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The evolution of phenotypic correlations among social traits in structured populations

English title The evolution of phenotypic correlations among social traits in structured populations
Applicant Lehmann Laurent
Number 166657
Funding scheme Project funding (Div. I-III)
Research institution Département d'Ecologie et d'Evolution Faculté de Biologie et de Médecine Université de Lausanne
Institution of higher education University of Lausanne - LA
Main discipline Genetics
Start/End 01.01.2017 - 31.12.2019
Approved amount 430'500.00
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All Disciplines (2)


Keywords (6)

Behavioural syndromes; Meta-populations; Genetic architecture; Kin selection; Social evolution; Quantitative genetics

Lay Summary (French)

Chez beaucoup d'espèces, notamment chez l'Homme, différents traits sociaux ont tendance à se retrouver ensemble dans différents individus. L'agressivité, par exemple, est souvent associée à l'audace. Comment ce type d'association émerge reste mal compris parce que les outils théoriques font l'hypothèse que les populations sont homogènes et que les individus interagissent aléatoirement. En réalité, les populations naturelles sont structurées dans l'espace, et les individus qui interagissent entre eux sont souvent apparentés. Parce que la sélection dépend de l'apparentement, la structure spatiale des espèces doit influencer la sélection sur l'association des traits sociaux.
Lay summary

Notre projet consiste à développer de nouveaux outils théoriques afin de comprendre comment les associations entre traits sociaux émergent et sont maintenues dans des populations structurées dans l'espace. Plus précisément, nous souhaitons identifier les rôles de plusieurs facteurs sur ces associations: (i) l'effet des associations sur le succès reproductif des individus; (il) le degré de structure spatiale; (iii) l'effet des mutations; et (iv), la façon dont les traits sont codés génétiquement.


Ce projet aidera à comprendre comment la sélection naturelle, la structure de la population, les mutations et les facteurs génétiques influencent les associations entre traits sociaux. Nos résultats offreront une perspective évolutionnaire sur la diversité des comportements sociaux observés dans la nature, et en particulier, chez l'Homme. 
Direct link to Lay Summary Last update: 03.11.2016

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
107364 Evolution of altruism and metapopulation demography 01.04.2005 Fellowships for prospective researchers


One of the fundamental goal of evolutionary biology is to explain patterns of phenotypic diversity, not only between but also within species. Among the most variable and striking phenotypes are social traits, i.e., traits that affect their carriers as well as other individuals like cooperative or aggressive behaviour. By repeatedly exposing animals to different social environments, a number of studies have shown that individuals are often consistent in their social behaviour, and that social traits not only vary among individuals, but also covary with each other within individuals. Furthermore, covariation among social traits is in many cases heritable, suggesting a genetic pre-disposition to composite social behaviour. These findings have generated considerable interest, but yet, the evolutionary causes behind patterns of covariation among social traits remain largely unexplored. Evolutionary models that seek to understand phenotypic correlations have so far focused on asocial traits in well-mixed populations. While these studies have brought valuable insights onto the forces that shape correlations, how these forces affect correlations among social traits, and how population structure, which is so important to evolution, influences traits' correlations is still unknown. In this project, we propose to study by means of mathematical modelling how correlations among social traits can be generated and maintained by evolution in spatially structured populations that can also be structured in classes, like sex or age. Three considerations will guide our research. First, selection can create phenotypic correlations by favouring combinations of traits over others, but selection critically depends on a population's demography and the environment. As a first step, we will therefore study when selection alone can generate phenotypic correlations in structured populations, and how demographic and environmental processes influence selection on correlations. Second, phenotypic correlations ultimately depend on a balance between the forces of selection and mutation. Mutations on genes that affect multiple traits introduce correlations within and between individuals, which in turn is expected to affect selection in structured populations. In a second step, we will therefore study how mutation and selection jointly mould phenotypic correlations in spatially-structured populations. Third, phenotypic correlations within and between individuals can also arise due to linkage among loci that code for different traits. But linkage can be strengthened or broken down due to selection on recombination. In our third and final step, we will study the conditions under which selection suppresses recombination among loci coding different facets of traits, and thereby create linkage groups that determine correlations among social traits in structured populations. Together, the models developed in this project will work towards providing a cohesive picture of the evolution of phenotypic correlations among social traits. This project will help better understand how selection, population structure, pleiotropic mutations, and recombination evolution affect correlations among social traits, and more generally, social behaviour. Overall, this project will provide a framework to understand the accumulating empirical evidence for correlational evolution among social traits.