Evolutionary ecology of phenotypic plasticity of morphological, life history and behavioural traits

Principal researcher: Laszlo Garamszegi

Period: 2015-2018

The main interest in evolutionary ecology lies on the variation in phenotypic traits, its link with fitness variation and how these are transferred across generations. This individual variation is not fixed in natural populations but flexibly changes across space and time depending on the prevailing environmental conditions. In factsome traits exhibit consistent variation among individuals, and still remain substantially variable at an individual level. Within an evolutionary point of view, such a dichotomy has been conceptually established by the joined action of selection and heritability of traits (microevolution) or by plastic expression according to the changing environmental circumstances (phenotypic plasticity). However, there is conceptual room to consider trait phenotypic plasticity per se an individual-specific characteristic linked to fitness, and thus susceptible to be selected upon. Such an evolutionary mechanism is yet to be quantified. To understand the evolution and ecology of most phenotypic traits in light of the changing environment, it is now becoming crucial to decompose different variance components and relate these to genetics, physiology and fitness, and also to study how fluctuations in the socio-ecological circumstances shape within- and between-individual (co-)variances. Such tasks are notoriously hard to accomplish in wild animal populations, because they typically necessitate the repetitive sampling of the same individuals under standardized conditions over long periods of time or across large geographic distances. In the current proposal, we aim to accomplish this challenging mission by taking advantage from the long-term studies (over 30 years) of wild populations of two closely related passerine species, the collared and pied flycatchers (Ficedula albicollis and F. hypoleuca) breeding in central and southern Europe, respectively. Using our long-term records in combination with targeted within-individual sampling at a shorter time scale, we will characterize different variance components for different types of traits (morphology, life history and behaviour). Exploiting the temporal and spatial resolution of our study, we will be able to investigate how predictable and unpredictable changes in various socio-ecological contexts (e.g. climate, food supply, predation pressure, demographic patterns, levels of competition) can have microevolutionary consequences for between-year, and between- and within-individual variances as well as for phenotypic plasticity. We will apply a rigorous framework based on quantitative genetics and individual-based models to determine which variance components are attributable to genetic and environmental effects, while we will also establish the evolutionary potential for phenotypic plasticity by exploring the proximate and ultimate mechanisms that can mediate the within-individual variance of different traits. The expected results will have major implications on how we understand ecological and evolutionary processes of adaptation, and how the consistency and plasticity of different phenotypic traits play roles in such processes. Ultimately, our findings will be fundamental for our comprehension of the origin and maintenance of biodiversity both at geographical and temporal scales.