Change in Oxidative Stress Biomarkers in Stream Caddisfly, Hydropsyche spp., Larvae Depending on Size and Season

Abstract

Extensive marine environment monitoring has been performed using oxidative stress biomarkers. However, progress regarding the use of these biomarkers in river environment monitoring has been insufficient. When applying oxidative stress biomarkers in river aquatic organisms, it is important to take into consideration the natural fluctuation of these markers. In this study, we investigate the effect of body size and seasonal changes on oxidative stress biomarkers in stream caddisfly, Hydropsyche spp., which is one of the primary consumers in river ecosystems. Body sizes were classified into 4 classes in accordance with wet weight. Catalase activity, which is a type of antioxidant enzyme, tended to differ depending on the class. Catalase activity and the oxygen radical absorbance capacity had a significant correlation with wet weight. On the other hand, examining the seasonal change for the same size class, the catalase activity, oxygen radical absorbance capacity, and oxidative damage showed different responses. Furthermore, Hydropsyche spp. in August, in a survey conducted immediately after a flood, indicated low oxidative damage. Hydropsyche spp. was able to adequately remove the reactive oxygen species produced as a result of stress caused by the flood.