D3097: Origin of invasive species Melanoplus differentialis in the South Korea

Invasive species are unintentionally introduced into new areas through the international trade. They are able to cause a variety of impacts on agricultural environment as well as biodiversity. The differential grasshopper, Melanoplus differentialis, is highly polyphagous insect and commonly distributed throughout the North America continent. In 2018, M. differentialis was firstly identified in Ulsan, Korea. Genetic variability among populations in Korea and North America was analyzed to identify the origin of M. differentialis in Korea. Total 234 differential grasshoppers were collected from both Ulsan, Korea and America including eight states in the U.S. and two states in Mexico. The genetic variation among populations was analyzed by using concatenated mitochondrial genes including NADH dehydrogenase subunit 2 (ND2), mitochondrial cytochrome oxidase subunit Ⅰ (COⅠ), mitochondrial cytochrome oxidase subunit Ⅱ (COⅡ), and Cytochrome B (CytB). Populations in America were mainly divided into Southern and Northeastern U.S. populations. Korea population was genetically the closest to Louisiana population in Southern U.S., which had pairwise FST value of 0.20172 between the two populations. Korea population was consisted of three haplotypes. The major haplotype of Korea population (Hap_8) showed only two nucleotide differences with major haplotype of Texas populations (Hap_9), which was also found from Korea population. In phylogenetic analysis, Korea population was also clustered with Southern U.S. population. Taken together, we suggest that Korea population of M. differentialis was likely invaded from the Southern U.S. including Texas and Louisiana.