Genetic Diversity and Fine-Scale Genetic Structure of Spodoptera litura Fabricius (Lepidoptera: Noctuidae) in Southern China Based on Microsatellite Markers

SIMPLE SUMMARY: Spodoptera litura is an important agricultural pest widely distributed around the world, which can damage numerous crops. Despite its economic importance, research on the population genetics of S. litura has been limited, preventing insight into the spread of the pest. In this study, we conducted a population genetic analysis of 24 populations of S. litura in Southern China using microsatellite markers, demonstrating the information on the genetic diversity and genetic structure of the tested populations. The results will provide pest control management strategies for S. litura in Southern China. ABSTRACT: Population genetic structure is strongly affected by dispersal events, especially for migratory species. The investigation of population structure is therefore conducive to increasing our understanding of species dispersal. Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is an important tobacco pest in China causing serious damage to multiple crops. In this study, we explore its dispersal dynamics by clarifying the fine-scale population genetics using 545 S. litura samples collected from tobacco plantations at 24 locations (mainly in Baise, Hechi, and Hezhou, Southern China). We analyzed the genetic diversity, genetic structure, and gene flow of these populations using seven microsatellite loci. Our results revealed high genetic diversity and low population genetic structure among S. litura. The genetic distance was uncorrelated with geographical distance, indicating the complete randomness of dispersal among the local populations. Our results suggest that the movement scope of contemporary S. litura might be much higher than the local-level spatial scale, which will provide a theoretical basis for pest management.