Members of the non-biting midge family Chironomidae are the most widespread and abundant group of aquatic insects in fresh waters. Although the composition of chironomid communities is considered to be a potential biotic index for water quality assessment, it has not been used easily because of the difficulties with species level identification for larvae. This study was to analyse the molecular operational taxonomic units (MOTU) in chironomid communities to appropriately apply a species level identification. A total of 41 chironomid larvae collected from 7 sampling sites in the Han river system according to water quality were used for analyses. Partial mitochondrial DNA cytochrome c oxidase I (COI) genes were sequenced and analyzed. As a result, 35 different haplotypes (MOTU01-13) were obtained from the 673bp COI sequences. Average genetic distance was 0.0041 (range 0.000 to 0.013) within the MOTU and was 0.1703 (range 0.1181 to 0.2456) between the MOTUs. Nine MOTUs were found at the stream sites represented water quality A, 2 MOTUs at water quality C, and 1 MOTU at water quality D.

We investigated the effects of cadmium exposure and various stress on the transcription of heat shock protein 70 and 82 (HSP70 and HSP82) from Pardosa astrigera wolf spider. To do this, P. astrigera HSP70 and HSP82 genes were cloned and its full-length sequence determined. Female spiders were long-term exposed to cadmium or to polychlorinated biphenyl (PCB) for 2, 4 and 6 weeks and short-term exposed to endosulfan by dietary uptake. Female spiders were also exposed to various temperatures. HSP82 did not show a clear tendency of transcription induction following exposure to cadmium. On the contrary, HSP70 transcription gradually increased during the exposure to 2, 20 and 40 mM of cadmium for 2, 4 and 6 weeks. Transcript level of HSP70 was not significantly changed by endosulfan and PCB exposure. In the short-term (3 hr) temperature exposure, an increased expression of HSP70 was observed under the heat shock to 30°C and then slightly decreased at 35°C. However, induction of HSP70 transcription was not observed during the long-term (7 days) temperature exposure. Taken together, HSP70 gene appears to be up-regulated by cadmium in a time-dependent manner but little affected by other potential contaminants. Analysis of HSP70 transcript levels in P. astrigera collected from various fields revealed that levels of cadmium concentration were well correlated with HSP70 transcript levels (r2 = 0.76). Taken together, it was suggested that transcript level of HSP70 could be useful as a biomarker for the long-term cadmium exposure of P. astrigera.