Strain difference in sensitivity to 3,4-dichloroaniline and insect growth regulator, fenoxycarb, in Daphnia magna

• Published in: Ecotoxicology and environmental safety 2007-07, Vol.67 (3), p.399-405
• Main Authors: Oda, Shigeto, Tatarazako, Norihisa, Dorgerloh, Michael, Johnson, Rodney D., Ole Kusk, K., Leverett, Dean, Marchini, Silvia, Nakari, Tarja, Williams, Tim, Iguchi, Taisen
• Format: Article
• Language: English
• Subjects: Aniline Compounds - toxicity; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Daphnia - drug effects; Daphnia - genetics; Daphnia magna; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Endocrine disruption; Female; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Insecta; Invertebrates; Juvenile hormone; Male; Male production; OECD test guideline 211; Phenylcarbamates - toxicity; Reproduction - drug effects; Reproduction - genetics; Sex Ratio; Species Specificity; Toxicity Tests; Water Pollutants, Chemical - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2006.12.010

Acute and reproductive toxicity tests were conducted on seven strains of Daphnia magna from six laboratories in five countries. 3,4-Dichloroaniline (DCA) and fenoxycarb were used as test chemicals. Acute toxicity tests revealed that estimated EC 50 (50% effective concentration) values for DCA varied by a factor of 2.1 among strains (310–640 μg/L), whereas the EC 50 values for fenoxycarb varied by a factor of 4 (210–860 μg/L). EC 50 values for reproductive toxicity tests with DCA ranged from 5.9 to 38 μg/L among strains. Fenoxycarb exposure induced the production of male neonates in all the strains used in the present study. Estimated EC 50 values for the induction of male offspring were highly variable among strains: sensitivity to fenoxycarb differed by a factor of approximately 23 overall (0.45–10 μg/L). The present pre-validation tests suggest that induction of male sex in neonates by a juvenile hormone analog is universal among genetically different strains. Decreased total numbers of neonates at increased concentrations of fenoxycarb as well as other juvenoids may, however, obscure the incidence of male neonates production in the 21-day reproduction tests due to the low statistical power.