비래해충인 혹명나방(Cnaphalocrocis medinalis)과 멸강나방(Mythimna separata)은 아시아의 주요 벼 재배국가에 광범위하게 분포하고 있는 벼의 주요 해충이다. 국내에서는 벼멸구, 흰등멸구와 함께 중국에서 비래하여 나타나는 것으로 알려져 있다. 혹명나방과 멸강나방의 발생지역과 통계적으로 유의미한 상관관계에 있는 환경변수를 확인하고, 국내에서의 지속적인 발생 가능성을 알아보기 위해 Maxent (Maximum Entropy Model) 3.3.2를 사용하였다.

Two complete mitochondrial genomes of the tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuoidea) and the rice leaf roller, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), were sequenced. Each 15,388 bp and 15,368 bp-long genome contained both the lepidopteran specific gene arrangement that differ from the most common arrangement of insects by the movement of tRNAMet to a position 5’-upstream of tRNAIle. Neither of the species have typical COI start codon. Instead, the CGA (arginine) sequence that is commonly present in other lepidopterans was also found both in S. litura and C. medinalis. The evolutionary rates among 13 protein-coding genes (PCGs) in Lepidoptera showed ATP8 the highest, whereas COI the lowest. The high A+T-content, which is characteristic of mitochondrial genome was well reflected in the two lepidopteran mitochondrial genomes: higher frequency of A/T-rich codons, severe A/T bias in 3rd codon position, and extremely high A/T content in the A+T-rich region. Because insect mitochondrial genomes harbor biased nucleotide and resultantly biased amino acid sequences, phylogenetic inference is often misled by them. Although each recoded and unrecoded datasets for nucleotide sequences and amino acid sequences of PCGs provided overall identical topology, regardless of recoded scheme, each nucleotide and amino acid dataset provided difference in the status of Macrolepidoptera, providing a monophyletic group by amino acid dataset, whereas non-monophyletic group by nucleotide dataset.

The rice leaf roller, Cnaphalocroci smedinalis Guenée (Lepidoptera: Pyralidae) is a leaf-feeding pest of rice world-widely distributed. For better understanding of the pest insect, geographic sequence variation of the species were performed using the mitochondrial A+T-rich region, with the samples collected from seven Korean and six Chinese localities. A total of 94 haplotypes obtained from 187 individuals showed the length variation, ranging from 339 bp to 348 bp. The maximum divergence of 4.57% appears to evidence a substantial sequence variation, indicating the applicability of this molecular marker to the study of geographic variation. Overall, a high per generation migration ratio (Nm = 3.67742 ~ infinite), a low level of genetic fixation (FST = 0 ~ 0.11969), and no discernable isolated population were noted in the most C. medinalis populations. AMOVA analysis to find out allocation of genetic variability of C. medinalis populations has shown allocation of majority of variation to the within-population, rather than among-populations and between-region, suggesting that the C. medinalis populations in both China and Korea are largely well connected. This result is consistent with current knowledge of the dispersal ability of the species. The structure analysis of the A+T-rich region has shown that the typical structural elements found in other lepidopteran insects also is well preserved in the C. medinalis A+T-rich region (i.e., a poly-T stretch and a microsatellite-like A/T repeat).

This study was carried out to investigate the effect of each single component of the synthetic sex pheromone in the rice green caterpillar, Naranga aenescens and rice leaf roller, Cnaphalocrocis medinalis. Trap catches with each single component or binary mixtures of the sex pheromone in N. aenescens were significantly lower than that with an optimum mixture (2: 1: 4) of Z9-14:Ac, Z9-16:Ac and Z11-16:Ac. But only few number of C. medinalis male was caught in trap baited with each component of the sex pheromone excepting Z13-18:Ald. In an optimum composition of the sex pheromone in C. medinalis, trap catches baited with an 11: 100: 11 mixture of Z11-18:Ald, Z13-18:Ald, and Z13-18:Ac without two alcohol components (Z11-18:OH and Z13-18:OH) was higher than that baited with an optimum mixture of Z11-18:Ald, Z13-18:Ald, Z11-18:OH, Z13-18:OH, and Z13-18:Ac. The efficacy of the sex pheromone lure of N. aenescens kept over 4 weeks. The occurrence of N. aenescens caught in trap baited with sex pheromone gave three peaks and C. medinalis showed two distinct peaks throughout the flight season. Therefore, it can be expected that pheromone-baited trap provides a simple tool for monitoring N. aenescens and C. medinalis in Korea.