Ecology and evolution of social impact and responsiveness in a wild sparrow population

• Applicant: Professor Dr. Niels Dingemanse
• Subject Area: Sensory and Behavioural Biology ; Evolution, Anthropology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455748869

Social interactions characterize all wild populations and affect evolution whenever heritable traits are plastic in response to heritable traits of conspecifics. The evolution of “social responsiveness” to and “social impact” on other’s phenotypes has attracted theoretical attention, but progress requires addressing key outstanding questions: Do wild populations contain individual variation in degrees of social impact and responsiveness? Does selection act on this variation, and which processes maintain it? These key challenges will be addressed in a research programme to understand social evolution. My overarching aim is to combine the strengths of cutting-edge behavioural ecology and quantitative genetics theory to uniquely study the interplay between social interactions and social selection in the wild. I will focus on social foraging strategies in house sparrows on Norwegian islands that use either private information and actively find food (“producers”) or social information to exploit food patches found by others (“scroungers”). Game theory predicts and empirical studies on this and other species have shown socially responsive shifts towards scrounging when others produce, and vice versa. Using innovative high-throughput behavioural screening of entire populations, I will assay >600 birds for their producer-scrounger social impact and responsiveness in >4,000 assays and determine genomic relatedness, survival, and reproductive fitness for all individuals. Key objectives are: (WP1) To establish whether individuals are repeatable in (i) average level of producing-scrounging (“personality”), (ii) level of adjustment in producing-scrounging to phenotypes expressed by partners (“social responsiveness”) and (iii) producing-scrounging elicited in partners (“social impact”). I will quantify covariances between these ‘traits’, describe (social) environmental sources of variation within and among individuals, and test for covariances with various key behavioural (aggression, exploratory tendency) and morphology traits (body size and shape) predicted by adaptive theory. (WP2) To quantify how natural selection acts on producing-scrounging reaction norms and study whether selection pressures covary with key socioecological conditions; and thus determine the pathways (components of fitness) by which selection acts on this variation in the social phenotype in this well-studied system. This will make it possible to start exploring the potential evolutionary consequences of selection on social impact and responsiveness in the wild, thereby providing crucial new insights into the evolution of social behaviour and the role of social interactions in ecological and evolutionary processes.

• DFG Programme: Research Grants