Abstract:         The mealybug species, Phenacoccus solenopsis Tinsley has caused severe economic losses during the last two decades in many countries. Recently this alien invasive species has been introduced in China and threatened the agricultural production. The rapid and accurate identification of the species has been the basis of the scientific research and management of the alien invasive species (IAS). In this study, the mitochondrial cytochrome oxidase subunit I (mt COⅠ) of the P. solenopsis materials collected from Sanya City and Lingshui County, Hainan Province were sequenced and compared with the known sequences of the species from Florida of the USA. We unexpectedly found that there were two divergent clades in the mealybug species, P. solenopsis, based on the phylogenetic tree. The genetic distance between the collections from China and those from the USA was approximately 3%. This was the first report on the molecular identification of P. solenopsis in China based on the mt COⅠ marker. These data suggest that P. solenopsis might be a species complex which includes at least two cryptic lineages or sibling species. The newly collected P. solenopsis materials from Sanya and Lingshui are of a cryptic lineage or species in the complex. The data also suggest the source of Sanya and Lingshui populations of P. solenopsis in the present study might not come from Florida of the USA. The discovery of the cryptic lineages in P. solenopsis complex is helpful for its accurate identification and the future research in its invasion ecology.

Key words: Phenacoccus solenopsis, biological invasion, species complex, cryptic lineages, mt COⅠ marker, phylogenetic analysis