Abstract: Microscopic examination of crop contents was used to determine the food prefefence of grasshoppers on typical steppe in Inner Mongolia. Results from the dietary analysis of 11 grasshopper species (Table 1) showed that 31 species of vascular plants, a species of fungus and mites were served as food sources (Table 3). The overlaps and breadths of trophic niches among these grasshopper species were studied by methods of popular indices (Table 2 & 4). On the basis of partition in utilization of food resources, the 11 grasshopper species were divided into 5 groups by thePrincipal Gomponent Analysis: graminivorous, mixed graminivorous, mixed forbivo rous, forbivorous and phytocarnivorous species (Fig. 1). The authors proposed a new concept and methods for measurement of potential and realized serious values of grasshopper species by combining average biomass of individual and realized bio mass of population of grasshopper with their plant value indices. The concept and methods are very useful for the evaluation of economic importance of the grasshopper species in this region. The coexisted relationships among these grasshopper species within the ecosystem of typical steppe are discussed.

Key words: Grasshopper——niche——food selection——utilization and par-