The Study On Geometric Morphometric And Biodiversity Of Eysarcoris(Hemiptera:Pentatomidae)

Eysarcoris belongs to Hemiptera,Heteropter,Pentatomidae,Pentatominae.Eysarcoris is a genus of small,mottled brown stink bugs found in Europe,Asia,Africa and Australia.Since it was established by Hahn in 1834,there are 14 species(nine in China)recorded in the Palearctic and Oriental Regions of China.Some species of this genus such as E.aeneus,E.ventralis and E.trimaculatus are main pests of rice in many rice-producing countries.Eysarcoris can be easily distinguished from other genera because of its basal angle feature in the scutellum with small,yellow,or pale smooth spots.Nevertheless,Eysarcoris species show complex variances.Traditionally,the taxonomy of this group is mainly based on the structure of the male genitalia.However,in addition to comparisons of male genitalia and morphological descriptions,novel methods should be developed to identify the species.This dissertation deal with the genus Eysarcoris from China,its brief research history,taxonomic,biodiversity and the geographic distribution pattern are studied.Seven charpters are organized to reveal the novel of the genus Eysarcoris in China.The seven charpters are generally devied into four parts,and they are the General introduction part,the Geometric morphometric analysis part,the Biodiversity part and the Conclusion part.For the General introduction part:the first charpter.The biology and the research history of the genus Eysarcoris in China,the remaining problems and economic pest are reviewed.The theory and application of geometric morphometric are also briefly reviewed within this partFor the Geometric morphometric analysis part:the second to fifth charpter.In the second charpter,geometric morphometric approach was employed to evaluate the shape variation of three characters(fore wing,hind wing and pygophore)of Eysarcoris aeneus,Eysarcoris annamita and Eysarcoris ventralis to ascertain whether this approach is a reliable method for the taxonomy of Eysarcoris,Analysis was conducted on the landmarks of the three characters of these groups.Our results demonstrate that for all the three characters,the distribution of the three studied species corresponds with their species status.No pygophore shape divergence is observed between E.aeneus and E.parvus(P>0.05),and the wing shape divergence presented by E.aeneus and E.parvus,is lower than those observed among other pairwise comparisons.This study demonstrates that the geometric morphometrics of pygophore might represent a possible tool for the identification of species within this genus.The shape the wing shape can be applied in intraspecific studies.In the third charpter,geometric morphometric methods is for the first time applied to investigate the shape variation of six characters(fore wing,hind wing,pygophore,head,pronotum,and scutellum)among nine Eysarcoris species from China.Canonical variate analysis show significant divergence in the shapes of the six characters among the studied species(P<0.05).Cluster analysis show the degree of similarity of characters among eight different species of Eysarcoris(except for E.trigonus).For all of the methods we used in this study,phenetic similarity based on all of the six studied characters are in agreement with traditional classification of the species.The geometric morphometrics of the characters represent a reliable tool for the identification of Eysarcoris species.In the fourth charpter,the statues of the genus Eysarcoris was examinated,and the results showed that it is clearly close to Dymantiscus and Carbula with border,shorter and tongue-shaped scutellum.In the fifth charpter,wing shape of E.aeneus,E.annamita and E.guttiger populations from different province were compared,and significant divergence were observed(P<0.05).For the Biogeography part:the sixth charpter.The diversity and geographic distribution pattern of the genus Eysarcoris in China was analysed with the use of Geographical Information System.The relationships between species richness and elevation is analysed.Our results show that under the affection of temperature and precipitation,there are more Eysarcoris in the eastern part of China than in the west,and more in the south than in the north.For the Conclusion part:the seventh charpter.Conclusions of the dissertation.