Origin and expansion of the Yunnan Shoot Borer, Tomicus yunnanensis (coleoptera: scolytinae): a mixture of historical natural expansion and contemporary human-mediated relocation.
The Yunnan shoot borer, Tomicus yunnanensis, is a recently-discovered, aggressive pest of the Yunnan pine stands in southwestern China. Despite many bionomics studies and massive controlling efforts, research on its population genetics is extremely limited. The present study, aimed at investigating the origin and dispersal of this important forestry pest, analyzed the population genetic structure and demographic history using a mitochondrial cox1 gene fragment. Our results showed that T. yunnanensis most likely originated from the Central-Yunnan Altiplano, and the divergence time analysis placed the origin approximately 0.72 million-years ago. Host separation and specialization might have caused the speciation of T. yunnanensis. Genetic structure analyses identified two population groups, with six populations near the origin area forming one group and the remaining six populations from western and eastern Yunnan and southwestern Sichuan comprising the other. Divergence time analysis placed the split of the two groups at approximately 0.60 million-years ago, and haplotype phylogenetic tree, network, as well as migration rate suggested that populations of the latter group were established via a small number of individuals from the former one. Migration analysis also showed a certain degree of recent expansion from southwestern Sichuan to eastern Yunnan. Our findings implied that T. yunnanensis underwent both historical expansion and recent dispersal. The historical expansion may relate to the oscillation of regional climate due to glacial and interglacial periods in the Pleistocene, while human-mediated transportation of pine-wood material might have assisted the relocation and establishment of this pest in novel habitats.
Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, 650091, China.
Jun
J
Lü
Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, 650091, China.
Shao-ji
SJ
Hu
Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; School of Mathematics and Computer Science, Yunnan University of Nationalities, Kunming, 650031, China.
Xue-yu
XY
Ma
Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming, 650091, China.
Jin-min
JM
Chen
Life Science College, Yunnan Normal University, Kunming, 650092, China.
Qing-qing
QQ
Li
Laboratory of Biological Invasion and Ecosecurity, Yunnan University, Kunming, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming, 650091, China.
Hui
H
Ye
D000818:Animals; D044822:Biodiversity; D001517:Coleoptera / Q000145:classification / Q000235:genetics; D004272:DNA, Mitochondrial; D017753:Ecosystem; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes; D006802:Human Activities; D006801:Humans; D008969:Molecular Sequence Data; D011157:Population Dynamics
D004272:DNA, Mitochondrial