| In this paper, we studied the biodiversity, feeding characteristics and food consumption of Calliptanus. italicus, as well as the pasture yield loss made by C. italicus in Nan Shan Pasture of Manasi county , Changji Hui Autonomous Prefecture of Xinjiang Uygur Autonomous Region. We studied the ecological threshold and established the control index of the grassland.We selected three habitats for trial: Salvia deserta habitat, Artemisia frigida habitat and Carex onoei habitat. In the three different habitats 58 species of insects which belonging to 10 orders were found totally. Twenty-one species (Seventeen species of Locusts, two species of long-horned grasshopper, one specie of cricket and one specie of Mole Cricket) was contained in Orthoptera order, and four species in Diptera, three species in Hemiptera, one species in Dermaptera, sixteen species in Coleoptera, four species in Lepidoptera, three species in Homoptera, one species in Odonata, one specie in Mantodea, four species in Hymenoptera, besides there were also another eleven species of spiders. The Shannon-winner index, Simpson index and Evenness index were significantly different in the three types of habitats when analysis with Duncan method atα= 0.05 level.The important values of five dominant species of local locusts in the three major habitats were different. The abundance value of C. italicus in Salvia deserta habitat, Carex onoei habitat and Artemisia frigida habitat was 110, 89.4 and 71 respectively.The occurrence rule of C. italicus in the different habitats is different. The Salvia deserta habitat is not suitable for C. italicus to oviposit, but the C. italicus immigrated from other places take more than 50% proportion at upper stage. Artemisia frigida habitat is not only the seedbed, but also is the immigratory destination of upper stage of C. italicus. Carex onoei habitat not only is the population source place of C. italicus. The population density more than 30 per square meter during the younger instars period.They started to migrate to different places when at 5 instar, migration rate of C. italicus.about 40%.The grass loss was heavier at Carex onoei habitat in the earlier stage, while it was heavier at Salvia deserta habitat and Artemisia frigida habitat in later period.The feeding characteristics of the adult of C. italicus was Artemisia frigida > Salvia deserta > Medicago falcate > Carex onoei > Achillea setacea > Heteropappus altaicus > Achnatherum regelianum > Stipa capillata >Festuca ovina = Agropyron cristatum=0, while that of nymphs was Artemisia frigida > Carex onoei > Salvia deserta > Achillea setacea > Medicago falcata > Stipa capillata > Achnatherum regelianum >Heteropappus altaicus > Festuca ovina = Agropyron cristatum=0.The average food consumption of the nymph from 3rd to 6th instars and the adult was 14.27mg, 18.77mg, 24.80mg, 27.65mg and 29.26mg respectively in one day. The correlation index was anyalysised between the average food consumption (dry weight) and the weight (dry weight) of different instar of C. italicus and the value of R is 0.912318,which shows that they have a high degree of correlation. Approximate digestibility of 3rd-6th instars of C. italicus's and the adult were as follows: 95%, 58%, 56%, 24%, 3%. With the insects growing, C. italicus approximate digestibility was declining. We used cover cage method and artificial simulated method to investigate the yield damage caused by C. italicus in different density. The yield loss of grass using cover cage method was 5.66g, 16.45g, 26.78g and 26.41g respectively when the population density of C.italicus was 4, 8, 12, 16 individuals/m2, while using artificial simulated method, it was 6.23g, 19.40g, 26.65g and 30.85g respectively. the value of R is 0.99086, which showed that both of the two methods can be used for measuring yield loss.Finally, we obtained the ecological thresholdof C. italicus with the ECT module, and it was 4.70/m2...
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