Effect of sublethal concentrations of pesticides on the feeding behavior of Daphnia magna.
Daphnia magna was exposed to sublethal levels (1/4, 1/2, and 2/3 LC50 and LC50) of endosulfan and diazinon to determine the effect of these pesticides on filtration and ingestion rates. The experiments were performed with the unicellular algae Nannochloris oculata in a density of 5 x 10(5) cells/ml. Prior to these experiments, the acute toxicity of both pesticides was evaluated to calculate the LC50s. The 24-hr LC50 values were 0.62 mg/liter and 0.9 microgram/liter for endosulfan and diazinon, respectively. Rates of filtration and ingestion declined with increasing toxicant concentrations after a short exposure of 5 hr. The effective concentration at which feeding rates were reduced to 50% of those in controls (EC50) was calculated for both pesticides. These values were 0.44 and 0.61 mg/liter for filtration and ingestion rates, respectively, in the case of endosulfan and 0.47 and 0.60 microgram/liter, respectively, in the case of diazinon.
Fernández-Casalderrey
A
A
Department of Animal Biology (Animal Physiology), Faculty of Biological Sciences, University of Valencia, Spain.
Ferrando
M D
MD
Andreu-Moliner
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E
D000818:Animals; D003621:Daphnia / Q000187:drug effects*; D003976:Diazinon / Q000633:toxicity; D004726:Endosulfan / Q000633:toxicity; D056890:Eukaryota; D005247:Feeding Behavior / Q000187:drug effects*; D005374:Filtration; D007928:Lethal Dose 50; D010575:Pesticides / Q000633:toxicity*
D010575:Pesticides; D004726:Endosulfan; D003976:Diazinon