The Taxonomic Study On The Special Gernera And Species Of Acridoidea In The Northeast Area(Orthoptera: Caelifera)

Acridoidea is a bigger superfamily in Caelifera of Orthoptera, with more than10000known species in worldwide. Acridoidea is typical phytophagous insects. Several specieswhose tegmina developed and body robusted have strongly migration capacity, so theybecome important pests in agriculture and forest. However, because of high content ofnutrients, they also become important food resource insects. This study on Acridoidea is notonly have theoretical significance but also practical value in pests control, plant protectionand resources usage.Special species refers species which distribution in one region, and at the same timeother regions do not have. These species are impact by biogeographic history of the processand the ecological environment. Special species are resourceful abundant in Northeast Area ofChina, but revelant reports are rare. In this paper, i first list a cataloge of Acridoidea specialspecies and describe their distribution, which distribute in Northeast Area. Because of most ofthem are closely related species, and are difficult to distinguish by morphological, then icollected34species of Acridoidea which belong to3families,10genera, decribed theirconfigurations separately, and researched them with the methods of anatomy, cytology andmolecular. Their purpose is to discuss the phylogenetic relationships.1．MorphologyIn this part, the configurations of34special genera and species of Acridoidea weredescribed using the traditional classification methods. During the collection process idiscovered two new species (P. angustifronsensis sp. nov. and P. squamopennis Lu, Wang etRen). The classification system that Xia brought up in1985, which devided Acridoidea intoeight families was used. The results are as follows.The34species of Acridoidea belong to3families,9genera are:①Family Catantopidae:Genus Zubovskia Dov.–Zap;Genus Anapodisma Dovnar-Zapolskii;Genus Primnoa Fischer-Waldheim;Genus Podisma Berthold;Genus Miramella Dovnar-Zapolskii;②Family Arcypteridae:Genus Podismopsis Zubovski;③FamilyAcrididae:Genus Chrysochraon Fisch; Genus Confusacris Yin et Li;Genus Mongolotettix Rehn.2．AnatomyIn this part, the alimentary canals of25species of Acridoidea were analyzed using themethod of the external anatomy and scanning electron microscope. The relation betweenmorphological characters of alimentary canals was briefly discussed, and the clusteringanalysis of these25species was studied based on their lengths of foregur, midgut, hindgut,crop, proventriculus, gastric cecum and cardia. The results are as follows.(1) The alimentary canals of grasshoppers include three parts: foregut, midgut andhindgut. The significant differences between different genera exist in the proventriculus andcardia.(2) For Acridoidea high level: there are some obviously differences in the morphologicalcharacters of alimentary canals between different families and different genera. It can be usedin classification of different families and different genera.(3) For Acridoidea low level: the selected species which used in this experiment areclosely related species. There some differences in the morphological characters of alimentarycanals among them, but this difference is not obvious. Even though, the morphologicalcharacteristics still can play a supporting role in the classification of the different species ofthe same genus.(4) The morphological characters of alimentary canals of grasshoppers are the result oflong-term selection and adaptation with plants. In another word, there is closely relationshipbetween morphological characters of alimentary canals and feeding habits. These interactionrelationship not only to provide basic information to analysis the feeding habits of differentkinds of grasshoppers, but also practical value in pests control.(5) The results of clustering analysis are consistent with those of morphologicalclassification．It showed that clustering analysis method has some reference value.3．CytologyIn this part, the chromosomal conventional karyotypes of18species of grasshopperswere studied, which belong to2families,6genera. At the same time the clustering analysis ofthese species was studied based on their chromosomal relative lengths, and the karyotypespattern graph was made. The results are as follows.(1) All the species of grasshoppers have the basic sex determining mechanism XX♀/X0♂. The family Catantopidae has the chromosome numbers of2n=23or21, chromosomeare all telocentric chromosomes; the family Arcypteridae has the chromosome numbers of2n=17, the first to the third paris of chromosome are sumbmetacentric chromosome, othersare telocentric chromosomes.(2) Zubovskia Dov.–Zap, Primnoa Fischer-Waldheim, Podisma Berthold, Miramella Dovnar-Zapolskii and Anapodisma Dovnar-Zapolskii of Catantopidae are withoutflying ability. Their cytology characters are similar. This may relevant that they acclimatizedthemselves to similar environmental conditions during perennial evolution.(3) There are some obviously differences about the cytological characters betweendifferent families and different genera. It can be used in classification of different families anddifferent genera.(4) Because of the same genus of different species have closely relationship, theircytological characters have some commonalities. But there are also have some differences ingenome formula, the size of chromosomes and their chromosomal relative lengths, the type ofsex chromosomes. The more species in the same genus which we studies, the moredifferences between species are obviously. Therefore, the chromosomal karyotype could usein different species.(5) The results of the clustering analysis are consistent with that of anatomy and theseresults are in line with the result of morphological classification. In another word, thekaryotype evolution of grasshoppers is parallel with that of morphology evolution.4．Molecular BiologyIn this part, total genomic DNA was extracted from26species,8genera,3families.21sequences of Cytb (492bp) and23sequences of16SrDNA (420bp) have been acquired byPCR amplification and sequenced using specific two pair primers. The base frequency, aminoacid frequency, base substitution and genetic distance of DNA sequence were analyzed usingsome biosoftware such as DNAMAN, DNAsp5and MEGA5.05software. The phylogeneticrelationships were reconstructed from the Cytb and16SrDNA, and the data was combinedusing PAUP4.0(NJ, MP), PHYMLv2.4.4(ML) and MrBayes3.1.2(BI). The results are asfollows.(1) In Cytb gene sequences (492bp): the average content of A, T, G, C of Cytb genesequence are40.3%、32.4%、16.0%and11.3%respectively, and the A+T average content is72.7%, the G+C average content is27.3%. The A+T average content of the first site, thesecond site and the third site is75.0%,64.2%and78.6%respectively.In16SrDNA gene sequences (420bp): The average content of A, T, G, C of Cytb genesequence are33.4%、37.9%、17.5%and11.2%respectively, and the A+T average content is71.3%, the G+C average content is28.7%. The A+T average content of the first site, thesecond site and the third site is72.1%,68.1%and72.9%respectively.The content about A+T and G+C are similar in Cytb gene sequences and16SrDNA genesequences. They all show a strong A+T bias.(2) In21sequences of Cytb, the average transition and transversion ratio (R) is1.29.Average transition is highly more than average transversion. The average transition andtransversion ratio (R) are different in different sites of codon. The transition and transversion ratio (R) of the second site is highly more than that of the first and the third site. Thetransition and transversion of the third site are all highly more than that of the first and thesecond site.In23sequences of16SrDNA, the transversion is highly more than transition. Theaverage transition and transversion ratio (R) is0.9different from that of Cytb. Transitionfrequently occurs between A and G, and transversion usually occurs between T and A. It isthe same as Cytb.(3) The relationship between P distance and R value are dependence. This dependence ofR is a typical characteristic of the insect mitochondrial DNA. As the P distance increases, theR value showed downward trend basically.(4) The phylogenetic trees were inferred from the Cytb,16SrDNA single gene andcombined gene sequences using4methods to construct NJ、MP、ML and BI. Although theclustering results of individual species exist difference, there is still a certain degree. And thesupport rates of the various branches of the trees of combined gene sequences significantlyhigher than that of a single gene(5) The phylogenetic trees were inferred from the Cytb,16SrDNA single gene andcombined gene sequences are all supported that family Catantopidae and Arcypteridae arenon-monophyly group. The conclusion is the same as the former.(6) I assumed that Podismopsis angustipennsis, Podismopsis dolichocerca, Podismopsistumenlingensis and Podismopsis mudanjiangensis are the same species of the genus ofPodismopsis.In the above results we can see that, the results of the above three parts are accordant andconsistent with those of morphological classification. Although individual species clusteringresult are difference, the result is the same as that of traditional classification. At the sametime the modern classification methods are absolutely used in identification of closely relatedspecies. The modern classification bear the accuracy, impersonality and delicacy and play as aremedy for the traditional classification, especially for closely related species. Because of thecharacteridtic of intuition, traditional classification is not given up. The results ofphylogenetics analyses based on traditional classification and modern classification are moreconvinced compared with the sole analyses.