树影藏林：欧洲水平隐存多样性和鳞毛蚊属/苏格兰蚊属复合体（双翅目：蠓科）的系统发育关系
The tree that hides the forest: cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level.
机构信息
ASTRE, Univ Montpellier, Cirad, INRAE, Montpellier, France.
Cirad, UMR ASTRE, 34398, Montpellier, France.
出版信息
Parasit Vectors. 2020 May 20;13(1):265. doi: 10.1186/s13071-020-04114-1.
BACKGROUND
Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex.
METHODS
Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex.
RESULTS
Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus.
CONCLUSIONS
To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.
背景
刺螫伊蚊是一种丰富且广泛分布的全北界吸血蠓，参与了蓝舌病病毒（BTV）和舍姆利肯病病毒（SBV）向野生和家养反刍动物的传播。该蚊种的雌性常与两种形态上非常接近的物种，即 C. scoticus 和 C. montanus，共同报告，形成了 Obsoletus/Scoticus 复合体。最近，在地理上遥远的地点报道了刺螫伊蚊内的隐种多样性。为了修订其分类地位并评估每个分类实体的媒介作用，必须明确区分物种并描述遗传变异性。我们的目标是描述和绘制 Obsoletus/Scoticus 复合体内部的隐种多样性。
方法
对属于 Obsoletus/Scoticus 复合体的 3763 只个体的 cox1 线粒体基因部分进行了测序。包括来自 20 个国家的种群，这些种群沿一个 Palaearctic 地中海横断带分布，从斯堪的纳维亚到加那利群岛（北到南），再到加那利群岛到土耳其（西到东）。cox1 条形码基因序列支持的遗传多样性，通过 16S rDNA 线粒体基因序列和编码核糖体 28S rDNA 的基因得到支持。使用多标记方法进行物种划分，以修订 Obsoletus/Scoticus 复合体的现行分类方案。
结果
我们的分析显示，在 C. obsoletus 内存在三个系统发育枝（C. obsoletus 枝 O2、C. obsoletus 枝暗和一个尚未命名和鉴定的枝）。这些分析还揭示了 C. scoticus 内的两个种内枝，并对 C. montanus 的分类地位提出了质疑。
结论
据我们所知，我们的研究首次在大地理尺度上对 Obsoletus/Scoticus 复合体进行了遗传特征描述，并允许对该复合体在 Palaearctic 地区重要的牲畜病毒媒介种群的现行分类分类进行修订。
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