Studies On Chromosomal Karyotypes Of Some Species Of Sinopodisma

This paper deals with chromosomal C-banding karyotype of some species of Sinopodisma such as S. lofaoshana, S.wulingshana, S.sinopocerca and their different populations which are all distributed in Hunan Province. The karyotype data of Sinopodisma are compared with their closer genus Caryanda and distant groups Eotmethis and Epacromiacris . On the basis of morphology , the author has analysed the thirty-five karyotype C-banding characters by the method of resemblance-near coefficient index( ), has discussed the relationship between the Sinopodisma and its close genus. Meanwhile , this paper have made a comparison in C-banding polymorphism among eight populations in Sinopodisma. And the differences of the eight populations distributed in Hunan are prelimaraily discussed. The morphological characters of three speciesBy the conventional morphological anatomy , the male circi and external genital organs of three species of the grasshoppers are observed and drawn . In the external morphology , the circus of male of S.lofaoshana wider, its apex obviously concave , forming up and low two branches(the top of the up branch blunt, while the low branch pointed). The circus of male of S.wulingshanna long-cylinderical , bendinginternally, its basis wider , its median not narrow and thin, its apex pointed-round and slightly flat. The circus of the male of S.spinorcerca wide and flat , the up branch of its apex blunt and round , while low branch like spine.The differences of the epiphalluses of three species of grasshoppers are showed in figure 2. 2. The differences of three species of grasshoppers in karyotypeThe materials used for this study are the spermary of male, the C-banding examinations were carried out according to the method of Summer(1972) with slight modifications. Five cells of metaphase of meiosis are counted in each species . The chromosomal number of three species all are 2n=20+XO, chromosomes are almost acrocentric, the chromosomal karyotypes of three species are similar. The relative length and the location of C-banding of X chomosome are resemble among three species , while the differences of C-banding in autosome are visible . These differences may be the characters differentiating these species. On the other hand, according to the method of Tan Yuan-de , the data is handled on DPS, by applying cluster analysis of karyotype resemblance-near coefficients index(), we have studied the phylogenetic relation of six species of grasshoppers. The cluster figure reflects objectively their phylogenetic relation ,and the phylogenetic relation is consistant with the results of the morphological systematics.We still find that the length of terminal and acrocentric C-banding inevery chromosome are stable, the range of ratio is between 1: 1.5 3 . 3. the discussions about differentiation of populationsOn the base of analysing and handling the data of C-banding karyotypes of eight populations of three species , it is showed some differences among the different populations .The differences can reflect fully the polymorphism of C-banding karyotypes in a species. Considering the grasshoppers of Sinopodima with small wing , it can offer some facts that the evolution of populations is coincident with geographical isolation.