본 연구는 서식 환경에 따라 구분된 3화기 미국흰불나방(Hyphantria cunea Drury)을 숙주로 하는 기생파리의 종과 기생률의 차이를 확인했다. 조사 기간은 2023년 10월 24일부터 29일까지로, 방제를 실시한 서천군 국립생태 원과 방제를 실시하지 않은 군산시 근린공원에서 숙주인 미국흰불나방의 유충을 채집하였다. 유충은 기주식물 인 수국을 급여하여 실내 개별 사육하였다. 각 조사지에서 미국흰불나방의 기주식물은 국립생태원에서 8종, 근린공원에서 6종이 확인되었다. 총 숙주 380마리 중 기생파리는 106개체로 총 27.9%의 기생률을 보였고(유충 92개체, 미동정 알 14개체), 기생률은 근린공원이(39.6%) 국립생태원(12.5%)보다 더 높았다. 성충의 우화율은 63.0%로, 동정 결과 4속 92개체가 나타났다. 전체 종과 가장 많은 개체가 확인된 Exorista japonica (Townsend, 1909)의 조사지에 따른 유충 생존율과 성충 우화율은 모두 근린공원이 더 높은 것으로 확인 되었다. 조사결과 E. japonica가 미국흰불나방의 생물적 방제제로 유효할 것이라 판단되며, 근린공원에서의 더 높은 기생파리 유충 생존율과 성충 우화율을 통해 인간에 의한 교란이 적은 환경에서 기생파리를 이용한 미국흰불나방 방제가 더 효과적일 것이라고 고려된다. 또한 숙주의 생존율과 기생파리의 우화율을 비교한 결과 해충 방제가 이뤄지지 않는 환경에서 천적 개체군이 유지될 가능성이 더 높다고 사료 된다.

The nutritional quality of host plant is critically important for insect herbivores to maximize their fitness, but it is relatively unexplored whether the ingestion of a specific host plant will have the same effects on insects under different thermal conditions. We have used a multi-factorial experimental design to investigate how the nutritional quality of host plant and temperature interact to affect life-history traits in a generalist caterpillar Hyphantria cunea (Lepidoptera: Arctiidae) feeding on five different host plants. Caterpillars raised on Platanus occidentalis, Sophora japonica and Prunus x yedoensis exhibited substantially higher survival, faster growth and heavier mass at pupation than those on Cornus kousa and Betula platyphylla. Caterpillars developed more quickly and attained a smaller final body mass at higher temperatures, but the way that these traits responded to temperature differed by host plant. Caterpillars on P.occidentalis displayed a monotonic decrease in development time with increasing temperature, but the development time of those on P. x yedoensis declined with temperature in a biphasic manner. Furthermore, the rate at which pupal mass increased with decreasing temperature was much greater for caterpillars on P.occidentalis than those on P. x yedoensis.

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), was originally distributed in North America and spread into central Europe and eastern Asia in the early 1940s. This species was first found in Seoul, Korea in 1958. In this study, the effect of temperatures on development in regional variation of the H. cunea was investigated. Local populations of fall webworm were collected in Goyang and Pusan, Korea and the larvae were reared on an artificial diet, incubated at seven constant temperatures of 17.5, 20.0, 22.5, 25.0, 27.5, 30.0 and 32.5℃ under the photoperiod 16L:8D. The average developmental periods decreased as the temperature increased at all stage in the Goyang population. The temperature dependent developmental rates in each stage were well described by linear and nonlinear Briere model in the Goyang population. The lower threshold temperature for development from egg to adult was 13.7℃ and all the eggs did not hatch at 32.5 ℃. Optimum temperatures for reproduction was 22.5℃, and average number of eggs laid by individual female at the temperature was 441.5±121.8. Developmental periods of larval and pupal stage in the Goyang population were not significantly different from those in the Pusan population at 25℃.

Hyphantria cunea is a fall webworm is considered an agricultural pest. It is a major pest of many board-leaved trees. H. cunea nucleopolyhedrovirus (HcNPV) and H. cunea granulovirus (HcGV) were isolated from the fall webworm cadavers in Korea. To better understand HcNPV and HcGV, their genomic sequences were determined, analyzed and compared to two viruses together. The entire nucleotide sequence of the HcNPV genome was fully sequenced using 454 pyrosequencing. The genome of the HcNPV was 131,302 bp with a 45 % G+C content. Computer assisted analysis predicted 146 open reading frames (ORFs) of 50 or more amino acids that showed minimal overlap. Further more, when the phylogenetic relationship was analyzed, HcNPV was closely related to Orgyia pseudotsugata MNPV (OpMNPV) which belong to Group I NPV. The HcGV genome was 114,557 bp with a 39% G+C content and contained 130 putative ORFs of 50 or more amino acids. When phylogenetic relationships were analyzed, HcGV was closely related to Xestia c-nigrum granulovirus, which belong to the Type-II GV. HcNPV shares 48 ORFs with HcGV. The most significant difference between HcNPV and HcGV is fgf gene. HcNPV contains one fgf gene, whereas HcGV contains three fgf genes. The presence of fgf reduces the time and efficient systemic infection it takes the virus to kill its host. The difference of fgf number from HcNPV and HcGV suggested that different affect for the speed of systemic infection.

미국흰불나방은 2011년 국내 35개 시군에서 발생과 피해가 확인되었고, 국내에서는 검은색 머리(black-headed form)를 가진 유충의 출현만 확인되었다. 미국흰불나방이 출현하는 곳의 서식지 분포비율은 가로수 66.7%, 조경수 19.4%, 산림 13.9%로 나타났다. 즉 가로수, 조경수가 86.1%로 인위적인 환경에서 피해가 심각하였다. 본 연구에서 확인된 기주식물은 총 44과 102종으로 조사되었고, 선행연구와 비교하여 29종이 추가되었다. 국내에서 최초 발견된 후 약 50년이 지난 현재 선행연구를 포함한 기주식물은 총 62과 219종으로 조사되었다. 그 중에서 식량작물 5종(2.3%), 채소류 6종(2.7%), 약용작물 4종(1.8%), 특용작물 1종(0.5%), 과수 13종(5.9%), 기타수원지 6종(2.7%), 기타작물 5종(2.3%)이 포함되어 있다. 기주식물의 원산지는 미국흰불나방의 원산지와 같은 북미 원산 식물 7종(18.4%), 중국 원산 식물 11종(29.0%), 일본 원산 식물 4종(10.5%), 유럽 원산 식물 4종(10.5%), 인도 원산 식물 4종(10.5%) 등으로 조사되었다. 유충에 의해 집중적으로 피해를 입은 수종은 양버즘나무(Platanus occidentalis L.), 느릅나무(Ulmus davidiana var. japonica (Rehder) Nakai), 산수유(Cornus officinalis Siebold & Zucc.) 등 총 17종으로 관찰되었다.

A MnSOD gene was cloned from the fall webworm, H. cunea. The MnSOD cDNAs encode precursor proteins of 215 amino acid residues. The deduced amino acid sequences of the H. cunea MnSOD cDNA showed 76% identity to B. mori MnSOD and 62-56% to MnSOD sequences from other organisms. MnSOD and Cu/ZnSOD in H. cunea is expressed from all tissues. MnSOD expression is changed at a trace level in infected larvae, while Cu/ZnSOD expression is strongly changed against bacteria, and fungi. The expression level of Cu/ZnSOD increased by different artificial photoperiod (24L:0D), UV irradiation (312nm), and starvation condition, while the expression level of MnSOD only increased by starvation condition. Also, expression of MnSOD and Cu/ZnSOD showed no significant change in 0L:24D condition. In addition to expression levels of Cu/ZnSOD in H. cunea significantly increased by temperature stress and injection with paraquat, but reduced by injection with 10% H2O2. The expression level of MnSOD significantly increased by temperature stress and reduced by injection with 10% H2O2 and paraquat.

Apolipophorin-III (apoLp-III) is a hemolymph protein whose function is to facilitate lipid transport in an aqueous medium in insects. Recently, apolipophorin-III in Galleria mellonella and Hyphantria cunea was shown to play an unexpected role in insect immune activation. We show here a novel possible function/role of the apoLp-III in insects. To investigate the genes which have a relationship with apoLp-III in fall webworm larvae, we reduced endogenous Hc apoLp-III mRNA levels in larvae via RNA interference (RNAi). The RNAi-mediated Hc apoLp-III reduction resulted in the reduction of antioxidants, like MnSOD, catalase, and glutathione S transferase as well as immune proteins. In particular, expression of MnSOD commonly decreased in fat body, midgut, and hemocytes following the knockdown of Hc apoLp-III, which induced an elevated level of superoxide anion in Hyphantria cunea larvae. The observed effect of Hc apoLp-III RNAi suggests that Hc apoLp-III is related to the action/expression of antioxidants, especially MnSOD.

A new insect member of the STAT family of transcription factors (HcSTAT) 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 transcribed in hemocyte, fat body, midgut, epidermis, and Malpighian tubule. Especially, hemocyte and Malpighian tubule showed transcriptional activation of HcSTAT upon Gram-negative and -positive bacteria challenge. Gram-negative and -positive bacteria challenge specifically results in nuclear translocation of HcSTAT protein and induction of DNA-binding activity that recognizes a STAT target site in H. cunea hemocyte. In vivo treatment with sodium orthovanadatetranslocates HcSTAT to the nucleus in hemocyte cells.

Reactive oxygen species (ROS) is toxic to living organisms, because its high reactivity causes oxidative damage to proteins, nucleic acids, and lipids. Superoxide dismutase (SOD) is an enzyme facilitating the removal of superoxide anions from living organisms. This study focused on the cloning of MnSOD cDNA from Hyphantria cunea and its induction upon bacterial infection and various stresses. The open reading frame of MnSOD is composed of 645 bp, encoding 215 amino acid residues. The theoretical molecular mass and pI of putative MnSOD was evaluated to be 24276 Da and 9.14, respectively. The MnSOD from H. cunea is highly similar to human MnSOD (59.5%) as well as Bombyx mori MnSOD (76.2%). MnSOD showed no big induction upon bacterial infection and stresses, compared to that of Cu/ZnSOD.

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.

Reactive oxygen species (ROS) is toxic to living organisms, because its high reactivity causes oxidative damage to proteins, nucleic acids, and lipids. Superoxide dismutase (SOD) is an enzyme facilitating the removal of superoxide anions from living organisms. This study focused on the cloning of MnSOD cDNA from Hyphantria cuneaand its induction upon bacterial infection and various stresses. The open reading frame of MnSOD is composed of 645 bp, encoding 215 amino acid residues. The theoretical molecular mass and pI of putative MnSOD was evaluated to be 24276 Da and 9.14, respectively. The MnSOD from H. cunea is highly similar to human MnSOD (59.5%) as well as Bombyx mori MnSOD (76.2%). MnSOD showed no big induction upon bacterial infection and stresses, compared to that of Cu/ZnSOD.

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.