Cryptic species of brown soft scales, Coccus hesperidum (Hemiptera: Coccidae) revealed by molecular analysis

The brown soft scales, Coccus hesperidum (Linnaeus, 1758) is one of the serious agricultural pests in the family Coccidae, particularly on Citrus spp. and various greenhouse crops. Ironically, C. hesperidum has a cosmopolitan distribution and an extremely wide range of host plants, despite the very low dispersal abilities. Their wide geographic distribution may be explained by human mediation or an unrevealed cryptic diversity. In order to investigate above questions, we analyses the genetic patterns of C. hesperidum populations collected from South Korea, Lao PDR and USA with available sequences of various geographical populations. In the results, all populations were grouped into three distinct clades with ~9% of high genetic divergence levels. In the major clade, their genetic divergence was observed regardless of geographical distances and/or host plant differences. Based on the results of molecular analyses, we propose cyptic species of C. hesperidum, and explain that a worldwide distribution of C. hesperidum is closely related to human mediated transport.