Genetic variation and phylogeographic structure of Laodelphax striatellus in China based on microsatellite markers

The small brown planthopper (SBPH), Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae), is an important agricultural pest that has caused serious economic losses in the major rice-producing areas of China. To effectively manage this insect pest, we analysed its genetic variation, genetic structure and population demographic history. We used nine nuclear microsatellite loci to investigate the genetic diversity and population genetic structure of SBPH at 43 sampling sites in China. High levels of genetic diversity and genetic differentiation among most populations were detected. Overall, neighbour-joining dendrograms, STRUCTURE and principal coordinate analysis (PCoA) revealed no genetically distinct groups and exhibited an admixed phylogeographic structure in China. Isolation by distance (IBD) and spatial autocorrelation analyses demonstrated no correlation between genetic distance and geographic distance. On the other hand, bottleneck analysis indicated that SBPH populations had not undergone severe bottleneck effects in these regions. This study provides useful data for resolving the genetic relationships and migration patterns of SBPH and thus contributes to developing effective management strategies for this pest.