Deuk-Soo Choi

Redescriptions of Two Closely Resembling Chrysotoxum Species (Insecta: Diptera: Syrphidae) New to Korea

As a result of ongoing systematic study of the genus Chrysotoxum, we have discovered C. ramphostomus and C. tuberculatum for the first time in Korea. These two species closely resemble each other and need to be identified with caution. We here provide detailed redescriptions and illustrations with their diagnostic characters indicated. Chrysotoxum tuberculatum can be readily distinguished from C. ramphostomus by the following characteristics: 1) hind trochanter with small tubercle; 2) compound eyes apparently bare; 3) basal 1/5 of hind femora brownish yellow; and 4) male genitalia asymmetrical in caudal view.

Oviposition and development potential of the spotted-wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), on uninjured Campbell Early grape

The spotted‐wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), originally distributed across a few Asian countries including South Korea, has invaded North America and Europe but is absent from Australia. In order to export the South Korean grape cultivar Campbell Early to Australia, its potential to serve as an oviposition and development medium for SWD must first be determined. In this study, we determined the oviposition and development potential of SWD on Campbell Early, after elucidating the SWD life cycle and establishing an artificial diet‐based mass‐culturing system. An investigation of the life cycle under five temperature regimes (16, 19, 22, 25 and 28°C) showed that the durations of the egg, larval and adult stages were shortened when temperature was increased from 16, 19, 22, 25 and 28°C, but pupal duration was shortest at 25°C and extended again at 28°C. A test of oviposition and development potential of SWD on Campbell Early grape clusters showed oviposition of 30.8 ± 6.8 eggs per cluster of injured grapes and 157.7 ± 16.2 eggs on a culture dish of artificial diet. However, in a similar experiment using uninjured grape clusters, only a single egg was deposited on the grape skin, which soon dried. In light of these results, newly harvested grapes left at vineyards during daily harvests are unlikely to serve as an oviposition and development medium for SWD, as long as the grapes remain uninjured.

Molecular systematics of the tephritoidea (Insecta: Diptera): Phylogenetic signal in 16S and 28S rDNAs for inferring relationships among families

Phylogenetic signal present in the mitochondrial 16S ribosomal RNA gene (16S rDNA) and the nuclear large subunit ribosomal RNA gene (28S rDNA) was explored to assess their utility in resolving family level relationships of the superfamily Tephritoidea. These two genes were chosen because they appear to evolve at different rates, and might contribute to resolve both shallow and deeper phylogenetic branches within a highly diversified group. For the 16S rDNA data set, the number of aligned sites was 1,258 bp, but 1,204 bp were used for analysis after excluding sites of ambiguous alignment. Among these 1,204 sites, 662 sites were variable and 450 sites were informative for parsimony analysis. For the 28S rDNA data set, the number of aligned sites was 1,102 bp, but 1,000 bp were used for analysis after excluding sites of ambiguous alignment. Among these 1000 sites, 235 sites were variable and 95 sites were informative for parsimony analysis. Our analyses suggest that: (1) while 16S rDNA is useful for resolving more recent phylogenetic divergences, 28S rDNA can be used to define much deeper phylogenetic branches; (2) the combined analysis of the 16S and 28S rDNAs enhances the overall resolution without losing phylogenetic signal from either single gene analysis; and (3) additional genes that evolve at intermediate rates between the 16S and 28S rDNAs are needed to further resolve relationships among the tephritoid families.

A review of the genus Adoxophyes (Lepidoptera Tortricidae) in Korea, with description of A. paraorana sp. nov.

Abstract We reviewed the genus Adoxophyes (Lepidoptera: Tortricidae) from Korea and recognized three species of the genus. Among them, A. paraorana sp. nov., formerly misidentified as A. orana in Korea, is described as new to science. Adoxophyes orana, a notorious pest known in most Eurasian countries for a long time, turns out to be only recently introduced or found in Korea. Photographs of the adults and genitalia of the species are provided. Specific distinction was supported by the COI barcode study.

Conservation of Hipparchia autonoe (Esper) (Lepidoptera: Nymphalidae), Natural Monument in South Korea

Hipparchia autonoe, designated Natural Monument no. 458, is a species inhabiting Mt. Halla on Jeju Island, which is the only habitat of H. autonoe in South Korea. Recently, this species is in danger of extinction as the population has been remarkably reduced because its host plants and nectar plants are gradually disappearing due to plant succession in its habitat. On the climbing road of Jeju Island Eorimok, H. autonoe used to be observed at and above 1300 m a.s.l. However, since Sasa quelpaertensis has recently expanded its habitat up to 1400 m, H. autonoe is now observed at and above 1500 m. In Mongolia, the population of H. autonoe seems quite stable as there are dense populations of a host plant and nectar plants. Accordingly it is judged that we can maintain a stable community for support of H. autonoe if we successfully manage the host plant and nectar plant communities by controlling the density of S. quelpaertensis using biological and physical control methods. Comparative analysis of DNA barcode region of COI (658 bp) was done to check the homogeneity and the genetic diversity of H. autonoe collected in Korea and Mongolia. The DNA sequence difference among individuals collected in South Korea was 0.0–0.2%, and in Mongolia 0.0–1.4%. This confirmed a 0.06–1.2% barcoding gap. We believe that this result will provide basic information useful to guide conservation of H. autonoe in South Korea.

Geographic variation in the spotted-wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), based on mitochondrial DNA sequences

Abstract The spotted-wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is an economically damaging pest that feeds on most thin-skinned fruits. It was originally native to a few Asian countries, including Korea, but is now found in North America and Europe. In this study, we sequenced portions of the mitochondrial (mt) COI and ND4 genes from a total of 195 individuals collected mainly from Korea. We then combined GenBank-registered COI sequences from all ancestral-range and introduced-range populations with our own COI data to assess the worldwide diversity, divergence, and relatedness of SWD haplotypes. A total of 139 haplotypes were obtained from the concatenated COI and ND4 sequences. Most haplotypes were confined to single localities, but 12 of them were found in more than two localities, and one haplotype (SWDCN61) was found from Korea to Canada. A dataset combining GenBank sequences with our own data identified a total of 94 worldwide COI haplotypes with a maximum sequence divergence (MSD) of 5.433% (32 bp). Although most haplotypes were found in only a single country, a few haplotypes were found commonly in China, Korea, and Japan; these occurred at a higher frequency and were often involved in introductions. A rough estimate of genetic diversity in each country showed higher diversity in ancestral distributional ranges, but the invasion over Asian countries seems to have been substantial because haplotype diversity was only 2.35 to 3.97-fold lower in the U.S.A, Canada, and Italy than that in the populations’ ancestral ranges.

Genetic relationships between Mt. Halla and Mongolian populations of Hipparchia autonoe (Lepidoptera: Nymphalidae)

Hipparchia autonoe belongs to the family Nymphalidae (Lepidoptera) and is designated as an endangered insect and national monument in Korea. It only inhabits a very restricted area on Mt. Halla but is widely distributed in several Asian countries including Mongolia. A previous study conducted to understand the genetic relationship between Mt. Halla and Mongolian H. autonoe for conservation purposes suffered from a limited number of samples. Therefore, we sequenced the DNA barcode region of an additional 36 H. autonoe individuals, combined them with previous data from 19 individuals, and performed phylogenetic and population genetic analyses. Furthermore, the internal transcribed spacer 2 (ITS2) region was also sequenced from the 36 samples as a nuclear DNA marker. The existence of independent haplotypes, sequence types, and significant FST estimates (P < 0.05) between Mt. Halla and Mongolian populations indicated hampered gene flow between the populations. Nevertheless, an absence of a reciprocal monophyletic group in Mt. Halla and Mongolian populations by cytochrome oxidase subunit I gene‐ and ITS2‐based phylogeny suggests that the genetic isolation of the Mt. Halla population from the Mongolian populations seemed not large enough to consider them independent genetic entities.

Phytosanitary Cold Treatment of Spotted-Wing Drosophila, Drosophila suzukii (Diptera: Drosophilidae) in ‘Campbell Early’ Grape

Abstract The effects of cold storage temperature and exposure duration on different developmental stages of spotted-wing drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) on ‘Campbell Early’ grapes were examined to establish a phytosanitary control method. The immature stages (eggs, larvae and pupae) of SWD were all dead after a 6-d cold treatment at 1°C and 8-d cold treatment at 1.5 and 2°C. Probit-9 estimated a fourfold increase in cold treatment duration to achieve 99.9968% mortality, compared with the observed mortality. Efficacy tests using pupae, which were the most cold-tolerant stage, confirmed the validity of the selected temperature and exposure durations. Based on these results, 1°C, which requires a shorter exposure for complete mortality, was selected for the test in conditions that mimic those of grape exportation. Six-day cold treatments at 1°C produced 99.57%, mortality in different replicates, although the surviving pupae died later. Conversely, the 8- and 10-d treatments at 1°C showed 100% mortality, suggesting that these treatments can provide quarantine security against infestations of SWD on exported Campbell Early grapes, although an additional experiment with an increased sample size is required for further reliable conclusion.

Complete mitochondrial genome of the spotted-wing drosophila, Drosophila suzukii (Diptera: Drosophilidae)

Abstract The spotted-wing drosophila, Drosophila suzukii (Diptera: Drosophilidae) is an Asian species introduced into North America and Europe. It damages a wide variety of thin-skinned fruits. We sequenced the complete mitochondrial genome (mitogenome) to better understand the mitogenomic characteristics of this species. The 16 230-bp complete mitogenome of the species consists of a typical set of genes, including 13 protein-coding genes (PCGs), two rRNA genes and 22 tRNA genes, and one major non-coding A + T-rich region, with an arrangement typical of insects. Twelve PCGs began with the typical ATN codon, whereas the COI began with TCG, which has been designated as the start codon for other Drosophila species. The 1525-bp A + T-rich region is the second longest in Drosophila species for which the whole mitogenome has been sequenced, after D. melanogaster. Phylogenetic analysis using the 13 PCGs of the Drosophila species indicated that D. suzukii is placed, with a strong support, in the basal lineage of the previously defined Melanogaster group.

Five Species of Syrphidae (Insecta: Diptera)Newly Recorded in Korea

In Korean Peninsula, a total of 175 syrphid species are currently known. As a result of ongoing systematic study of the family Syrphidae, we have discovered the following five species for the first time in the Korean Peninsula: Mallota rossica Portschinsky, 1877, M. shatalkini Mutin, 1999, Sphiximorpha rachmaninovi (Violovitsh, 1981), Volucella bivitta Huo et al., 2007, and V. inanoides Herve-Bazin, 1923. Among these taxa, Sphiximorpha Rondani, 1850, is the genus recorded for the first time in Korea. In total, three subfamilies, 16 tribes, 70 genera, and 180 species are now officially recognized for the Korean syrphid fauna. In order to facilitate their identification, we here provide specific diagnoses and color photographs for the species listed.