The silkworm (Bombyx mori) is of great economic value from an industrial perspective. Casual discrimination and accumulation of genetic information from a diverse variety of silkworms are essential for practical utilization and long-term conservation. In this study, a total of 54 silkworm strains preserved in Korea were typed for nine polymorphic microsatellite loci. We determined per-locus numbers of alleles ranging from 3 to 17 with an average value of 7.5, per-locus observed heterozygosity ranging from 0.04 to 0.98, and per-locus polymorphic information content (PIC) ranging from 0.06 to 0.86, thereby indicating that some of these loci are profoundly variable. Phylogenetic analysis using the nine concatenated microsatellite loci showed no clustering on the basis of known strain characteristics and origin. A total of 17 strain-specific apomorphic alleles, which discriminate 14 among 54 silkworm strains, were obtained from eight loci. These strain-specific alleles can, therefore, be casually utilized to discriminate between applicable strains, without any further typing of other loci. Furthermore, a substantial number of homozygote strains, represented by 24 among 67 alleles in nine loci, were also detected. These results collectively implicate silkworm microsatellite DNA as useful and potentially important molecular markers for the eventual discrimination of silkworm strains, hundreds of which are currently preserved in Korea.

The bumblebee species, Bombus, is an invaluable natural resource for greenhouse pollination. Low levels of genetic variation of Bombus ardens have been reported in a previous mitochondrial (mt) gene study. In this study, we sequenced the complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA obtained from 100 B. ardens individuals collected from several Korean localities, in an effort to assess its usefulness in characterizing the genetic diversity and relationships among populations of B. ardens. The ITS2 sequences of B. ardens were shown to be longest among known insects, ranging in size from 1,971 í 1,984 bp. The sequences harbor four duplicated repeatsí~27 bp repeats, ~20 bp repeats, ~33 bp repeats, and ~34 bp repeatsíwhich have never before been reported in other insect ITS2 rDNA. The maximum sequence divergence of 1.01% among 96 sequence types confirmed the applicability of this molecule to the study of intraspecific variation, revealing higher sequence variation as compared to the previously studied mt COI gene. Overall, a very high per generation migration ratio (Nm = 5.83~infinite) and a very low level of genetic fixation (FST = 0 í 0.08) were noted to exist among populations of B. ardens. The high estimation of gene flow among most populationsíin particular, between the remote island Ulleungdo and several inland populationsísuggest that historical events may be more responsible for the contemporary population structure of B. ardens. The finding of the lowest genetic diversity (ʌ) in the population on Ulleungdo Island (ʌ = 0.007434) may be reflective of a relatively small population size and the geographical isolation of the population as compared with other inland populations.

To identify novel bioinsecticidal agents, a bacterial strain, Serratia sp. EML-SE1, was isolated from a dead larva of the lepidopteran diamondback moth (Plutella xylostella) collected from a cabbage field in Korea. In this study, the insecticidal activity of liquid cultures in Luria-Bertani broth (LBB) and nutrient broth (NB) of a bacterial strain, Serratia sp. EML-SE1 against thirty 3rd and 4th instar larvae of the diamondback moth was investigated on a Chinese cabbage leaf housed in a round plastic cage (Ø 10 x 6 cm). 72 h after spraying the cabbage leaf with LBB and NB cultures containing the bacterial strain, the mortalities of the larvae were determined to be 91.7% and 88.3%, respectively. In addition, the insecticidal activity on potted cabbage containing 14 leaves in a growth cage (165 x 83 x 124 cm) was found to be similar to that of the plastic cage experiment. The results of this study provided valuable information on the insecticidal activity of the liquid culture of a Serratia species against the diamondback moth.

The superfamily Yponomeutoidea, one of the early-derived groups in the order Lepidoptera, consists of 11 families. However, mitochondrial genome (mitogenome) sequences, popularly used for phylogeny and evolutionary tracing, are available for only seven species across six genera and five families. Thus, a larger variety of mitogenome sequences in Yponomeutoidea are required to improve our understanding of lepidopteran phylogeny and genomic evolution. In this study, we present the complete mitogenome of Atteva aurea (Fitch, 1856), the first species in the family Attevidae (superfamily Yponomeutoidea, order Lepidoptera) to be sequenced. The complete mitogenome comprises 16,329 bp and contains a typical set of genes and one non-coding region. Within Yponomeutoidea, the mitogenome of A. aurea has a unique trnI-trnM-trnQ arrangement at the A + T-rich region and ND2 junction and trnA-ND3 arrangement at the trnG and trnR junction. Twelve of the 13 protein-coding genes (PCGs) of A. aurea have a typical ATN starting codon, whereas COI has the atypical CGA codon, which is frequently found in the starting region of lepidopteran COI. Phylogenetic analyses, based on the concatenated sequences of 13 PCGs and two rRNA genes, using the Maximum Likelihood method, revealed a sister relationship between Attevidae and Praydidae with moderately low nodal support (bootstrap support = 64%).

The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is widely utilized for greenhouse pollination in South Korea. Understanding the magnitude of genetic diversity and geographic relationships is of fundamental importance for long term preservation and utilization. As a first step, we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to the "DNA barcode" region and the complete internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA from 88 individuals collected in nine South Korean localities. The complete ITS2 sequences were longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated 112-bp long repeats. The 658-bp long mtDNA sequences provided only six haplotypes with a maximum sequence divergence of 0.61% (4 bp), whereas the ITS sequences provided 84 sequence types with a maximum sequence divergence of 1.02% (21 sites). The combination of the current COI data with those of published data suggest that the B. ignitus in South Korea and China are genetically a large group, but those in Japan can be roughly separated into another group.Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population were found to exist among the South Korean populations of B. ignitus, which suggests panmixia. This finding is consistent with our understanding of the dispersal capability of the species.