Russian wheat aphids (Diuraphis noxia) in China: native range expansion or recent introduction?

Authors

  • B. ZHANG,

    1. Faculty of Science & Technology, Queensland University of Technology, GPO Box 2434, Brisbane, Qld 4001, Australia
    2. State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
    3. Cooperative Research Centre for National Plant Biosecurity, LPO Box 5012, Bruce, ACT 2617, Australia
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  • O. R. EDWARDS,

    1. Cooperative Research Centre for National Plant Biosecurity, LPO Box 5012, Bruce, ACT 2617, Australia
    2. CSIRO Ecosystem Sciences, Centre for Environment and Life Sciences, Underwood Avenue, Floreat, WA 6014, Australia
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  • L. KANG,

    1. State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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  • S. J. FULLER

    1. Faculty of Science & Technology, Queensland University of Technology, GPO Box 2434, Brisbane, Qld 4001, Australia
    2. Cooperative Research Centre for National Plant Biosecurity, LPO Box 5012, Bruce, ACT 2617, Australia
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Le Kang, Fax: +86-10-64807099; E-mail: lkang@ioz.ac.cn

Abstract

In this study, we explore the population genetics of the Russian wheat aphid (RWA) (Diuraphis noxia), one of the world’s most invasive agricultural pests, in north-western China. We have analysed the data of 10 microsatellite loci and mitochondrial sequences from 27 populations sampled over 2 years in China. The results confirm that the RWAs are holocyclic in China with high genetic diversity indicating widespread sexual reproduction. Distinct differences in microsatellite genetic diversity and distribution revealed clear geographic isolation between RWA populations in northern and southern Xinjiang, China, with gene flow interrupted across extensive desert regions. Despite frequent grain transportation from north to south in this region, little evidence for RWA translocation as a result of human agricultural activities was found. Consequently, frequent gene flow among northern populations most likely resulted from natural dispersal, potentially facilitated by wind currents. We also found evidence for the long-term existence and expansion of RWAs in China, despite local opinion that it is an exotic species only present in China since 1975. Our estimated date of RWA expansion throughout China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. We conclude that western China represents the limit of the far eastern native range of this species. This study is the most comprehensive molecular genetic investigation of the RWA in its native range undertaken to date and provides valuable insights into the history of the association of this aphid with domesticated cereals and wild grasses.

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