Climate change has led to increased insect pests and pest distribution changes. Traditionally, chemical control using synthetic pesticides has been the main method for pest management, but the emergence of pesticide-resistant pests has become a problem. There is a need to develop new pest control agents to overcome these issues. Entomopathogenic fungi used in pest management have minimal environmental side effects and possess a mechanism of action distinct from that of synthetic pesticides. However, there is a need for the development of technologies to maximize the insecticidal effects of fungi against pests, and expressing and releasing dsRNA within the fungi can preemptively knock out the activation of the insect’s defense system, thereby enhancing the insecticidal effect. Controlling insect defense genes and using entomopathogenic fungi as bio-carriers forms a new pest management strategy. This approach, described as a “microbial insecticide agents development strategy of cassette concept, ” can versatilely modify genes and microbes. It is expected to overcome the limitations of synthetic pesticides.

It is well known that invertebrates do not have adaptive immunity because of their short life cycle. Especially, insects have a strong innate immune system, including antimicrobial peptides (AMPs) production, to protect themselves from a wide range of pathogens. Previously, we identified over 60 genes related to AMP production, including Toll and Imd pathways, and characterized their immunological role in response to pathogenic infection through target gene-specific RNAi. This resulted in decreased expression levels of most AMPs in the larvae which were injected with target gene-specific dsRNA and microbes. Currently, we are focusing on studying the regulation of AMP production through epigenesis. It may help us understand how to regulate the innate immune system induced by pathogenic infection.

곤충면역학은 주로 위생해충인 모기와 말라리아 (또는 Wolbachia)를 중심으로 많은 연구가 이뤄졌으며, 농업해충분 야에서는 곤충병원선충, 기생봉, Polydnavirus, 백강균, Bt 등에 대한 기주곤충과의 상호작용 연구가 기주면역저하와 관련한 생물적방제 인자에 대한 대안으로써 진행되고 있다. 이 가운데, 세균이 생성하는 Bt와 같은 내독소단백질은 기주곤충의 중장에 존재하는 수용체(cadherin, aminopeptidase N, alkaline phosphatase)와의 상호작용으로 기주에 대한 살충효과가 나타는 것을 설명하고 있으며, 최근에는 막관통단백질인 ATP-binding cassette transporter (ABC transporter)는 해독작용과 더불어 Bt와 수용체간의 상호작용에 관여하고 있음이 조명되고 있다. 따라서 곤충의 ABC transporter에 대한 생리적 기능 구명은 기주곤충과 병원체 상호작용 연구의 새로운 장으로 조명될 수 있을 것이다.

자연생태계 내에서 곤충은 식물과 다양한 관계를 맺고 살아가고 있는 중요한 분류군이라 할 수 있다. 특히, 대부분의 곤충은 식물을 먹이로 하는데 잎, 줄기 및 뿌리 등 먹이선호도에 따라 가해부위가 다르며, 가해특성에 따라 흡즙성, 저작성, 종자가해성, 혹형성 및 잠엽성과 같은 다양한 기능군으로 나누어 볼 수 있다. 최근에는 곤충에 의한 화분매개의 중요성이 재조명됨에 따라 이를 증진시킬 수 있는 방안에 대한 논의가 활발하게 이루어지고 있다. 이외에도 중요 식물종의 보존과 곤충의 연관성에 초점을 두고 보전의 효율을 증대할 수 있는 방안도 시도될 필요성이 있다. 본 연구에서는 우리나라에서의 곤충과 식물과의 상호관계에 대해 폭넓게 살펴보고 향후 연구가 필요한 분야를 제시하고자 한다.

Entomopathogenic fungi are potential pesticides as biological control agents. However, many previous studies have focused on basic researches to control pest using insect-pathogenic fungi. Herein, the molecular characteristics of insect defense mechanisms against fungal pathogens and fungal pathogenicity to insects were investigated. The whole genome of Beauveria bassiana (Bb) JEF-007 was sequenced (36,538,394 bp) using Pacbio sequencing. Based on this data, the transcriptomes of bean bug and fungus were analyzed using RNA-seq. In the transcriptome analyses, six and five genes were validated to be involved in the fungal pathogenicity and insect defense, respectively. This work can provide an understanding of the insect-pathogen interactions

Global warming can seriously influence on the interaction between pest and natural enemy in the agroecosystem due to the differences in optimal temperature ranges. Two aphid-ladybug systems, Myzus persicae-Coccinella septempunctata (M-C) and Aphis gossypii-Coccinella septempunctata (A-C) in the pepper crop were simulated, respectively under four different temperature scenarios including crop development over 244 days with the assumption that the average temperature is higher by 1, 3, and 5 °C than that in Seoul in 2000. Temperature-dependent functions for each aphid-ladybug system were embedded in Rosenzweig-Macathur predator-prey model to explore their population dynamics, and then Dynamic Index was used to quantify the strengths of species interactions. The result shows that the predator-prey population cycles as well as species interactions are getting shorter and stronger in both systems as temperature increased. Especially, the excessively high temperature scenario in Aphis gossypii-Coccinella septempunctata system could result in the extreme species interaction. Therefore, the increasing temperature can facilitate the effectiveness of biological control because of growing crop plant development and much stronger species interaction, although there are increases of the frequency of pest occurrences.

식물은 유도저항성이나 천적류의 공격활동 변화를 유발하여 관련 초식성 곤충류 간 상호작용관계에 불리한 영향을 미칠 뿐만 아니라 식물 체내 영양물질 동태나 타감물질 그리고 외부 형태적 변화 등을 통하여 초식곤충류에 유리한 영향을 미치기도 한다. 본고에서는 식물이 개재되었 을 때 초식 곤충류간의 상호작용 관계와 초식성 곤충 가해에 대한 식물의 여러 가지 반응특성과의 관계나 곤충류 생활사 특성이 초식성 곤충군집 의 구조에 미치는 영향을 살펴보고 그의 군집학적 의의를 고찰하였다.

Coevolution is a large part of evolution and the patterns of adaptation and speciation may be modified by coevolution processes. The arms races between insects and plants in natural system are one of coevolutionary processes and the mechanistic and predictive processes of the system may be helpful to understand the interaction between host plants and herbivores in agricultural systems. Furthermore, human activities may give direct and/or indirect effects on ecological and evolutionary processes in natural and agricultural ecosystems and have selection power as well as natural selection. Recent studies showed that the fundamental principles of evolution – variation (genetic difference, phenotypic plasticity, epigenetic change, and nongenetic inheritance), selection (directional or fluctuating), connectivity and eco-evolutionary dynamics – are important to understand the interplay between insects and plants. The coevolutionary processes between plants and herbivores were also interpreted by the geographic mosaic theory. The evolutionary effects on ecological dynamics in natural ecosystems were classified four categories: trophic specialization, evolution of defense, interaction outcome and loss of traits in absent of interaction. It was reviewed that it is necessary to consider the ecological response in evolutionary studies as well as evolutionary variation in ecological researches.