Abstract: The trophic niche and interspecific food competitive model of 12 grasshopper species in Ningxia desert grassland were studied.Microscopic examination of crop contents was used to analyze the food preference and food utilization menu to determine the overlap and breadths of trophic niches among these grasshopper species.On the basis of the differentiation characteristics of ecological niches,the 12 grasshopper species were divided into 4 trophic demanded groups:forbivorous,mixed forbivorous,mixed graminivorous,and mixotrophicus species.Anew model to evaluate the interspecific food competition was proposed by combining feeding frequency,biomass and population density of grasshopper,and the interspecific food competitive interactions among 12 grasshopper species were discussed.

Key words: Grassland grasshopper, Tropic niche, Food selection, Competitive evaluation, Grassland ecosystem, leaf N and P stoichiometry, rocky desertification, plant functional group