Final Report Summary - SOCECOL (Evolutionary Social Ecology in Wild Populations)
Almost all animals are social at some stage in their lives, but a striking aspect of social behaviour is that it varies across individuals. We have little understanding of the origins of this variation, and what consequences it has for the operation of other processes in populations. The main aims of this study were to develop a novel and large-scale method for quantifying social behaviour in wild populations and to use this to understand causes and broader consequences of social behaviour. We achieved this by developing an automated logging system than enabled us to track, and quantify social behaviour, for thousands of wild birds simultaneously. Using this approach, we developed analytical methods that allowed us to construct social networks, that provide an objective means to understand an individual's relationship to other individuals, but also to place that individual in a the context of all other individuals in the population. We applied these approaches to construct multi-species social networks for >7500 birds of 5 species, over four consecutive winters, and used ecological data, and measurements of survival and reproductive success to interpret these social networks. Our analyses reveal that many aspects of social network structure vary in important ways, of which the main findings are that: (i) In non-manipulated data, individuals are strikingly consistent in social behaviour over both short and long-term time scales, even to the extent that behaviour is consistent across years. (ii) this individual variation is simultaneously influenced by large-scale and local-scale ecological processes. We demonstrated experimentally that short-term perturbations in the environment (e.g. momentary simulated predator attacks) can have long-term social consequences. (iii) Using data on genetic relationships among individuals we have shown the components of variation in social behaviour have a genetic origin, but that the genetic variation for this trait is complex, since part of the social behaviour of a focal individual can be shown to result from genetic variation in those individuals that it interacts with. This form of 'indirect' genetic effect is of particular interest because it can lead to unexpected evolutionary effects. (iv) We showed that individual behavioural variation ('personality') underlies many aspects of social network structure. Using a range of experiments, we have tested the importance of social networks. Two key areas of our findings are (i) demonstrating that interactions between species are important for the ecology of the constituent species and (ii) the development of novel understanding about how information can spread between individuals in wild populations, and how it may become established and stable across generations.