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Pharmacology, Toxicology and Environmental Health

University of Nebraska - Lincoln

Toxicology

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Full-Text Articles in Life Sciences

Monarch Butterflies: Rearing Methodologies And The Impact Of Fungicide And Insecticide Exposures, Matthew Greiner May 2022

Monarch Butterflies: Rearing Methodologies And The Impact Of Fungicide And Insecticide Exposures, Matthew Greiner

Department of Entomology: Dissertations, Theses, and Student Research

The North American migratory monarch butterfly, Danaus plexippus L., populations has experienced a ca. 90% decline over the past two decades. The decline is attributed to climate change, loss and degradation of overwintering habitat, and the loss of milkweed plants in the midwestern United States. The remaining milkweed stands often occur close to agricultural fields, and efforts to establish additional milkweed on the landscape focus on agricultural systems. However, milkweed plants near agricultural fields are likely exposed to pesticides that could adversely impact monarch caterpillars. Effective management of milkweed habitat supporting monarch caterpillars requires knowledge about the toxicological impacts of …


Cardenolide, Potassium, And Pyrethroid Insecticide Combinations Reduce Growth And Survival Of Monarch Butterfly Caterpillars (Lepidoptera: Nymphalidae), Annie J. Krueger, Emily A. Robinson, Thomas J. Weissling, Ana M. Vélez, Troy D. Anderson Dec 2021

Cardenolide, Potassium, And Pyrethroid Insecticide Combinations Reduce Growth And Survival Of Monarch Butterfly Caterpillars (Lepidoptera: Nymphalidae), Annie J. Krueger, Emily A. Robinson, Thomas J. Weissling, Ana M. Vélez, Troy D. Anderson

Department of Entomology: Faculty Publications

The monarch butterfly, Danaus plexippus L., has evolved to be insensitive to milkweed cardenolides via genetic modifications of Na+/K+-ATPase. There is concern for insecticide exposures near agriculture, with little information on monarch caterpillar toxicology. It is unclear how cardenolide insensitivity may affect the sensitivity of monarch caterpillars to pyrethroid insecticides. Additionally, potassium fertilizers may affect monarch caterpillar physiology and cardenolide sequestration. Here, we investigated the growth, survival, and development of caterpillars exposed to the cardenolide ouabain, bifenthrin, and potassium chloride (KCl) alone and in combination. Caterpillars were either exposed to (1) ouabain from third- to fifth-instar …


Toxicology Of Chemical Stress To Monarch Butterflies (Danaus Plexippus L.), Annie Krueger Aug 2021

Toxicology Of Chemical Stress To Monarch Butterflies (Danaus Plexippus L.), Annie Krueger

Department of Entomology: Dissertations, Theses, and Student Research

Monarch butterfly (Danaus plexippus L.) population declines have caught the attention of the country and prompted nationwide conservation initiatives. The United States Fish and Wildlife Service has identified insecticide exposure and loss of milkweed (Asclepias spp.) reproductive habitat as primary threats to the monarch. In the Midwestern US, milkweed largely occurs around cropland borders where there may be a spatial and temporal overlap of monarch larvae, insecticide usage, and fertilizer applications. In this study, the acute toxicity and sub-lethal effects on growth and diet consumption of two commonly used pyrethroid insecticides, bifenthrin and beta-cyfluthrin, were characterized …