Karyotype And Cytotaxonomy Of Panorpidae (Mecoptera)

Cytotaxonomy is an important branch of taxonomy,it uses cytology knowledge, especially the characteristics of chromosomes to identify taxonomic categories and study their phylogenesis, and also promotes the development of classic taxonomy. Chromosomes are the carriers of hereditary material, and they carry the important information of specific heredity and variation that accumulated in the long evolution process. The chromosomal number, size, and behavior indicate the special status of categories, so they provide useful evidences for taxonomy.The chromosomal karyotypes of six scorpion flies from China have been studied in this paper. Several conclusions were found by comparing, analyzing and discussing.Panorpa obtusa Cheng and Panorpa qinlingensis Chou & Ran belong to the same genus and have the same chromosome number which is n (♂)=21. Sex determining mechanism is XO. And they have a very closer phylogenetic relationship.The chromosome numbers of Panorpa emarginata Cheng, Panorpa sexspinosa Cheng, and Panorpa curva Carpenter are not consistent, but are quite contiguous: n(♂)=20, n(♂)=19, and n(♂)=18. The three species share an XO sex determining mechanism, their phylogenetic relationship is quite chose, and these three species are similar in the level of cytology probably because of the adaptation of the environment in during the long-termed evolution period.The chromosome number of Neopanorpa pulchra Carpenter is n(♂)=11, which is quite different from the Panorpa insects. The sex determining mechanism is also XO, and its karyotype is quite primordial.According to the unattached cytological characteristics between the genus Panorpa Linn. and Neopanorpa Weele, the conclusions obtained by cytological study are in line with the results of morphological classification.The range of chromosome numbers in genus Panorpa Linn. is n(♂)=18-22. This indicates that they can only be used as the reference of taxonomy.