The evolutionary dynamics of laying date in the pied flycatcher Ficedula hypoleuca

Abstract

Current global warming is unequivocally impacting biodiversity at an unprecedent rates. Such negative impact can be quantified on species distribution and diversity, but understanding biodiversity loss can only be fully achieved by considering the capacity of populations to track prevailing environmental conditions. Thus, an evolutionary approach is inevitable to comprehend how populations of species adapt under a scenario of climate change. This PhD follows a research agenda to quantify the variation of the timing of breeding laying date and the relative role of environmental variation on phenotypic selection along the evolutionary mechanisms that may explain local adaptation. Taking advantage of a long-term monitored population of pied flycatchers Ficedula hypoleuca, I detected a lack of temporal trend of laying date over 29 years despite highly variable environmental conditions during the same time period. A lack of repeatability of the date of breeding, suggesting a high variability among individuals in laying date and explaining variance of laying date. The intensity of phenotypic selection on laying date was strongest when environmental conditions were poor, specifically when minimum temperatures in April were lowest and May were highest. Despite negative selection on laying date, there was no evolutionary response at genetic level, suggesting that non-genetic mechanism may explain local adaptation. Accordingly, we found individual-by-environment interactions explaining phenological variation that can be partially explained by genotype-by-environmental interaction. This PhD stresses first, the crucial role that multiple environmental factors may play on the evolutionary dynamics of life-history traits and, second, that evolutionary mechanisms that do not involve genetic changes, namely genotype-by- environmental interactions, may play a pivotal role on local adaptation.