We investigated the distribution of ixodid ticks in severe fever with thrombocytopenia syndrome (SFTS) case reported areas using flagging method from May to November 2014 in Korea. We collected 13,471 ixodid ticks with 2 genera and 3 species. Among them, Genus Haemaphysalis and Ixodes accounted for 99.9% (13,455) and 0.1% (16), respectively. Genus Haemaphysalis consisted of 2 species, H. longicornis (96.2%) and H. flava (3.7%). I. nipponensis was only collected in Genus Ixodes. H. longicornis was the dominant species (over 90%) in most study areas. Ixodid ticks were evenly distributed at various environmental sites, such as residences, hills, grassfields, fields, graves, copses, other sites. The further study on SFTSV infection in ixodid ticks will be needed.
Insects are among the most diverse groups of animals on the planet, representing more than half of all known living organisms. These insects are found in nearly every environment. Although humans regard certain insects as pests and attempt to control them using insecticides, most insects perform complex ecological functions, and provide either direct or indirect economic benefits to humans. Recently, the importance of insects used as food sources or as pets has increased in many countries, including Korea. In addition, several insects have a strong influence on people's emotion. Insect-mediated mental healthcare program is designed to help people who have disorders with physical, behavior and development. Children who have mental disorder, the experimental group that was provided with an insect-mediated mental healthcare program over a total of 8 sections, one section per week, 60 minutes per section, followed by pre-test and post-test. They responded to therapeutic effect after the completion of the program. Further research on the basis of this study is expected to help children with emotional therapy in other areas.
A surveillance of chigger mites was performed to monitor the incidence of scrub typhus vectors at 4 environmental collection points of 6 locations from September to November 2014 in Korea. During the survey period, 420 chigger mites were collected and the dominant species was Leptotrombidium scutellare (42.6%). The first appearance of chigger mite was at 37th week (9.3.-9.10.) and the collected numbers of chigger mites was the highest at 43rd week (10.17.-10.23.). In Goryeong-gun, 299 chigger mites were collected, whereas 5 chigger mites were collected In Yesan-gun. The high environmental collecting rates were recorded at rice field (56%) and waterway (20%). The annually collected numbers (2012-2014) of chigger mites were compared with the average temperatures in August. This result suggests that the average temperature in August might be related with the annual incidence of scrub typhus vectors in Korea. However, the relationship between climate factors and the density of chigger mites needs to be studied by long-term periodical surveillance.
Trombiculid mites are known to be the vector of scrub typhus by transmitting rickettsial pathogen, Orientia tsutsugamushi, to human. In this study, we tried to establish a monitoring system for trombiculid mites using chigger mite collecting traps instead of the conventional rodent-capture method. For selection of collecting points, 10 environmental points were chosen from three regions (Taean, Jinan and Chungju) and two field collections were performed in spring (March-May) and autumn (October-November) seasons from 2013 to 2014. Among 10 environmental points, waterway (37.9%), grass field (28.0%), rice field and field near mountain side (11.4%) and reservoir/wet field (7.3%) showed high collecting rates and they should be included for the representative collecting points for surveillance using chigger mite collecting trap. In order to test the possibility that the dried chigger mites from collecting trap can be used for detection of O. tsutsugamushi, we pooled 30, 10 and 5 chigger mites separately and performed the nested PCR. The infection of O. tsutsugamushi was successfully detected from 5 chigger mites pooling sample. This study shows that chigger mite collecting trap could be an alternative method for monitoring system of scrub typhus vectors.
The population of managed honey bees has been dramatically declining the recent past in worldwide. The one of most common disease of bees is nosemosis, the nosemosis is caused by microsporidia in the genus Nosema. Nosema apis and N. ceranae have been described as honeybee pathogens. These microsporidia are highly evoloved fungi with an obligately intracellular parasitic lifstyle. The disease causes significant detriment to honey production and results in economic losses. In our knowledge, Fumagillin is the only antibiotic approved for control of nosemosis in honey bees, however this antibiotic may have unintended effects on the honey bee host, ultimately contributing to increased prevalence and pathogenicity of Nosema. Therefore, we screened anti-Nosema substances from entomopathogenic fungal culture filtrates using in vitro polar tube germination assay. These fungal metabolites are employed as antibiotic agents. As results, Total 3 samples (23% of 13 total samples) showing the germinating inhibition against N. ceranae. This screening method may be useful for the detection of anti-Nosema substances from various samples and selected samples in this study may be a good feature to be used in the development of a new biocontrol method of nosemosis.
The small brown planthopper (SBPH), Laodelphax striatellus Fallén (Hemiptera: Delphacidae) is one of the major insect pest against rice, Oryza sativa L. in Korea. High density of SBPH could cause severe damage on rice plant by directly sucking and indirectly transmitting viral pathogens, Rice stripe virus and Rice streaked dwarf virus. As a preliminary study for de novo whole-genome sequencing of SBPH, we investigated 6 transcriptomes isolated from different developmental stages, sex, and tissue (egg, 1st ~ 3rd nymphs, 4th ~ 5th nymphs, female and male adults, salivary gland). Clean-sequence data of 19.3 Gb were obtained from total 47.8 Gb raw data after adaptor and quality trimming (Q30) and overlapped reads joining. As a suitable assembler, Bridger was selected based on the results of reference mapping (93.45%) and CEGMA completeness (95.97%). Finally, we obtained 158,207 reads (size range: 201 ~ 22,162 bp; Mean size: 1,048.04 bp; N50: 2,417 bp) after clustering the assembly results by CD-HIT-EST (similarity threshold: 99%). Based on these results, we are conducting further studies such as transcript expression pattern among different developmental stages and gene annotation.
Occurrence characterization of oriental corn borer, Ostrinia furnacalis, in a paddy-upland rotation field for 8 maize and 7 sorghum varieties was surveyed. In a monitoring study using a pheromone trap carried out from 15 May to 10 September, the density of O. furncalis adults increased rapidly from about 2 weeks after corn planting and reached the highest density at mid June. After that, their density was decreased and increased a little at earlier September. In a survey carried out at harvest period using 8 corn varieties, the damage ratio was Daehakchal (94%), Mibaek 2 (92%), Ilmichal (71%), Eolrukchal 1 (64%), Chalok 4 (54%), Miheukchal (52%), Heugjeom 2 (45%). The number of invasive pore per Ilmichal stem by O. furnacalis larvae was 1.4 and those of the others was less than 1.0. In another survey carried out at harvest period using 7 sorghum varieties, their damage ratios were DS-202 (95%), Moktaksusu (76%), Sodamchal (75%), Nampungchal (67%), Anzunbaengisusu (57%), Donganme (46%), and Hwanggeumchal (34%). The damage of sorghum varieties was much higher and severer than that of corn by O. furnacalis larvae. These results may be useful for the establishment of a management strategy to control oriental corn borer in paddy-upland rotation fields for maize and sorghum.
Methyl bromide (MB) fumigation is still allowed to use in quarantine treatment on imported timbers and logs, even though IPPC(International Plant Protection Convention) was strongly recommended to reduce their use in case of existing alternatives. A newly developing MB alternative fumigant, ethanedinitrile (EDN), showed the potential in terms of better efficacy to various timber pests and penetration into the timber than MB. Herein, for suggestion of quarantine guideline in Korea, we had verified the efficacies under different temperature conditions(5, 5-15, >15℃) and monitored TLV(Threshold limited value) of EDN post-fumigation for worker safety. The 6 scheduled doses of EDN depending on types of timber pest and temperature conditions had evaluated with PVC-Tarp tent(>100m3) with 40-50% loading factors of imported logs. To control normal wood related pests such as Japanese termite (Reticulitermes speratus) and bark beetle(Cryphalus fulvus), the scheduled doses 30, 40 and 40 g/m3 for 24hr fumigations showed >99% efficacy at 5, 5-15 and >15℃, respectively. The scheduled doses 100, 120 and 150 g/m3 for 24hr fumigations was also successful to gain the proved efficacies at 5, 5-15, >15℃, respectively, for the quarantine guideline to notorious wood related pests such as Japanese pine sawyer (Monochamus alternatus) and pine wilt nematode (Bursaphelenchus xylophilus). The recommended ventilation times with atmospheric conditions at ports was > 1 and > 2 hr under the fully uncovered and partially uncovered of fumigation tent conditions, respectively.
The mirine plant bug genus Paramiridius, which has been known only by a single Taiwanese species, is reported from Indochinese Laos for the first time and redefined. Two additional species, P. indochinensis and P. laomontanus, are described as new to science. The female genitalic structures are from the first time figured for the genus. A key is provided for all three known Paramiridius species.
This study is carried out to know the insect diversity at Gonggeomji wetland in Sangju city where the first designated as a rice paddy wetland protection area from Ministry of Environment of Korea. As the results, 330 species of 234 genera belonging to 90 families in 10 orders were collected and a total of 1,327 individuals were surveyed in this study. Among them, highest collection ratio was 54. 3% (162 species) of Coleoptera, next order was 22% (66 species) of Hemiptera. In seasonal variation, 28 species were surveyed in the first quarter, 81 in the second, 78 in the third, and 87 in the fourth. Ancylopus pictus asiaticus in Coleoptera, Nysius (Nysius) plebejus in Hemiptera were the most dominant species. As a diversity analyses, species diversity index (H'), dominance index(DI), species richness index and evenness index (EI) were provided in here.
A predatory genus Cryptalaus Ôhira, 1967 (Coleoptera: Elateridae) in Korea is taxonomically reviewed in this study. Up to date, two species of the genus Cryptalaus, C. berus Candèze, 1865 and C. larvatus pini Lewis, 1894, have been reported from Korea. From the present study, C. yamato Nakane, 1957 which has been regarded as an endemic to Japan, is reported from the Korean peninsula for the first time. A key to the Korean species of the genus Cryptalaus, diagnosis, illustrations of diagnostic characteristics are provided.
Vespa crabro and V. analis are social hornet species commonly found in Asia, including Korea. Mastoparan is one of the major venom peptides of these two hornets but its amino acid sequence defers substantially. To examine the differences in the potential toxicity and bioactivity of mastoparans between these two social hornets, differential toxicological and pharmacological activities of synthesized mastoparan were investigated. V. analis mastoparan showed a 7-fold higher hemolytic activity, suggesting its higher cytotoxic potential compared with V. crabro mastoparan. Mastoparans from both hornet species exhibited similar levels of antimicrobial activities against Staphylococcus aureus and Botrytis cinerea, whereas the mastoparan from V. analis showed more potent antimicrobial activities against Escherichia coli and Candida albicans. Nevertheless, the antimicrobial activities of mastoparans of V. crabro and V. analis were relatively lower compared with those of other wasps. Both mastoparans also exhibited some levels of antitumor activity but the activity was significantly higher in V. analis mastoparan. In summary, the hemolytic, antimicrobial, and antitumor activities of synthesized V. analis mastoparan were higher than those of V. crabro mastoparan. These differential bioactivities are likely due to the amino acid sequence differences in the mature peptides. In particular, the additional Lys residue present in V. analis mastoparan may contribute to the higher levels of bioactivity as proposed by secondary structure prediction.
The hornets Vespa crabro and V. analis are widely distributed in Asia and are known to be aggressive when disturbed, resulting in frequent stinging accidents. To investigate the differences in venom properties and toxicities between these two hornets, the transcriptomic profiles of venom glands, in conjunction with the venom components, were analyzed and compared. A total of 35 venom-specific genes were identified in both venom gland transcriptomes, but their transcriptional profiles were different between V. crabro and V. analis. In addition, the major venom components were identified and confirmed by mass spectroscopy. Prepromastoparan, vespid chemotactic precursor and vespakinin were the top three genes most prevalently transcribed in the venom gland of V. crabro, and their transcription rates were 112-, 16- and 161-fold higher, respectively, compared with those in V. analis, as judged by FPKM values. In the venom gland of V. analis, however, vespid chemotactic precursor was the most abundantly transcribed gene, followed by premastoparan and vespakinin. In general, most major venom genes were more abundantly expressed in V. crabro, whereas some minor venom genes exhibited higher transcription rates in V. analis, including muscle LIM protein, troponin, paramyosin, calponin, etc. Our findings reveal that the overall venom components of V. crabro and V. analis are similar, but that their expression profiles and levels are considerably different. The comparison of venom gland transcriptomes suggests that V. crabro likely produces venom with more highly enriched major venom components, which has potentially higher toxicity compared with V. analis venom.
The family Scelionidae is distributed all around the world, which has approximately 3,000 species within 150 genera in the world. To date 39 species of 15 genera from 3 subfamilies in Scelionidae are recorded in South Korea. In this study, we report a new record of the genus Idiris with one species.
There are many parasitory and predatory insects specializing on spider eggs. Among scelionids, some species (Baeus achaearneus, Comastichus zopheros, Idris sp.) parasitize spider eggs. However, there was no Korean record for scelionid wasps parasitizing in egg sacs of spider. Based on morphology, ecology, and DNA identification, we recognized this species, Idris sp., being new to Korea. All examined specimens and DNA samples are deposited in Kunsan National University.
In this study, a genus Eumasia Chrétien is reported for the first time from Korea. This study was conducted to report a newly recorded genus and species, Eumasia muscella Saigusa and Sugimoto based on the material from Haemee-castle, Seosan-si, Korea. All available information for the species including distributional ranges and host plants were presented in this study. Also the larval characteristics and DNA barcode for the species are provided.
Bacillus thuringiensis (Bt) is a gram-positive and spore-forming bacterium that produces parasporal inclusions containing Cry and Cyt proteins during sporulation. These inclusions or proteins are highly toxic to lepidopteran, dipteran, coleopteran larvae, and nematodes. Because of their selectable specificity and safety to non-target organisms and environment, Bt is considered as a valuable and safe alternative to chemical pesticides for eradication of insect pests. Bt biopesticide products has been commercialized and used very widely and successfully in agriculture, forestry and medical care markets since 1930s. In Korea, the screening for isolation of new Bt strains such as Bt Nt0423 (Tobbagi) and Bt GB-413 (Solbichae) have been performed and their commercial products were launched in agricultural markets. In terms of public health, mosquito larvicidal products made by Bt subsp. israelensis have been registered by Korean ministry of food and drug safety and used since 1995. Recently, a new mosquitocidal serovar (H3a3b3d), Bt subsp. mogi was isolated and its molecular characteristics were analyzed. In our opinion, Bt biopesticides might be still an effective and safe tool for insect pest control in agriculture and public health. Key words: Bacillus thuringiensis, biopesticide, Bt subsp. israelensis, mosqui
To clarify the geographical distribution of scrub typhus vectors in Korea, the first survey of chigger mites was conducted from 2005 to 2007 by collecting wild small mammals twice a year (spring and autumn) at 24 sites nationwide. The two predominant mite species were Leptotrombidium pallidum (52.6%) and L. scutellare (27.1%). However, the proportions of L. scutellare in southern areas, including endemic provinces such as Chungcheongnam-Do, Jeollabuk-Do, Jeollanam-Do, and Gyeongsangnam-Do, were relatively higher than in central Korean regions where L. pallidum was predominant. In autumn, the ratio of L. scutellare increased to 42% while the ratio of L. pallidum decreased. The geographical distribution map of the L. scutellare chigger index was identical to the incidence pattern of scrub typhus, whereas those of overall mites and L. pallidum showed no relationship with case incidence patterns. Distribution mapping analysis shows an identical geographical distribution of L. scutellare and epidemic incidence of scrub typhus in South Korea. The second periodical survey was performed from 2011 to 2013. The result suggests that the distribution of L. scutellare has not been changed remarkably in comparison to the first survey.
There are over 3,000 different species of mosquitoes throughout the world; currently 56 species are reported in Korea. Mosquitoes can act as vectors for many disease-causing viruses and parasites during blood sucking. Various species of mosquitoes are estimated to transmit various types of disease to more than 700 million people annually in Africa, South America, Central America, Mexico, Russia, and much of Asia, with millions of resultant deaths. At least two million people annually die of these diseases, and the morbidity rates are many times higher still. To prevent the spread of diseases, KNIH (Korea National Institute of Health) used three categorized methods; identifying or taxonomic analysis of mosquitoes, detecting virus caring mosquitoes, and detecting malaria from Anopheline mosquitoes. We have proved that taxonomic analysis using DNA barcording method (COI gene) is useful to complement identification of mosquito species. In detecting virus, we have reported Cx. orientalis as a new potential Japanese encephalitis virus (JEV) vector. We also reported that the Anopheline mosquito species composition and Plasmodium vivax infection rates in malaria hot spot in Korea.
Leptotrombidium pallidum is the major vector mites for Orientia tsutsugamushi, the causative agent of scrub typhus. To understand the molecular mechanism of L. pallidum, we sequenced the whole genome using Illumina sequencing technology. Totally four genomic libraries with different insert sizes ranging from 280 bp to 8 kb were used to generate 45.1 Gb of genome in the combination of paired-end and mate-pairs sequencing reads. Quality filtering and correction of paired-end reads for very small and/or bad-quality sequences yielded 26.9 Gb of high-quality sequences, which are used to estimate the genome size as 175 Mbusing kmer methods and assembled into a 193.7 Mb genomic sequence scaffolds with N50 length of 92,945 bp. Furthermore, 94% of CEGMA completeness score were obtained from genome scaffold assembly. To facilitate gene annotation, we used a combination of de novo and homology based tools to predict gene models in the chigger mite genome. A combination of evidence-based and de novo approaches predicted 15,842 high-confidence protein-coding genes with an average transcript length of 1,511 bp and 2.4 exons per gene which corresponds to about 12.4% total gene length. Bacterial endosymbiosis are very common in mite species and can range from mutualistic to pathogenic associations. Henceforth, the endosymbionts in L. pallidum were predicted using the NCBI microbial draft genomes and mitochondrial genome. Besides, this L. pallidum draft genome can be used as a significant reference for comparative genomic studies across mite species.
Sensory system of insect is important for their fitness in the environment. Riptortus pedestris (Hemiptera: Alydidae) is a major pest of bean plants and some fruit trees in Korea, Japan, China, and South Asian countries. This study was conducted to investigate morphology and distribution of antennal sensilla of R. pedestris, using scanning electron microscopy. Antennae of R. pedestris was 11 and 9.84 mm in length in male and female, respectively, and consists of four segments; scape, pedicel, flagellum 1 and 2 (F1 and F2). Five types of sensilla (s.) trichodea, four types of s. basiconica, two types of s. chaetica, and one type of s. coeloconica were preliminary identified in both sexes of adult R. pedestris, based on their size, shape, presence of socket and surface structure. Three types of trichoid sensilla, four types of basiconic sensilla, one type of chaetic sensilla and coeloconic sensilla had numerous pores along the surface of the sensilla, suggesting their olfactory function. Eight types of sensilla (3 trichoid, 2 basiconic, a chaetic and a coeloconic) showed a distinct socket structure at the base of each sensillum. Different types of sensilla showed different distribution along the antennal segments. Two types of trichoid sensilla and two types of basiconic sensilla were distributed on scape, pedicel and F1 flagella subsegment. However, the distribution of eight other types of sensilla was limited to one of two flagella subsegments.