Abstract
The benthic community in an outdoor model stream was exposed to the organophosphorus insecticide temephos, at a concentration of 5 mg litre −1 for 30 min, or chlorphoxim at 2 mg litre −1 for 3 h. Three species of chironomids were predominant in this stream in the first experiment, together with Hydropsychodes brevilineata in the second experiment. Both insecticides killed the majority of the zoobenthos, and resulted in a bloom of epilithic algae. The extent of grazing pressure by chironomids on algae was assessed. The chironomid populations recovered quickly but the trichopteran larvae recovered slowly. There were some differences in the toxicity between the two insecticides. Paracyclops fimbriatus and Procladius sp. were affected only by chlorphoxim.
Published Version
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