We investigated the duration of laying worker oviposition and egg-laying behavior in three queenless colonies of A. cerana by in situ video recording. Egg load was determined by dissecting laying workers in September 2012. Egg size, length and breadth, shape index and egg elongation were calculated. To determine the number of eggs laid by laying workers per cell at 24, 53, 74, 120 and 171 hours was also monitored. To estimate the number of eggs per cell per week, a small comb was squeezed between two frames. The combs were collected at given hours and weekly to count the number of eggs, respectively. The results showed that the duration of oviposition of laying workers on average was 109.2 ± 67.5 seconds per cell. During oviposition, egg-laying workers showed two types of behaviors, viz; a still phase, where the egg-laying workers did not move, and a recovery phase, where the egg-laying workers vigorously wagged their abdomens after oviposition. The results showed that on average, 4.0 ± 5.1 of worker eggs per cell per week was recorded. The highest number of eggs was recorded at 120 hours compare to at 24, 53, 74 and 171 hours. Three different shapes of the eggs namely oval, elongated long and elongated curve shaped was laid by workers. The results showed that the laying worker carried 1 to 4 mature eggs in her ovaries and may lay from one to four per oviposition. In conclusion, the laying worker shows a still and a recovery phase during and after laying the eggs. The laying workers retain 1 to 4 eggs in their ovaries. The breadth of eggs is strong positive relationships with length. One worker cell can accumulate up to 33 eggs in queenless colonies.

Ovarioles are smooth, gradually widening white tubes with different stages of eggs. The ovarioles were gently removed, and the right and left ovarioles were separated and counted the ovarioles. We observed that the ovaries of laying queens were extended from second abdominal up to fourth abdominal segments. Each ovariole is supplied with tracheae. The tracheae are auriferous types characterized by coating spiracle tubules with permeable cuticle, which may bring the tracheal air into close contact with haemolymph.

RNA interference(RNAi) is the method which controls phenotypes of gene in live cells. Chitinase is the enzyme helping digestion and absorption of old cuticles during the ecdysis of insects. In order to investigate molting-inhibition effect with the chitinase related gene in Spodoptera litura, RNA was extracted from the 5th instars. cDNA was synthesized and then we obtained about 645bp size chitinase. After PCR products were cloned into a pGEM T-easy vector, colonies were picked. DNA was extracted from the colony cultures. EcoR I enzyme was used to check whether PCR products were inserted or not. To synthesize the dsRNA, each DNA was cut with Spe I and Nco I enzymes. After synthesis, of dsRNA, approximately 5ul dsRNA was injected into the 3rd abdominal segment of S. litura 4th larvae. We confirmed insects that were phenotypically abnormal - for instance molting inhibition, change of integument color, malformation.

As a part of disease vector and possible overseas inflow caused by global warming monitoring around airport and port area, the distribution of domestic mosquitoes was investigated using BG-sentinel trap. Mosquitoes were collected during 5-days per each area in early September, using 10 traps in Cheongju (airport) and 15 traps in Pyeongtaek (port). The numbers of mosquitoes collected in Cheongju and Pyeongtaek area were 1,762 including 10 species and 1,042 including 11 species respectively. In Cheongju, Aedes albopictus (657 individuals, 37.3%) and Culex pipiens complex (415 individuals, 23.6%) were dominant species; while in Pyeongtaek, Cx. pipiens complex (806 individuals, 77.4%) was dominant followed by Anopheles spp. (90 individuals, 8.6%) and Ochlerotatus koreicus (79 individuals, 7.6%). Similar species were collected in both Choengju and Pyeongtaek area. Although most species collected in both Cheongju and Pyeongtaek area were the same, Cx. inatomii was only collected in Pyeongtaek. In case of the Genus Aedes, more number of Ae. albopictus was collected compared to Oc. koreicus in Cheongju; while Oc. koreicus was more in Pyeongtaek. In case of the genus Culex, the individuals belonging to the vishinui group were collected such as Cx. bitaeniorhynchus, Cx. tritaeniorhynchus and Cx. orientalis. This study may provide basic information for efficient prevention of vector mosquito and potential overseas inflow of diseases, also we would try to expand different area in Korea.

We are currently developing the smart mosquito counter device (height 1080mm × width 560mm × diameter 320mm, 220V 60Hz 30W), which can attract the blood sucking female mosquitoes by emitting CO2 gas (300ml/min), can count the number of the captured mosquitoes by an infra-red beam area sensor, and can send the captured mosquitoes’ number through the CDMA module at real time. We operated the 8 – 16 devices with mosquito sensor networks and a server at the Youngdeungpo-gu areas in Seoul city of south Korea for three years (2011-2013) and we could efficiently control mosquitoes at the high mosquito density area based on the mosquito sensor’s data. We found that the accuracy of the device was about over 93% compared the real mosquito data and transmitted data by CDMA. We also found the water reservoir areas to control floods in Seoul metro city had relatively higher mosquito density than other normal areas, because those flat water areas were preferred by mosquitoes. Because our pest control office knew the mosquito occurrence peak times and areas from mosquito data transmitted by the mosquito sensor devices, we efficiently controlled mosquito larva and adults at the right time. We could accomplish very systematic mosquito control policy and we had the high credibility with the results. Based on the mosquito occurrence data, we selectively and scientifically controlled mosquitoes. Therefore, we reduced pesticide usage and saved annually pesticide expenses up to 2/3. Conclusively, if there is no mosquito, we don’t have to control mosquitoes.

A surveillance of chigger mites was conducted to clarify the incidence of scrub typhus vectors by new chigger mite collecting traps instead of trapping wild rodents for surveillance from each 4 collection points of 5 regions from September to November 2012 in Korea. During the surveillance period, 2,829 chiggers were collected and 10 species of 4 genera were identified. The first appearance of chigger mite and patients was 39 week (9.19~9.25) and the density of chigger mites had the peak in 43 week (10.17~10.23) and the density of patients had the peak in 44 week (10.24~10.30), respectively. In Goryeong-gun, a total of 1,797 mites representing 4 genera and 6 species were collected and the predominant species were Leptotrombidium scutellare (86.0%), L. pallidum (6.5%) and L. palpale (4.7%) whereas, In Gurye-gun, a total of 89 mites representing 2 genera and 3 species were collected and the predominant species were L. scutellare (46.5%) and L. palpale (36.2%) in similar to the natural environment. The high collecting rates were recorded at rice field (71.8%) and waterway (11.6%). This result shows that the surveillance of scrub typhus vectors by new chigger mite collecting trap is useful as an eco-friendly method.

Macroinvertebrates were examined to elucidate community structures of a total of 5 rice paddy types, Korea. A total of 67 species were found in the study sites. Generally, macroinvertebrates were dominated by Pomacea canaliculata. Limnodrilus gotoi, Ephydridae sp. in organic rice field. Also, aquatic insects were dominated by Diptera, which constituted 25% (17 species) of the total number of species collected. The diversity of macroinvertebrate in several organic rice paddies was higher than that of conventional rice field. The organic rice paddy and nonpesticide agricultural area were also diverse. Samplings were used to detect the influence of farming activities on macroinvertebrate community variation. The study indicated that studied sites showed difference in their macroinvertebrate composition, and these differences are strongly related to differences in habitat quality and microhabitats.

Anoplophora isa moderate-sized genus with 36 species of woodboring cerambycid beetles that occur throughout Asia, with the highest diversity in the tropical and subtropical region. Two species, A. chinensis (Forster) and A. glabripennis (Motchulsky) are known in the Korean peninsula. The latter is an infamous invasive species, commonly called the Asian longhorned beetle, in the U.S. causing economic damage on hard woods. For the present study, we carried out field surveys from 2010 to 2013 and literature review on the host plants of Korean Anoplophora species. A. chinensis is associated with 14 host plant species in 4 families and A. glabripennis 17 species of 11 families. Most importantly, the Manchurian striped maple, Acer tegmentosum Maxim. (Aceraceae), is newly recognized as a host of the Asian longhorned beetle. In the present study, a revised host plant checklist of Korean Anoplophora species is provided, with correction of scientific and Korean names of the host plants.

The Zena hawk moth(Langia zenzeroides) is one of the most dangerous insect pest feeding on Rosaceae fruits(Prunus persica Batsch, Prunus salicina Linnaeus) in Korea because of gregarious diet. The study was conducted to investigate biology and the temperature effect on adult emergence of overwintering L. zenzeroides pupae at five different constant temperatures (15, 20, 25, 27.5 and 30°C) with photoperiod 10:14(L:D) and relative humidity 60%. The lower developmental thresholds of L. zenzeroides were 9.7°C. Developmental period of overwintering pupae to adults decreased with increasing temperature from 15 to 30°C. Mortality of five different constant temperatures (15, 20, 25, 27.5 and 30°C) was 4, 8, 20, 8 and 48%. Especially mortality of constant temperature 30°C was higher than other conditions and survival rate of 15°C was the highest. Thermal constants of L. zeroenzides were 109.5DD. The relationship between the developmental rate and temperature was fitted by linear and one nonlinear developmental rate models (Lactin 1). The development variation of overwintering pupae was described by the two-parameter Weibull distribution model. We investigated development period in the study site by using 70 eggs. From egg to pupa period was 84.9±0.4.

Frankliniella occidentalis (Pergande) and Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) are sympatric thrips species infesting crops including strawberry and pepper. Recently, F. intonsa was found as a dominant species locally even though F. occidentalis has been considered as a major species in Korea. We suggested interspecific competition as a underlying mechanism for the asymmetrical abundance. Effect of the competition on adult reproduction and longevity of the two thrips species was assessed in leaf cage and microtube arena, respectively. The number of reproduced progeny was reduced by 79% for F. occidentalis and only 43% for F. intonsa in competition condition. The mean longevity was also reduced greater in F. occidentalis (by 41%) than in F. intonsa (23%). Based on these results, it is probable that interference competition exists between the two species, and F. intonsa is better competitor than F. occidentalis. Therefore, interspecific competition might affect field occurrence pattern of the two thrips species.

This study was conducted to determine the effect of six different leguminous seeds a) cowpea, b) white kidney bean c) soybean (Cheongja) d) soybean (Daepung) e) mung bean and f) azuki bean on the nymphal development, mortality, adult longevity, fecundity and hatchability of Riptortus pedestris (F.) (Hemiptera: Alydidae). Total developmental time ranged from 18 to 25 days; R. pedestris fed on white kidney bean took the longest time. There was no difference in mortality among the bugs fed on the legumes except those fed on white kidney bean which had the highest mortality (94%). Also, adult bugs fed on white kidney bean showed the shortest longevity. Total number of eggs laid by adult female and the hatchability of the eggs were highest from the bugs fed on cowpea. Higher reproductive success of R. pedestris fed on cowpea suggests that cowpea could be very suitable legume for the bug and it can be used as a trap crop against the bean bug.

Several pentatomids and an alydid are reported inflicting losses in several host plants ranging from leguminous crops to fruit orchards in Korea. Understanding their visual preference would help develop mass trapping or efficient monitoring device. Visual preference of the major pentatomids and an alydid bugs to different colors and light emitting diodes (LED) of different wavelengths were observed. Adults of pentatomid such as Halyomorpha halys Stål, Plautia Stali Scott, and Nezara sp., and an alydid Riptortus pedestris (F.) were exposed to seven different colors (black, yellow, green, blue, white, cream, orange) in a multiple choice tests. Also, adult and second instar nymphs of the bugs were released inside a hexagonal LED boxes consisting of LED lamps of six different wavelengths (375 to 630 nm). Most of the pentatomids showed highest preference to blue color followed by yellow and 530 nm LED. However, R. pedestris showed higher preference to the yellow color followed by blue and black. Second instar nymphs of all the tested species also showed higher preference to 530 nm. Their color and LED lamp preference would help in development of mass trapping device.

The intracellular endosymbiont bacterium Wolbachia is currently considered the most abundant in arthropods. Many Wolbachia manipulate host reproductive systems, it lead to male-killing, cytoplasmic incompatibility, parthenogenesis and feminization of genetic males with large impact on host ecology and evolution in arthropods. In this study, we investigated the distribution of Wolbachia infection in Ae. albopictus according to geographical distribution. We selected 9 areas and collected Ae. albopictus, these areas were distinguished with mountain chain and waterway. Whole genomic DNA were extracted from collected specimens and PCR analysis were accomplished in each specimen using Wolbachia specific primers such as 16S and WSP genes. As a results, we collected 730 Ae. albopictus at least 30 specimens in each area. Wolbachia infection rate showed different patterns between geographical region. Cheonbook, Cheonnam and Yeongdong showed 100% infection rate followed by Jeju (97%), Chungchung (88%), and Gyungnam (85%) with two Wolbachia marker genes. Our results indicated that Ae. albopictus are commonly infected with Wolbachia, it is possible that Wolbachia may act as endosymbiont in Ae. albopictus regardless of geographical region. Although, low infection rate of Wolbachia, we need continuous survey for the evaluation of Wolbachia strain within Ae. albopictus as a vector of dengue fever.

Lepidopterous pests can be a problem in corn cultivation in the southern region. This study investigated the occurrence of Ostrinia furnacalis, Helicoverpa armigera and Pseudaletia separata in corn field of southern region. O. furnacalis has investigated aspects occur in Iksan, Buan and Gochang. H. armigera and P. separata has investigated the aspects occur in Buan and Gochang. Occur from early May in sex pheromone trap, showing the highest density occurs in late May, the 1st occurrence of O. furnacalis adult was reduced since the beginning of June. the 2nd occurrence of O. furnacalis adult occurs in late August and showed the highest density occurred in early September. Occurrence time showed aspects similar to the three regions of the O. furnacalis adult. 1st adult occurs in early May from Buan, H. armigera showed the highest density occurs in early August and showed the highest density occurs in early July from Gochang. The 1st adult P. separata occurs in late April, showed the highest density occurs in late June from Gochang. However, the incidence density was lower in Buan.

The species diversity of macrolepidoptera (larger species of moths) was surveyed using light traps at forests near the Forest Environmental Research Institute located in 9 provinces (Gyeonggi, Gangwon, Chungbuk, Chungnam, Jeonbuk, Jeonnam, Kyeongbuk, Kyeongnam, Jeju) in 2012. Sampling was conducted weekly or biweekly from April to October. Using light traps in 8 forests, 2,961 individuals belong to 530 species from 20 families were collected. The species richness between study sites ranged from 4 (Kyeongnam) to 258 (Chungbuk). Similarly, abundance was the highest at Gyeonggi (1,235 individuals) and lowest at Kyeongnam (11 individuals). Species diversity (H’) was the highest at Chungbuk (5.14) and lowest at Kyeongnam (1.29). Composition of macrolepidopteran species also changed seasonally, showing regional variations. Dominant species in 9 study sites were Lamoria glaucalis in Gyeonggi, Ivela auripes in Gangwon, Idiotephria amelia in Chungbuk, agrotis tokionis in Chungnam, Acosmeryx naga in Jeonbuk, Glyphodes perspectalis in Jeonnam, Spodoptera depravata in Gyeongbuk, Xestia dilatata in Gyeongnam and Lithosia quadra Jeju. Among the species, Ivela auripes, Lamoria glaucalis, and Glyphodes perspectalis were known to be sporadic forest insect pests. Therefore, continuous monitoring can be needed to prevent the potential outbreaks of such insect pests.

The dispersal distance and the flight behaviour of adult Platypus koryoensis were examined using mark-release-recapture experiment in central Korea in 2013. Sticky traps were attached to the trunks of oak trees toward release point and opposite direction up to 48.8m from the release point. For each direction, two traps were attached on upper (1.5m from ground) and lower (0.5m from ground) trunk. Platypus koryoensis which emerged within 24 hours were marked with fluorescent powder and released at 11:00 a.m. The number of recaptured beetles was counted after 30 and 90 minutes after release. The experiment was replicated three times on 20, 21, and 26 June. The numbers of beetles released were 299, 810, and 208, respectively. Recapture rates at 90 minutes after release on 20, 21, and 26 June were 0.09, 0.06, and 0.03, respectively. More than 85 percent of recaptured beetles were caught in 30m. The numbers of beetles caught by sticky traps in upper and lower trunk were not significantly different, indicating that P. koryoensis do not hover but just land and move to explore suitable for living site in trunk when they attack oak tree. The valley breeze which drive upward the valleys and mountain slopes in the daytime blew during experiment periods and maximum flight distance of P. koryoensis was 43m, even though the beetles flew against the wind.

Habitats for migratory birds provide good blood source for blood sucking insects including mosquitoes, which may lead to high population mosquito species. This study was intended to know mosquito fauna in habitats for migratory birds that have preference for bird’s blood. We selected 7 locations for migratory birds (Ansan: a great reedy marsh in lake of Shihwa; Cheonan, Gyeongju, and Pyeongtaek: pine forest; Seosan: a reclaimed land near bay of Cheonsu ; Ulsan: great bamboo forest around Teahwa river) and subdivided each location with four habitats (forest, swamp, cow shed and downtown area) as mosquito collecting site. We used two types of trap for mosquito collection such as CDC black light trap and BG Sentinel trap. Additionally, we use black light and dry ice as an attractive source, respectively. A total of 27,615 mosquitoes representing 9 genera and 18 species were collected. In Ansan, 9 genera and 17 species were collected and in the other locations only 11 to 12 species. Representing by habitats shows this; in forest 9 genera and 17 species, in swamp 8 genera and 16 species, in cow shed 6 genera and 12 species, in downtown 8 genera and 17 species. The dominant species was Culex pipiens (60%) followed by Aedes vexans (11%), Anopheles spp. (8%), Aedes albopictus (7%), and Armigeres subalbatus (5%).

Cuticular proteins (CPs) and the polysaccharide chitin are the major components of the exo- and endocuticular layers or procuticle. CPs contain a conserved sequence known as the Rebers & Riddiford (R&R) motif, which may function as a chitin-binding domain that helps to coordinate the interaction between chitin fibers and the protein network. We identified two highly abundant RR-2 CPs, TcCPR18 and TcCPR27, in protein samples extracted from elytra (rigid cuticle) of Tribolium castaneum adults and determined that these two CPs are required for rigid cuticle morphology. In this study, we identified the third most abundant protein (TcCP30) extracted from the elytra, and cloned a full-length cDNA. It encodes a very unusual 171 amino acid residue protein of which 36% of the residues of the mature protein are Glu, 21% are His, 19% are Arg, and 16% are Gly, organized in a regular pattern but not R&R consensus motif. TcCPR18 and TcCPR27 genes are expressed at 4 d-old pupae, while TcCP30 is highly expressed at 5 d-old pupae (last pupal stage) and 0 d-old adults. Immunohistochemical studies revealed the presence of TcCP30 in rigid adult cuticle (e.g. elytron, pronotum and ventral abdomen) but not soft cuticle (e.g. hindwing and dorsal abdomen). Injection of dsRNA for TcCP30 into late instar larvae had no affect on larval and pupal growth and development. The subsequent pupal-adult molt, however, more than 50% adults were unable to shed their exuvium and died. In addition, the resulting adults exhibited wrinkled, warped and split elytra. TcCP30-deficient adults could not fold their hindwings properly. These results indicate that TcCP30 may play critical roles in rigid adult cuticle formation, development and insect growth and survival. This work was supported by NRF (NRF-2012R1A2A1A01006467).

Insect chitinases (CHTs), which belong to family 18 glycosylhydrolases (GH-18), have been detected in molting fluid and gut tissues and are predicted to mediate the digestion of chitin present in the exoskeleton and peritrophic matrix (PM) in the gut. Based on amino acid sequence similarity and phylogenetic analysis, insect CHT family proteins have been classified into eight groups (group I to VIII). The CHTs belonging to different groups have distinctly different developmental patterns of expression and tissue specificity, suggestive of distinct biological functions. CHT7s belong to Group III chitinase contain two catalytic domains and one chitin binding domain (CBD). The catalytic domain 1 of this group of chitinases exhibits greater sequence similarity to one another than to the catalytic domain 2 in the same protein(s), suggesting distinct functions and/or evolutionary origins for each of these two catalytic domains. This group of chitinases, unlike most insect CHTs, possesses a predicted transmembrane segment at the N-terminal region. The recombinant T. castaneum CHT7 that was expressed in Hi-5 insect cells was bound to the cell membrane. Apparently, the catalytic domains of this CHT face the extracellular space as revealed by its ability to hydrolyze an artificial chitin substrate added to the medium. DsRNA-based functional studies (RNAi) for several CHT genes in Tribolium castaneum indicated that CHTs belong to groups I (TcCHT5) and II (TcCHT10) are critical for molting and turnover of chitin in the old cuticle. In other hand, RNAi for TcCHT7 did not affect any types of molting such as larval-larval, larval-pupal and pupal-adult. The resulting pupae or adults, however, failed to wing-expansion and abdominal contraction. Immunohistochemical analysis revealed that TcCHT7 protein is localized in newly synthesized procuticle, suggesting that TcCHT7 could be released form the plasma membrane of epidermal cells by proteolysis. Chitin seems to accumulate within the assembly zone of the elytral and body wall cuticle in dsTcCHT7-treated animals. Transmission electron microscopy revealed that down-regulation of TcCHT7 transcripts resulted in disorganization of chitin laminar and vertical canals in the procuticle. These results suggest that TcCHT7 may have critical roles in the laminar assembly and synthesis and/or deposition of cuticular chitin. This work was supported by NRF (NRF-2012R1A2A1A01006467).

Insect cuticle/exoskeleton is a first physical barrier to protect their body from multifarious environments such as desiccation, natural enemies and entomopathogenic microorganisms. Cuticle tanning (sclerotization and pigmentation) is a vital procedure for generating suitable cuticle depending on body region by sclerotization and pigmentation in insects. Insect cuticle tanning is a complex process involves hydroxylation of tyrosine to 3,4-dihydroxyphenylalanine (DOPA), decarboxylation of DOPA to dopamine, N-acylation of dopamine to N-acetyldopamine (NADA) or N-β-alanyldopamine (NBAD), oxidation of NADA and NBAD to their corresponding quinones, and reactions between the quinones or quinone derivatives with cuticle protein (CP) side chains resulting in protein cross-linking. One type of pigmentation (quinone tanning) is associated with the covalent linkage of CPs to the ring component of NBAD. In contrast, linkage of CPs to the side chain of NADA (b-sclerotization) is correlated with colorless cuticle. N-acetyltransferase (NAT) catalyzes the conversion of dopamine to N-acetyl dopamine (NADA) in cuticle tanning pathway. In this study, we studied function of TcNAT1 on adult cuticle tanning by double stranded-RNA (dsRNA) mediated gene silencing. Injection of dsTcNAT1 had no affect on animal development, growth and molting such as larva to larva, larva to pupa and pupa to adult. However, some of the resulting adults (~70%) showed split elytra that could not cover their abdomen, resulting in improper folding of their hindwings. Interestingly, body color of the mature adults (older than 3 days) was darker than that of control dsTcVer treated adults because probably due to the buildup of abnormally high levels of dopamine, which is used for dopamine eumelanin pigment synthesis (black pigment) and dopamine quinone-mediated protein crosslinking. On elytra and hindwings of these adults, darker pigments were observed around the sensory bristles that are located in the intervein regions, suggesting that NADA mediated b-sclerotization is occurred at these regions. Similarly, darker pigment was evident at veins of the hindwings of the dsTcNAT1-mature adults. These results suggest that TcNAT1 have important roles in sclerotization and pigmentation of adult body and wings (elytron and hindwing). This work was supported by NRF (NRF-2012R1A2A1A01006467).