Pleistocene demographic expansion and high gene flow in the Globe Skimmer dragonfly Pantala flavescens Fabricius (Odonata: Libellulidae) in Peninsular Malaysia

The demographic history, population structure, and intraspecific diversity of the Globe Skimmer dragonfly Pantala flavescens Fabricius in Peninsular Malaysia were characterized based on variation of the mitochondria-encoded cytochrome c oxidase subunit I (COI) sequences. A median-joining network of 94 taxa inferred 71 unique haplotypes across four distinct geographic regions (i.e., northern, southern, central, and eastern). The distribution of these haplotypes, however, revealed no apparent geographical pattern, indicating minimal population genetic structure and high gene flow among all populations. A Mantel test showed an absence of isolation by distance (IBD), no significant association between genetic distance and geographic distance was observed. Mismatch distribution and neutrality tests provided evidence of demographic expansion during the Pleistocene dating back to 190,000-260,000 years ago. Additionally, species delimitation analyses revealed two operational taxonomic units (OTUs) within so-called P. flavescens, one restricted to the isolate from Korea; and the other representing isolates from Malaysia, Japan, and India. The present DNA analyses reflect the impact of the Quaternary glaciation in shaping the current genetic diversity and genetic structure of P. flavescens in Peninsular Malaysia.