The giant water bug, Lethocerus deyrolli, is an endangered wetland insect found throughout East Asia. In 2006, the light-attraction flight of L. deyrolli was studied in Gyodong Island, Korea, using artificial light. The flight of L. deyrolli was observed from early June to late October, and two peaks in the numbers of attracted insects were noted in the middle of June and September. L. deyrolli begins to exhibit flight behaviour at a daily mean air temperature of 15°C and above, but optimal flight temperatures for the insect are between 17°C and 19°C, with a wind speed of less than approximately 1.8 m/sec and a relative humidity of around 80%. The length of daylight did not substantially influence the flight pattern. Daily flight occurred principally between 9 pm and 10:30 pm. L. deyrolli individuals attracted by the artificial light were frequently consumed by magpies or house rats. It appears most probable that artificial lights, such as street lights and tennis court lights, constitute a critical factor in the local extinction of L.deyrolli.

Pediciinae crane flies belonging to the genus Dicranota Zetterstedt, 1838 of the Korean Peninsula were studied beginning in 1933, but only seven species have been recorded from North Korea so far; the genus was unknown from South Korea. Seventeen species were found during our studies on the Peninsula, three of them described as new: D. (Eudicranota) distincta Podenas, sp. nov., D. (Rhaphidolabis) seoi Podenas, sp. nov., D. (Rhaphidolabis) yeongokia Podenas, sp. nov. Ten new species are added to the Korean species list, five of them new for North Korea with total number reaching twelve, and eleven species new for South Korea. Habitat, elevation range, and seasonality data is presented for each species. Images of taxonomically important morphological characters, distribution maps, and an identification key for all Korean species of the genus Dicranota are presented.

Giant water bugs (Hemiptera: Belostomatidae) are top predators in wetland ecosystems, serving as biological indicators of the health of lentic ecosystems and as effective biological control agents for freshwater snails and mosquitoes. This study aimed to predict the current and future distribution of two Korean giant water bugs, Appasus japonicus and Diplonychus esakii, under three climate change scenarios, contributing to the sustainable management of wetland ecosystems in South Korea. Using MaxEnt models, we employed seven climatic and three non-climatic variables to investigate the habitat preferences and distribution patterns of the species. The results revealed that A. japonicus is likely to experience a northward range contraction due to climate change, while D. esakii is predicted to expand its distribution northward without losing its current range. These responses may lead to occupancy turnover between the two species, potentially driving reassembly in aquatic organism community. Elevation was the primary factor influencing the distribution of A. japonicus, whereas annual mean temperature was the most informative variable for D. esakii, both factors derived under the current climate conditions. These findings suggest that both species are highly sensitive to climate change, with potential range shifts toward higher latitudes and elevations. This study provides insights into how climate change could impact two giant water bugs, thereby supporting future efforts to manage and conserve wetland ecosystems in this country.

Diplonychus esakii, a water bug from the family Belostomatidae, plays an important role in freshwater ecosystems as one of the top predators. In this study, we investigated the genetic diversity and population structure of D. esakii by analyzing 318 specimens across 27 sites in South Korea. We found that the populations of D. esakii possess 11 haplotypes with a haplotype diversity of 0.623. This represents a relatively low level of genetic diversity compared to other known belostomatids and endangered species. AMOVA and F_ST analyses revealed significant genetic differentiation among populations, with most populations harboring only 1–2 haplotypes, suggesting restricted gene flow between populations and a low level of genetic diversity. This low genetic diversity and limited gene flow suggest a potential vulnerability to environmental changes and an increased risk of extinction, indicating that D. esakii should be designated as a protected species in South Korea as part of future conservation efforts. Based on the results of this study, Upo Wetland, which maintains relatively high levels of genetic diversity and Jeju Island, which, despite its lower genetic diversity compared to the mainland, does not share haplotypes with other regions, should be considered key conservation units for this species. This study highlights the importance of incorporating genetic information into conservation status assessments under the Red List Categories and Criteria and also emphasizes the need to evaluate this species on the Korean Red List. The data provided here will serve as essential baseline information and valuable resources for the development of effective conservation strategies.

Brithura Edwards, 1916 (Diptera: Tipulidae) is a small genus of crane flies currently comprising 16 described species distributed across the East Palaearctic and Oriental regions. Although the adults of this genus rank among the largest representatives of the family Tipulidae, their immature stages have remained undocumented until now. In this study, mitochondrial cytochrome c oxidase subunit I (COI) gene fragment sequences (DNA barcodes) of Brithura sancta Alexander, 1929 were analyzed using both recently collected adult specimens from the Republic of Korea and historical museum specimens from China (collected in 1933). These sequences were compared with COI data obtained from larvae collected in Republic of Korea. We present the first description, with detailed illustrations and ecological information, of the previously unknown final instar larva of Brithura, specifically for the East Palaearctic species B. sancta. Diagnostic larval characters for the genus are discussed. Additionally, a redescription and comprehensive morphological documentation of the adult male and female B. sancta, including habitus and genitalia, are provided. This study represents the first phylogenetic contribution to the taxonomy of Brithura larvae based on mitochondrial COI sequence data.