Innate immunity responses are triggered by the immune challenge and therefore involve signaling processes. The cellular response is initiated by hemocytes and mainly involves phagocytosis and encapsulation of intruders by these cells. To address whether Hc-STAT is activated upon bacterial challenge, we examined the subcellular location of STAT protein in hemocyte by immunostaining. A new insect member of the STAT family of transcription factors (Hc-STAT) has been cloned from the lepidopteran, Hyphantria cunea. The domain involved in DNA interaction and the SH2 domain are well conserved. The gene is transcribed at a low level during all stages of development, and the protein is present in hemocytes, fat body, midgut, epidermis, and Malphigian tuble (Mt). Especially, hemocytes and Mt showed transcriptional activation of Hc-STAT upon Gram (-) bacteria and fungal challenge. Gram (-) bacteria and fungal challenge specifically results in nuclear translocation of Hc-STAT protein and induction of DNA-binding activity that recognizes a STAT target site in H. cunea hemocyte. In vitro treatment with pervanadate translocates Hc-STAT to the nucleus in hemocyte cells. Here we report the first evidence for the involvement hemocyte JAK/STAT pathway upon microbial infection in lepidopteran insect.

The bumblebees, Bombus species are valuable natural resources being utilized for greenhouse pollination. Low level of genetic variation of Bombus species has been reported previously. In this study, we sequenced complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA from 100 individuals of B. ardens collected from seven localities in Korean peninsula. The ITS2 sequence of B. ardens is longest, ranging in size from 1,940 bp-1,954 bp among known in insects, which ranges approximately from 241 bp-1,728 bp. The ITS2 sequences have ~51% of C+C content and contain each two 27 bp repeats, 20 bp repeats, 33 bp repeats, and 34 bp repeats at the beginning. Such repeats were not found in other insects. Uncorrected pairwise distance among 96 sequences that were obtained from 100 individuals revealed a maximum sequence divergence of 1.03%. Genetic diversity (π) of each population ranged from 0.007801 to 0.009627, and the lowest diversity was obtained from islet population of Ulleungdo, indicating possibly small, isolation of the population. Significant level of genetic distance was only found when Ulleungdo population was compared to two other mainland populations. Except for this, overall, a very high rate of per generation migration ratio (Nm=7.1-infinite) and a very low level of genetic fixation (FST=0-0.06546) were detected between pairs of localities. Analysis of hierarchical relationships among localities consistently revealed no statistically significant structure among populations. Taken these together, the B. ardens populations on the Korean peninsula are panmictic this is consistent with our understanding of the dispersal capability.

Sweet potato whitefly Bemisia tabaci is a serious pest of various economically important crops. For the control of B. tabaci in an environment-friendly way, we demonstrated the effect of azadirachtin, which is an active conpound of neem oil as an botanical insecticide, on the development of B. tabaci by using an assay of single tomato leaf. Egg hatch rates were 53.6, 50.3% at 5 and 10 ppm, respectively. Adult eclosion rates were 30.0, 22.9% at these doses. We determined the whitefly control efficacies of two application methods of neem-based products by comparing between a direct spray of liquid-type into leaves and a soil treatment of pellet-type. Soil treatment of neem was greatly inhibited adult colonization by 75%. Those plants also inhibited the rates of oviposition and larval development. However, single treatment of foliar spray of neem (5-10 ppm) did not significantly inhibit the initial colonization of adult whiteflies. Furthermore, adult colonization was gradually increased regardless of neem spray.

A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR includes 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR showed high similarities with other moth PBANRs and its expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. To accomplish the funcional expression of Plx-PBANR, Human uterus carcinoma was stably transfected with Plx-PBANR gene and Plx-PBANR expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea, as ionomycin as a positive control does. To inhibit Plx-PBNAR expression in vivo, RNAi fragment for Plx-PBANR was injected into pupae. Suppression of PBANR expression was confirmed by RT-PCR and also induced inhibition of mating behavior in adults, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. RNAi-treated adults showed reduced pheromone production. These results suggests that inhibition of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.

The root zone applications of a systemic insecticide, carbofuran, were evaluated for their impacts on the brown planthopper, Nilaparvata lugens (Stål), and spider populations in the greenhouse and rice paddy fields. In the green house experiments, no BPH nymphs were hatched at root zone treated on 40 to 50 day-old rice, while around 20 to 54 nymphs per pot were emerged in broadcasting and foliar spray treatments. This indicates that the root zone treatment can kill the eggs of BPH effectively. This is the first study ever demonstrated the high egg mortality of BPH due to the root-zone application. In the field experiments, the density of BPH in root zone treated plots were four to six times lower than in broadcasting and foliar spray plots at the 21 days after application. The BPH outbreaks and hopper-burns were observed at all treatments except the root zone treated plot at the 28 days after application. The root-zone application did not impact on the spider population, while foliar spray killed most of all spiders just one day after application. The densities of spider in foliar spray plots were always lower than in root-zone treated and control plots. The results indicated that the root-zone application of carbofuran can control BPH effectively without adverse effects to the spiders inhabited on the paddy field.

The 15,389-bp long complete mitogenome of the endangered red-spotted apollo butterfly, Parnassius bremeri (Lepidoptera: Papilionidae) was determined. This genome has a gene arrangement identical to those of all other sequenced lepidopteran insects, which have the gene order of tRNAMet, tRNAIle, and tRNAGln at the beginning. Due to the uncertainty the start codon for COI gene in insect has been discussed extensively. We propose the CGA sequence as the start codon for COI gene in lepidopteran insects, based on complete mitogenome sequences of lepidopteran insects including our P. bremerii and additional sequences of the COI start region from a diverse taxonomic range of lepidopteran species (a total of 51 species belonging to 15 families). As has been suggested in other sequenced lepidopteran insects the 18 bp-long poly-T stretch and the downstream conserved motif ATAGA that were previously suggested to serve as a structural signal for minor-strand mtDNA replication also was found at the 3’-end region of the P. bremerii A+T-rich region. In an extensive search to find out tRNA-like structure in the A+T-rich region, each one tRNATrp-like sequence and tRNALeu (UUR)-like sequence were found in the P. bremeri A+T-rich region, and most of other sequenced lepidopteran insects were shown to have tRNA-like structure within the A+T-rich region, thereby indicating that such feature is frequent in the lepidopteran A+T-rich region. Phylogenetic analysis using the concatenated 13 amino acid sequences and nucleotide sequences of PCGs of the four macrolepidopteran suferfamilies together with Tortricoidea and Pyraloidea well recovered a monophyly of Papilionoidea and a monophyly of Bombycoidea. However, Geometroidea and Noctuoidea were unexpectedly clustered as one group and placed this group to the sister group to Bombycoidea, instead of Papilionoidea in most analyses.