Studies On The Chromosomes Of Chinese Typhlocybinae (Hemiptera: Cicadellidae)

At present the classification of Typhlocybinae is mainly depend on the comparative morphology. The study about karyotype of Typhlocybinae is rarely, but the study of karyotype characteristic provides datas for the classification classification. Therefore, the study tries to discuss the change of each level of Typhlocybinae though the chromosome number and the change, the relative size and chromosome behaviour, meanwhile, it has also provides cytology datas for the division of allied species.Male meiosis karyotypes of 6 tribes, 23 generas, 56 species of Typhlocybinae in Erythroneurini,Typhlocybini,Zyginellini,Empoascini,Dikraneurini,Alebrini were studied in this paper, and the relative volumes of every chromosome were calculated. The paper has selected the characteristics of chromosome number, relative size and meiosis behaviors to analysis the changes of chromosomes of Typhlocybinae. The conclutions were:1. Chromosome numbers and range: Within 56 species of Typhlocybinae from China, the chromosome numbers vary from 2n=12 to 22, with the predominant type of 2n=16(14+XO), and 2n= 14, 18 also have a high frequency. Positive trend on chromosome number evolution is not found.2. Sex determination: In all species the sex determination mechanism is XO type, and XY is not discovered.3. Meiosis behaviors: A bouquet stage is common at meiosis prophaseⅠin Typhlocybinae. At metaphase I, the spatial arrangement of the chromosomes is: the autosomes show clavate and homologous chromosomes form a ring;the sex chromosome general presents round shape and arrangement in the central of the ring. In the fact the sex chromosome mostly locates in one side of the ring due to squashed to different angle. In anaphaseⅠ, homologous chromosomes appear separation and go to one pole of the cell respectively. The sex chromosome is behind the autosomal separation and goes to one pole. The behavior has not species specificity through the studies.4. The range of chromosome numbers is stable, so it can be used as the reference of the analysis of phylogeny. The karyotypes of every species have its specificity, thus it can provide the cytology data for the identification of allied species.The part of classification problems of Typhlocybinae are discussed through the karyotype analysis: Typhlocybinae is belonged to more evolved group among Cicadellidae, and further prove the difference between Eupteryx complex with other complexes in the tribe of Typhlocybini. The partition of species groups of Alebroides get the supporting from datas of cytology, but the species groups of Eurhadina need further study. Based on the cytology data, the species of Empoasca (s.str) sakaii and Empoasca (s.str) lutowa are independent respectively, though they are very similar in the traditional morphological view.