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Anthropogenic Zinc Exposure Increases Mortality and Antioxidant Gene Expression in Monarch Butterflies with Low Access to Dietary Macronutrients

Shephard AM, Brown NS, Snell-Rood EC. Environmental toxicology and chemistry, March 2022.

Read the paper Free to read · doi:10.1002/etc.5305

What this paper is about

Monarchs were exposed to zinc, a common roadside and agricultural contaminant, while being fed diets varying in nitrogen and phosphorus.

The butterflies that died were the ones on poor diets. Tolerance of a pollutant depended on nutrition, not just on the dose.

Summarised here from the abstract below. Not the authors’ words.

Abstract

Biologists seek to understand why organisms vary in their abilities to tolerate anthropogenic contaminants, such as heavy metals. However, few studies have considered how tolerance may be affected by condition-moderating factors such as dietary resource availability. For instance, the availability of crucial limiting macronutrients, such as nitrogen and phosphorous, can vary across space and time either naturally or due to anthropogenic nutrient inputs (e.g., agricultural fertilizers or vehicle emissions). Organisms developing in more macronutrient-rich environments should be of higher overall condition, displaying a greater ability to tolerate metal contaminants. In monarch butterflies (Danaus plexippus), we factorially manipulated dietary macronutrient availability and exposure to zinc, a common metal contaminant in urban habitats that can be toxic but also has nutritional properties. We tested whether (1) the ability to survive zinc exposure depends on dietary macronutrient availability and (2) whether individuals exposed to elevated zinc levels display higher expression of antioxidant genes, given the roles of antioxidants in combatting metal-induced oxidative stress. Exposure to elevated zinc reduced survival only for monarchs developing on a low-macronutrient diet. However, for monarchs developing on a high-macronutrient diet, elevated zinc exposure tended to increase survival. In addition, monarchs exposed to elevated zinc displayed higher expression of antioxidant genes when developing on the low-macronutrient diet but lower expression when developing on the high-macronutrient diet. Altogether, our study shows that organismal survival and oxidative stress responses to anthropogenic zinc contamination depend on the availability of macronutrient resources in the developmental environment. In addition, our results suggest the hypothesis that whether zinc acts as a toxicant or a nutrient may depend on macronutrient supply. Environ Toxicol Chem 2022;41:1286-1296. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.

Key terms

ZincAntioxidantHeavy metalOxidative stressNutritional ecologyMacronutrientMonarch Butterfly

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APA Milkweed USA. (2026). Anthropogenic Zinc Exposure Increases Mortality and Antioxidant Gene Expression in Monarch Butterflies with Low Access to Dietary Macronutrients (listing). Retrieved DATE, from https://milkweedusa.com/research/anthropogenic-zinc-exposure-increases-mortality-and-antioxidant-gene-expression-2022/
MLA "Anthropogenic Zinc Exposure Increases Mortality and Antioxidant Gene Expression in Monarch Butterflies with Low Access to Dietary Macronutrients (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/anthropogenic-zinc-exposure-increases-mortality-and-antioxidant-gene-expression-2022/. Accessed DATE.
Chicago Milkweed USA. "Anthropogenic Zinc Exposure Increases Mortality and Antioxidant Gene Expression in Monarch Butterflies with Low Access to Dietary Macronutrients (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/anthropogenic-zinc-exposure-increases-mortality-and-antioxidant-gene-expression-2022/.
BibTeX @misc{milkweedusa_researchanthropogeniczincexp, title = {Anthropogenic Zinc Exposure Increases Mortality and Antioxidant Gene Expression in Monarch Butterflies with Low Access to Dietary Macronutrients (listing)}, author = {{Milkweed USA}}, year = {2026}, url = {https://milkweedusa.com/research/anthropogenic-zinc-exposure-increases-mortality-and-antioxidant-gene-expression-2022/}, note = {Accessed DATE} }