Grapevines are cultivated globally, and are also damaged by a large number of insect pests especially including leafhoppers. Leafhoppers are one of the important insect pests on various crops including grape. Among them, the genus Arboridia Zachvatkin (Hemiptera: Auchenorrhyncha: Cicadellidae: Typhlocybinae) was known as insect pests against grape farming. Eighty species were described in the genus in the world, and eight species were recorded in the Korean Peninsula so far, which are: Arboridia apicalis, A. kakogawana, A. koreacola, A. maculifrons, A. nigrigena, A. okamotonis, A. silvarum, A. suzukii. Among them, A. apicalis, A. kakogawana, A. maculifrons, A. nigrigena, A. suzukii have been known as important insect pests on grapes. In this talk, we propose a new species from the Korean Peninsula, and confirmed two new records: A. agrillacea and A. lunula. Additionally we present differential diagnoses of the Arboridia species damaging on grapevines for the field of applied biology.
The ant species, Vollenhovia emeryi Wheeler (Hymenoptera: Myrmicinae) is endemic in East Asia and has invaded into North America. In this species, the queen caste shows polymorphism in its wing morphology; long-winged queen and short-winged queen, and two morphs are thought not to coexist in nature. This research is conducted to 1) deduce the phylogeographical structure of the two wing morphs in South Korea and to trace the distribution pattern from East Asia to North America, and 2) investigate the Wolbachia and WO phage infection frequency of the species. Either individuals or colonies of V. emeryi were collected from 80 locations, encompassing 68 locations in South Korea, 11 in Japan, and one in USA. Among the collected samples in South Korea, the long-winged morph is dominant and considered as the ancestral type, while the short-winged morph is very rare and derived character. The origin of the US population is neither Korea nor Japan at least in this study. However, we do not exclude the possibility that its origin is the other parts of Japan or the other countries. All of the long-winged morph are infected with Wolbachia, while the short-winged seems to be geographically partially infected. It suggests the possibility that the short wing trait is linked with the evolution of resistance to Wolbachia infection. Bacteriophage WO infection status has no correlation with host insect lineage.
The present study was carried out to revise the species of Chlaeniini in Carabidae from South Korea, using both classic taxonomy and molecular analysis. Another aim is to decide the taxonomic position of Chlaenius micans Fabricius of which subgeneric status in the genus has been in question. As a part of the results, Chlaenius spathulifer Bates, 1873 was newly recognized to Korean insect fauna. With this new addition Korean Chlaeniini contains now in total 34 species and two genera. Molecular analyses using CO1 sequences of representative species for six subgenera in Chlaenius were conducted to determine the position of C. micans. The result of the analyses suggested that C. micans did not belong to the subgenus Achlaenius where C. micans had been doubtfully positioned despite distinct morphological differences from the other four species of the variicornis-group (C. sericimicans, C. variicornis, C. kurosawai and C. ocreatus) in the subgenus. This study provids a key to species, photos of adult habitus, photos of male genitalia and redescriptions of 28 Korean species in Chlaeniini.
Alzheimer’s disease (AD) is the most common type of presenile and senile dementia. Human β-amyloid precursor cleavage enzyme (BACE-1) is a key enzyme responsible for amyloid plaque production. We assessed anti-BACE-1 and behavioral activities of curcuminoids from Curcuma longa, curcumin (CCN), demethoxycurcumin (DMCCN), and bisdemethoxycurcumin (BDMCCN) against AD fly models. Neuro-protective ability of curcuminoids was assessed using fly model system overexpressing BACE-1 and its substrate APP in compound eyes and entire neurons. BDMCCN has the strongest inhibitory activity toward BACE-1 with 17 μM IC50, which was 20 and 13 times lower than those of CCN and DMCCN respectively. Expression of APP/BACE-1 resulted in the progressive and measurable defects in morphology of eyes and locomotion. Supplementing diet with either 1 mM BDMCCN or CCN rescued APP/BACE1 expressing flies and kept them from developing both morphological and behavioral defects. Structural characteristics and hydrophobicity appear to play a role in determining inhibitory potency of curcuminoids on BACE-1.
The previous studies for phylogenetic relationships within Elateridae were carried out, but not constructed a reliable evolutionary hypothesis. This study attempted to establish a robust evolutionary hypothesis, focusing on major subfamilies of the family Elateridae sensu stricto, using extensively selected 12 genetic markers, COI, 16S rRNA, 18S rRNA, 28S rRNA and 8 nuclear genes. As the results, phylogenetic analyses for 12 multiple genes constructed robust phylogeny with almost very strongly supported nodal values (>90%) and represented that the previously questioned systematic positions of nine subfamilies are fully resolved, excepting the basal lineage split. Especially, three subfamilies, which were recently reduced into tribal rank, Hypnoidinae, Oxynopterinae, and Denticollinae are monophyletic, respectively, and it is supported the traditional taxonomic schemes that had been treated these three taxa in subfamily rank. Whereas, Elaterinae, Hiopinae, and Melanotinae are clustered to a monophyletic group. Two tribes, Denticollini and Ctenicerini in Denticollinae are paraphyletic, respectively and it needs to reclassify their systematic positions. This study recovering of relationships between subfamilies using 12 gene loci resulted that their phylogenetic relationships are sufficiently and successfully resolved with strong supported nodes and provided more possible interpretations from subfamily to tribal levels than the previous studies.
The phylogenetic analysis the queen polymorphic Vollenhovia emeryi ant reveals derivation of the Wolbachia- free short-winged from the Wolbachia-infected long-winged. However, intriguingly, some Japanese short-winged colonies harbor Wolbachia. Wolbachia specific bacteriophage (WO) is also detected in more than half of the infected colonies with no clear distribution pattern across the host insect lineage. We hypothesized that 1) the infected Japanese short-winged is in the intermediate stage to complete loss of Wolbachia and 2) the phage invaded the host after the host insect diverged. To test the hypotheses, we studied the strain diversity using the multi-locus sequence typing (MLST) of five ant colonies; three longwinged colonies from Korea and one long-winged colony and one short-winged colony from Japan. Both Korean and Japanese V. emeryi colonies show unexpectedly high level of Wolbachia strain diversity. However, the diversity is not significantly different between the long-winged and the short-winged against our first hypothesis. Phylogenies of Wolbachia show Korean strains and Japanese strains are largely monophyletic indicating prior infection before the host divergence. The strain diversity of the phage is also surprisingly high. Phylogenies of orf2 and orf7 genes are incongruent to that of Wolbachia and geographically distinct. This indicates that the phage is spatially static and the current infection pattern may be the consequence of local repeated gain and loss of the phage.
Camouflage can be attained via mechanisms such as background matching (resembling the general background) and disruptive coloration (hindering the detection of an animal’s outline). However, despite much conceptual work with artificial stimuli there have to date been few studies of how such camouflage types work in real animals in their natural environments. Here, using avian vision models and image analysis, we tested which concealing mechanisms operate to provide camouflage during behavioral choice of a resting position in two bark-resting moths, Hypomecis roboraria and Jankowskia fuscaria. We found that both species reinforced their crypticity in terms of both background matching and disruptive coloration. However the detailed mechanisms (such as achromatic/chromatic matching or pattern direction matching) that each species exploits differed between the two species. Additionally, we found substantial correlation between the degree of background matching and disruptive coloration, which supports previous work suggesting that these two different concealing mechanisms work together to confer camouflage. Our results clearly demonstrate that an appropriate behavioral choice of background is essential to improve camouflaged against natural predators, and highlight the interrelation between different concealing mechanisms in real prey.
Integrin is a cell surface protein that is composed of α and β heterodimer and mediates cell interaction with extracellular matrix or other cells including microbial pathogens. A full length cDNA sequence (2,517 bp) of a integrin subunit β1 (HaITGβ1) was cloned from the oriental tobacco budworm, Helicoverpa assulta. Phylogenetic analysis showed that HaITGβ1 was clustered with other insect β integrin subunits with the highest amino acid sequence identity (61%) to β1 of other Noctuidae such as Spodoptera exigua and S. litura. Structural analysis of the HaITGβ1 possessed all functional domains known in other insect β1 integrins. RT-PCR analysis showed that HaITGβ1 was expressed in all developmental stages and all tested tissues of H. assulta. Injection of double-stranded HaITGβ1 RNA (dsHaITGβ1) into third instar of H. assulta suppressed HaITGβ1 expression and resulted in significant delay from last larval stage to pupal stage. The dsHaITGβ1 injection significantly impaired nodule formation of H. assulta in response to bacterial challenge and hemocyte adherence. These results suggest that HaITGβ1 plays crucial roles in cellular immune responses as well as development in H. assulta.
Acetylcholinesterase (AChE) plays a pivotal role in the synaptic transmission in the cholinergic nervous system of most animals, including insects. Most insects possess two AChEs (i.e., AChE1 vs. AChE2), which are encoded by two paralogous loci originated from the duplication that occurred before the radiation of insects. The phylogenetic analysis suggested that the last common ancestor of ace1 and ace2 shared its origin with those of Platyhelminthes. In addition, ace1 lineage showed a lower evolutionary rate (d and dN/dS ratio) compared to ace2 lineage, suggesting that the ace1 lineage has maintained relatively more essential functions following duplication. Furthermore, structural modeling of AChEs revealed that consistent structural alteration in their active-site gorge topology was caused by amino acid substitution, likely leads to functional differentiation between two AChEs. The functional transition of ace in some hymenopteran insects appears to have occurred by only a few mutations resulting in dramatic alteration of AChE activity. Taken together, our findings provide basic information on when the ace duplication occurred and what structural features have been associated with the differentiation of two AChEs during evolution.
The toxicity of cade oil (Juniperus oxycedrus), its constituents and structurally related compounds toward adult house dust mite Dermatophagoides farina was examined. Results were compared with two commercially available acaricides, benzyl benzoate and deet. The cade oil constituents were identified by GC-MS analysis. Citral (LC50, 1.13 μg cm–2) and methyleugenol (LC50, 5.78 μg cm–2) were the most toxic compounds, followed by eugenol (LC50,12.52 μg cm–2), nerol (LC50, 21.4 μg cm–2) and terpinen-4-ol (LC50, 29.55 μg cm–2) were shown significant mortality against adult of D. farina. Toxicity of citral, methyleugenol were higher than that of benzyl benzoate, and above listed compounds was all more toxic than deet. Given the result of vapour-phase mortality tests that these compounds were more toxic in closed containers than in open ones, we concluded that vapour action plays a great role in their mode of delivery. Cade applied as 3 and 4% experimental sprays provided 96 and 100% mortality against the mites respectively, whereas permethrin (cis:trans, 25:75) 2.5 g/l spray treatment resulted in 17% mortality. Cade oil, and its constituents shown their potentials as effective alternatives for harmful synthetic acaricides for the control of Dermatophagoides populations as fumigants in contact and therefore illustrated the need for further study of this essential oil.
This study was conducted to develop the biological insect pest control on pear orchard by using the native natural enemy from 2011 to 2013.
We selected the green lacewing, Chrysoperla nipponensis (Okamoto) for useful natural enemy and developed the artificial mass rearing technique, and tested finally in pear orchard located in Anseong city. Nine species of insect pests including Pseudococcus comstocki on pear and seven species of natural enemies including C. nipponensis were investigated in Gyeonggi area. The optimum developmental temperature, humidity and photoperiod for C. nipponensis were 20 ∼25℃, 60∼70%, and 16L : 8D respectively. One C. nipponensis during larval stage could feed about 440 2nd nymphs of P. comstocki at 20℃. The more prey density increase, the more feeding amount C. nipponensis larva was increased. The eggs of almond moth, Ephestia cautella were useful as a substitute diet for natural enemy, C. nipponensis. Three commercial insecticides which registered as insecticide on pear shown the low toxicity to natural enemy, C. nipponensis will be suitable for integrated pest management (IPM) in pear orchards. C. nipponensis shown the about 80% of control value against the P. comstocki in field test when had committed from the early May to the early July. Controlling the P. comstocki by using of C. nipponensis, not only the 30% of yield was increased, but also the quality especially fruit sugar was increased.
The effect of electron beam irradiation on development and reproduction of susceptible strain (S) and imidacloprid-resistance strain (IMI-R) of Aphis gossypii were compared. Nymphs and adults of S and IMI-R strain were irradiated at target doses of 50, 100, 150, and 200 Gy. When nymphs were irradiated, emergence rate was not affected at all target dose, but number of F1 nymphs was perfectly inhibited at 150 Gy in both strains when irradiated to the adults, longevity slightly decrease at 150 Gy and above. Fecundity was strongly decreased at 100 Gy, but was not completely inhibited even at 200 Gy. Emergence rate of F1 nymph was decreased at 100 Gy and completely inhibited at 200 Gy. However, there was no significant differences on development and reproduction of S and IMI-R strain. We also conducted the comet assay immediately after irradiation and over the following 7 day periods. In addition, we performed quantitative real-time PCR on several genes.
The antifeedant activity of 20 plant essential oils, constituents from clove stem oil and related compounds were tested against the third instar larvae from both moth Spodoptera litura and Spodoptera exigua by used leaf dipping bioassay. Among the oils tested, clove stem (94%), thyme oil red (85%), and savory oil (80%) were showed high antifeedant activity against both S. litura and S. exigua third instar larvae. Thyme oil white (91%), geranium (90%), and cinnamon bark oil (85%) were shown high antifeedant activity against only S. exigua when compare other oils. The other plant essential oils were showed moderate (40-50%) or low (>20%) antifeedant activity against third instar larvae of both S. litura and S. exigua. The most active clove stem oil constituents were indentified by GC-MS. The major constituents eugenol (95%), farnesene (81%) and structurally related compounds isoeugenol (96%), nerolidol (80%) were showed significant antifeedant activity against both S. litura and S. exigua. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on the essential oils and their constituents describes as potential insecticides for the control of moth population with antifeedant activity.
Establishment of rapid resistance level detection system is essential step to adopt the adaptive management for the control of various kinds of resistant pest population. Here, we established acaricides resistance detection methods based on residual contact vial bioassay (RCV) and quantitative sequencing methods (QS), and applied to determine the resistance levels from several populations in two-spotted spider mite, Tetranychus urticae, which has been considered as major notorious pest in rose cultivation area in worldwide. 12 acaricides were applicable to the RCV among 19 representative acaricides by showing the dose-dependent mortality within 8 hr, suggesting the acaricide suitability for the RCV might be varied by toxicity mechanism in each acaricides. The QS regression was established for 10 point mutations associated with five number of acaricides resistance such as organophosphate, pyrethroid, abamectin, bifenazate and etoxazol. The 95% prediction level was ranged from 10.8±5.4∼92.2±3.2%. The resistance levels were determined by above two detection methods from a total 12 strains. The laboratory-reared populations were revealed high susceptibility with low resistance allele frequencies to some acaricides, suggesting the several acaricides would be chosen for the control of those populations. However, the field-collected populations were exhibited a severe cross resistance with low susceptibility and high resistance allele frequency to almost tested acaricides, suggesting the current acaricides resistance levels are serious in rose cultivation area in Korea. The RCV and QS methods would be useful for the rapid and accurate collection of valuable information associated with acaricide resistance.
Frankliniella occidentalis (Pergande) and F. intonsa (Trybom) have been shown asymmetrical occurrence pattern in pepper and strawberry fields. To explain this phenomenon, interactive influence of temperatures (20, 25, and 30ºC) and relative humidities [Low (50-55%), Medium (70-75%), and High (90-95%)] were assessed on pupal and adult stage of the two thrips species. In pupal stage, mortality of both species decreased as the humidity increased without significant difference between the species. Also, pupal duration of the two thrips decreased as RH increased from low to high in all the temperatures tested, but significantly shorter duration was found in F. intonsa. In adult stage, F. intonsa survived better than F. occidentalis only in high humidity at both 20 and 25ºC. Frankliniella intonsa survived 2.5 and 2.4 times longer as RH increased from low to high at 20 and 25ºC, respectively, whereas F. occidentalis survived 1.8 and 1.6 times longer, respectively. In conclusion, both pupae and adults of F. intonsa performed better at higher RH condition compared to F. occidentalis. Thus, difference in relative susceptibility to changing environmental condition can be one of the underlying mechanisms for the differential occurrence pattern in the fields.
담배가루이(Bemisia tabaci)는 외래해충으로 바이러스벡터로 작용하여, 토마토에 토마토황화잎말림병바이러스(TYLCV)를 비롯한 약 100여종의 바이러스를 매개하는 중요한 해충이다. 담배가루이는 화학합성 작물보호제에 대한 저항성 발현이 빨라서 이들의 방제에 어려움을 겪고 있다. 이러한 저항성 문제를 해결하기 위한 방편의 일환으로 RNA interference(RNAi)를 이용한 해충방제가 시도되고 있다. 뿐만 아니라, RNAi를 이용하면 해당 해충의 target 유전자를 연구하는데 도움이 될 수 있다. 본 연구에서는 RNAi를 이용하여 담배가루이 방제를 위한 target 유전자들을 선발하기 위해 gateway system을 이용한 담배가루이 cDNA library 제작을 시도하였다. 그 결과 RNAi에 적절한 약 100∼400bp의 insert를 확인하였으며, blast search 및 EST database 비교 분석 결과, 대부분이 담배가루이 관련 유전자임을 확인하였고, 최종적으로 1.75⨉106 titer의 담배가루이 cDNA library를 완성하였다. 이러한 cDNA library는 att site를 가지는 TRV2(tobacco rattle virus) vector에 LR recombination한 다음 Agrobacterium tumefaciens (EHA105)에 transformation 후 토마토에 접종하여 담배가루이가 섭식하여 체내에서도 RNAi의 발현을 유도하면 담배가루이 살충 또는 기피효과를 행동학적 변화로 확인하고, 또한 이와 관련된 target 유전자를 선발하는데 이용될 수 있을 것으로 사료된다.
The effects of X-ray irradiation on development and reproduction of Spodoptera litura were examined. Eggs, larvae, pupae, and adults were irradiated at target doses of 10 - 250 Gy. When eggs were irradiated with 30 Gy, egg hatching was completely inhibited. When irradiated to the larvae, pupation was inhibited at 100 Gy and larval period was delayed. When irradiated to the pupae, emergence was inhibited at over 100 Gy. When irradiated to the adults, longevity and fecundity did not show any differences. However, egg hatching was significantly decreased at 70 Gy and above. Also, X-ray irradiation was not induced the rapid death of S. litura. Reciprocal crosses between irradiated and unirradiated moths demonstrated that males were more radiotolerant than females. The levels of DNA damage in S. litura adults were evaluated using the alkaline comet assay. Our results indicate that X-ray irradiation increased levels of DNA damage. The recovery of DNA damage in S. litura adults increased as time passed. But DNA damage hasn't recovered fully. These results indicate that X-ray irradiation induced abnormal development and reproduction by DNA damage in S. litura.
Bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae) causes serious damage to Leguminosae. Herein an entomopathogenic fungal virulence assay system against bean bugs was established to construct a fungal database which can be used in integrated pest management (IPM). First to obtain as many bean bugs as possible at the same stage, host plant-preference and developmental synchronization of bean bugs were investigated. In the preference assay, five pairs of adults were infested in a plastic cage, where a pot of green bean, pea or cowpea was previously placed. The highest fecundity and the fastest development of bean bug was observed in the green bean cage. Secondly, in the synchronization experiment, eggs were collected from the cage of adults in 1, 3, 5 and 7 days after oviposition and transferred to a fresh cage with green beans. From the every 4 days of survey, similar stages of bean bugs were found in the cages with the oviposition for 1 and 3 days, rather than the longer times of oviposition. A fungal bioassay against bean bugs was conducted using the bean bugs from the above insect rearing system. Ten Beauveria bassiana isolates were cultured on quarter-strength Sabouraud dextrose agar (¼SDA) for 7 days at 25°C. Ten 4th instar of nymphs were placed on a cultured plate for 1 hour and tranferred to a fresh moisturized plate with grains of green bean. ERL836 isolate treatment showed the highest virulence and fungal mycosis was observed on the bean bugs. In conclusion, these results can be useful to establish an entomopathogenic fungal database for IPM.
Teratocytes (TCs) are the cells derived from the embryonic serosal membrane of some parasitic hymenopteran insects. As a parasitic factor, TCs are multifunctional in host regulation by inducing nutritional, immune, and developmental alterations. However, little is understood about their genetic constituents. This study reveals a comprehensive view of the genes expressed by TCs through a transcriptome analysis based on RNAseq technology. More than 6.29 Gb sequences were used to assemble 34,686 contigs (>200 bp) and annotated into different functional categories. The TC transcriptome profile was clearly distinct from those of hemocytes and the fat body. The TC transcriptome contained components of insulin signaling and biosynthesis of juvenile hormone and 20-hydroxyecdysone. TCs also expressed various groups of digestive enzymes, supporting its nutritional role for the growing parasitoid larvae in parasitism. Furthermore, this transcriptome analysis annotated two kinds of immunosuppressive serine protease inhibitors (serpins) and Rho GTPase-activating proteins (RhoGAPs). To determine the biological functions of these factors, we devised ex vivo RNA interference (RNAi) by conducting knockdown of gene expression in in vitro cultured TCs followed by injection of the treated TCs to test insects. Ex vivo RNAi revealed that some serpins and RhoGAPs expressed in TCs inhibited host cellular immunity. This study reports a transcriptome of the unique TC animal cell, and its immunosuppressive genetic factors using ex vivo RNAi technology.
Bemisia tabaci is a serious pest in various horticultural crops in the world. Due to use of chemical pesticide for their management they develop pesticide resistance and environmental contamination. It is necessary to develop alternative bio-pesticides using natural products from plants and natural enemies. Nicotiana benthamiana is a variety of wild tobacco plants and produce acyl sugars from glandular trichomes in the leaves. When adult whiteflies were reared with fresh N. benthamiana leaves, they were completely dead within 84 h. Oral feeding of 20% N. benthamiana extracts using ethanol and water showed complete mortality of whiteflies within 48 hours. Spray of N. benthamiana extracts into the leaves was lethal to eggs but not to nymphs of whiteflies. Further, tomato plants sprayed with N. benthamiana extracts were highly repellent to adult whiteflies. Quantitative real-time PCR indicated that the expression of various genes of B. tabaci was changed by oral feeding of N. benthamiana extract. This study suggests N. benthamiana extract is a useful for the control of whiteflies and can be used as an alternative natural pesticide for the whitefly management.