same direction as selection. However, many organisms possess traits that appear to be costly for individuals, while plant and animal breeding experiments reveal that selection may lead to no response or even negative responses to selection. We formalize both of these instances as cases of "opposite responses to selection." Using quantitative genetic models for the response to selection, we outline when opposite responses to selection should be expected. These typically occur when social selection opposes direct selection, when individuals interact with others less related to them than a random member of the population, and if the genetic covariance between direct and indirect effects is negative. We discuss the likelihood of each of these occurring in nature and therefore summarize how frequent opposite responses to selection are likely to be. This links several evolutionary phenomena within a single framework.
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Affiliation(s)
- David N Fisher
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
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12
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Townsend AK, Taff CC, Jones ML, Getman KH, Wheeler SS, Hinton MG, Logsdon RM. Apparent inbreeding preference despite inbreeding depression in the American crow. Mol Ecol 2019; 28:1116-1126. [PMID: 30222228 DOI: 10.1111/mec.14866] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 08/18/2018] [Accepted: 09/04/2018] [Indexed: 11/28/2022]
Abstract
Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.
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Affiliation(s)
| | - Conor C Taff
- Cornell University Laboratory of Ornithology, Ithaca, New York
| | - Melissa L Jones
- Avian Sciences Graduate Group, University of California, Davis, California
| | | | - Sarah S Wheeler
- Sacramento-Yolo Mosquito and Vector Control District, Elk Grove, California
| | - Mitch G Hinton
- Animal Behavior Graduate Group, University of California, Davis, California
| | - Ryane M Logsdon
- Animal Behavior Graduate Group, University of California, Davis, California
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13
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Troianou E, Huisman J, Pemberton JM, Walling CA. Estimating selection on the act of inbreeding in a population with strong inbreeding depression. J Evol Biol 2018; 31:1815-1827. [PMID: 30230082 PMCID: PMC6334283 DOI: 10.1111/jeb.13376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/05/2018] [Accepted: 09/13/2018] [Indexed: 12/15/2022]
Abstract
Inbreeding depression is widely regarded as a driving force in the evolution of dispersal, mate choice and sperm selection. However, due to likely costs of inbreeding avoidance, which are poorly understood, it is unclear to what extent selection to avoid inbreeding is expected in nature. Moreover, there are currently very few empirical estimates of the strength of selection against the act of inbreeding (mating with a relative), as opposed to the fitness costs of being inbred. Here, we use data from the individual-based study of red deer on the Scottish island of Rum, a strongly polygynous system which harbours a large inbreeding load, to estimate selection against the act of inbreeding for each sex. We use pedigree and genomic estimates of relatedness between individuals and measure fitness using both lifetime breeding success (number of calves born) and lifetime reproductive success (number of calves surviving to independence), with the latter incorporating inbreeding depression in calf survival. We find for both sexes that the repeatability of the act of inbreeding was low (< 0.1), suggesting little among-individual variation for this trait on which selection can act. Using the genomic measures, there was significant selection against the act of inbreeding in males, but not in females, and there was considerable uncertainty in the estimate in both sexes. We discuss possible explanations for these patterns and their implications for understanding the evolution of inbreeding avoidance in natural populations.
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Affiliation(s)
- Eva Troianou
- Institute of Evolutionary BiologySchool of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Jisca Huisman
- Institute of Evolutionary BiologySchool of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Josephine M. Pemberton
- Institute of Evolutionary BiologySchool of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Craig A. Walling
- Institute of Evolutionary BiologySchool of Biological SciencesUniversity of EdinburghEdinburghUK
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14
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Hajduk GK, Cockburn A, Margraf N, Osmond HL, Walling CA, Kruuk LEB. Inbreeding, inbreeding depression, and infidelity in a cooperatively breeding bird. Evolution 2018; 72:1500-1514. [PMID: 29761484 PMCID: PMC6099473 DOI: 10.1111/evo.13496] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 04/06/2018] [Accepted: 04/18/2018] [Indexed: 01/17/2023]
Abstract
Inbreeding depression plays a major role in shaping mating systems: in particular, inbreeding avoidance is often proposed as a mechanism explaining extra-pair reproduction in socially monogamous species. This suggestion relies on assumptions that are rarely comprehensively tested: that inbreeding depression is present, that higher kinship between social partners increases infidelity, and that infidelity reduces the frequency of inbreeding. Here, we test these assumptions using 26 years of data for a cooperatively breeding, socially monogamous bird with high female infidelity, the superb fairy-wren (Malurus cyaneus). Although inbred individuals were rare (∼6% of offspring), we found evidence of inbreeding depression in nestling mass (but not in fledgling survival). Mother-son social pairings resulted in 100% infidelity, but kinship between a social pair did not otherwise predict female infidelity. Nevertheless, extra-pair offspring were less likely to be inbred than within-pair offspring. Finally, the social environment (the number of helpers in a group) did not affect offspring inbreeding coefficients or inbreeding depression levels. In conclusion, despite some agreement with the assumptions that are necessary for inbreeding avoidance to drive infidelity, the apparent scarcity of inbreeding events and the observed levels of inbreeding depression seem insufficient to explain the ubiquitous infidelity in this system, beyond the mother-son mating avoidance.
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Affiliation(s)
- Gabriela K. Hajduk
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Andrew Cockburn
- Division of Evolution and Ecology, Research School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Nicolas Margraf
- Division of Evolution and Ecology, Research School of BiologyThe Australian National UniversityCanberraACTAustralia
- Current Address: Nicolas Margraf, Musée d'histoire naturelle de La Chaux‐de‐FondsAv. Léopold‐Robert 63CH‐2300La Chaux‐de‐FondsSwitzerland
| | - Helen L. Osmond
- Division of Evolution and Ecology, Research School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Craig A. Walling
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Loeske E. B. Kruuk
- Division of Evolution and Ecology, Research School of BiologyThe Australian National UniversityCanberraACTAustralia
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15
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Sakaluk SK, Thompson CF, Bowers EK. Experimental manipulation of incubation period reveals no apparent costs of incubation in house wrens. Anim Behav 2018; 137:167-177. [PMID: 30026615 DOI: 10.1016/j.anbehav.2018.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Fitness costs of incubation ensue whenever the trade-off between incubation and foraging leads to suboptimal incubation or decreased parental body condition. We examined the costs of incubation in a wild population of house wrens, Troglodytes aedon, by experimentally extending or decreasing the incubation period by cross-fostering eggs between nests at different stages of incubation (eggs from control nests were cross-fostered at the same stage of incubation). We determined whether parents or offspring bear the costs of incubation by measuring effects on females and offspring within the same breeding season during which the manipulation occurred, but also by evaluating potential trade-offs between current and future reproduction by monitoring return rates of experimental females and recruitment rates of offspring in subsequent breeding seasons. There was no difference in hatching or fledging success across treatments. There was also no effect of incubation duration on female size-corrected mass, and females from different treatments were equally likely to produce a second brood. Nestlings produced by females did not differ in body mass, tarsus length or residual mass. Neither return rates of females, nor the number of offspring recruited, differed across treatments. We conclude, therefore, that although prolonged incubation entails increased energy expenditures, females are able to offset these losses while foraging, thereby mitigating the costs of incubation. This resiliency is more likely to be seen in income breeders, such as house wrens, that retain some ability to recoup energy expended in incubation, than in capital breeders that are constrained by stored energy reserves.
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Affiliation(s)
- Scott K Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, U.S.A
| | - Charles F Thompson
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, U.S.A
| | - E Keith Bowers
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, U.S.A.,Department of Biological Sciences and Edward J. Meeman Biological Station, University of Memphis, Memphis, TN, U.S.A
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Duthie AB, Bocedi G, Reid JM. When does female multiple mating evolve to adjust inbreeding? Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait. Evolution 2016; 70:1927-43. [PMID: 27464756 PMCID: PMC5053304 DOI: 10.1111/evo.13005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/06/2016] [Indexed: 12/18/2022]
Abstract
Polyandry is often hypothesized to evolve to allow females to adjust the degree to which they inbreed. Multiple factors might affect such evolution, including inbreeding depression, direct costs, constraints on male availability, and the nature of polyandry as a threshold trait. Complex models are required to evaluate when evolution of polyandry to adjust inbreeding is predicted to arise. We used a genetically explicit individual‐based model to track the joint evolution of inbreeding strategy and polyandry defined as a polygenic threshold trait. Evolution of polyandry to avoid inbreeding only occurred given strong inbreeding depression, low direct costs, and severe restrictions on initial versus additional male availability. Evolution of polyandry to prefer inbreeding only occurred given zero inbreeding depression and direct costs, and given similarly severe restrictions on male availability. However, due to its threshold nature, phenotypic polyandry was frequently expressed even when strongly selected against and hence maladaptive. Further, the degree to which females adjusted inbreeding through polyandry was typically very small, and often reflected constraints on male availability rather than adaptive reproductive strategy. Evolution of polyandry solely to adjust inbreeding might consequently be highly restricted in nature, and such evolution cannot necessarily be directly inferred from observed magnitudes of inbreeding adjustment.
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Affiliation(s)
- A Bradley Duthie
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, Tillydrone Avenue, University of Aberdeen, Aberdeen, AB24 2TZ, United Kingdom.
| | - Greta Bocedi
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, Tillydrone Avenue, University of Aberdeen, Aberdeen, AB24 2TZ, United Kingdom
| | - Jane M Reid
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, Tillydrone Avenue, University of Aberdeen, Aberdeen, AB24 2TZ, United Kingdom
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Reid JM, Bocedi G, Nietlisbach P, Duthie AB, Wolak ME, Gow EA, Arcese P. Variation in parent-offspring kinship in socially monogamous systems with extra-pair reproduction and inbreeding. Evolution 2016; 70:1512-29. [PMID: 27174154 PMCID: PMC4949684 DOI: 10.1111/evo.12953] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/19/2016] [Accepted: 05/04/2016] [Indexed: 01/18/2023]
Abstract
Female extra‐pair reproduction in socially monogamous systems is predicted to cause cuckolded socially‐paired males to conditionally reduce paternal care, causing selection against extra‐pair reproduction and underlying polyandry. However, existing models and empirical studies have not explicitly considered that cuckolded males might be related to their socially‐paired female and/or to her extra‐pair mate, and therefore be related to extra‐pair offspring that they did not sire but could rear. Selection against paternal care, and hence against extra‐pair reproduction, might then be weakened. We derive metrics that quantify allele‐sharing between within‐pair and extra‐pair offspring and their mother and her socially‐paired male in terms of coefficients of kinship and inbreeding. We use song sparrow (Melospiza melodia) paternity and pedigree data to quantify these metrics, and thereby quantify the joint effects of extra‐pair reproduction and inbreeding on a brood's total allelic value to its socially‐paired parents. Cuckolded male song sparrows were almost always detectably related to extra‐pair offspring they reared. Consequently, although brood allelic value decreased substantially following female extra‐pair reproduction, this decrease was reduced by within‐pair and extra‐pair reproduction among relatives. Such complex variation in kinship within nuclear families should be incorporated into models considering coevolutionary dynamics of extra‐pair reproduction, parental care, and inbreeding.
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Affiliation(s)
- Jane M Reid
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland.
| | - Greta Bocedi
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland
| | - Pirmin Nietlisbach
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - A Bradley Duthie
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland
| | - Matthew E Wolak
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland
| | - Elizabeth A Gow
- Department of Forest and Conservation Sciences, 2424 Main Mall, University of British Columbia, Vancouver BC, Canada, V6T 1Z4
| | - Peter Arcese
- Department of Forest and Conservation Sciences, 2424 Main Mall, University of British Columbia, Vancouver BC, Canada, V6T 1Z4
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Wolak ME, Reid JM. Is Pairing with a Relative Heritable? Estimating Female and Male Genetic Contributions to the Degree of Biparental Inbreeding in Song Sparrows (Melospiza melodia). Am Nat 2016; 187:736-52. [DOI: 10.1086/686198] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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