Contribution 402 from the Environmental, Earth and Ocean Sciences Department, University of Massachusetts, Boston, MA, USA.
Evolution of cadmium resistance in Daphnia magna†
Article first published online: 9 DEC 2009
Copyright © 2005 SETAC
Environmental Toxicology and Chemistry
Volume 24, Issue 9, pages 2341–2349, September 2005
How to Cite
Ward, T. J. and Robinson, W. E. (2005), Evolution of cadmium resistance in Daphnia magna. Environmental Toxicology and Chemistry, 24: 2341–2349. doi: 10.1897/04-429R.1
- Issue published online: 9 DEC 2009
- Article first published online: 9 DEC 2009
- Manuscript Accepted: 14 MAR 2005
- Manuscript Received: 30 AUG 2004
- Metal adaptation;
- Evolved resistance;
- Daphnia magna
A diverse laboratory population of Daphnia magna Straus was established by combining individuals from eight sources. Artificial selection for increased resistance to the acute toxic effects of cadmium was performed, and after eight generations, the average median effective concentration increased from 61 to 180 μg/L. No differences in life span, offspring production, time to first brood, number of offspring in the first brood, or intrinsic rate of population increase (r) were observed between the cadmium-adapted population and the controls under ideal conditions or under conditions of temperature or feeding ration stress, but cadmium-adapted daphnids were smaller. Control and cadmium-adapted populations were equally sensitive to copper and malathion, but the cadmium-adapted population was less sensitive to lead and more sensitive to phenol. Analysis of amplified fragment-length polymorphisms indicated a significant decrease in genetic diversity in the cadmium-adapted population. Although the evolved cadmium resistance would allow adapted populations to exist in areas where cadmium concentrations would be toxic to unadapted populations, the decreased genetic diversity, smaller size, and increased sensitivity to at least one other toxicant could reduce the probability of long-term survival even in the absence of future cadmium exposure.