Our research interests lay on the formation of variations within and between species. To investigate the causes and consequences of these variations, we broadly apply methods in behavioral ecology, along with population genomics, to study these evolutionary questions. Currently we are working on two topics: (1) speciation, and (2) mating systems and mating strategy.
Speciation is often a long and windy road in which populations of the same ancestral species diverged into two separated species. In most cases, natural selection caused by environmental factors altered divergent selection and resulted in adaptive divergence between taxa (i.e. ecological speciation). In this process, sexual selection sometimes reinforces such divergent selection through assortative mating or female preference on species-specific traits to speed up the speciation process. However, when gene flow occurred during speciation, the divergent selection could be weakened by genetic admixture caused by interbreeding (Figure).
We are currenting focusing on the divergence between two damselfly subspecies: Psolodesmus mandarinus mandarinus and P. m. dorothea. These two sister-subspecies differ morphologically and distribute in different areas. Morphologically intermediate individuals can be found in their contact zones, suggesting the possibility of hybridization (and thus gene flow) between these two subspecies. Our research aim is to investigate how the speed and consequences of speciation will result from the complex situation where natural selection, sexual selection and gene flow interact with each other in this damselfly system.
Mating systems and mating strategy
Animal mating systems can roughly be categorized into four types: monogamy, polygyny, polyandry and promiscuity. Interestingly, In some species, multiple mating systems can co-occur in the same population. We therefore are interested in how different mating systems evolved and being maintained.
Our current research interest focuses on extra-pair mating in socially monogamous birds. Extra-pair mating is commonly occurred in most socially monogamous passerines. On the one hand, extra-pair mating is beneficial to the males – this mating strategy increases male fitness by increasing the number of their offspring, without much costs because they usually provide zero paternal care to extra-pair offspring. However, when females engage in extra-pair mating, they are under the costs of reduced offspring fitness due to reduced paternal care from their cuckolded partners. Therefore, most hypotheses posit that females should be able to obtain benefits from extra-pair mating, such as producing extra-pair offspring with higher fitness by mating with larger, stronger, sexier extra-pair males or males with compatible genes with themselves. However, recent meta-analysis did not support these adaptive explanations (Figure). Our research is therefore aiming at investigating other potential explanations of female extra-pair mating.
Awards & Honors
PhD, University of Otago, New Zealand
MSc, National Taiwan University, Taiwan
BSc, National Taiwan University, Taiwan
2018 – present
Department of Life Sciences, National Cheng Kung University
2015 – 2018
Post-doctoral research fellow.
Systematics and Evolutionary Biology Laboratory, National Taiwan Normal University, Taiwan
Wei-Hsuan Fang, Yu-Hsun Hsu, Wen-Long Lin, Shih-Ching Yen (2020) The function of avian mobbing: an experimental test of “attract the mightier” hypothesis. Animal Behavior 170: 229-233.
Chun-Yu Lin, Yu-Hsun Hsu, Jo-Fan Wang, Chung-Ping Lin (2019) New damselfly hosts and species identification of an aquatic parasitoid Hydrophylita emporos (Hymenoptera: Trichogrammatidae) in Taiwan. Journal of Natural History 53(35-36): 2195-2205.
Hsu, Yu-Hsun, Reginald B. Cocroft, Robert L. Snyder & Chung-Ping Lin (2018) You stay, but I hop: Host-shifting
instead of coevolution dominated evolution of Enchenopa treehoppers. Ecology and Evolution 8(4): 1954-1965.
Winney, Isabel, Julia Schroeder, Shinichi Nakagawa, Yu-Hsun Hsu, Mirre JP Simons, Alfredo Sánchez-Tójar, Maria-Elena Mannarelli & Terry Burke (2017) Heritability and social brood effects in personality across life stages in a wild passerine. Journal of EvolutionaryBiology 31(1): 75-87.
Hsu, Yu-Hsun, Mirre JP Simons, Julia Schroeder, Antje Girndt, Isabel Winney, Terry Burke & Shinichi Nakagawa (2017) Age-dependent trajectories differ between within-pair and extra-pair paternity success. Journal of Evolutionary Biology 30(5): 951-959
Hsu, Yu-Hsun, Julia Schroeder, Isabel Winney, Terry Burke & Shinichi Nakagawa (2015) Are extra-pair males
different from cuckolded males? A case study and a meta-analytic examination. Molecular Ecology 24(7): 1558-71.
Winney, Isabel, Shinichi Nakagawa, Yu-Hsun Hsu, Terry Burke & Julia Schroeder (2015) Troubleshooting the
potential pitfalls of cross-fostering. Methods in Ecology and Evolution 6(5): 584-592.
Hsu, Yu-Hsun, Julia Schroeder, Isabel Winney, Terry Burke & Shinichi Nakagawa (2014) Costly infidelity: Low
lifetime fitness of extra-pair offspring in a passerine bird. Evolution 68(10): 2873-2884.
Winney, Isabel & Yu-Hsun Hsu (2012) Long-term studies of house sparrows (Passer domesticus) on Lundy. LFS Annual Report 2011: 97-98.
Hsu, Yu-Hsun & Lucia Liu Severinghaus (2011) Nest-site selection of the greater painted snipe (Rostratula benghalensis benghalensis) in fallow fields of I-Lan, Taiwan. Taiwania 56(3): 26-36.
Hsu, Yu-Hsun, Lucia Liu Severinghaus, Shou-Hsien Li, & Yu-Cheng Hsu (2010) Detecting obscure hybrids of light-vented bulbul (Pycnonotus sinensis formosae) and Styan’s bulbul (P. taivanus) with microsatellite. Journal of National Park 20(1), 26-36 (In Chinese with English abstract).
Books and Chapters
Yu-Hsun Hsu. Consequences of infidelity in non-human animals (2021)In Todd Shackelford and Tara DeLecce (Eds.) The Oxford Handbook of Infidelity . Oxford University Press. Forthcoming.