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García‐Campa J, Müller W, Morales J. Offspring plumage coloration as a condition-dependent signal in the blue tit. Ecol Evol 2023; 13:e9787. [PMID: 36744078 PMCID: PMC9889846 DOI: 10.1002/ece3.9787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 02/04/2023] Open
Abstract
In many species, offspring display conspicuous coloration already early in life, even though they might be very vulnerable to predation at this stage. However, most attention has been drawn to the conspicuous plumage displayed by adult individuals in a sexual context, while other signaling functions have been explored much less. Here, we investigated whether the yellow breast plumage of blue tit (Cyanistes caeruleus) nestlings shows patterns of condition dependence and hence signals individual quality, as has been described for adult birds. During three consecutive breeding seasons, we, therefore, explored the association between nestling body mass and three color components of the yellow breast plumage (i.e., UV chroma, carotenoid chroma, and total brightness), considering both within and among nest effects. Variation in carotenoid chroma was not related to body mass. However, UV chroma and total brightness varied with body mass on an among-nest level, suggesting that they might signal aspects of genetic quality or parental rearing capacity. Interestingly, we also found a within-nest effect of body mass on total brightness, suggesting that this is a good candidate for a condition-dependent signal within the family. Thus, other family members could rely on brightness to adjust their behavioral strategies, such as feeding behavior in parents. Our study thus reveals that certain color components of the yellow breast plumage might signal different aspects of offspring quality, and they might have a correlated signaling value across life-history stages.
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Affiliation(s)
- Jorge García‐Campa
- Department of Evolutionary EcologyNational Museum of Natural Sciences – Spanish National Research Council (CSIC)MadridSpain
| | - Wendt Müller
- Department of Biology, Behavioural Ecology and Ecophysiology GroupUniversity of AntwerpAntwerpBelgium
| | - Judith Morales
- Department of Evolutionary EcologyNational Museum of Natural Sciences – Spanish National Research Council (CSIC)MadridSpain
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2
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Lopez-Idiaquez D, Teplitsky C, Grégoire A, Fargevieille A, Rey MD, Franceschi CD, Charmantier A, Doutrelant C. Long-term decrease in coloration: a consequence of climate change? Am Nat 2022; 200:32-47. [DOI: 10.1086/719655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Soler JJ, Martínez-Renau E, Azcárate-García M, Ruiz-Castellano C, Martín J, Martín-Vivaldi M. OUP accepted manuscript. Behav Ecol 2022; 33:494-503. [PMID: 35592878 PMCID: PMC9113258 DOI: 10.1093/beheco/arac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 01/14/2022] [Accepted: 02/25/2022] [Indexed: 11/25/2022] Open
Abstract
Animal coloration results from pigments, nanostructures, or the cosmetic use of natural products, and plays a central role in social communication. The role of cosmetic coloration has traditionally been focused in scenarios of sexual selection, but it could also take place in other contexts. Here, by using spotless starlings (Sturnus unicolor) as a model system, we explore the possibility that nestlings cosmetically use their intensely yellow-colored uropygial secretion to signal their genetic and/or phenotypic quality. In agreement with the hypothetical cosmetic use of the uropygial secretion, (i) video recorded nestlings collected secretion with the bill at the age of feathering, (ii) cotton swabs turned to the color of secretion after rubbing with them nestlings’ gape, and (iii) gape and skin colorations correlated positively with that of secretion. Furthermore, we found that (iv) secretion coloration has a genetic component, and (v) associated positively with Vitamin E supplementation and (vi) with plasma carotenoid concentration, which highlights the informative value of nestling secretion. Finally, (vii) coloration of begging-related traits and of secretion of nestlings predicted parental feeding preferences. Consequently, all these results strongly suggest that the cosmetic use of colored uropygial secretion might also play a role in parent-offspring communication, complementing or amplifying information provided by the flamboyant colored gapes and skin of nestlings. The use of makeups by offspring for communication with relatives has been scarcely explored and we hope that these results will encourage further investigations in birds and other taxa with parental care.
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Affiliation(s)
- Juan José Soler
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain
- Unidad asociada (CSIC): Coevolución: cucos, hospedadores y bacterias simbiontes, Universidad de Granada, 18071-Granada, Spain
- Address correspondence to Juan José Soler. E-mail:
| | - Ester Martínez-Renau
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain
| | - Manuel Azcárate-García
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain
| | - Cristina Ruiz-Castellano
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain
| | - José Martín
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), 28006-Madrid, Spain
| | - Manuel Martín-Vivaldi
- Unidad asociada (CSIC): Coevolución: cucos, hospedadores y bacterias simbiontes, Universidad de Granada, 18071-Granada, Spain
- Departamento de Zoología, Universidad de Granada, 18071-Granada, Spain
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4
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Fan M, Hall ML, Roast M, Peters A, Delhey K. Variability, heritability and condition-dependence of the multidimensional male colour phenotype in a passerine bird. Heredity (Edinb) 2021; 127:300-311. [PMID: 34188194 PMCID: PMC8405751 DOI: 10.1038/s41437-021-00453-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Elaborate ornamental traits are commonly assumed to be honest signals of individual quality, owing to the presumed costs involved in their production and/or maintenance. Such traits are often highly variable, possibly because of condition-dependence and/or high underlying genetic variation, and it has been suggested that their expression should be more sensitive to condition and/or more heritable than non-ornamental traits. Many bird species display colourful plumage with multiple distinct patches of different developmental origins, forming complex colour phenotypes. Despite this complexity, colourful ornaments are often studied in isolation, without comparison to suitable non-ornamental controls. Based on plumage reflectance data collected over 8 years, we assessed the signalling potential of the multidimensional male colour phenotype in a tropical bird: the purple-crowned fairy-wren Malurus coronatus. Specifically, we tested the predictions that the expression of putative ornamental colours (purple and black - the breeding colours - and blue) is (1) more variable, (2) more heritable and (3) more condition-dependent compared to year-round non-ornamental colours (buff-white and brown). Our results show that ornamental colours exhibit greater levels of variability, and some chromatic components of purple and blue colouration appear slightly heritable (h² = 0.19-0.30). However, contrary to predictions of heightened condition-dependence in ornaments, only brightness of the buff-white and brown colouration increased with male body condition, although brightness of the purple colouration was related to male age as expected. Despite partial support for predictions, the lack of consistent patterns illustrates the complexity of visual signals and highlights the need to study colour phenotypes in their entirety.
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Affiliation(s)
- Marie Fan
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - Michelle L Hall
- School of BioSciences, University of Melbourne, Melbourne, Parkville, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Michael Roast
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Max Planck Institute for Ornithology, Radolfzell, Germany.,Max Planck Institute for Ornithology, Seewiesen, Germany
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5
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Martínez‐Renau E, Ruiz‐Castellano C, Azcárate‐García M, Barón MD, Soler JJ. Coloration of spotless starling nestlings shows genetic and environmentally determined characteristics while begging for food. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ester Martínez‐Renau
- Departamento de Ecología Funcional y Evolutiva Estación Experimental de Zonas Áridas (CSIC) Almería Spain
| | - Cristina Ruiz‐Castellano
- Departamento de Ecología Funcional y Evolutiva Estación Experimental de Zonas Áridas (CSIC) Almería Spain
| | - Manuel Azcárate‐García
- Departamento de Ecología Funcional y Evolutiva Estación Experimental de Zonas Áridas (CSIC) Almería Spain
| | | | - Juan José Soler
- Departamento de Ecología Funcional y Evolutiva Estación Experimental de Zonas Áridas (CSIC) Almería Spain
- Unidad Asociada (CSIC): Coevolución: Cucos, Hospedadores y Bacterias Simbiontes Universidad de Granada Granada Spain
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6
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Pélabon C, Hilde CH, Einum S, Gamelon M. On the use of the coefficient of variation to quantify and compare trait variation. Evol Lett 2020; 4:180-188. [PMID: 32547779 PMCID: PMC7293077 DOI: 10.1002/evl3.171] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/06/2020] [Accepted: 03/31/2020] [Indexed: 11/29/2022] Open
Abstract
Meaningful comparison of variation in quantitative trait requires controlling for both the dimension of the varying entity and the dimension of the factor generating variation. Although the coefficient of variation (CV; standard deviation divided by the mean) is often used to measure and compare variation of quantitative traits, it only accounts for the dimension of the former, and its use for comparing variation may sometimes be inappropriate. Here, we discuss the use of the CV to compare measures of evolvability and phenotypic plasticity, two variational properties of quantitative traits. Using a dimensional analysis, we show that contrary to evolvability, phenotypic plasticity cannot be meaningfully compared across traits and environments by mean‐scaling trait variation. We further emphasize the need of remaining cognizant of the dimensions of the traits and the relationship between mean and standard deviation when comparing CVs, even when the scales on which traits are expressed allow meaningful calculation of the CV.
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Affiliation(s)
- Christophe Pélabon
- Centre for Biodiversity Dynamics, Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
| | - Christoffer H Hilde
- Centre for Biodiversity Dynamics, Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
| | - Marlène Gamelon
- Centre for Biodiversity Dynamics, Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
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7
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Class B, Kluen E, Brommer JE. Tail colour signals performance in blue tit nestlings. J Evol Biol 2019; 32:913-920. [PMID: 31127961 DOI: 10.1111/jeb.13489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022]
Abstract
Indirect sexual selection arises when reproductive individuals choose their mates based on heritable ornaments that are genetically correlated to fitness. Evidence for genetic associations between ornamental colouration and fitness remains scarce. In this study, we investigate the quantitative genetic relationship between different aspects of tail structural colouration (brightness, hue and UV chroma) and performance (cell-mediated immunity, body mass and wing length) in blue tit (Cyanistes caeruleus) nestlings. In line with previous studies, we find low heritability for structural colouration and moderate heritability for performance measures. Multivariate animal models show positive genetic correlations between the three measures of performance, indicating quantitative genetic variation for overall performance, and tail brightness and UV chroma, two genetically independent colour measures, are genetically correlated with performance (positively and negatively, respectively). Our results suggest that mate choice based on independent aspects of tail colouration can have fitness payoffs in blue tits and provide support for the indirect benefits hypothesis. However, low heritability of tail structural colouration implies that indirect sexual selection on mate choice for this ornament will be a weak evolutionary force.
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Affiliation(s)
- Barbara Class
- Department of Biology, University of Turku, Turku, Finland
| | - Edward Kluen
- HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Research Program in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jon E Brommer
- Department of Biology, University of Turku, Turku, Finland
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8
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Muff S, Niskanen AK, Saatoglu D, Keller LF, Jensen H. Animal models with group-specific additive genetic variances: extending genetic group models. Genet Sel Evol 2019; 51:7. [PMID: 30819110 PMCID: PMC6394059 DOI: 10.1186/s12711-019-0449-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 02/07/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The animal model is a key tool in quantitative genetics and has been used extensively to estimate fundamental parameters, such as additive genetic variance or heritability. An implicit assumption of animal models is that all founder individuals derive from a single population. This assumption is commonly violated, for instance in crossbred livestock or when a meta-population is split into genetically differentiated subpopulations. Ignoring that base populations are genetically heterogeneous and thus split into different 'genetic groups' may lead to biased parameter estimates, especially for additive genetic variance. To avoid such biases, genetic group animal models, which account for the presence of more than one genetic group, have been proposed. Unfortunately, the method to date is only computationally feasible when the breeding values of the groups are allowed to differ in their means, but not in their variances. RESULTS We present an extension of the animal model that permits estimation of group-specific additive genetic variances. This is achieved by employing group-specific relatedness matrices for the breeding value components to different genetic groups. We derive these matrices by decomposing the full relatedness matrix via the generalized Cholesky decomposition, and by scaling the respective matrix components for each group. We propose a computationally convenient approximation for the matrix component that encodes for the Mendelian sampling variance, and show that this approximation is not critical. In addition, we explain why segregation variances are often negligible when analyzing the complex polygenic traits that are frequently the focus of evolutionary ecologists and animal breeders. Simulations and an example from an insular meta-population of house sparrows in Norway with three distinct genetic groups illustrate that the method is successful in estimating group-specific additive genetic variances, and that segregation variances are indeed negligible in the empirical example. CONCLUSIONS Quantifying differences in additive genetic variance within and among populations is of major biological interest in ecology, evolution, and animal and plant breeding. The proposed method allows to estimate such differences for subpopulations that form a connected set of populations, and may thus also be useful to study temporal or spatial variation of additive genetic variances.
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Affiliation(s)
- Stefanie Muff
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland. .,Department of Biostatistics, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, Switzerland.
| | - Alina K Niskanen
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Høgskoleringen 5, Trondheim, Norway.,Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, Oulu, Finland
| | - Dilan Saatoglu
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Høgskoleringen 5, Trondheim, Norway
| | - Lukas F Keller
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland.,Zoological Museum, University of Zurich, Karl-Schmid-Strasse 4, Zurich, Switzerland
| | - Henrik Jensen
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Høgskoleringen 5, Trondheim, Norway
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9
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Gruson H, Andraud C, Daney de Marcillac W, Berthier S, Elias M, Gomez D. Quantitative characterization of iridescent colours in biological studies: a novel method using optical theory. Interface Focus 2018; 9:20180049. [PMID: 30603069 DOI: 10.1098/rsfs.2018.0049] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2018] [Indexed: 11/12/2022] Open
Abstract
Iridescent colours are colours that change with viewing or illumination geometry. While they are widespread in many living organisms, most evolutionary studies on iridescence do not take into account their full complexity. Few studies try to precisely characterize what makes iridescent colours special: their angular dependency. Yet, it is likely that this angular dependency has biological functions and is therefore submitted to evolutionary pressures. For this reason, evolutionary biologists need a repeatable method to measure iridescent colours as well as variables to precisely quantify the angular dependency. In this study, we use a theoretical approach to propose five variables that allow one to fully describe iridescent colours at every angle combination. Based on the results, we propose a new measurement protocol and statistical method to reliably characterize iridescence while minimizing the required number of time-consuming measurements. We use hummingbird iridescent feathers and butterfly iridescent wings as test cases to demonstrate the strengths of this new method. We show that our method is precise enough to be potentially used at intraspecific level while being also time-efficient enough to encompass large taxonomic scales.
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Affiliation(s)
- Hugo Gruson
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Christine Andraud
- CRC, MNHN, Ministère de la Culture et de la Communication, CNRS, Paris, France
| | | | | | - Marianne Elias
- ISYEB, CNRS, MNHN, EPHE, Sorbonne Université, Paris, France
| | - Doris Gomez
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France.,INSP, Sorbonne Université, CNRS, Paris, France
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10
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Yong L, Lee B, McKinnon JS. Variation in female aggression in 2 three-spined stickleback populations with female throat and spine coloration. Curr Zool 2018; 64:345-350. [PMID: 30402077 PMCID: PMC6007237 DOI: 10.1093/cz/zoy020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/02/2018] [Indexed: 11/13/2022] Open
Abstract
Despite growing interest in female ornament evolution, we still have a rudimentary understanding of female display traits relative to similar traits in males. Under one popular adaptive scenario, female ornaments are hypothesized to function in female–female competition and serve as badges of status, such that their expression is linked with elevated aggression in some cases. In this study, we investigated the relationship between 2 female ornaments—male-like red throat color and red spine coloration—and female aggression in 2 independently derived stream-resident populations of three-spined stickleback Gasterosteus aculeatus. Using simulated intrusions, we tested whether females with redder ornaments were generally more aggressive, and for variation in aggressive and social behaviors between the 2 populations. We found that the red intensity of the throat and spine did not predict aggression levels in either population, suggesting a limited role for both female ornaments during female–female interaction. The 2 populations exhibited different levels of aggressive behaviors, unrelated to the color patches. Our results suggest that variation in selective pressures between populations may promote interpopulation variance in aggressive behavior but not the correlation between female ornamentation and aggression, and raise the possibility that red coloration may have evolved through different mechanisms or processes in the 2 populations.
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Affiliation(s)
- Lengxob Yong
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Brittney Lee
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Jeffrey S McKinnon
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
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11
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Fargevieille A, Grégoire A, Charmantier A, Del Rey Granado M, Doutrelant C. Assortative mating by colored ornaments in blue tits: space and time matter. Ecol Evol 2017; 7:2069-2078. [PMID: 28405273 PMCID: PMC5383486 DOI: 10.1002/ece3.2822] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/06/2017] [Accepted: 01/28/2017] [Indexed: 01/16/2023] Open
Abstract
Assortative mating is a potential outcome of sexual selection, and estimating its level is important to better understand local adaptation and underlying trait evolution. However, assortative mating studies frequently base their conclusions on small numbers of individuals sampled over short periods of time and limited spatial scales even though spatiotemporal variation is common. Here, we characterized assortative mating patterns over 10 years in four populations of the blue tit (Cyanistes caeruleus), a passerine bird. We focused on two plumage ornaments-the blue crown and the yellow breast patch. Based on data for 1,657 pairs of birds, we found large interannual variation: assortative mating varied from positive to negative. To determine whether there was nonetheless a general trend in the data, we ran a within-study meta-analysis. It revealed that assortative mating was moderately positive for both ornaments. It also showed that mating patterns differed among populations and especially between two neighboring populations that displayed phenotypic divergence. Our results therefore underscore that long-term studies are needed to draw broad conclusions about mating patterns in natural populations. They also call for studying the potential role of assortative mating in local adaptation and evolution of ornaments in both sexes.
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Affiliation(s)
| | - Arnaud Grégoire
- CEFE UMR5175 CNRS - Université de Montpellier Montpellier France
| | - Anne Charmantier
- CEFE UMR5175 CNRS - Université de Montpellier Montpellier France
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12
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Wolak ME, Reid JM. Accounting for genetic differences among unknown parents in microevolutionary studies: how to include genetic groups in quantitative genetic animal models. J Anim Ecol 2017; 86:7-20. [PMID: 27731502 PMCID: PMC5217070 DOI: 10.1111/1365-2656.12597] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 09/23/2016] [Indexed: 11/30/2022]
Abstract
Quantifying and predicting microevolutionary responses to environmental change requires unbiased estimation of quantitative genetic parameters in wild populations. 'Animal models', which utilize pedigree data to separate genetic and environmental effects on phenotypes, provide powerful means to estimate key parameters and have revolutionized quantitative genetic analyses of wild populations. However, pedigrees collected in wild populations commonly contain many individuals with unknown parents. When unknown parents are non-randomly associated with genetic values for focal traits, animal model parameter estimates can be severely biased. Yet, such bias has not previously been highlighted and statistical methods designed to minimize such biases have not been implemented in evolutionary ecology. We first illustrate how the occurrence of non-random unknown parents in population pedigrees can substantially bias animal model predictions of breeding values and estimates of additive genetic variance, and create spurious temporal trends in predicted breeding values in the absence of local selection. We then introduce 'genetic group' methods, which were developed in agricultural science, and explain how these methods can minimize bias in quantitative genetic parameter estimates stemming from genetic heterogeneity among individuals with unknown parents. We summarize the conceptual foundations of genetic group animal models and provide extensive, step-by-step tutorials that demonstrate how to fit such models in a variety of software programs. Furthermore, we provide new functions in r that extend current software capabilities and provide a standardized approach across software programs to implement genetic group methods. Beyond simply alleviating bias, genetic group animal models can directly estimate new parameters pertaining to key biological processes. We discuss one such example, where genetic group methods potentially allow the microevolutionary consequences of local selection to be distinguished from effects of immigration and resulting gene flow. We highlight some remaining limitations of genetic group models and discuss opportunities for further development and application in evolutionary ecology. We suggest that genetic group methods should no longer be overlooked by evolutionary ecologists, but should become standard components of the toolkit for animal model analyses of wild population data sets.
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Affiliation(s)
- Matthew E. Wolak
- Institute of Biological and Environmental SciencesSchool of Biological SciencesUniversity of Aberdeen, Zoology Building, Tillydrone AvenueAberdeen AB24 2TZUK
| | - Jane M. Reid
- Institute of Biological and Environmental SciencesSchool of Biological SciencesUniversity of Aberdeen, Zoology Building, Tillydrone AvenueAberdeen AB24 2TZUK
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