Effect of Chronic Neonicotinoid Insecticide Exposure upon Monarch Development
The long-term viability of monarch butterfly (Danaus plexippus) populations in North America is in doubt.
The Science Issue and Relevance: The long-term viability of monarch butterfly (Danaus plexippus) populations is in doubt. The U.S. Fish and Wildlife Service was petitioned to list the monarch under the Endangered Species Act and is currently assessing the status of the population and the potential impact of multiple threats to determine if the listing is warranted. Monarch populations face many threats, including possible loss of habitat quality throughout their breeding grounds due to insecticide use. While much is unknown, insecticide use has the potential to severely impact the monarch population. There are three widely used neonicotinoid seed coat formulations that protect young crop plants (e.g., corn and soybean) against pest herbivory: thiamethoxam, imidacloprid, and chlothianidin. Our hypothesis is that reduced larval growth due to insecticide exposure leads to reduced pupation and adult butterfly emergence. If the presumption is correct, this would affect monarch fitness and reproductive success.
Methodology for Addressing the Issue: Our objective is to generate data that relate neonicotinoid pesticide contamination of milkweed plants to effect levels in monarch butterflies. This will be accomplished by following monarch development from egg to adult emergence. Larval growth, advancement to pupae stage, and emergence will be measurement endpoints quantified for each exposure level. In addition, a model between neonicotinoid concentrations in leaves and effects in monarchs will be developed for risk estimation based on field monitoring data.
Next Steps: Continue to use this exposure system to evaluate the risk of neonicotinoid insecticides to monarch butterflies.
Below are other science projects associated with this project.
Monarch Butterfly Utilization of Milkweed Plants Grown in Close Proximity to Corn Treated by a Neonicotinoid Insecticide (Seed Treatment)
The long-term viability of monarch butterfly (Danaus plexippus) populations in North America is in doubt.
The Science Issue and Relevance: The long-term viability of monarch butterfly (Danaus plexippus) populations is in doubt. The U.S. Fish and Wildlife Service was petitioned to list the monarch under the Endangered Species Act and is currently assessing the status of the population and the potential impact of multiple threats to determine if the listing is warranted. Monarch populations face many threats, including possible loss of habitat quality throughout their breeding grounds due to insecticide use. While much is unknown, insecticide use has the potential to severely impact the monarch population. There are three widely used neonicotinoid seed coat formulations that protect young crop plants (e.g., corn and soybean) against pest herbivory: thiamethoxam, imidacloprid, and chlothianidin. Our hypothesis is that reduced larval growth due to insecticide exposure leads to reduced pupation and adult butterfly emergence. If the presumption is correct, this would affect monarch fitness and reproductive success.
Methodology for Addressing the Issue: Our objective is to generate data that relate neonicotinoid pesticide contamination of milkweed plants to effect levels in monarch butterflies. This will be accomplished by following monarch development from egg to adult emergence. Larval growth, advancement to pupae stage, and emergence will be measurement endpoints quantified for each exposure level. In addition, a model between neonicotinoid concentrations in leaves and effects in monarchs will be developed for risk estimation based on field monitoring data.
Next Steps: Continue to use this exposure system to evaluate the risk of neonicotinoid insecticides to monarch butterflies.
Below are other science projects associated with this project.