DNA Barcode Of The Tribe Tropidocephalini(Hemiptera:fulgoromorpha:Delphacidae)from China

The planthopper tribe Tropidocephalini belonging to the subfamily Delphacinae(Hemiptera: Fulgoromorpha: Delphacidae),is the second largest tribe in the Delphacinae.To date,more than 190 species in 36 genera were recorded in the world,and 107 species in 23 genera were reported from China.In this thesis,DNA barcode of the tribe Tropidocephalini from China was studied.The main contents include the screening of DNA barcoding genes,phylogenetic analysis in intergeneric and interspecific,molecular identification of related genera and species,and application of DNA barcodes in the establishment of new taxonomies.The main results were as follows:1.DNA barcoding gene fragment screeningBased on COI,16 S rDNA and 28 S rDNA gene sequence,the sequence composition,R value and genetic distance were analyzed.The results showed that the COI showed obvious A+T preference,with R value was 0.97.The intergeneric genetic distance,interspecific genetic distance and intraspecific genetic distance were significantly different.It was an ideal DNA barcode gene fragment.In this thesis,42 COI barcodes of 28 species in 11 genera of the tribe Tropidocephalini were obtained and the DNA barcoding database was initially constructed.2.Analysis of intergeneric system development based on DNA barcode.This study was based on the COI gene sequence,using Stenocranus as an outgroup to perform phylogenetic analysis on 18 genera of the Tropidocephalini.The results showed that the original group was Paranectopia,among which Lauriana and Epeurysa,Bambusiphaga and Yuanchia,Purohita and Neocarinodelphax,Malaxa and Belocera,Arcifrons and Parabelocera were sister groups,indicating that their relationship were closed.3.Analysis of interspecific system development based on DNA barcode.Based on the COI gene sequence and Epeurysa infumata as an outgroup,16 species of Bambusiphaga were studied for phylogenetic relationships analysis.The results showed that 16 species of Bambusiphaga were divided into 4 major branches,the branch 1 was B.maculata +((B.kunmingensis + B.fascia))+(B.taibaishana +B.basifusca)),the species of this branch having black-brown markings on its forewings base half;branch 2 containing only B.mirostylis,and the other species being sister groups;branch 3 was((B.yingjiangensis sp.nov.+ B.nigropunctata)+(B.hainanensis + B.bakeri));branch 4 was((B.luodianensis + B.citricolorata)+(B.taiwanensis + B.huangi)+(B.jinghongensis + B.furca)).Based on the COI gene sequence and Carinodelphax carinatus as an outgroup,the interspecific phylogenetic relationships of Arcofacies were analyzed.The results showed that A.moliensis and A.strigatipennis,A.fullawayi and A.maculatipennis were sisters to each other,indicating that their relationships were closed.This conclusion is consistent with the results of morphological studies.4.Molecular identification of relative genus and species based on DNA barcodeBased on the COI gene sequence and P.theognis as an outgroup,the two related species,P.sinica and P.taiwanensis of Purohita were identified.The results showed that the interspecific genetic distance of COI was significantly greater than the intraspecific genetic distance;the same species was clustered into one and the support was 100%.This conclusion is consistent with the results of morphological studies.Based on the COI gene sequence and Arcofaciella as an outgroup,4 species of Arcofacies and 1 species of Arcifrons were used to analyze the genetic distance and phylogenetic.The results showed that the intergeneric genetic distance was0.124~0.181,and the interspecific genetic distance of Arcofacies was 0.131~0.191.The intergeneric genetic distance and ginterspecific genetic distance was overlapped.The species from the bottom to the end of the NJ tree was A.maculatipennis,A.moliensis,A.arcifrontalis,A.strigatipennis and A.fullawayi.5.New taxon based on morphology and DNA.In this thesis,a new genus and 2 new species were established based on morphological feature,and the establishment of a new taxonomic unit was supported using the molecular data of DNA barcodes.The new taxa are: new genus,Parabelocera gen.nov.;new species: Parabelocera touchia sp.nov.,Bambusiphaga yingjiangensis sp.nov.The type specimens of the new species are deposited in the Institute of Entomology,Guizhou University,Guiyang,China(IEGU).