Studies for assessing the impact of pesticides on riverine insects

Abstract

A new method for the mass-rearing of Cheumatopsyche brevilineata was developed. The rearing system supported the full life cycle year-round, and the culture scale supplied sufficient larvae for bioassays every week. We also developed a series of insecticide bioassays for each larval instar of the caddisfly and determined the sensitivity of first-instar larvae to 30 paddy insecticides. After comparing the sensitivity of the caddisfly and other aquatic arthropods to the insecticides, the caddisfly appears to be a valid additional surrogate test species for riverine insects and will be valuable for assessing the ecological impacts of insecticides, whose impact on aquatic invertebrates is prone to underestimation by daphnid bioassays. © Pesticide Science Society of Japan.