Species Delimitation And The Comparative Analysis Of Mitochondrial Genomics Of Blattidae

The purpose of this thesis is to explore the molecular species delimitation,the comparative analysis of mt genomes,and the phylogenetic relationship of Blattidae.Blattidae belongs to Dictyoptera,Blattodea,Blattoidea.There are four subfamilies(Archiblattinae,Blattinae,Macrocercinae,Polyzosteriinae)recorded in the world.The studies on this family in the past mainly focused on the identification on the basis of external morphology.Therefore,based on the traditional morphological research,this study uses molecular markers data and mt genome data to further slove the problems existed in this family.There are mainly three parts in this study: 1)COI gene using the molecular species delimitation to help identify the species of Blattidae combined with the morphological data.We combined the morphological characters and two molecular species delimitation methods: ABGD and GMYC using COI genes to explore the species diversity.2)mt genomics of Blattidae.This study deals with comparative analyses of base composition,evolution rate,gene rearrangement of 26 mt genomics sequences(including 13 from this study and 13 from NCBI);3)On the one hand,6genes(12S,16 S,18S,28 S,COII and H3)are concatenated to construct maximum likelihood(ML)and Bayesian inference(BI)phylogenetic trees in order to infer the phylogeny of Blattidae,and even discuss the relationships of the morphologically similar genera Homalosilpha St?l,1874 and Mimosilpha Bey-Bienko.On the other hand,in order to infer the phylogenetic relationship and taxonomic status of the Blattidae,61 mt genomes were used to construct phylogenetic trees using maximum likelihood and Bayesian methods.The results show:(1)The DNA-based technique,two molecular species delimitation methods(ABGD and GMYC),was proved to be effective to discriminate species of Blattidae combined with morphological data.Most of the 26 morphspecies are supported by ABGD and GMYC,of which,some species widely distributed appeared to be defined as two or more molecular operating units(MOTUs).The COI gene also solves the problems caused by sexual dimorphism and polymorphic species.(2)The base composition is stable,and t RNA genes,PCGs,r RNA and D-loops of all species exhibit positive AT-skew and negative GC-skew.The evolution rate of COI genes is the most conservative,while the ATP8 is the fastest.There is gene rearrangement occurred in all of 26 Blattidae mt genomes in this study.(3)The phylogenetic study based on 6 gene markers showed that Blattidae is a monophyletic group,and every genus involved is also a monophyletic group;but Archiblattinae and Blattinae are proved to be paraphyletic.Homalosilpha and Mimosilpha are recovered to be sister groups not only in BI but also in ML analysis.The phylogenetic analysis shows that BI and ML analyses base mt datasets produced highly identical trees.Blattidae + Tryonicidae is well recovered to be the sister of Lamproblattidae and Anaplectidae.The genus Hebardina is the basal clade of Blattidae,which forms a monophyletic group;all species of Polyzosteriinae are clustered together and form a monophyletic group;Archiblattinae and Blattinae are also proved to be paraphyletic.According to the results,a new subfamily,Hebardininae,is established,and Archiblattinae is determined as the synonym of Blattinae.The new subfamily,new species,new genus as follows:New subfamily: Hebardininae subfam.nov.New genera: Paraprotagonista gen.nov.New species: Paraprotagonista spinata sp.nov.,Paraprotagonista longissima sp.nov.,Homalosilpha obtusangula sp.nov.,Homalosilpha recta sp.nov.,Homalosilpha alba sp.nov.,Homalosilpha clavellata sp.nov.