Tracing the Origin of Korean Invasive Populations of the Spotted Lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae)

SIMPLE SUMMARY: Lycorma delicatula (White), the spotted lanternfly (SLF) is known to be native to China, India, and Vietnam, but after the first detection in 2004 as invasive in Korea, it was also found in Japan in 2008 and the United States in 2014. As a polyphagous sap-sucking insect, the SLF seriously damages the host plant by sucking phloem sap and producing honeydew, which causes sooty mold disease on leaves and this damage eventually results in an economic loss by reducing the quality and yield of the fruits. After the emergence and spread of SLF in Korea, it has not been confirmed yet where they came from and how they invaded from the source region. To infer the most likely source population for the Korean invasive populations, we investigated the population structure of SLF including its native region (China) and invasive regions (Japan and Korea) using 15 microsatellite loci which were previously developed. Our study set out to solve the correlation between the source and invasive populations of SLF, especially with regards to identifying artificial transfer possibly reoccurring in other invasive regions. ABSTRACT: Lycorma delicatula (White) suddenly arrived in Korea where it rapidly spread out in the central region of Korea and caused serious damage to grape vineyards. To trace the source region of its invasiveness, population genetic structures were compared between the native region, China, and the introduced regions, Korea and Japan. We examined 762 individuals from 38 different population collections using 15 microsatellite loci. Both principal coordinate and structure analyses displayed that the Chinese populations were separated into three subgroups which were located significantly far apart from each other. Among them, the Shanghai population was located closest to most Korean populations. Based on the genetic relationships and structures, it was revealed that the multiple introductions into Korea occurred at least three times. In addition, the Shanghai population was strongly estimated to be a source of initial invasive populations of Korea. In addition, analysis of the approximate Bayesian computation suggested simultaneous spread from two distant locations early in the invasion by artificial transportation of the host plants bearing egg masses. Our population genetics study can provide a precedent case with regards to identifying spreads by anthropogenic outcomes in other invasive regions.