Wonhoon Lee

Taxonomic status of the Bemisia tabaci complex (Hemiptera: Aleyrodidae) and reassessment of the number of its constituent species.

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 1059 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.

Reassessment of Species Diversity of the Subfamily Denticollinae (Coleoptera: Elateridae) through DNA Barcoding

The subfamily Denticollinae is a taxonomically diverse group in the family Elateridae. Denticollinae includes many morphologically similar species and crop pests, as well as many undescribed species at each local fauna. To construct a rapid and reliable identification system for this subfamily, the effectiveness of molecular species identification was assessed based on 421 cytochrome c oxidase subunit I (COI) sequences of 84 morphologically identified species. Among the 84 morphospecies, molecular species identification of 60 species (71.4%) was consistent with their morphological identifications. Six cryptic and/or pseudocryptic species with large genetic divergence (>5%) were confirmed by their sympatric or allopatric distributions. However, 18 species, including a subspecies, had ambiguous genetic distances and shared overlapping intra- and interspecific genetic distances (range: 2.12%–3.67%) suggesting incomplete lineage sorting, introgression of mitochondrial genome, or affection by endosymbionts, such as Wolbachia infection, between species and simple genetic variation within species. In this study, we propose a conservative threshold of 3.6% for convenient molecular operational taxonomic unit (MOTU) identification in the subfamily Denticollinae based on the results of pairwise genetic distances analyses using neighbor-joining, mothur, Automatic Barcode Gap Discovery analysis, and tree-based species delimitation by Poisson Tree Processes analysis. Using the 3.6% threshold, we identified 87 MOTUs and found 8 MOTUs in the interval between 2.5% to 3.5%. Evaluation of MOTUs identified in this range requires integrative species delimitation, including review of morphological and ecological differences as well as sensitive genetic markers. From this study, we confirmed that COI sequence is useful for reassessing species diversity for polymorphic and polytypic species occurring in sympatric and allopatric distributions, and for a single species having an extensively large habitat.

Unexpected problem in Aphid DNA barcoding by universal primers

DNA barcode (mitochondrial COI) sequences have allowed for species identification of aphids. In this study, we newly found a DNA barcoding problem in a part of the DNA sequences for Sitobion avenae. Five S. avenae individuals showed differences of, on average, 32.60% in the DNA sequences from other conspecific individuals, and a 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.

Rapid diagnostic method for discriminating two types of COI sequences in the gall-forming aphid Tetraneura nigriabdominalis (Hemiptera: Aphididae) by multiplex polymerase chain reaction

Tetraneura nigriabdominalis (Sasaki, 1899) is a galling aphid that is distributed widely in Eurasia. In the present study, a diagnostic multiplex polymerase chain reaction (PCR) protocol was developed to discriminate two types of the cytochrome oxidase subunit I (COI) sequences in this species, and its usefulness was examined from 25 samples of T. nigriabdominalis. Multiplex PCR and electrophoresis revealed that 10 and 15 samples had one band of 133 bp (type A) and 426 bp (type B), respectively. This discrimination was identical to the division of the 25 samples based on the alignments of COI sequences (511 bp), indicating high accuracy of this protocol in distinguishing the two types. This protocol is useful for studying microgeographic distributions of the two types and genetic diversities in T. nigriabdominalis.

The complete mitochondrial genome of the subterranean termite, Reticulitermes speratus kyushuensis Morimoto, 1968 (Isoptera: Rhinotermitidae)

Abstract We have determined the mitochondrial genome of Reticulitermes speratus kyushuensis Morimoto, 1968. The total length of the R. speratus kyushuensis is 15,898 bp with 65.3% A + T content. It consists of 13 PCGs, 22 tRNA, and 2 rRNA genes and an A + T–rich control region. All the protein-coding genes used ATN as start codon. But the stop codons were TAA, TAG, and an incomplete termination codon (T) abutting an adjacent tRNA gene. The A + T–rich control region was 1105 bp in length with 67.8% A + T content.

Three Species of the Bemisia tabaci (Hemiptera: Aleyrodidae) Complex in the Republic of Korea; Detection by an Extensive Field Survey Combined with a Phylogenetic Analysis

Abstract 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.

Genetic Variability of the Invasive Species Metcalfa pruinosa (Hemiptera: Flatidae) in the Republic of Korea.

Abstract Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) has caused substantial agricultural damage since its recent introduction to the Republic of Korea; however, the source of this introduction is still unclear. To examine the genetic divergence and phylogenetic relationships among several populations of M. pruinosa from Korea and foreign countries, 251 COI sequences from 251 samples collected from Korea, France, Italy, Spain, Slovenia, and the United States were newly analyzed, together with seven published COI sequences from Canada. In total, 19 haplotypes were detected from the 258 COI sequences, and three haplotypes, H1, H3, and H9, were detected from samples in Korea. The MJ network and Bayesian inference revealed that the three haplotypes of Korea were closely connected with samples of Italy, Spain, Slovenia, France, and the United States. Our study revealed the possibility of multiple invasions of M. pruinosa from Europe and/or North America into Korea.

Recent multiple introductions of the gall-forming aphid Pemphigus bursarius into Japanese islands

Recently, the number of collection records of Pemphigus galls from Populus nigra has been increasing in Japan. To identify the galls on P. nigra, mitochondrial COI sequences were analyzed from galling aphid samples collected on P. nigra in Tokyo and Hokkaido. From the BLAST search and neighbor‐joining (NJ) analysis, the aphid samples were identified as Pemphigus bursarius, which has not been recorded from Japan. Two samples from Tokyo and Hokkaido showed a genetic difference of 0.30%. This result suggests that different strains of P. bursarius might have been introduced into the Japanese islands at least twice.

A New Species of the Genus Aulacorthum (Hemiptera: Aphididae) from the Korean Peninsula and Its Discrimination from a Closely—Related Species using Morphological and Molecular Characters

Aulacorthum sp. collected on Artemisia princeps and Artemisia stolonifera (Asteraceae) in the Korean Peninsula was compared with the eight Aulacorthum species using molecular and morphological characters. In the sequence analysis, the genetic divergences of two mitochondrial genes, COI and CytB, between Aulacorthum sp. and the congeneric species were higher than those among the congeneric species. In the morphometric analysis, principal components analysis using 13 morphological characters reveals that Aulacorthum sp. is distinguished from the congeneric species, especially Aulacorthum albimagnoliae, which is morphologically most similar to Aulacorthum sp.. Based on these results, we propose a new species, Aulacorthum (Aulacorthum) artemisiphaga Lee, Havelka, and Lee sp. nov., with a description of apterous and alate viviparous females and an identification key to species in the genus Aulacorthum in the Korean Peninsula based on apterous viviparous females.

Two new species of the genus Aphis (Hemiptera: Aphididae) on Veronica nakaiana and Vitex negundo, from Korea.

ABSTRACT Two new aphids, Aphis veroniciphaga sp. nov. and A. vitexicola sp. nov. (Hemiptera: Aphididae), are described from specimens collected on Veronica nakaiana Ohwi (Scrophulariaceae) and Vitex negundo L. (Verbenaceae), respectively, in Korea. They are illustrated and measured for the apterous and alate viviparous females. A key to the species of the genus Aphis on the host plant families Scrophulariaceae and Verbenaceae is presented, including polyphagous Aphis in the Far Eastern Asia.