Yeon Jae Bae

Freshwater biomonitoring with macroinvertebrates in East Asia

This paper summarizes the history and current status of efforts to implement macroinvertebrate biomonitoring protocols for surface water pollution in China, Japan, South Korea, Malaysia, Mongolia, Russia (Far East), and Thailand. Impediments to biomonitoring in some of these countries include: (1) lack of knowledge about macroinvertebrate fauna and their tolerance values, especially during the aquatic, immature stages; (2) the scarcity of research programs and formal training opportunities for biomonitoring offered in universities; (3) the shortage of high-quality microscopes and other necessary equipment; and (4) limited government understanding and support for biomonitoring, few skilled regulatory staff, and the persistence of old and unusable biomonitoring protocols. A recently established regional network, the Aquatic Entomological Society of East Asia (AESEA), and several major recent publications are helping to coordinate and promote science and technology in East Asia.

Benthic macroinvertebrates for uses in stream biomonitoring and restoration

Biomonitoring is the use of biological responses of populations and communities of certain indicator organisms to evaluate mainly anthropogenic environmental changes. Stream ecosystem biomonitoring using benthic macroin vertebrates is reviewed from a historical perspective. Case studies are provided from the biomonitoring and restoration projects in the Han River system: main watercourse of the Han River, Cheonggye-cheon, Jungnang-cheon, Wangsuk-cheon, and Gapyeong-cheon. From the case studies as well as other various biomonitoring projects conducted in Korea, respresentative benthic macroinvertebrate groups, which are use ful for the biomonitoring and restoration programs in Korean streams, are suggested with a list of endangered, rare, and ecoenvironmentally valuable species of freshwater arthropods.

Light-attraction flight of the giant water bug, Lethocerus deyrolli (Hemiptera: Belostomatidae), an endangered wetland insect in East Asia

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.

Aquatic insect diversity in a tropical Vietnamese stream in comparison with that in a temperate Korean stream

A comparative investigation on aquatic insect diversity was conducted in a tropical stream in Southeast Asia (the Dak Pri stream in southern Vietnam; stream orders II–V, two sites per stream order) with a reference temperate stream in Northeast Asia (the Gapyeong stream in central Korea) in March 2001 and April 2000, respectively. The numbers of aquatic insect taxa in Dak Pri stream (268 species, mostly undescribed, 230 genera, 91 families, and 9 orders; 110.5 ± 17.1 species per site) were about twice those in Gapyeong stream (133 species, 98 genera, 51 families, and 8 orders; 60.3 ± 8.5 species per site). Coleoptera, Trichoptera, Ephemeroptera, and Diptera were the major aquatic insect orders with high taxonomic richness, and Coleoptera, Odonata, and Hemiptera contributed to the higher degree of aquatic insect diversity in Dak Pri stream. The species diversity indices of Dak Pri stream (4.37 ± 0.19) were higher than those of Gapyeong stream (3.73 ± 0.42), whereas the dominance indices of Dak Pri stream (0.195 ± 0.046) were lower than those of Gapyeong stream (0.346 ± 0.113). Collector-gatherers were predominant in both streams; shredders were more abundant in Dak Pri stream while scrapers were more abundant in Gapyeong stream. Factors affecting the higher degree of aquatic insect diversity in Dak Pri stream are discussed.

A Rare Tropical Stonefly Brahmana flavomarginata (Plecoptera: Perlidae: Acroneuriinae) from Vietnam

The perlid stonefly Brahmana flavomarginata Wu, originally described from China from the male adult, is described using reared male and female adults and nymphs from Vietnam. The male adult of B. flavomarginata is distinguished from its congeners by the blackish-brown body color and distinct head marking, hemitergal triangular chitin plates, and a median semicircular smooth subgenital plate (hammer) on the abdominal sternum IX. The female adult has a large and round subgenital plate which extends to the posterior margin of the abdominal sternum X. The nymph can be distinguished by the relatively small compound eyes and the body covered by many long stout setae and short golden brown hair-like setae. This species is known in southwestern China (Yunnan Province) and northern Vietnam (Lao Cai Province, Cao Bang Province).

Molecular phylogeny of the higher taxa of Odonata (Insecta) inferred from COI, 16S rRNA, 28S rRNA, and EF1‐α sequences

In this study, we sequenced both two mitochondrial genes (COI and 16S rRNA) and nuclear genes (28S rRNA and elongation factor‐1α) from 71 species of Odonata that represent 7 superfamilies in 3 suborders. Phylogenetic testing for each two concatenated gene sequences based on function (ribosomal vs protein‐coding genes) and origin (mitochondrial vs nuclear genes) proved limited resolution. Thus, four concatenated sequences were utilized to test the previous phylogenetic hypotheses of higher taxa of Odonata via Bayesian inference (BI) and maximum likelihood (ML) algorithms, along with the data partition by the BI method. As a result, three slightly different topologies were obtained, but the BI tree without partition was slightly better supported by the topological test. This topology supported the suborders Anisoptera and Zygoptera each being a monophyly, and the close relationship of Anisozygoptera to Anisoptera. All the families represented by multiple taxa in both Anisoptera and Zygoptera were consistently revealed to each be a monophyly with the highest nodal support. Unlike consistent and robust familial relationships in Zygoptera those of Anisoptera were partially unresolved, presenting the following relationships: ((((Libellulidae + Corduliidae) + Macromiidae) + Gomphidae + Aeshnidae) + Anisozygoptera) + (((Coenagrionidae + Platycnemdidae) + Calopterygidae) + Lestidae). The subfamily Sympetrinae, represented by three genera in the anisopteran family Libellulidae, was not monophyletic, dividing Crocothemis and Deielia in one group together with other subfamilies and Sympetrum in another independent group.

The wingless stonefly family Scopuridae (Plecoptera) in Korea

A comprehensive examination of stonefly material from South Korea resulted in the recognition of three species from the wingless stonefly family Scopuridae: Scopura gaya sp. n, S. laminata Uchida (♂ and ♀ previously unknown), and S. scorea sp. n. Descriptions of all life stages with macro-photos of the key characters are provided. Differential diagnoses, distributional, habitat, and ecological notes, along with taxonomic remarks, are also provided.

Distribution and genetic characteristics of Ephoron shigae (Ephemeroptera: Polymitarcyidae) in Korea

Ephoron shigae is distributed in Far East Russia, Korea and Japan, where it inhabits rivers, streams and lakes. Although this mayfly is a geographically parthenogenetic species, unisex populations have been observed only in Japan. We aimed to answer the following three questions: (i) whether there is a unisex population of E. shigae in Korea; (ii) whether migration and gene flow exists between E. shigae populations in Korea and Japan; and (3) whether E. shigae populations are fragmented in Korea because of mountains running to the north and south. We observed 20 populations across Korea and investigated the sex ratio in 12 populations. Our results showed that all the populations were bisex, and we believe that there is no unisex population of E. shigae in Korea. In addition, we examined the genetic structure of E. shigae in Korea by using the COI gene. The results showed that the Korean populations were clearly divergent from the Japanese populations; the level of genetic distance between the Korean and Japanese populations was interspecific rather than intraspecific. Therefore, parthenogenetic populations of E. shigae probably belong to unisex populations that originated in Japan, while the individuals would have not migrated to Korea. The Korean populations did not show clear fragmentation by geographic barrier, although this mayfly with extremely short adult stage (up to 2 h) could be a comparatively strong disperser across Korea.

Exposure of mayfly Ephemera orientalis (Ephemeroptera) eggs to heavy metals and discovery of biomarkers

The objective of this study was to assess acute toxicity of heavy metals in eggs of mayfly Ephemera orientalis McLachlan, and to elucidate relationships between heavy metal toxicity and protein expression patterns determined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Acute toxicity analysis was conducted using five heavy metals (cadmium, chromium, copper, lead, and mercury), and the toxicity endpoint was established from the egg hatching rate during a 14-day exposure period. Median hatching toxicity (HC₅₀) values were determined for each heavy metal, and the most toxic heavy metal was found to be mercury (0.11 mg/L), followed by copper (0.32 mg/L) and lead (4.39 mg/L). E. orientalis eggs were highly tolerant to cadmium and chromium (>120 mg/L). Proteinchip array analysis using a strong anion exchange proteinchip (Q10) in conjunction with SELDI-TOF-MS was used to assess the protein expression patterns after exposure to heavy metals at the EHC10 (prohibiting hatching concentration to 10% eggs), except for cadmium and chromium, which were used at concentrations of 1, 10, and 100mg/L. Three novel biomarker candidate proteins, i.e., 4269, 4283, and 4623 m/z, were identified for the detection of heavy metal toxicity in aquatic ecosystems at the level of HC₁₀ in E. orientalis eggs. SELDI-TOF MS analysis for detecting differential expression of proteins was found to be more effective than Q10 proteinchip separation in the mayfly eggs.

Life history and emergence pattern of cloeon dipterum (Ephemeroptera: Baetidae) in Korea

ABSTRACT Cloeon dipterum (L.) (Ephemeroptera: Baetidae), the common wetland mayfly, emerges and oviposits every season, except winter, and has overlapping generations in the temperate region. We investigated the life history of C. dipterum associated with drought. Field experiments and sampling were conducted in a wetland (25 by 80 m) located in central Korea. Larvae were sampled weekly within two habitat types (a large, deep wetland and a small, shallow wetland) using a dredge sampler, and adults were sampled every 2 d with cube emergence traps, from July 2011 to September 2012 (except winter). C. dipterum had an extended emergence period from late April to early October with four peaks: early May, mid-June, July, and August/September. When the water depth was shallow because of drought, emergence was suppressed and delayed. The accumulated degree-days and body length of the overwintering cohort that emerged in spring 2012 were markedly larger and longer than those of other cohorts. Adults emerged intensively around sunset. C. dipterum has a multivoltine life cycle with four cohorts per year; its life history and population density can be changed by natural disturbances such as drought and fish predation.