绿带闭目天蛾和构月天蛾在海南岛及周边大陆的遗传分化

Genetic differentiation of Callambulyx rubricosa and Parum colligata in Hainan Island and the surrounding mainland

海南岛是与周边大陆存在地理隔离的大陆性岛屿,探索该岛屿与邻近大陆上生物的遗传分化有助于理解地理隔离对生物遗传分化的影响。在海南岛及其周边大陆15个地点采集两种鳞翅目天蛾科(Lepidoptera:Sphingidae)昆虫(绿带闭目天蛾Callambulyx rubricosa 88头和构月天蛾Parum colligata 57头),选择线粒体基因COI、Cytb和核基因EF-1α作为分子标记开展遗传多样性研究。基于COI-Cytb分析的结果表明,两物种的核苷酸多样性均较低(分别为0.00434和0.00818),且均在广东广西、越南和海南岛群体之间存在明显的谱系地理结构。两个物种在三个群体间均检测出低水平的基因流(Nm分别为0.09—1.22和0.18—0.57)和高水平的遗传分化(F_(ST)分别为0.29—0.84和0.47—0.73)。两个物种最高的遗传分化都发生在海南岛与大陆群体之间,且海南岛群体的单倍型数量少于周边大陆群体。Mantel检验结果表明遗传距离与地理距离之间存在显著正相关关系,中性检验结果表明两个物种均未经历显著的种群扩张。综上,研究认为绿带闭目天蛾(C.rubricosa)和构月天蛾(P.colligata)的海南岛群体与邻近大陆群体间的基因交流较少,遗传分化程度较高,推测地理隔离可能是其产生遗传分化的重要原因之一,这一结果将为海南岛生物多样性的保护提供宝贵的建议。

As a continental island,Hainan Island is geographically isolated from the surrounding mainland.Exploring the genetic differentiation of insects among this island and the surrounding mainland will help us to further understand the effects of geographical isolation on genetic diversity.In this study,samples of two moth species(Lepidoptera:Sphingidae)were collected from 15 locations in the Hainan Island and the surrounding mainland,including 88 samples of Callambulyx rubricosa and 57 of Parum colligata.Two mitochondrial genes COI,Cytb and one nuclear gene EF-1αwere selected as molecular makers to proceed following genetic diversity and differentiation analyses.The results based on the COI-Cytb analyses showed that the nucleotide diversity of the C.rubricosa and P.colligata was 0.00434 and 0.00818,respectively.There were obvious phylogeographic structures among the populations in Guangdong-Guangxi,Vietnam,and Hainan Island.Both species showed weak gene flow(Nm were 0.09—1.22 and 0.18—0.57,respectively)and distinct genetic differentiation(F_(ST) were 0.29—0.84 and 0.47—0.73,respectively)between these three populations.The highest genetic differentiation was detected between Hainan Island and the mainland populations.Meanwhile,the number of haplotypes in Hainan Island population was less than that of the surrounding mainland populations.Moreover,Mantel tests indicated that there were significantly positive correlations between genetic distance and geographic distance,and neutrality tests suggested that neither species has undergone significantly population expansion.In conclusion,our results implied that there were flaccid gene flows and distinct genetic differentiation of C.rubricosa and P.colligata between Hainan Island population and the surrounding mainland populations.The geographic isolation could be one of the important reasons for these noticeable differentiation,which might provide valuable advice for the biodiversity conservation in Hainan Island.