TY - JOUR
T1 - Effects of the herbicide atrazine on Ambystoma tigrinum metamorphosis
T2 - Duration, larval growth, and hormonal response
AU - Larson, Diane L.
AU - McDonald, Susan
AU - Fivizzani, Albert J.
AU - Newton, Wesley E.
AU - Hamilton, Steven J.
PY - 1998/11
Y1 - 1998/11
N2 - 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.
AB - 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.
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U2 - 10.1086/515999
DO - 10.1086/515999
M3 - Article
C2 - 9798254
AN - SCOPUS:0032215842
SN - 0031-935X
VL - 71
SP - 671
EP - 679
JO - Physiological Zoology
JF - Physiological Zoology
IS - 6
ER -