Abstract: 【Aim】 Galeruca daurica (Joannis)is a new pest causing damages seriously in Inner Mongolia grasslands in recent years. This study aims to investigate the genetic differentiation and gene flow among different geographic populations of G. daurica in Inner Mongolia. 【Methods】 By using five microsatellite primer pairs, we analyzed the genetic diversity, gene flow and genetic differentiation among eight populations of G. daurica. 【Results】 The number of alleles and effective number of alleles per locus ranged from 10 to 18 and 9.2796 to 16.0388, respectively. The polymorphic information content per locus ranged from 0.6760 to 0.8985 and the expected heterozygosity ranged from 0.3430 to 0.5284, demonstrating the high degree of polymorphism. Moreover, the expected heterozygosity of the eight populations ranged from 0.2216 to 0.3701, with the average of 0.2680. The genetic differentiation index (F_ST) ranged from 0.1244 to 0.4116, with the average of 0.2521, and the gene flow (N_m) ranged from 0.3574 to 1.7596, with the average of 0.9622. Eight populations were clustered into three groups according to their genetic distances, and the genetic distance between populations showed a highly significant correlation with the geographical distance (r=0.4854, P=0.0180). 【Conclusion】 The G. daurica populations are characterized by low genetic diversity. The gene exchange seldom exits and high genetic differentiation occurs between different geographic populations. The lower migration ability of this leaf beetle and geographic obstacles might be the main reason for the low gene flow and high genetic differentiation.

Key words: Galeruca daurica, microsatellite marker, genetic diversity, genetic differentiation, gene flow, Inner Mongolia