中国钝绥螨亚科系统发育研究

Amblyseiinae is the biggest subfamily of family Phytoseiidae. Many species in this subfamily are important natural enemies of agro-forestry damage mites and small pests. The currently applied phytoseiid mites mostly belong to this subfamily. It is of great economic importance. Phytoseiid mites are very tiny (＜0.5mm) and the morphological characteristics are difficult to identify and variable greatly. There are many debates about the traditional taxanomy system of this subfamily and the taxanomy in genera and subgenera level is unstable. Taxanomy error, genus belonging confusion and cryptic species existence seriously affect the practical application. This project aims to study the phylogenetic relationships of this subfamily among genera based on the theories and methods of comparative morphology, cladistics and molecular systematics etc. By examining the mass specimens in our lab and collecting fresh specimens in wild, combined morphological data with molecular data, based on morphological taxanomy and the genetic analysis of mitochondrion 12S rRNA, COI, ribosomal ITS gene sequence and nuclear gene EF-1α, the phylogenetic relationships of genera groups in this subfamily are rebuilt. Then based on the new phylogenetic relationships, the debates about genera belongs of doubtful species and species definition of cryptic species are resolved. The results will improve the classification system of this subfamily. It is not only of great significance to promote the level of systematic research of sub-family Amblyseiinae and family Phytoseiidae, but also can provide scientific support for developing and applying phytoseiid mites.

钝绥螨亚科是植绥螨科中最大亚科，其大部分种类是农林害螨、害虫的重要天敌，具有重要的经济价值。但因植绥螨个体极微小(＜0.5mm），形态不易观察且分类特征变异大，导致基于形态特征的传统分类系统存在很大争议，部分种类鉴定错误、归属疑难及存在隐存种现象，严重影响到实际应用工作。本项目拟采用比较形态学、支序系统学和分子系统学等理论和方法研究该类群属间系统发育关系。通过检视课题组现有的大量标本及野外补充采集新标本，在传统形态分类基础上，以线粒体12SrRNA、COI，核糖体ITS序列和核基因EF-1α相结合的多基因联合遗传分析等方法重建中国钝绥螨亚科属级及以下阶元的系统发育关系；并依据系统发育关系澄清疑难种的归属问题，及确立物种界定的方法，鉴别隐存种类，建立健全该亚科的自然分类系统。研究结果不仅对提升钝绥螨亚科及植绥螨科的系统学研究水平具有重要意义，而且能为植绥螨的资源开发和有效利用提供科学依据。

钝绥螨亚科Amblyseiinae是植绥螨科Phytoseiidae中最大亚科，中国现有植绥螨科种类328种，钝绥螨亚科种类193种，约占60%。McMurtry and chant（2007）和De moraes et al.（2004）两大分类系统存在较多分歧，该亚科很多种类的归属问题不统一。本项目除了检视课题组现有的大量库存标本，还在广东、广西、江西、浙江等地补充采集了一些争议种和确定种的新鲜标本，共采集到8属16类群的53个种，基本涵盖中国钝绥螨亚科各个类群。通过形态特征比较研究以及利用线粒体COI、12SrRNA，核糖体ITS和核基因EF-1α四种分子标记分别构建系统发育树，综合分析重建了中国钝绥螨亚科属级的系统发育关系，并依据亲缘关系推断一些分类疑难种的归属。如基于形态特征的肩绥螨属Scapulaseius从分子系统发育关系分析并不成立。该属争议较多的一些种类分散存在于钝绥螨属Amblyseius、新小绥螨属Neoseiulus以及真绥螨属Euseius中。此外，分析得到钝绥螨亚科种内的遗传距离分别是CO I(0-6%)、12S rRNA(0–3%)、ITS(0-3%)和EF-1a(0-2%)。基于遗传距离判断，乌龙真绥螨Euseius oolong 和尼氏真绥螨Euseius nichosi应为同物异名。本研究采集到近4000号标本，贡献了大量中国钝绥螨亚科种类的线粒体COI、12SrRNA，核糖体ITS和核基因EF-1α序列，丰富了植绥螨科的标本库和分子数据库，以及理清了一些系统发育关系，澄清了部分疑难种的归属，健全了中国钝绥螨亚科的分类系统。该项目共发现5个新种，发表SCI论文两篇，主编出版学术专著1本，建设“植绥螨资源数字化与共享”平台1个。参加国内国际学术交流两次。研究结果不仅对提升钝绥螨亚科及植绥螨科的系统学研究水平具有重要意义，而且能为植绥螨的资源开发和有效利用提供科学依据。