Abstract
In animals, as in humans, not all individuals pair for life. Pair-bonds and their stability likely affect survival and reproduction and hence influence all major evolutionary and ecological processes. Yet, we are far from understanding why some pairs persist while others do not, and how this stability influences fitness. Such processes extend beyond the breeding season, but this has been almost exclusively neglected in previous studies. My aims are firstly, to unravel for the first time the link between pair-bond stability and survival. Secondly, I will test for multi-level factors (environmental, demographic, social, individual traits) that act during and between breeding seasons to influence divorce and its fitness consequences for females and males at different spatio-temporal scales –both across and within populations and years. I have a unique opportunity to combine the power (statistical, and among-population variability in ecological and social factors) of large datasets with new statistical approaches, animal tracking technologies, and my expertise in these topics. I will compile the largest world-wide, long-term database (>60 populations) on a wild species (the great tit). I will build on my adaptable multi-event capture-mark-recapture model, which can, based on captures of breeders: i) test among hypotheses on how winter/breeding environmental and demographic (population-level) factors influence annual divorce rates (Objective 1), ii) quantify the survival cost of divorce and test for the population-level factors that influence it for both sexes across their life-time (Objective 2). Finally, using data on winter sociality (3 populations with radio-tagged individuals) I will test iii) how fine-scale female and male social environments influence divorce and its costs (Objective 3). My results will bring a major advance to the study of pair-bond stability and the evolution of social monogamy by considering this bond as a continuous process, which acts outside of (and not only within) the breeding season.
Netherlands