Heung-Sik Lee

In this study, we assessed the genetic diversity of the Asian spongy moth, Lymantria dispar asiatica Vnukovskii (Lepidoptera: Erebidae), in Korea. We obtained 123 sequences of the species, including those from 26 regions in Korea. We analyzed the genetic diversity within the Korean samples (n = 87) and haplotype networks between the Korean and global samples (123 sequences from 26 regions in Korea and five other countries) using median-joining (MJ) network analysis. The results showed low nucleotide diversity and high haplotype diversity (π = 0.00159; Hd = 0.660). The neutrality tests were also significantly negative. The MJ network recovered a star-shaped network with diverse populations in Korea, with 12 haplotypes and a dominating haplotype, H07, in all regions. Two haplogroups, Middle and Southern, were identified. The Middle haplogroup included haplotypes from Shandong, China, indicating shared populations between the two regions. In contrast, the Southern haplogroup, primarily found in ship and harbor samples, likely originated from invasive populations. This pattern reflects the influence of human activities such as international trade, highlighting the importance of strict monitoring at ports to prevent the introduction of invasive pests and to support effective forest pest management.

Parasitic moths are common in social wasp (Hymenoptera) nests, attacking many species of Polistinae and a few species of Vespinae. In the Republic of Korea, two moth species are known to parasitize the brood of Polistes rothneyi koreanus: Pyralis regalis (Pyralidae) and Anatrachyntis japonica (Cosmopterigidae). Although previously reported elsewhere, a novel case of parasitization was recently documented in the Republic of Korea, in which Hypsopygia mauritialis (Pyralidae) was identified in the nests of social wasps. Pyralis regalis is the most common parasitic moth in the Republic of Korea, feeding on the nests of 11 species of social wasps, mostly the Korean Vespa species. To that list of hosts, we add a species of Dolichovespula and two species of Polistes. Parasitism of Vespa velutina nigrithorax, an invasive alien hornet, by both P. regalis and H. mauritialis, was observed for the first time. However, their potential to control invasive alien hornets is expected to be low. This study provides new insights into the diversity of nest-parasitic moths in social wasp nests and their hosts in the Republic of Korea, and highlights the potential for these moths to impact pest populations.

We compared the population genetic structure between populations of the blueberry gall midge—Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae)—from blueberry and cranberry and determined the genetic relationships among geographical subgroups by genotyping 632 individuals from 31 different populations from their native USA regions (New Jersey, Michigan, and Georgia) and from invaded Korean regions using 12 microsatellite loci. Our population genetic analyses showed a clear separation between the two host-associated D. oxycoccana populations from blueberry and cranberry. Using data from only the blueberry-associated D. oxycoccana populations, we identified five genetically isolated subgroups. An analysis of the approximate Bayesian computation suggests that the invasive D. oxycoccana population from Korea appears to have been introduced from an unsampled source population rather than directly from its native range. Our findings will allow for an easier identification of the source of D. oxycoccana into newly invaded regions, as well as to determine their association with blueberry and cranberry, which based on our results can be considered as two distinct species.

The translocation of orchids (Orchidaceae) cannot be successful if one is unaware of their effective pollinators and plant–pollinator interactions. Cypripedium guttatum is a generalized food-deceptive orchid, which is highly threatened in the Republic of Korea, thus, requiring immediate translocation actions. Although effective pollinators of the orchid are well known in China, little is known about the pollinators in the Republic of Korea and the ecological context in which the orchid can be successfully pollinated. To briefly assess the pollination of C. guttatum prior to translocation, we conducted a one-month survey of general pollination and the community-wide plant–pollinator network properties. Over 21 h of observation, we found that an effective pollinator of the orchid was the sweat bee Lasioglossum virideglaucum. The network was significantly specialized and modular, but not significantly nested. L. virideglaucum (pollinator) and Arabis gemmifera (plant) were determined to be keystone species, based on network metrics. A total of six network modules were identified and the flower colors of the plant species belonging to the C. guttatum module were purple, white, and yellow. After comparing the daily network patterns, we found that pollination of the orchid was accomplished when various flowering plant species bloom, and the nestedness value was high. This study revealed that high plant and pollinator richness could increase the chance that the deceptive orchid would be pollinated. Our study suggests that the network properties of this food-deceptive orchid community could provide useful insight into understanding the ecologically suitable habitat for the translocation of the highly threatened orchid species C. guttatum.

To infer the introduction sources of the oriental fruit fly, Bactrocera dorsalis, we used a mitochondrial marker to reconstruct the haplotype network and 15 microsatellite loci to reveal genetic structure and relationships between the geographically or temporally different collections from Asia. We performed Approximate Bayesian computations to infer a global origin and a source of the quarantine collections found in Korea. As a result, the 40 populations were divided into three groups, of which genetic similarity is not related to the geographic vicinity. Korean samples had a similar genetic structure to Taiwan and Thailand ones. Our results suggest that the place of origin of the B. dorsalis specimens found in Korea’s border quarantine is likely to be Taiwan or Thailand. As the global origin of B. dorsalis, we estimated that Taiwan and Thailand were most likely the global origins of Southeast Asian populations by testing hypothetical scenarios by the approximate Bayesian computation analyses. Our results will allow easier identification of the source region of the forthcoming invasion of quarantined B. dorsalis specimens.

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.

In this study, we analyzed the potential distribution of red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in response to climate change in South Korea using CLIMEX, a species distribution model. We further attempted to evaluate the risk of the distribution/invasion and subsequent dispersion by considering climatic suitability, and functional characteristics of cities and covered cultivated areas. The climatic suitability has extended from the southern and coastal regions to inland regions due to climate change. The number of areas with EI (Ecoclimatic Index) values of more than 20 was 9 (12%) in the current climate; the value was assumed to increase to 23% (2040), 24% (2060), 42% (2080), and 62% (2100) from the South Korea coast to inland. We predicted that May to October would be the most active period in seven domestic high-habitation areas. We also analyzed the invasive risk of the red imported fire ant into covered domestic cultivation areas. Considering climatic suitability, we determined that Jeju, Pohang, Busan, Ulsan, Mokpo, and Gosan would be the most affected areas. This study can provide baseline data for the management of invasive species nationally and for regional control through predictions of the probability of settlement and direction of spread.

Infestation of phosphine (PH₃) resistant insects threatens global grain reserves. PH₃ fumigation controls rice weevil (Sitophilus oryzae) but not highly resistant insect pests. Here, we investigated naturally occurring strains of S. oryzae that were moderately resistant (MR), strongly resistant (SR), or susceptible (wild-type; WT) to PH₃ using global proteome analysis and mitochondrial DNA sequencing. Both PH₃ resistant (PH₃–R) strains exhibited higher susceptibility to ethyl formate-mediated inhibition of cytochrome c oxidase than the WT strain, whereas the disinfectant PH₃ concentration time of the SR strain was much longer than that of the MR strain. Unlike the MR strain, which showed altered expression levels of genes encoding metabolic enzymes involved in catabolic pathways that minimize metabolic burden, the SR strain showed changes in the mitochondrial respiratory chain. Our results suggest that the acquisition of strong PH₃ resistance necessitates the avoidance of oxidative phosphorylation through the accumulation of a few non-synonymous mutations in mitochondrial genes encoding complex I subunits as well as nuclear genes encoding dihydrolipoamide dehydrogenase, concomitant with metabolic reprogramming, a recognized hallmark of cancer metabolism. Taken together, our data suggest that reprogrammed metabolism represents a survival strategy of SR insect pests for the compensation of minimized energy transduction under anoxic conditions. Therefore, understanding the resistance mechanism of PH₃–R strains will support the development of new strategies to control insect pests.

We conducted quarantine insect species diversity monitoring using DNA barcoding with 517 lepidopteran samples that were obtained from quarantine inspections of foreign vessels entering Korea. For species delimitation and species identification of the analyzed samples, we applied a 2% cutoff rule. Consequently, 145 (368 samples) were considered taxonomically identified. Therefore the number of samples that were identified to the species level was relatively low, at approximately 71%. Thirty of 145 species were not known in Korea, three, i.e., Noctua pronuba (Noctuidae), Orthosia hibisci (Noctuidae), and Pieris brassicae (Pieridae), were checked as ‘Regulated pests’ in Korea.