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Media type:
E-Article
Title:
Zinc Resistance in Chironomus riparius: Evidence for Physiological and Genetic Components
Contributor:
Miller, Mark P.;
Hendricks, Albert C.
Published:
North American Benthological Society, 1996
Published in:
Journal of the North American Benthological Society, 15 (1996) 1, Seite 106-116
Language:
English
ISSN:
0887-3593;
1937-237X
Origination:
Footnote:
Description:
<p> Heavy metal resistance has been well documented in many aquatic invertebrate species, but its nature has been clearly demonstrated on only a few occasions. We investigated 2 mechanisms, acclimation and adaptation, that are commonly thought to be responsible for this resistance. Data were obtained from growth and respiration experiments using instar III and IV Chironomus riparius under the influence of 0.0, 62.5, 125, 250, and 500 μg/L Zn. Comparisons were made between larvae that were cultured in clean water conditions and larvae from cultures that had been exposed to 10 μg/L for >18 mo. Instar III larvae from clean water cultures showed significant reductions in growth and respiration rates when exposed to zinc concentrations ≥62.5 μg/L; in instar IV larvae, growth and respiration rates were significantly reduced at 250 and 62.5 μg/L, respectively. Instar IV larvae from zinc cultures had increased tolerance to the metal whereas instar III larvae displayed no additional tolerance. To determine if the resistance was due to acclimation or population adaptation, additional growth and respiration experiments were conducted with F2 progeny of zinc-cultured adults that had been reared in clean water. Growth rates of F2 progeny larvae were affected by the same concentration that affected untreated larvae, suggesting that acclimation-based resistance to zinc can be induced in C. riparius. Because respiration rates of F2 generation instar IV larvae were affected only by high zinc concentrations (500 μg/L), the results suggest that larvae evolved resistance to Zn during the course of this study. </p>