Behavioral and sex ratio modification of Japanese medaka (Oryzias latipes) in response to environmentally relevant mixtures of three pesticides
Article first published online: 14 FEB 2005
Copyright © 2005 Wiley Periodicals, Inc.
Volume 20, Issue 1, pages 110–117, February 2005
How to Cite
Teather, K., Jardine, C. and Gormley, K. (2005), Behavioral and sex ratio modification of Japanese medaka (Oryzias latipes) in response to environmentally relevant mixtures of three pesticides. Environ. Toxicol., 20: 110–117. doi: 10.1002/tox.20084
- Issue published online: 14 FEB 2005
- Article first published online: 14 FEB 2005
- Manuscript Accepted: 16 OCT 2004
- Manuscript Revised: 14 OCT 2004
- Manuscript Received: 19 MAY 2004
- University of Prince Edward Island Senate Research Grant
- Japanese medaka;
- sublethal effects;
- sex ratio
We exposed Japanese medaka (Oryzias latipes) to environmentally relevant concentrations of azinphos-methyl, chlorothalonil, endosulfan, and mixtures of all three to determine if combinations of these pesticides result in additive, less-than-additive, or more-than-additive effects. Medaka were exposed from fertilization until 7 days posthatching, and end points included survival, time to hatch, size at 7 days posthatching, activity level (as measured by distance swam) and foraging ability at 3 weeks posthatching, and adult size, liver size, and sex ratio at 5 months posthatching. Although exposure to individual pesticides or pesticide mixtures did not affect survival, hatching time, or foraging ability, fry exposed to azinphos-methyl were significantly smaller at 1 week of age, and those exposed to chlorothalonil and a combination of the chemicals showed reduced activity. Adult sex ratios were biased toward females in all groups exposed to pesticides, with those exposed to azinphos-methyl, chlorothalonil, and the pesticide mixture departing significantly from an even sex ratio. There was no evidence of additive or synergistic effects of pesticide mixtures. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 110–117, 2005.