Environmental effects on extra-pair mating in birds
PhD studentship based in Taiwan 2025-2029
About the Project:
Extra-pair mating occurs when an individual mates with one(s) outside of his or her pair bond. It is a prevalent behaviour in birds and has been reported in more than 75% of studied socially monogamous species. However, the causes and consequences of this common behaviour remain unclear.
In birds, extra-pair mating increases male reproductive success (Dunning et al., 2024), while females face trade-offs, like reduced paternal care from their social partners (Schroeder et al., 2016). Adaptive explanations suggest that females obtain indirect benefits such as good genes and genetic compatibility to offset the costs, but supportive evidence is limited (Hsu et al., 2014; Hsu et al., 2015).
Alternative hypotheses suggest that extra-pair mating could be initiated and/or sustained by context-dependent paternity benefits, where extra-pair offspring enjoy higher fitness under specific scenarios, or within- or between-sex correlation, such as positive selection on male extra-pair mating and female responsiveness to within-pair copulation. Our preliminary analyses with theoretical modelling highlight the context-dependent paternity effects (Yeh & Hsu, under review), shedding light on the evolution of extra-pair mating in birds. However, more empirical studies to evaluate these effects in wild populations are essential.
Research Objectives
This PhD project aims to understand how various environmental factors influence extra-pair mating. It will explore the biotic factors, including within-species effects and the interaction with other species (e.g. predation risk), as well as abiotic factors, such as bioclimatic effects. The long-term study dataset will provide this project with an ideal opportunity to explore various environmental effects and their interactions with extra-pair mating.
Methodology
Fieldwork will be taken on an offshore UK island where a wild population of house sparrows has been monitored for over twenty years. Activities will involve nest searching, banding, and social interaction observations. The PhD will analyse data using advanced statistical models to explore how environmental conditions impact mating behaviour.
Candidate Profile
This PhD project will be based at the Department of Life Sciences, National Cheng Kung University (NCKU), Taiwan. Applicants must be able to undertake fieldwork in the UK as part of a joint project. Applicants should review the minimum entry requirements for the NCKU 2025 Fall Admission. Ideal candidates are motivated, independent, and interested in evolution and field biology. Experience with fieldwork and statistical analysis is essential.
Funding
This PhD project will be funded by various sources. A successful candidate awarded the competitive Veritas et Conscientia Scholarship from NCKU for the first year will be guaranteed NT$360,000/yr (the basic living expense for taxpayers in Taiwan in 2023 is NT$202,000), supported by both the NCKU scholarship and the supervisor’s research grant for the first three years. From the 4th year onwards, we will support the PhD candidate in applying for the competitive scholarship from NCKU, as well as from various resources.
How to apply
To apply, please send your CV, the name of two referees, a concise statement of your research interests, and the transcripts of your BSc and MSc as a single PDF file to Dr Yu-Hsun Hsu (yuhsunhsu@ncku.edu.tw). All documents should be in English. The deadline for application is 30th November 2024. An online interview will be held soon after that. After the interviews, the successful candidate must go through the official application process for NCKU 2025 Fall Admission (the application platform will be open in January 2025).
For more information concerning this position, please contact Dr Yu-Hsun Hsu (yuhsunhsu@ncku.edu.tw).
Application Information for NCKU: NCKU 2025 Fall Admission and application instructions
Related Information
Related publication
Yeh, J. D. & Y.-H. Hsu. Extra-pair mating may evolve under changing environments. Under review
Hsu, Y.-H. 2022. Consequences of infidelity in non-human animals in T. Shackelford, and T. DeLecce, eds. The Oxford Handbook of Infidelity. Oxford University Press.
Hsu, Y.-H., M. J. P. Simons, J. Schroeder, A. Girndt, I. Winney, T. Burke, and S. Nakagawa. 2017. Age-dependent trajectories differ between within-pair and extra-pair paternity success. Journal of Evolutinary Biology 30:951-959.
Hsu, Y.-H., J. Schroeder, I. Winney, T. Burke, and S. Nakagawa. 2015. Are extra-pair males different from cuckolded males? A case study and a meta-analytic examination. Molecular Ecology 24:1558-1571.
Hsu, Y.-H., J. Schroeder, I. Winney, T. Burke, and S. Nakagawa. 2014. Costly infidelity: Low lifetime fitness of extra-pair offspring in a passerine bird. Evolution 68:2873-2884.
Related collaboration
Dunning, J., A. Sanchez-Tójar, A. Girndt, T. Burke, Y.-H. Hsu, S. Nakagawa, I. Winney, and J. Schroeder. 2024. Extrapair paternity alongside social reproduction increases male lifetime fitness. Animal Behaviour 213:117-123.
Schroeder, J., Y.-H. Hsu, I. Winney, M. J. P. Simons, S. Nakagawa, and T. Burke. 2016. Predictably philandering females prompt poor paternal provisioning. American Naturalist 188:219-230.
Department of Life Sciences in NCKU
Office of International Affairs in NCKU