Effects of the herbicide atrazine on Ambystoma tigrinum metamorphosis: Duration, larval growth, and hormonal response

Diane L. Larson, Susan McDonald, Albert J. Fivizzani, Wesley E. Newton, Steven J. Hamilton

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

We exposed larval tiger salamanders (Ambystoma tigrinum) reared in the laboratory from eggs collected from a prairie wetland in North Dakota to three concentrations of atrazine (0, 75, and 250 μg/L) in a static renewal test to determine the pesticide's effect on (1) plasma corticosterone and thyroxine concentrations, (2) larval size, and (3) days-to-stage at stages 2 and 4 of metamorphic climax. We found significant effects of atrazine on each of these response variables. Plasma thyroxine was elevated in both atrazine-exposed groups compared with the control group; plasma corticosterone was depressed in the 75 μg/L treatment compared with both the control and 250 μg/L treatment. Larvae exposed to 75 μg/L atrazine reached stage 4 later but at a size and weight comparable to the control group. By contrast, larvae in the 250 μg/L treatment progressed to stage 4 at the same time but at a smaller size and lower weight than larvae in the control group. These results indicate that the herbicide has the potential to influence tiger salamander life history. We present a model consistent with our results, whereby corticosterone and thyroxine interact to regulate metamorphosis of tiger salamanders based on nutrient assimilation and adult fitness.

Original languageEnglish (US)
Pages (from-to)671-679
Number of pages9
JournalPhysiological Zoology
Volume71
Issue number6
DOIs
StatePublished - Nov 1998

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