外来入侵毒蜘蛛红头隐蛛的种群遗传结构、基因流动与扩散规律

The Mediterranean recluse spider, Loxosceles rufescens Dufour 1820 (Araneae: Sicariidae) is a wildspread invasion species, and it is infamous for it's ability to cause severe skin necrosis known as loxoscelism in humans. There are several reports of loxoscelism caused by L. rufescens in numerous parts of the world; such as in western Asia, it was blamed for an outbreak of skin lesions in orchard workers, in Turkey, a case of loxoscelism which after 20 days caused severe necrosis has been reported and other reports from Greece, Jordan and Palestine. Loxosceles rufescens is a cosmopolitan species that is native to the Europe-North African region but has spread to various other countries by means of human activity. By far the most widespread member of its genus (for which it is the type species), it occurs from the southern Mediterranean area and Middle East, and has been introduced to North America, southeast Asia from India to China, Australia. In China, the Mediterranean recluse spider is an important species in Guangxi, Guizhou and Yunnan province and invading to Sichuan, Hunan, Jiangxi, Anhui, Jiangshu and Zhejiang province. They are often found in parks, building, outbuilding and caves. Having the cytotoxicity of the venom and its urban distribution in mind, L. rufescens is probably among the more important spider species of China. In recent years, studies of this species of spiders have attracted increasing attention because of its high medical importance and wildspread introduction. Howerver, imformation on population structure, gene flow and population dispersal of L. rufescens is important for the clarification of their invasion mechanism, and the success of control technologies of this harmful spider. Although the increase cases of a severe dermonecrotic araneism (loxoscelism) caused by this species has been reported in many countries and the area of invasion expanded rapidly, the population genetic structure and gene flow patters among populations are unknown in these countries. In this study, we will mainly collect L. rufescens populations throughout the invaded regions of China. Next-generation cDNA sequencing (RAD-SEQ) and mitochondrial genes will be used to investigate the characteristics of population genetic structure, the gene flow patters among these sampled populations and the population dispersal patters. The findings of this study may have important implications for invasion risk assessment, invasive routes predicting and IPM (Integrated Pest Management) of L. rufescens populations in China. Additionally, a knowledge of invasion history of the Mediterranean recluse spider can help for interpretations of the difficult questions of hunman migregation into China.

红头隐蛛Loxosceles rufescens是一种入侵性极强、危害人类健康（咬人后引起皮肤局部坏死，俗称隐蛛中毒）的外来有害生物，原产于地中海地区，通过人类活动在全球广泛扩散。红头隐蛛自入侵我国后，已分布在长江以南的几乎所有（省）区，目前随全球气候变暖，正继续向北方扩张，形势十分严峻。然而，关于我国红头隐蛛的研究尚未全面展开。本课题主要从我国分布区内采集红头隐蛛样本，运用RAD-SEQ高通量测序技术和线粒体标记，从基因组水平研究红头隐蛛入侵我国的时间、路径，以及入侵到我国各分布区后种群的遗传结构、种群分化、种群间的基因流动与种群扩散规律。研究结果能够阐明我国红头隐蛛种群的来源、种群的遗传分化与演变特点，以及种群间的基因流动与种群扩散特点。研究结果对于开展我国红头隐蛛的监测、检疫及综合治理具有重要的意义。红头隐蛛与人类共居，了解红头隐蛛的入侵历史还能够帮助解释人类迁徙史中的疑难问题。

红头隐蛛Loxosceles rufescens隶属于蜘蛛目Araneae、刺客蛛科Sicariidae，是全球性入侵生物，也是重要的医学物种。本课题利用群体遗传学和谱系地理学方法，比较我国红头隐蛛种群（扩张种群）与希腊种群（原有种群）的遗传多样性、种群遗传结构和历史动态，分析我国红头隐蛛种群的起源与扩散；并结合前人的数据，研究人类共居物—红头隐蛛的全球殖民历史及与人类迁徙史的关系。结果表明：希腊红头隐蛛种群和中国种群都具有高的单倍型多样性和低的核酸多样性，希腊种群的遗传多样性明显高于中国种群。在中国，西南地区种群的遗传多样性最高，特别是其中的广西种群。全球红头隐蛛种群包含2个主要世系，世系A广泛分布在非洲北部、欧洲、亚洲、北美和澳大利亚；世系B仅分布在非洲北部、欧洲和亚洲。我国的红头隐蛛种群也由这2个主要世系构成，世系A由来自广西、贵州、重庆、湖南和江西的个体组成；世系B仅包含来自云南和广西的群体。该种毒蜘蛛可能从南亚入侵我国，进入西南地区后迅速向其他地区扩张。我国红头隐蛛种群近期发生过显著扩张事件、遗传漂变和选择。全球红头隐蛛起源于非洲北部地区，历经3次独立扩散，与现代人的殖民路线一致。北非的红头隐蛛最初入侵以色列，并扩散到希腊，随后一个支系入侵伊朗和东南亚，该殖民路径与现代人的南部扩散理论相吻合。中国种群的扩张时间是42710–46008年前，中国种群与希腊种群分离时间是41420–44444年前，这个时间与现代人扩散到东南亚及东亚的时间一致。因此，红头隐蛛入侵亚洲的过程反映了现代人的殖民历史。红头隐蛛为简单生殖器类蜘蛛，物种鉴定极其困难。因此本课题基于经典分类学方法和分子生物学技术对该物种进行了形态学再描述和分子系统分类学研究，并对其线粒体基因组全序列进行了测定与分析。利用RAD-Seq技术和线粒体基因组全序列分析，对这种害虫开展进一步的遗传学研究工作还在继续。本课题的研究结果对于毒蜘蛛—红头隐蛛的控制，以及人类健康和生态环境保护等具有重要的意义，推动了人类学相关研究领域的发展。