Mathenge Catherine W, Riegler Markus, Beattie G Andrew C, Spooner-Hart Robert N, Holford Paul
School of Science and Health, University of Western Sydney (Hawkesbury Campus).
Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia.
Insect Sci. 2015 Mar;22(3):360-74. doi: 10.1111/1744-7917.12120. Epub 2014 May 20.
The tomentose cochineal scale insect, Dactylopius tomentosus (Lamarck) (Hemiptera: Dactylopiidae), is an important biological control agent against invasive species of Cylindropuntia (Caryophyllales: Cactaceae). Recent studies have demonstrated that this scale is composed of host-affiliated biotypes with differential host specificity and fitness on particular host species. We investigated genetic variation and phylogenetic relationships among D. tomentosus biotypes and provenances to examine the possibility that genetic diversity may be related to their host-use pattern, and whether their phylogenetic relationships would give insights into taxonomic relatedness of their host plants. Nucleotide sequence comparison was accomplished using sequences of the mitochondrial cytochrome c oxidase I (COI) gene. Sequences of individuals from the same host plant within a region were identical and characterized by a unique haplotype. Individuals belonging to the same biotype but from different regions had similar haplotypes. However, haplotypes were not shared between different biotypes. Phylogenetic analysis grouped the monophyletic D. tomentosus into 3 well-resolved clades of biotypes. The phylogenetic relationships and clustering of biotypes corresponded with known taxonomic relatedness of their hosts. Two biotypes, Fulgida and Mamillata, tested positive for Wolbachia (α-Proteobacteria), a common endosymbiont of insects. The Wolbachia sequences were serendipitously detected by using insect-specific COI DNA barcoding primers and are most similar to Wolbachia Supergroup F strains. This study is the first molecular characterization of cochineal biotypes that, together with Wolbachia sequences, contribute to the better identification of the biotypes of cochineal insects and to the biological control of cacti using host-specific biotypes of the scale.
绒毛胭脂虫蚧，学名Dactylopius tomentosus（拉马克）（半翅目：胭蚧科），是一种针对入侵性圆柱仙人掌属植物（石竹目：仙人掌科）的重要生物防治剂。最近的研究表明，这种蚧由与宿主相关的生物型组成，这些生物型在特定宿主物种上具有不同的宿主特异性和适应性。我们研究了绒毛胭脂虫蚧生物型和种源之间的遗传变异和系统发育关系，以检验遗传多样性是否可能与其宿主利用模式相关，以及它们的系统发育关系是否能为其宿主植物的分类学相关性提供见解。使用线粒体细胞色素c氧化酶I（COI）基因序列进行核苷酸序列比较。同一区域内来自同一宿主植物的个体序列相同，并具有独特的单倍型。属于同一生物型但来自不同区域的个体具有相似的单倍型。然而，不同生物型之间不共享单倍型。系统发育分析将单系的绒毛胭脂虫蚧分为3个解析良好的生物型分支。生物型的系统发育关系和聚类与它们宿主已知的分类学相关性相对应。两种生物型，Fulgida和Mamillata，检测到沃尔巴克氏体（α-变形菌纲）呈阳性，沃尔巴克氏体是昆虫常见的内共生菌。通过使用昆虫特异性COI DNA条形码引物意外检测到了沃尔巴克氏体序列，这些序列与沃尔巴克氏体超群F菌株最为相似。本研究是胭脂虫生物型的首次分子特征描述，该研究连同沃尔巴克氏体序列，有助于更好地识别胭脂虫的生物型，并利用宿主特异性生物型的蚧对仙人掌进行生物防治。
