The fall armyworm (Spodoptera frugiperda, FAW) is an invasive migratory pest that has recently spread to Korea, damaging several corn cultivars with significant economic value. Comparisons of the growth stages of FAW were conducted based on the preferred feed. Therefore, we selected six maize cultivars, including three categories: (i) commercial waxy corn (mibaek 2-ho, heukjeom 2-ho, dreamoak); (ii) popcorn (oryun popcorn, oryun 2-ho); and (iii) processing corn (miheukchal). A significant effect was observed during the larvae period, pupal period, egg hatching ratio, and larvae weight, whereas the total survival period and adult period did not show significant variation among the tested corn cultivars. We identified variations in the FAW gut bacterial community that were dependent on the genotype of the corn maize feed. The identified phyla included Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. Among these genera, the most abundant bacterial genus was Enterococcus, followed by Ureibacillus. Enterococcus mundtii was the most abundant among the top 40 bacterial species. The intergenic PCR-based amplification and gene sequence of the colony isolates were also matched to the GenBank owing to the prevalence of E. mundtii. These results showed that the bacterial diversity and abundance of particular bacteria in the guts of FAWs were influenced by the six major maize corn cultivars.

Background: Aedes mosquitoes are important invasive species contributing to the spread of chikungunya, dengue fever, yellow fever, zika virus, and other dangerous vector-borne diseases. Aedes albopictus is native to southeast Asia, with rapid expansion due to human activity, showing a wide distribution in the Korean peninsula. Aedes flavopictus is considered to be native to East Asia, with a broad distribution in the region, including the Korean peninsula. A better understanding of the genetic diversity of these species is critical for establishing strategies for disease prevention and vector control. Methods: We obtained DNA from 148 specimens of Ae. albopictus and 166 specimens of Ae. flavopictus in Korea, and amplified two mitochondrial genes (COI and ND5) to compare the genetic diversity and structure of the two species. Results: We obtained a 658-bp sequence of COI and a 423-bp sequence of ND5 from both mosquito species. We found low diversity and a nonsignificant population genetic structure in Ae. albopictus, and high diversity and a nonsignificant structure in Ae. flavopictus for these two mitochondrial genes. Aedes albopictus had fewer haplotypes with respect to the number of individuals, and a slight mismatch distribution was confirmed. By contrast, Ae. flavopictus had a large number of haplotypes compared with the number of individuals, and a large unimodal-type mismatch distribution was confirmed. Although the genetic structure of both species was nonsignificant, Ae. flavopictus exhibited higher genetic diversity than Ae. albopictus. Conclusions: Aedes albopictus appears to be an introduced species, whereas Ae. flavopictus is endemic to the Korean peninsula, and the difference in genetic diversity between the two species is related to their adaptability and introduction history. Further studies on the genetic structure and diversity of these mosquitos will provide useful data for vector control.

In this study, we first determined the mitochondrial genome sequence of Aedes koreicus collected in South Korea. Its mitochondrial genome is 15,840 bp in length and consists of 13 protein-coding genes, 22 transfer-RNA genes, 2 ribosomal-RNA genes, and a non-coding A + T rich region. The overall base composition in the heavy strand was as follows: A, 40.1%; G, 8.7%; C, 13.6%; T, 37.5%; and the G + C content was 22.4%. Phylogenetic analysis revealed that Aedes spp. form a monophyletic group.

Plastic electronics with deformable semiconducting polymer layers have emerged as a promising future technology. The design of semiconducting layers with tunable mechanical properties is crucial to improving the performance and reliability of plastic electronics, particularly for flexible and stretchable devices. Here, a method is demonstrated for systematically controlling the persistence length, allowing improvement of the mechanical properties of a single conjugated polymer system without the need for complex chemical modifications to the rigid backbone. The effects of plasticizing molecular additives (PMAs) on the rigidity of conjugated chains are thoroughly investigated through persistence length analysis. Solution‐based small‐angle neutron scattering reveals how different PMAs influence the persistence length of the benchmark rigid conjugated polymer PDPP2T‐TT‐OD. The mechanical, thermal, morphological, and electrical properties of PMA‐blended films are evaluated under deformation. The results show that the mechanical modulus is primarily influenced by modification of the persistence length and the formation of uniformly entangled networks with smaller crystalline grains. The analysis suggests that the uniform distribution of PMAs in PDPP2T‐TT‐OD films, combined with physically crosslinked chains, significantly enhances thin film deformability. Notably, charge mobility remains stable even after stretching to 100% strain. These findings provide valuable insights into the design principles of PMA‐blended conjugated polymer systems, offering a pathway for tailoring mechanical properties in future plastic electronics.

Aedes albopictus is native to Southeast Asia and has emerged as a major vector for vector-borne diseases that are spreading rapidly worldwide. Recent studies have shown that Ae. albopictus populations have different genetic groups dependent on their thermal adaptations; however, studies on Korean populations are limited. In this study, we analyzed the genetic diversity and structure of two mitochondrial genes (COI and ND5) and sixteen microsatellites in mosquitoes inhabiting Korea, Japan, and Laos. The results indicate that the Korean population has low genetic diversity, with an independent cluster distinct from the Laos population. Mixed clusters have also been observed in the Korean population. On the basis of these findings, two hypotheses are proposed. First, certain Korean populations are native. Second, some subpopulations that descended from the metapopulation (East Asian countries) were introduced to Japan before migrating to Korea. Furthermore, we previously demonstrated that Ae. albopictus appears to have been imported to Korea. In conclusion, the dengue-virus-carrying mosquitoes could migrate to Korea from Southeast Asian epidemic regions, where they can survive during the severe winter months. The key findings can be used to establish an integrated pest management strategy based on population genetics for the Korean Ae. albopictus population.