Distribution and genetic characteristics of bisexual and parthenogenetic Haemaphysalis longicornis in South Korea

e Asian longhorned tick, Haemaphysalis longicornis, transmits several pathogens, including severe fever with thrombocytopenia syndrome virus (SFTSV) to humans and animals. H. longicornis is known to be maintained through two reproductive strategies, bisexual and parthenogenesis. Parthenogenetic individuals were found to have a larger genital apron and longer body length compared to bisexual individuals. Additionally, two thymine ‘T’ were inserted in the mitochondrial 16S rDNA of parthenogenetic individuals. In this study, we investigate the distribution and genetic differences of bisexual and parthenogenetic H. longicornis collected from 12 cities in the Republic of Korea. Bisexual and parthenogenetic individuals were found to be predominant in the southwestern and northeastern regions, respectively. The analysis of haplotype diversity using concatenated sequences of mitochondrial cytochrome c oxidase subunit I (COI) and cytochrome B (CytB) revealed that H. longicornis was grouped into two major haplotypes. Two major haplotypes were correlated with the reproductive strategies, either bisexual or parthenogenesis. Taken together, bisexual and parthenogenetic H. longicornis coexist in varying proportions depending on their locations and the genetic characteristics of these females are determined by their respective reproductive systems rather than their geographical location.