Neuropeptides are the largest group of neurohormones that act in intercellular communication to regulate various physiological and behavioral events during development and reproduction in animals. One of these families is Pyrokinin/PBAN (Pheromone Biosynthesis Activating Neuropeptide) family defined by a similar 5-amino-acid C-terminal sequence (FXPRLamide) that is the active core fragment for these peptides. This motif has been identified from a variety of insect orders, and even a crustacean species. This family of peptides has been implicated in various physiological functions: 1) moth pheromone biosynthesis, 2) larval melanization, 3) moth embryonic and pupal diapause, 4) visceral muscle contraction in the cockroach, 5) fly puparium formation in different insect species. To date, ~159 PBAN/Pyrokinin family peptides have been identified from 40 species. It is one of the largest neuropeptide families in insects; however, the physiological function of most of these peptides is unknown. The mechanism of PBAN control over pheromone production is only well defined for sex pheromone biosynthesis in a limited number of lepidopteran moths. No other insect groups have been reported to regulate pheromone biosynthesis using PBAN. Conventional insecticides target synapses and/or sodium channels that result in neurotoxicity in the nervous system. Unfortunately, this mode of action affects non-target animals as well. These methods remain the major tool for pest control, and the side effects cause many global problems that result in increased environmental and human health expenses. Therefore, we are faced with a requirement to develop new targeted control agents that will lead to pesticides with new modes of action. This is not impossible, but not easy. Every species-specific neuropeptide is expected to play a critical physiological function in metamorphosis and development of insects. There are no exceptions. Our long-standing question is – “how can interference/disruption ofthe insect (neuro)hormonal system be used to discover novel control tools”. To solve this question a novel approach is being applied for finding and screening novel agonist and/or antagonist to gene products, neuropeptide and receptor, from the in vitro system and through virtual modeling. This concept will be a new paradigm opening the window for the next generation of the pest control, and the principle method will be adapted for insect specific pests. Another research interest here will be presented on exocrinal products, such as semiochemicals produced from insects and plants for chemical communication that regulates insect/insect and insect/host interactions. These studies have included the identification of pheromones and the biosynthetic pathway of their production from insects. The ultimate goal of this research is to discover novel biologically-based green pesticides that are environmental-friendly pest control alternatives.

Upon mating, females of many animal species undergo dramatic changes in their behavior. In Drosophila melanogaster, post-mating behaviors are triggered by sex peptide (SP), a key modulatory substance produced in the male seminal fluid and transferred to female during copulation. SP modulates female behaviors by acting on the sex peptide receptor (SPR) located in a small subset of internal sensory neurons that innervate the female uterus and project to the central nervous system (CNS). Interestingly, however, SPR is also expressed broadly in the CNS of both sexes. Moreover, SPR is also encoded in the genomes of insects that lack obvious SP orthologs. Based on these observations, we speculated that SPR may have additional ligands that are only distantly related to SP, if at all. If so, then this also raises questions on the evolution of SP-SPR signaling. To begin to address these questions, we set out to identify additional ligands for SPR. Here, we identify myoinhibitory peptides (MIPs) as a second family of SPR ligands that is conserved across a wide range of invertebrate species. MIPs are potent agonists for Drosophila, Aedes and Aplysia SPRs in vitro, yet are unable to trigger post-mating responses in vivo. In contrast to SP, MIPs are not produced in male reproductive organs, and are not required for post-mating behaviors in Drosophila females. We conclude that MIPs are evolutionarily conserved ligands for SPR, which are likely to mediate functions other than the regulation of female reproductive behaviors. Therefore, we propose that SPR has a different ancestral function, with a role in post-mating behavior arising only recently in Drosophila evolution, concomitant with the emergence of its novel SP ligand.

Due to their ease of sequencing and high levels of nucleotide diversity mitochondrial (mt) genes have long been favoured targets for investigations of species level issues in systematic entomology particularly species delimitation and diagnostic identification. Advances in sequencing technology and price reductions have now made routine sequencing of whole insect mt genomes feasible and thus the application of much larger datasets to these perennial problems can be attempted. I will present two examples – the development of diagnostic targets within forensically important blowflies (Diptera: Calliphoridae) from scans of whole mt genome variability and the determination of species status within the cotton bollworm (Lepidoptera: Noctuiidae: Helicoverpa) – to illustrate the ease and comparative cheapness of genomics level approaches to these age old problems.

Mosquito-borne viral pathogens infect millions of people worldwide, often resulting in fatal infections. Our research interests in mosquito vector biology focuses on understanding of the molecular and genetic basis of mosquito resistance to arbovirus infections. Unlike mammalian cells including humans, for instance, mosquito cells do not show pathologic symptoms when infected by arboviruses. This observation led us to embarking a microarray study to investigate mosquito-virus interactions using Anopheles gambiae and o’nyong-nyong virus (ONNV) as a model system. As a result, we found that transcription of the hsc70B gene is increased about 2.6-fold in ONNV-infected An. gambiae compared to non-infected controls. Subsequently, in vivo RNAi silencing of the hsc70B transcript caused enhanced ONNV replication in female mosquitoes. Therefore, these results suggest that the hsc70B protein has an inhibitory effect on ONNV replication. A promoter analysis of the hsc70B locus further demonstrated that the hsc70B promoter is able to induce transcription of hsc70B in response to ONNV infection. In addition, hsc70B transcription was also induced by West Nile or La Crosse virus infection. Collectively, our findings indicate that hsc70B plays a role in suppressing virus replication as a general antiviral mechanism. Implications of hsc70B research and our other research endeavors toward the control of mosquito-borne infectious diseases will be discussed.

The functional response and spatial distribution of parasitoid may be useful for understanding host-parasitoid dynamics because information on these will give knowledge of the host-parasitoid interaction, which could lead to the development of strategy for biological control of insect pests. The functional responses of A. asychis on the green peach aphid and potato aphid was investigated in eggplant leaf-disc arena. As a result, among the three types of functional response, type III best described the A. asychis response to the aphid densities, according to the Bayesian Information Criterion (BIC). Functional response and spatial distribution of A. asychis on green peach aphid, Myzus persicae, was investigated on 5x5 eggplants in the net cage. After M. persicae were inoculated uniformly at the densities of 1, 3, 6, 9 and 12 (per plant) on upper, middle and lower leaves of each 25 eggplants, one mated female of A. asychis was introduced on the central eggplant. Each aphid density was duplicated. A. asychis showed a type II functional response different from that estimated on the eggplant leaf-disc arena. Although the initial distribution of the aphids in the 25 eggplants was uniform vertically and horizontally, the aphids became gradually concentrated on the upper leaves of eggplants, so did immature A. asychis.

Population genetics is the study of genetic constitution of Population across space and over time. Population genetics plays a pivotal role in characterizing dispersal behavior of insects and provides important clues to questions in the field of insect behavior and ecology. Understanding dispersal behavior of insects is of important issue not only for academic interests but also for application purposes including management and eradication. Dispersal is one of major evolutionary forces that can influence genetic variation of population. Dispersal is mostly driving genetic homogenization of diverging populations. Moreover, understanding dispersal pattern and capacity of insects is a key component for designing effective management and resistance management strategies of many insect pests since dispersal ability determines the spread rate of disease and resistance gene. The capability of predicting insect movement therefore is an essential component of agricultural production management systems. Here I introduce application of population genetics to insect dispersal study with the case studies of three agricultural insect pests, cotton boll weevil (Anthonomus grandis), Western con rootworms (Diabrotica vergifera) and European corn borer (Ostrinia nubilalis). These insects all are invasive and major pests of crops of U.S.A during the last ~100 years.

Strawberry, Fragaria ananassa Duchesne, is one of the important horticultural crops cultivated in greenhouses. Tetranychus urticae is one of major strawberry pests, and Neoseiulus californicus and Phytoseiulus persimilis have been used as biological control agents for control of T. urticae. The interactions between T. urticae and N. californicus and between T. urticae and P. persimilis were investigated to compare their control efficiency for T. urticae on a spatially-structured strawberry leaf disc area at different temperatures and on different treatments. The experimental arena was an array of leaf discs (3 cm diameter) placed upside down on a water-saturated cotton pad in an aluminum pan (17.4 x 21.5 cm). Twenty leaf discs (4 x 5) were placed adjacent each other for allowing dispersal of T. urticae and its predatory mites. The temperature conditions were 20, 25, and 30°C and there were six different treatments. The overall population densities of T. urticae were influenced by temperature (20, 25, and 30°C) in N. californicus treatment. In the same temperature condition, P.persimilis was more effective than N. californicus to control T. uritcae. Two predator systems were better than one predator systems to suppress the population density of T. urticae at 25°C. Some results of this study could be used to understand the spatial association of T. urticae and its predatory mites in greenhouse crops and fields.

2005년 제주도 30지역에서 곤충병원성 선충 분포 조사를 실시하였다. 미끼곤충 인 꿀벌부채명나방 유충을 이용하여 토양 내 곤충병원성 선충을 조사하였는데 1차 적으로 치사유충의 색깔 변화로 Steinernema속과 Heterorhabditis속을 구별하였 다. 30곳의 토양 시료들 중 곤충병원성 선충이 검출된 지역은 5지역으로 검출율은 16.7%였다. 분리 된 곤충병원성 선충은 모두 Steinernema spp.였는데 형태학적, 분 자학적, 생물학적 특징으로 분류, 동정 한 결과 Steinernema monticolum과 S. longicaudum으로 동정 되었다. Steinernema monticolum은 조천읍, 어리목, 성판 악, 1100도로 주위 산림에서 발견 되었고, S. longicaudum은 성산읍 한 곳에서 발견 되었다. 곤충병원성 선충의 서식처로는 산림에서 28.6%, 해안가에서 12.5% 발견 되었고, 토성은 모두 사양토였다. S. longicaudum은 공주와 논산지역에서 발견 된 바 있고, S. monticolum은 지리산에서 발견 되었었는데 제주도에서 발견 된 것은 처 음이다. 분리한 곤충병원성 선충의 계통과 접종 농도는 병원성에 영향을 주었다.

Taxonomic resolution of the Nosema/Vairimorpah clade has been augmented with DNA sequences of the small subunit (SSU) and large subunit (LSU) ribosomal RNA (rRNA) and the arrangement of SSU and LSU. Based on the two characteristics, the clade is largely divided into two, i.e. 'true' Nosema sub-group and 'non-true' Nosema sub-group within the clade. Our study shows that a novel Nosema species isolated from Pieris rapae has mixed characteristics of the 'true' and non 'true' Nosema sub-group based on the topology of SSU and LSU sequences, and rRNA of the isolate is normally organized. Additionally, the length of ITS can be a diagnostic tool to distinguish 'true' Nosema from non 'true' Nosema in the Nosema/Vairimorpha clade based on its nucleotide length as reported before. To our knowledge, this is the first report of recombination event in the Nosema/Vairimorpha clade.

The subfamily Dendrometrinae is a large group in Elateridae with about 2000 species world wide. However, this subfamily were not taxonomically reviewed in the Korean fauna. As the result of taxonomic review, 40 species are confirmed from Korea, with the description of two new genera, 11 new species, and one new subspecies. A total of 11 species are also recognized for the first time from Korea.

A new species of Closterocerus (Hymenoptera: Eulophidae: Entedoninae) is described from South Korea. The species is reported for the first time as an egg parasitoid of Pachynematus itoi Okutani (Hymenoptera: Tenthredinidae), of which recent sudden outbreak caused severe damage in larch forests. In total 61 species in Chalcidoidea are recorded as primary parasitoids of various tenthredinid sawflies in the Palaearctic area. However, no chalcidoid parasitoids have previously been recorded from P. itoi. The genus Closterocerus is cosmopolitan in distribution, and with an extremely wide host range from Symphyta, leaf-mining and gall-inducing insects to scale insects and plant lice. In Korea, one species of Closterocerus, three Chrysonotomyia, two Desmatocharis, one Neochrysocharis and one Teleopterus were known; most of them, except Chrysonotomyia sudoensis Paik, now are placed under Closterocerus. The new species is compared with 13 other species of Closterocerus that are known from the Far East.

The genus Scolytus of the family Scolytidae comprises more than 120 species through the world. Fifteen species of the genus Scolytus are revised from Korean peninsula. The genus Scolytus can be distinguished from the other genera by combination of following characteristics: frons slightly concave or convex with vertical wrinkles; club longer than 7-segmented funicle; pronotum fairly large, shining, punctured, narrowed towards the front, turning into a more slight or distinct neck-like constriction; vicinity of scutellum deeply impressed; elytra flat with punctures densely or sparsely arranged in rows; abdominal sternites from 2nd to 5th obliquely, convexly, concavely or vertically ascendant and with or without process or tubercles at middle. Scolytus frontalis Blandford, 1894 is new record to Korea. This species was collected from living Zelkova tree, Zelkova serrata which were planted along the street. We provide the habitus of this species and its biological informations.

In the family Sciaridae, only 3 species have been recorded in Korea, as the pests on various crops and mushrooms in glasshouse (Bradysia difformis Frey, 1948, Bradysia procera (Winnertz, 1868), Lycoriella ingenua (Dufour, 1839)), even though Sciaridae is one of the species-rich families in the order Diptera. There are plenty of species unknown in Korea which are very hard to identify by morphological characters in the larval, pupal stages and also female adults as well. Therefore, using the sequences of cytochrome oxidase I gene (COI) from adult male, we tested the utilities of DNA barcode to identify the species of sciarid flies.

We performed molecular and morphological analyses to determine generic limit of the genus Aulacorthum including several species with controversial taxonomic histories. The sequences of four mitochondrial genes, COI, COII, srRNA and lrRNA, and one nuclear gene, EF1a, implied that Aulacorthum is not monophyletic, with Aulacorthum magnoliae and Aulacorthum nipponicum forming a clade that is not sister to other currently recognized Aulacorthum species. Morphometric analysis based on 20 morphological characters also showed that A. magnoliae and A.nipponicum exhibited morphological characteristics distinct from congeneric species. Based these results, we propose a new genus, Neoaulacorthum ge. n. for A.magnoliae and A.nipponicum.

Investigating the molecular clock, the ancestral character states, and the correlated evolution of discrete binary traits on phylogenetic trees, we studied the evolutionary history of the family Anthocoreidae, using ~3000bp of the mitochondrial 16S rRNA and nuclear 18S rRNA and 28S rRNA genes for 44 taxa. The BEAST and BayesTraits were used to examine the divergence times, cladogenesis, and historical habitat patterns. The correlated evolution of discrete characters was tested by reversible-jump Markov chain Monte Carlo. Our results suggest that (i) the ancestral habitat patterns of dead plants may have served as an important rule for the stem group of anthocorids; (ii) the radiation of angiosperms and the prey insect in the mid-Cretaceous might have provided anthocorids with more habitat options; and (iii) the transition of habitats played an important role for the change of ovipositor patterns in the family Anthocoreidae.

The species-rich genus Aphis consists of more than 500 species, many of them host-specific on a wide range of plants, yet very similar in general appearance due to morphological resemblance toward particular morphological types. Most species have been historically clustered into four main phenotypic groups (gossypii, craccivora, fabae, and spiraecola groups). To confirm whether these morphological relationships are correlated with the genetic relationships, we compared the morphometric dataset of 28 characters measured/counted from 33 representative species with a phylogeny reconstructed from the combined dataset of four DNA regions (3,842 bp). The correlation of the rates of evolution between morphological and DNA datasets was highly significant in their diversification. Analysis of trait evolution revealed that the morphological traits found to be significant based on the ANOVA were confidently correlated with the phylogeny. The dominant patterns of trait evolution resulting in increased rates in short branches and temporally later evolution are likely suitable for the modality of Aphis speciation because they have adapted species-specifically, rapidly, and more recently for many different host plants.

The genus Loxoblemmus has three speices in Korea: L. doenitzi, L. campestris and L. equestris. Males of L. doenitzi have flat heads and triangular horns on both sides of their frons, whereas males of L. campestris and L. equestris have flat heads and no horns. The latter two species are not clearly distinguished based on morphology and thus may constitute cryptic species. We studied the divergence in morphology, calling songs, and genetic sequences to understand patterns of differentiation of these three species. Distributions of the number of file teeth and wing morphology overlapped in L. campestris and L. equestris. In calling songs, the number of pulses in a chirp was four in L. campestris, but that was greater than or equal to six in L. equestris. The genetic sequence analyses using 16S rRNA and COI barcode revealed that L. doenitzi diverged off earlier from the other two species. Thus, the genetic data were congruent with the calling song data in three Loxoblemmus species. Our results suggest that the speciation processes may be closely related to differentiation in calling songs in the Loxoblemmus complex.

Two complete mitochondrial genomes (mitogenomes) of the endangered, lycaenid butterflies, Spindasis takanonis and Protantigius superans (Lepidoptera: Lycaenidae), were sequenced. Each 15,349 bp and 15,248 bp-long genome contained both the lepidopteran specific gene arrangement that differ from the most common arrangement of insects by the movement of tRNAMet to a position 5’-upstream of tRNAIle. Neither of the species have typical COI start codon. Instead, the CGA (arginine) sequence that is commonly present in all other lepidopterans was also found in both lycaenids. The possible binding site for the transcription termination peptide, TACTA sequence, also was well retained in both species. The high A+T-content, which is a characteristic of insect mitogenomes was well reflected in the genomes in the form of higher frequency of codons with A/T nucleotides, severe A/T bias in 3rd codon position, and extremely high A/T content in the A+T-rich region. The 19 bp-long poly-T stretch and the downstream conserved motif ATAG, which were suggested previously to function as a structural signal for minor-strand mtDNA replication, was also well conserved in the A+T-rich region of both lycaenids. Phylogenetic analysis among lepidopteran superfamilies supported the relationships of either (((((Bombycoidea + Geometroidea) + Noctuoidea) + Papilionoidea) + Pyraloidea) + Tortricoidea) by concatenated amino acid sequence or (((((Bombycoidea + Geometroidea) + Noctuoidea) + Pyraloidea) + Papilionoidea) + Tortricoidea) by concatenated nucleotide sequences of 1st and 2nd codon positions of 13 protein-coding genes, two rRNA genes, and 22 tRNA genes, revealing fluctuating positions of Papilionoidea and Pyraloidea between the two data sets.

Seeking to improve the weak resolution of deeper divergences in an initial study based on five nuclear genes (6.6kb total) in 123 exemplars, we nearly tripled the total sequence (to 26 genes, 18.4 kb total) in one third (41) of the taxa. The expanded, deliberately incomplete data matrix consistently increased bootstrap support for previously-identified groupings, while introducing no contradictory groupings of the kind that missing data have been predicted to produce. To test the relative effectiveness of “more genes” versus “more taxa” sind that we compared two largely complete matrices, the initial 5 gene × 123 taxon and the 26 gene × 41 taxon data sets, that contain roughly equal amounts of sequence. The “more genes” data set yielded consistently, sometimes dramatically higher bootstrap support that is generally not attributable to taxon number alone. We also found that a gene-rich taxon subset provides reassuring evidence of strong underlying signal that is not obvious in subsequent larger analyses, helping to encourage and guide the search for deep relationships amid the noise of expanded taxon sampling.

Synanthedon haitangvora (Lepidoptera: Sesiidae) is an economically important pest of apple trees in Korea and China. We report here the identification of compounds in pheromone gland extracts of female S. haitangvora, and the male responses to blends of different components and ratios in the field. Two major components from pheromone gland extracts of S. haitangvora females were identified as Z3,Z13-18:OAc and E2,Z13-18:OAc, and the average ratio of these components was about 1:1. Seven minor components, Z9-16:OAc, Z11-16:OAc, Z9-18:OAc, Z13-18:OAc, E3,Z13-18:OAc, Z3,Z13-18:OH, and E2,Z13-18:OH, also were identified from gland extracts. Field tests showed that male S. haitangvora were attracted to Z3,Z13-18:OAc alone, but the maximum number of males was attracted to the binary blend of Z3,Z13-18:OAc and E2,Z13-18:OAc mimicking the blend found in female extracts. The addition of minor components to a 1:1 blend of Z3,Z13-18:OAc and E2,Z13-18:OAc did not increase the numbers of moths captured. The only significant effect of minor components was the strong inhibitory effect of adding Z3,Z13-18:OH to the primary binary blend. Increasing doses of the optimum pheromone blend in the lures from 0.1 to 2.0 mg increased trap catches of male S. haitangvora.