Effect of low dissolved oxygen on aquatic life stages of the caddisfly Clistoronia magnifica (Limnephilidae)

Abstract

Embryos, larval stages (instars I-V), pupal stages, and pharate adults of the caddisfly Clistoronia magnifica (Limnephilidae) were exposed to a range of dissolved oxygen (DO) concentrations (0.9-8.3 mg/L) for 4-88 days in the laboratory. Some embryos suspended growth at low DO, resuming growth and hatch when DO was increased. Embryos and larvae all had 96-h EC50 values (50% mortality at 96 h) of about 2.0 mg/L DO. The statistical Effect and No-Effect Thresholds for larvae exposed through two molts from instars I-III were 1.6 and 2.4 mg/L, respectively. At DO concentrations below 4.6 mg/L, egg hatch, larval development, molting success, time of molting, pupation, and adult emergence were delayed.