Phylogenetic Relationships And Molecular Evolution Of 7 Species In Lac Insects (Homoptera: Tachardiidae)

Lac insects are one kind of resource insects with great economic value, which belong to order Homoptera, superfamily Cocoidea, family Lacciferidae, genus Kerria. It has mostly been distributed over tropic and sub-tropic zone such as India, Thailand, Burma, China, Laos, Bangladesh, Pakistan, Vietnam and other countries. Around the world, there are about more than 20 species of Lac insects in which only 19 species have been identified.In this dissertation, by using cladistic approach, karyotype resemblance-near coefficients, the technique of random amplified polymorphic DNA (RAPD) and sequencing of 28SrRNA gene and EF1α gene, the phylogenetic relationships among 7 commercial species of lac insects have been discussed in three levels of Morphology, cell and molecule.1. Cladistic analysis of morphology: Based on the morphological study, 22 apomorphies , including the length of anal tubercle and height of branchia are selected for the attempt to interpret the phylogenetic relationships among the 7 commercial species by a cladistic approach while the Kerria greeni, Metatachardia myrica, Tachardina albida are chosed as composite outgroups in this study.The results show that Kerria chinensis is the earliest diverging member of this group in case of its special morphological characters. The other 6 species can obviously be divided into two natural groups. In one group, Kerria sindica and Kerria lacca have a closest relationship and formed as sister taxon. In the other group, Kerria pusana is the close taxon to the sister-branch of Kerria ruralis and Kerria yunnanensis followed by Kerria nepalensis.2. Karyotypic cluster: By the air-dried method, the numbers and the shape structure of chromosomes in 7 species are compared through the optic microscope. Using specific software IM50, karyotype analyses are made and the model karyotype charts are built with which the karyotypic parameters are calculated in advance.By applying karyotype resemblance-near coefficients (λ) and the evolution distance with specific software, we have studied the phylogenetic relation of lac insect and built the dendrogram clustered using UPGMA.The results show that the 7 species can obviously be divided into two natural groups. In...