COMBINED EFFECTS OF PREDATORY FISH AND SUBLETHAL PESTICIDE CONTAMINATION ON THE BEHAVIOR AND MORTALITY OF MAYFLY NYMPHS

摘要

We evaluated the potential interaction of pesticide effect and predatory fish on behavior and mortality of a stream mayfly. Experiments in laboratory stream microcosms compared the activity, drift, and mortality of Baetis mayfly nymphs in the absence of fish with that in the presence of Cape galaxias (Galaxias zebratus), both species inhabiting the same stream environments in the Western Cape of South Africa. These two predator treatments were combined with exposure either to no pesticide or to 0.2 μg/L of the organophosphate insecticide azinphos-methyl (AZP) or 0.2 μg/L of the pyrethroid insecticide fenvalerate (FV).