Spatial and temporal genetic structure of Laodelphax striatellus Fallén (Hemiptera: Delphacidae) on 2013 populations in South Korea

The Small brown planthopper (Laodelphax striatellus Fallén, SBPH) is serious migration pest, damaged to paddy field, in Asia regions. The source of migration was known to China. In South Korea, regular migration has been mainly western parts in early June(or late May). Also, it overwintered in paddy field. Under migration history and density, genetic structure was expected to differentiation between overwintering and migration populations SBPH in South Korea. SBPH was collected 27 samples (2 time in same site) in paddy field using the beating and sweeping methods in 2013. Sampling timing was divided into April (overwintering populations) and September (3~4 generations after overwintering). Extracted 1,091 DNA samples were genotyped by performing the multiplex PCR using nine microsatellite markers. Therefore, we compared the genetic structure of SBPH among/between overwintering and migration populations. The expected heterozygosities (H_E) and observed heterozygosities (H_O) ranged from 0.772 to 0.846 and 0.391 to 0.571, respectively. Genetic differentiation(F_ST) ranged from -0.0064 to 0.0231. IBD (Isolation By Distance) showed not significant in all populations (p=0.3, r² =0.0015) indicating the high gene flow and/or recent range expansion. This results will be used important information for migration pest management of SBPH in South Korea. Further, we discuss the relationship between RSV(Rice Stripe Virus) and SBPH on the dispersal abilities.