Reticulitermes speratus (Kolbe) is economically important pest in East Asia including Korea, Japan and China where they infest wooden structures in urban areas. In this study, we report the first record of R. speratus speratus from Korea, which was verified using soldier morphology and molecular characteristics obtained from a mitochondrial gene. R. speratus speratus Kolbe, 1885 (Blattodea: Rhinotermitidae) are found in several provinces, mainly southern regions in Korea, whereas R. speratus kyushuensis are distributed throughout the country. Our morphological comparison showed that R. speratus speratus can be distinguishable from R. speratus kyushuensis by the ratio of the posterior postmentum width to length. In the molecular comparison, R. speratus speratus revealed genetic differences of 3.06% (range 2.60–4.10%) from R. speratus kyushuensis using cytochrome oxidase subunit II gene sequences.

The JpL species is one of the 31 species belonging to the Bemisia tabaci complex and is distributed in two countries, Korea and Japan. To clarify genetic relationships among different populations of the JpL species in Korea, 83 cytochrome oxidase subunit I (COI) sequences generated from 83 individuals collected from eight Korean provinces were analyzed together with published 16 Korean COI sequences. A total of eight haplotypes were detected from the 99 COI sequences, and 82 COI sequences shared one haplotype, hap-2. The remaining 17 COI sequences were assigned to seven haplotypes, hap-1, 3, 4, 5, 6, 7, and 8. The median-joining networks of the eight haplotypes revealed that the Korean JpL species has undergone genetic variations separately according to two groups, Korean Peninsula and Jeju Island. In addition, the phylogenetic trees constructed based on the 99 COI sequences and published seven Japanese COI sequences were divided into two clades: clade(A) consisted of 97 COI sequences from the Korean Peninsula group, and clade(B) consisted of 19 COI sequences from the Jeju Island and Japan groups. Our study suggests that the Korean populations of the JpL species might have spread and be undergoing genetic variations separately according to the two groups, Korean Peninsula and Jeju Island.

Field surveys for the Bemisia tabaci complex were conducted from 2009 to 2013 in Korea, and the results were compared with published data of the B. tabaci complex. Three species, MED, MEAM1, and JpL, were collected from several provinces. The MED was mainly collected in greenhouses, displacing the earlier invasive species, MEAM1, and the JpL species was collected in the field. JpL is newly confirmed as a unique species of B. tabaci species complex in Korea and Japan.

Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important insect pests in the world. In the present study, the taxonomic status of B. tabaci and the number of species composing the B. tabaci complex were determined based on 1,059 COI sequences of B. tabaci and 509 COI sequences of 153 hemipteran species. The genetic divergence within B. tabaci was conspicuously higher (on average, 11.1%) than interspecific genetic divergence within the respective genera of the 153 species (on average, 6.5%). This result indicates that B. tabaci is composed of multiple species that may belong to different genera or subfamilies. A phylogenetic tree constructed based on 212 COI sequences without duplications revealed that the B. tabaci complex is composed of a total of 31 putative species, including a new species, JpL. However, genetic divergence within six species (Asia II 1, Asia II 7, Australia, Mediterranean, New World, and Sub Saharan Africa 1) was higher than 3.5%, which has been used as a threshold of species boundaries within the B. tabaci complex. These results suggest that it is necessary to increase the threshold for species boundaries up to 4% to distinguish the constituent species in the B. tabaci complex.

Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important insect pests in the world. In the present study, the taxonomic status of B. tabaci and the number of species consisting of the B. tabaci complex were determined based on 1059 COI sequences of B. tabaci and 509 COI sequences of 153 hemipteran species. The genetic divergence within B. tabaci was conspicuously higher (onaverage,11.1%) than interspecific genetic divergence within the respective genera of the 153 hemipteran species (on average, 6.5%). This result indicates that B. tabaci is composed of multiple biological species that may belong to different genera or subfamilies. The phylogenetic tree constructed based on 212 COI sequences without duplications revealed that the B. tabaci complex is composed of a total of 31 putative species, including a new species, JpL. However, genetic divergences within five species, Asia III, Asia II 7, Mediterranean, New world, and Sub Saharan Africa 1, were higher than 3.5%, which has previously been used as a threshold of genetic boundary in distinguishing species of the B. tabaci complex. These results suggest the necessity to redefine the threshold for species boundaries to best distinguish the constituent species in the B.tabaci complex.

DNA barcode (mitochondrial COI) has been widely attempted for species identification of many animal groups including aphids. In this study, we newly found a DNA barcoding problem in a case study of the grain aphid, Sitobion avenae. Unexpectedly, five S. avenae individuals showed considerable differences of, on average, 32.6% in the DNA sequences from other conspecific individuals. BLAST search revealed that the five sequences are similar to those of aphid parasitoids such as Aphidius, Ephedrus, and Praon spp. (Hymenoptera: Braconidae). Based on these results, we concluded that the universal primers used in aphid DNA barcodes can amplify barcode sequences from parasitoid species within host aphids.

DNA ‘barcoding’ has potential applications in insect pest monitoring and quarantine since large numbers of DNA sequences for insect species identification have been reported in recent years. However, the exact number of relevant COI sequences in public databases such as NCBI (http://www.ncbi.nlm.nih.gov/) is not readily available. The IMGD (Insect Mitochondrial Genome Database; http://www.imgd.org) contains 162,847 partially sequenced mitochondrial gene entries originated from 35,067 hexapod species and makes it possible to check whether DNA sequences have been previously reported or not for certain insect species. In this study, we applied the IMGD to establish baseline data for the forest pest insects in Korea, before constructing a DNA barcode system. Retrieving data from the IMGD, we recognized that DNA sequences were already available for 73 of 259 species known as forest pest insects in Korea. Most of the 73 species with DNA sequences are common pests worldwide but there maining 186 species are endemic to the Eastern Palearctic region. Based on these data, we are proceeding to construct a Korean Forest Insect Pest DNA barcode database.

Fourteen species of the genus Aulacorthum Mordvilko 1914 (Sternorrhyncha: Aphididae) are recognized from the Korean Peninsula. One new species, Aulacorthum artemisiphaga sp. nov. on Artemisia princeps and Artemisia stolonifera (Asteraceae) was compared with the seven congeneric species based on their morphological and molecular characteristics. Morphometric analysis using 29 morphological characters shows that A.artemisiphaga sp. nov. can be distinguished from the seven congeneric species. In comparisons of COI and CytB genes, A. artemisiphaga sp. nov. had inter-specific genetic distances (average 7.5% for COI and average 7.4% for CytB) similar to those of other congeneric species. Host plants of the Korean Aulacorthum are reviewed.

The IMGD (Insect Mitochondrial Genome Database; http://www.imgd.org) archives 113,985 partially sequenced hexapod mitochondrial genome entries (PMEs), providing various information such as the number of mitochondrial genes or taxonomic information. The 113,985 PMEs show most PCGs including much larger number of PMEs than rRNAs and tRNAs, and the family, genus, and species information are focused on five orders, Coleoptera, Diptera, Lepidoptera, Hymenoptera, and Hemiptera in 31 hexapoda orders. The alignment of 58,238 COI gene entries shows discordance in fragment length and portion, resulting DNA barcode using 5′-region cannot be applied for all COI gene entries overall hexapod orders.

Mitochondrial genomes offer markers useful for understanding evolutionary relationships among insects. The Insect Mitochondrial Genome Database (IMGD), which was developed to support phylogenetic studies using insect mitochondrial genome sequences and comparison of genomic features across species, currently archives fully sequenced mitochondrial genomes of 114 species and 86,078 genes in partially sequenced mitochondrial genomes from 21,605 species. The IMGD provides tools supporting phylogenetic analyses and comparison of individual genome sequences (e.g., GC ratio and order of genes) via the species-driven user interface (SUI). Through SUI users can quickly analyze mitochondrial genomes at any taxon level using eight functions. The IMGD will serve as a versatile informatics platform not only for archiving rapidly increasing insect mitochondrial gene sequences but also for conducting systematic phylogenetic and comparative analyses of insects.