Lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of glycosidic bonds in crystalline polysaccharides including chitin and cellulose. The recent discovery of LPMO family proteins in many insect species suggests that they presumably play a role in chitin degradation in the cuticle/exoskeleton, tracheae and peritrophic matrix during insect development. Insect LPMOs belong to auxiliary activity family 15 (AA15/LPMO15) and have been classified into at least four groups based on phylogenetic analysis. In this study, we identified and investigated the physiological functions of group I LPMO15 (MaLPMO15-1 and PhLPMO15-1) in two longhorn beetle species, Monochamus alternatus and Psacothea hilaris. In both species, depletion of LPMO15-1 transcripts by RNAi resulted in a lethal pupal-adult molting defect. The insects were unable to shed their old pupal cuticle and died entrapped in their exuviae. Furthermore, TEM analysis revealed a failure of degradation of the chitinous procuticle layer of their old cuticle, retaining intact horizontal laminae and vertical pore canals containing perpendicularly oriented chitin fibers (pore canal fiber, PCF) in their core. These results indicate that MaLPMO15-1 and PhLPMO15-1 are required for turnover of the chitinous old cuticle, which is critical for insect molting.

Lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of glycosidic bonds in crystalline polysaccharides including chitin and cellulose. The recent discovery of LPMO family proteins in many insect species suggests that they presumably play a role in chitin degradation in the cuticle/exoskeleton, tracheae and peritrophic matrix during insect development. Insect LPMOs belong to auxiliary activity family 15 (AA15/LPMO15) and have been classified into at least four groups based on phylogenetic analysis. In this study, we identified, characterized and investigated the physiological functions of group I LPMO15 (MaLPMO15-1 and PhLPMO15-1) in two longhorn beetle species, Monochamus alternatus and Psacothea hilaris. In both species, depletion of LPMO15-1 transcripts in last instar larvae by RNAi had no effect on subsequent larval-pupal molting and the resulting pupae developed normally. However, adverse effects on their development were observed during the pupal-adult molting period. The pharate adults were unable to shed their old pupal cuticle and died entrapped in their exuviae probably due to a failure of degradation of the chitin in their old cuticle, which is critical for completion of the insect molting and continuous growth.

The notorious lamiine species Asian Longhorn Beetle, Anoplophora glabripennis, is one of the major invasive pests of street trees, which is an endemic species of Korea and China. By far, the distributional range of Korean A. glabripennis population is restricted to only central to northeastern forest region of South Korea. In this study, we found unreported A. glabripennis populations in 4 different port cities and adjacent cities. These new populations are found in very much urbanic regions; Incheon, western part of Seoul, Busan and Ulsan. These populations can be distinctly differentiated with previously reported populations by massive damage on trees, unusual usage of host plant and spotted elytral pattern. To test their identity, we analyse the genetic patterns of the A. glabripennis populations sampled across South Korea based on three mitochondrial genes, Cytochrome Oxidase I – leucin tRNA – Cytochrome Oxidase II (COI-tRNALeu- COII). Additionally, we used available sequences of COI - tRNALeu - COII of 104 Chinese and 15 Korean individuals from NCBI. Here we show that Korean population is distinctly divided into two major clades, namely native populations and non-native ones, with 0.7% ~ 1.2% of genetic divergence. Hence, the non-native ones can be divided into two subgroups, which we call Incheon-Seoul complex and Busan-Ulsan complex. We observed that these newly found groups, Incheon-Seoul complex and Busan-Ulsan complex share perfectly identical COI haplotype within each group. This study strongly suggests that newly found populations are introduced respectively and these populations might be derived from very small number of introduced founders.

The pine wilt disease that blocks the path for water and nutrition in pine trees is caused by the nematode, Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae). The nematode relies on the longhorn pine sawyer beetle Monochamus alternatus and Monochamus saltuaris (Coleoptera: Cerambycidae) as vectors. Recently, 2-(undecyloxy)ethanol was identified as a male-produced aggregation pheromone of Monochamus species. In this study, we investigated the effect of 2-(undecyloxy) ethanol along with host plant volatiles -pinene and ethanol on attracting M. alternatus at a pine forest in Pohang, Korea from May, 2014 to July, 2014. To sustain the volatility of 2-(undecyloxy)ethanol and host plant volatiles, a superabsorbent polymer based on polyacrylic acids and water were added to the pheromone mixture. A total of 46 M. alternatus were collected from two field bioassays. Our results indicate that 2-(undecyloxy)ethanol is effective in attracting M. alternatus in Korea. Our study suggests that the aggregation pheromone could be used for detection and population monitoring of the beetles as well as for the effective mass trapping in outbreak situations.

직접적인 기주식물 조사와 기존 문헌자료의 기록을 재검토하여, 한국산 하늘소과(딱정벌레목: 잎벌레상과) 6아과 103속 181종의 기주식물 목록을 작성하였다. 유리알락하늘소의 새로운 기주식물로 산겨릅나무가 확인된 것을 포함하여 총 14종의 하늘소와 기주식물 관계를 구명하였다. 기주식물로 44과 107속 170종 이상이 정리되었다. 이 중, 네 과(느릅나무과, 소나무과, 참나무과, 자작나무과)가 주요 기주식물 과(하늘소 기록 종수의 23% 이상 차지)인 것으로 확인되었다. 기존 문헌들에서 기주식물과 하늘소류의 무효한 학명과 국명들은 현재 통용하고 있는 유효한 학명과 국명으로 수정하였다.