Abstract
Background: Speciation with gene flow is an alternative to the nascence of new taxa in strict allopatric separation. Indeed, many taxa have parapatric distributions at present. It is often unclear if these are secondary contacts, e.g. caused by past glaciation cycles or the manifestation of speciation with gene flow, which hampers our understanding of how different forces drive diversification. Here we studied genetic, phenotypic and ecological aspects of divergence in a pair of incipient shorebird species, the Kentish (Charadrius alexandrinus) and the White-faced Plovers (C. dealbatus), shorebirds with parapatric breeding ranges along the Chinese coast. We assessed divergence based on molecular markers with different modes of inheritance and quantified phenotypic and ecological divergence in aspects of morphometric, dietary and climatic niches. Results: Our integrative analyses revealed small to moderate levels of genetic and phenotypic distinctiveness with symmetric gene flow across the contact area at the Chinese coast. The two species diverged approximately half a million years ago in dynamic isolation with secondary contact occurring due to cycling sea level changes between the Eastern and Southern China Sea in the mid-late Pleistocene. We found evidence of character displacement and ecological niche differentiation between the two species, invoking the role of selection in facilitating divergence despite gene flow. Conclusion: These findings imply that ecology can indeed counter gene flow through divergent selection and thus contributes to incipient speciation in these plovers. Furthermore, our study highlights the importance of using integrative datasets to reveal the evolutionary history and assist the inference of mechanisms of speciation.
Original language | English |
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Article number | 135 |
Journal | BMC Evolutionary Biology |
Volume | 19 |
Issue number | 1 |
DOIs | |
Publication status | Published - 27 Jun 2019 |
Funding
This study was supported by the National Natural Science Foundation of China, Grant/Award Number: 31301875 and 31572251 to Y.L., 31600297 to P.J.Q. and 31572288 to Z.W.Z., the Open Grant of the State Key Laboratory of Biocontrol of Sun Yat-sen University to Y.L. and T.Z. (SKLBC13KF03) and the Youth Innovation Promotion Association CAS (2015304) to J.H.H.. Computational machinery work was granted by the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase) under Grant No. U1501501 to Y.L. We declare that these funding bodies played no role in the design of the study, the collection, analysis, and interpretation of data and in writing the manuscript.
Keywords
- Character displacement
- Ecological niche
- Gene flow
- Hybridization
- Parapatry
- Stable isotope analysis
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics