Research
Our research interests lay on the causes and consequences of variation and diversity from between species to within individuals. To investigate the evolutionary process of these variations, we broadly apply methods in behavioural ecology, along with population genomics and comparative analyses, to study these evolutionary questions. We are currently focusing on three topics:
The causes and consequences of speciation
A case study in the diverging Psolodesmus mandarinus subspecies in Taiwan
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.
We are currently 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 hybridisation (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.
The evolution of mating strategies
Mainly focus on extra-pair mating in birds
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.
The evolution of mating systems
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.
We applied both comparative analysis with data across different avian lineages and also field survey of breeding shorebirds in Taiwan, in order to investigate this evolutionary question from various scales in space and time.