Abstract: Oedaleus asiaticus Bei-Bienko is one of the major pest insects in the grasslands and agro-pastoral ecotone in North China. By using 8 microsatellite primer pairs, the genetic diversities of 15 geographic populations of O. asiaticus in Inner Mongolia, northern China were analyzed in order to evaluate the genetic variability within populations and genetic differentiation among populations of O. asiaticus at the molecular level. The results showed that the effective number of alleles was 3.4517-13.2881, the polymorphic information content was 0.5601-0.8563 and the Shannon’s diversity index was 0.7018-4.1789. The mean expected heterozygosity of the 15 populations was 0.6836, with the Nei’s expected heterozygosity of 0.5303-0.6513 and genetic distance of 0.1092-0.4235. The mean fixation index (Fst) and the mean gene flow (Nm) were 0.1612 and 1.6164, respectively. The 8 microsatellite loci selected are of high polymorphism, this grasshopper keeps a high genetic differentiation and moderate gene flow among populations, and the genetic variability among individuals within a population is higher than that among populations. O. asiaticus populations from 15 areas were classified into 6 groups according to the genetic distance. Genetic differentiation between populations shows a positive correlation with geographical distance. High mountains and deserts always block the population migration between areas, which is possibly the main cause of genetic differentiation. The study investigates the intrinsic connection among populations from different areas at the molecular level and provides some basic information on molecular biology for developing integrated management strategies against O. asiaticus.

Key words: Oedaleus asiaticus, geographic population, genetic diversity, microsatellite marker, genetic differentiation, cluster analysis