English Version

The role of niche divergence and geographic arrangement in the speciation of Eared Pheasants (Crossoptilon, Hodgson 1938)

2017-05-08 15:07:06

The role of niche divergence and geographic arrangement in the speciation of Eared Pheasants (Crossoptilon, Hodgson 1938)
Pengcheng Wang

 One of the most contentious theories in current ecology is the ecological niche conservatism, which is defined as conservatism among closely related species; however, the ecological niche can also be shifted, as documented in several cases. Genetic drift and ecological divergent selection may cause ecological niche divergence. The current study aims to test whether the ecological niche is conserved or divergent and to determine the main factor that drives ecological niche divergence or conservation. We analyzed the phylogenetic relationship, ecological niche model (ENM) and demographic history of Eared Pheasants in the genus Crossoptilon (Galliformes: Phasianidae) to test niche conservatism with respect to different geographically distributed patterns. The phylogenetic relationship was reconstructed using *BEAST with mitochondrial cytochrome b (cyt b) and 44 unlinked autosomal exonic loci, and ENMs were reconstructed in MAXENT using an average of 41 occurrence sites in each species and 22 bioclimatic variables. A background similarity test was used to detect whether the ecological niche is conserved. Demographic history was estimated using the isolation with migration (IM) model. We found that there was asymmetric gene flow between the allopatric sister species Crossoptilon mantchuricum and C. auritum and the parapatric sister species C. harmani and C. crossoptilon. We found that ecological niches were divergent, not conserved, between C. mantchuricum and C. auritum, which began to diverge at approximately 0.3 million years ago. However, the ecological niches were conserved between C. crossoptilon and C. harmani, which gradually diverged approximately half a million years ago. Ecological niches can be either conserved or divergent, and ecological divergent selection for local adaptation is probably an important factor that promotes and maintains niche divergence in the face of gene flow. This study provides a better understanding of the role that divergent selection has in the initial speciation process. The platform combined demographic processes and ecological niches to offer new insights into the mechanism of biogeography patterns.

Molecular Phylogenetics and Evolution
Zhengwang Zhang

北京师范大学版权所有 联系地址:北京市海淀区新街口外大街19号 北京师范大学生物多样性与生态工程教育部重点实验室 邮编100875