Conclusions
Here we according to the morphological characteristics and the phylogenetic tree constructed based on the 6 genes, phylogenetic relationship of the genus Diestramima is shown. At present, the interspecies morphological characteristics and molecular phylogeny relationships of all the samples have maintained extremely high consistency. However, at the subgenus level, it is difficult to give a reasonable explanation on the phylogenetic tree although we found that some groups share some common characteristics. In phylogenetic clades ofDiestramima , similarity in geographic distribution is as important as similarity in morphological characteristics. This phenomenon may be related to their lack of wings and weak mobility. Combined with the results of biogeographic analysis, the ancestors of the genus Diestramima had already arrived in Guangxi and Yunnan provinces in China before the Miocene. The two temperature rises in the Palacocene and Miocene may have intensified the dispersal of the ancestors of the genus Diestramima in the Oriental realm. The temperature drop and the uplift of the Qinghai-Tibet Plateau were the main reasons for the divergence within the genus Diestramima . In addition, changes in humidity and changes in surface plant communities are also important factors affecting their divergence. The low mountainous hilly region of Guangxi, Guizhou and Hunan is the area where the insects of this genus are most differentiated. At the early Pliocene, they may have reached most of the areas where they are now. The arrival of the Quaternary Ice Age has caused these species to undergo violent and complex evolution in inland China.