This project is one of a number that are in competition for funding from the NERC Great Western Four+ Doctoral Training Partnership (GW4+ DTP). The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus five Research Organisation partners: British Antarctic Survey, British Geological Survey, Centre for Ecology and Hydrology, the Natural History Museum and Plymouth Marine Laboratory. The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme please see http://nercgw4plus.ac.uk/
Location: University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE
Dr Andrew Young Department of Biosciences, College of Life and Environmental Sciences, University of Exeter.
Professor Alastair Wilson Department of Biosciences, College of Life and Environmental Sciences, University of Exeter.
Professor Duncan Baird School of Medicine, University of Cardiff
In many cooperative societies offspring initially delay dispersal from their natal group, and forego reproduction while helping to rear future generations of their parents’ young. While it is often assumed that individuals simply help (principally to accrue indirect fitness) while waiting to seize a breeding position of their own (to accrue direct fitness), strong trade-offs may exist between the two, leading to the evolution of alternative life-history trajectories. For example, poor quality individuals may have little chance of seizing hotly contested breeding vacancies, and so may invest heavily in helping as their primary route to fitness. Similarly, high quality individuals may help little, given the potential for investments in helping to trade-off against their successful seizure of a breeding vacancy. Despite considerable interest in the causes of individual variation in helper contributions, few studies of vertebrate societies have considered the possibility of such alternative life-history trajectories, in which individuals are arrayed along a social continuum from generous helpers with poor prospects to would-be breeders who contribute little. This project will test the alternative life-history trajectories hypothesis using long-term life-history, behavioural and genetic data from our field study of cooperatively breeding white-browed sparrow weaver societies in the Kalahari desert.
Project Aims and Methods
The project will combine cutting-edge field and laboratory methods to test the alternative life-history trajectories hypothesis, and to establish the extent to which individual variation in trajectories arises from plasticity versus genetic differences among individuals, by addressing three main aims.
1. Test whether an individual’s future breeding prospects predict their helper contributions, and whether the relationship is negative (as predicted by the alternative life-history trajectories hypothesis) or positive (e.g. if high quality individuals are more likely to both help and become a breeder).
2. Investigate the early-life predictors of an individual’s prospects of becoming a breeder (i.e. predictors of their future competitive ability or environment), and whether there is evidence of plastic changes in helping behaviour according to these cues.
3. Use quantitative genetic modelling to investigate whether there is heritable genetic variation among individuals in their helper contributions, and whether this reflects genetic variation in their position on the hypothesised life-history continuum.