Rapid Identification Of The Genus Podismopsis And Similar Genera(Species)in Morphology Based On Geometric Morphology(Orthoptera: Acridoidea)

Podismopsis belongs to the Acridoidea of Orthoptera.At present,there are 45 known species(subspecies)in the world,in which 22 known species(subspecies)are in China,they are mainly live in the forest edge.Because they can make use of the friction between the forewing and the hind femur,they have strict requirements on the living environment,and in addition,there are some endemic species within the genus.Therefore,it is of great significance to carry out species origin,song differentiation and biogeography.However,due to the fact that there are not only extremely similar forms between species within the genus Podismopsis,but also evolutionary convergence with other groups living in similar environments.In addition,in the process of collecting and sorting out relevant research data,it was also found that a large number of species were named only by single sex individuals,and the original description of many known species were unknown,lacking accurate and clear identification feature maps or photographs.As a result,domestic and foreign scholars have great differences in the classification status of the genus Podismopsis,thus hindering further international communication.Therefore,it is extremely urgent to find a method for accurate and rapid identification of the genus Podismopsis and its morphological similarity.Based on the above situation,this study selected two identification characteristics,forewings and stridulatory files,which play an important role in the classification of grasshoppers.A total of 18 species of grasshoppers in 6 genera were studied by geometric morphology.At last,the most suitable characteristic for geometric morphological identification was selected,which was the forewing.Based on this,this study initially constructed a rapid identification system for grasshoppers and verified the system.The results are as follows:1.Geometric morphology research based on morphological characteristics of forewings(1)Study on the geometric morphology of the taxonomic rank of genera.The results of the study on six genera show that the forewing morphology tends to be short and wide.As the six genera involved in this experiments are all short-winged groups,it can be preliminarily inferred that the forewings of locusts are evolving towards wingless direction;compared with principal component analysis,canonical variable analysis is more able to completely distinguish the genus Podismopsis and its similar morphological genera.(2)Study on geometric morphology of the taxonomic elements at species level.The resultsshow that the variation trend of forewings,the results of principal component analysis and the results of canonical variables are similar to those of genera.Compared with principal component analysis,canonical variable analysis can better distinguish 18 species of grasshoppers.Cluster analysis show that there are 18 species of grasshoppers in P.mudanjiangensis and P.tumenlingensis.The morphological similarity of the forewings is very high.This is consistent with the results of morphological classification,the difference between the two species is mainly due to the ratio of the width of the anterior vein domain to the width of the subfrontal vein domain.2.Geometric morphology research based on the morphology of stridulatory files.(1)Study on the geometric morphology of the taxonomic rank of genera.The results of the study on 5 genera show that compared with principal component analysis,the results of canonical variable analysis can better distinguish the genus Podismopsis and its similar genera in morphology.(2)Study on the geometric morphology of the taxonomic elements at species level.A total of 12 species of grasshoppers were studied.The results show that compared with principal component analysis,canonical variable analysis can better distinguish the 12 grasshoppers.3.Selection of optimal features based on geometric morphology.In view of the great difference between the results of the study on the geometric morphology of the forewings and the stridulatory files,and in order to exclude the differences caused by the different research types,this part of the experiment made principal component analysis,canonical variable analysis and cluster analysis on the forewings of 12 species of grasshoppers corresponding to the study of stridulatory files.The results of forewing are more ideal and closer to the results of external morphological classification.This may be due to the fact that the stridulatory file will be gradually worn out with the increase of time in the process of locust’s friction and vocalization,thus changing the morphology.In addition,if the surface of stridulatory file is not clean during the preparation of SEM samples,the experimental results will also be affected.4.A rapid identification system for grasshoppers was constructed.Based on the above research results,a rapid identification system for grasshoppers were established and tested by using the forewings as geometric morphological identification characteristics.To sum up,forewing is more suitable for morphological identification of the genus Podismopsis and its similar genera(species)based on geometric morphology,and thestridulatory file can be used as an auxiliary identification feature.This study not only makes up for the lack of rapid identification methods for the genus Podismopsis and its similar morphological genera(species),but also provides a new idea and method for rapid identification of other species.