A comparison of feeding efficiency and swimming ability of Daphnia magna exposed to cypermethrin

• Published in: Aquatic toxicology Vol. 73; no. 2; pp. 210 - 220
• Main Authors: Christensen, Birthe Thordahl, Lauridsen, Torben L., Ravn, Helle Weber, Bayley, Mark
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.06.2005; Elsevier Science
• Subjects: Analysis of Variance; animal behavior; Animal Nutritional Physiological Phenomena; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; carbohydrate content; Carbohydrates; Chlorophyll; Chlorophyll - metabolism; Chlorophyll - pharmacokinetics; Chromatography - methods; cypermethrin; Daphnia - drug effects; Daphnia - physiology; Daphnia magna; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; feeding behavior; Fundamental and applied biological sciences. Psychology; General aspects; high performance planar chromatography; High performance planar chromatography (HPPC); Insecticides - toxicity; liquid chromatography; Locomotion - drug effects; Pyrethrins - toxicity; Pyrethroid; water pollution; Pyrethroid; Chlorophyll; Carbohydrates; High performance planar chromatography (HPPC); Insecticide; Ecotoxicology; Cladocera; Pesticides; Pyrethroids; Feed conversion efficiency; Crustacea; Aquatic environment; Arthropoda; Cypermethrin; Carbohydrate; Swimming; Invertebrata; Performance; Branchiopoda; Daphnia magna
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2005.03.011

Microcosm and mesocosm studies evidence that pyrethroid insecticides may have a severe effect on zooplankton populations. The effect may cascade to phytoplankton communities and thus worsen the impact of eutrophication and algal blooms. In natural freshwater systems, pyrethroids are usually only detectable during the first 24 h after application to adjacent areas, a period too short for mesocosm and microcosm studies to reveal potential effects. In this study we compare the effects of environmentally realistic concentrations of the pyrethroid cypermethrin on: (i) the swimming ability of Daphnia magna; (ii) the feeding efficiency, measured as the content of chlorophyll pigments in the gut; and (iii) the total body carbohydrate content. The latter two were measured using a newly developed high performance planar chromatography (HPPC) system. Sublethal effects on the gut content of chlorophyll pigments, carbohydrate substances and the swimming ability of D. magna were observed at nominal concentrations between 0.05 and 0.6 μg cypermethrin L −1, which lies within the concentration range occurring in freshwater systems after pesticide application. In addition, the content of chlorophyll pigments in the gut was significantly reduced (>50%) after only 6 h of exposure to 0.1 μg cypermethrin L −1. Most of the D. magna had recovered 3 days after exposure doses lower than 0.2 μg cypermethrin L −1. We conclude that HPPC analysis of the gut content of chlorophyll pigments was the most sensitive endpoint of our study due to its capacity to detect significant reductions in feeding within hours of exposure to environmentally realistic concentrations of cypermethrin.