During a laboratory exposure study, tadpole movement decreased with increased concentrations of clothianidin, a neonicotinoid pesticide. Decreased movement could affect a tadpole’s ability to forage, escape predation, and metamorphose before ponds dry.
Neonicotinoids, a class of insecticides used for pest control on a variety of crops, persist in water and soils, are easily transported in the environment, and have been detected in surface waters throughout the United States. Amphibians using surface waters during various life stages could be exposed to these contaminants and may be more susceptible to dermal exposure than other species owing to their highly permeable skin. Little is known about the potential effects of neonicotinoid exposure on animals other than insects, such as amphibians, and clothianidin currently is under registration review at the U.S. Environmental Protection Agency. Therefore, scientists evaluated the sublethal effects of the neonicotinoid clothianidin on the behavior of southern leopard frog tadpoles (Rana sphenocephala).
Scientists from the U.S. Geological Survey (USGS) and academia completed a laboratory study exposing 500 tadpoles to clothianidin in a for 96 hours at six different environmentally-relevant concentrations. The scientists assessed measures of tadpole movement for 1 hour post-exposure and measured total displacement, mean velocity, maximum velocity, and time spent moving.
The survival rate of the tadpoles was 99 percent after 96 hours of exposure; however, additional testing demonstrated that exposed tadpoles generally moved less distance, moved more slowly, and spent less time moving. Two of the measures, total displacement and mean velocity, had a strong negative association with clothianidin exposure concentration.
This laboratory study demonstrated that exposure to neonicotinoids can slow tadpole behavioral responses, even at environmentally relevant, sublethal concentrations. These findings could indicate that amphibian exposure to clothianidin in the environment could affect a tadpole’s ability to forage, escape predation, and metamorphose before ponds dry. This study adds to the growing body of evidence that there can be sublethal effects of neonicotinoid insecticides on non-target organisms.
This research was funded by the USGS Ecosystems Mission Area; the USGS Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology); the University of Missouri College of Agriculture, Food, and Natural Resources; and the Missouri Cooperative Fish and Wildlife Research Unit, which is jointly sponsored by the Missouri Department of Conservation, the University of Missouri, the U.S. Fish and Wildlife Service, and the Wildlife Management Institute.
Below are other science projects associated with this research.
Scientists Examined Native Pollinator Exposure Risk to Neonicotinoids in Native Prairie Strips
Native Bees are Exposed to Neonicotinoids and Other Pesticides
First National-Scale Reconnaissance of Neonicotinoid Insecticides in United States Streams
Neonicotinoid Insecticides Documented in Midwestern U.S. Streams
Below are publications associated with this research.
Effects of the neonicotinoid insecticide clothianidin on southern leopard frog (Rana sphenocephala) tadpole behavior
- Overview
During a laboratory exposure study, tadpole movement decreased with increased concentrations of clothianidin, a neonicotinoid pesticide. Decreased movement could affect a tadpole’s ability to forage, escape predation, and metamorphose before ponds dry.
Southern Leopard Frog (Credit: Gabriel Kamener. Public domain.) Neonicotinoids, a class of insecticides used for pest control on a variety of crops, persist in water and soils, are easily transported in the environment, and have been detected in surface waters throughout the United States. Amphibians using surface waters during various life stages could be exposed to these contaminants and may be more susceptible to dermal exposure than other species owing to their highly permeable skin. Little is known about the potential effects of neonicotinoid exposure on animals other than insects, such as amphibians, and clothianidin currently is under registration review at the U.S. Environmental Protection Agency. Therefore, scientists evaluated the sublethal effects of the neonicotinoid clothianidin on the behavior of southern leopard frog tadpoles (Rana sphenocephala).
Scientists from the U.S. Geological Survey (USGS) and academia completed a laboratory study exposing 500 tadpoles to clothianidin in a for 96 hours at six different environmentally-relevant concentrations. The scientists assessed measures of tadpole movement for 1 hour post-exposure and measured total displacement, mean velocity, maximum velocity, and time spent moving.
The survival rate of the tadpoles was 99 percent after 96 hours of exposure; however, additional testing demonstrated that exposed tadpoles generally moved less distance, moved more slowly, and spent less time moving. Two of the measures, total displacement and mean velocity, had a strong negative association with clothianidin exposure concentration.
Neonicotinoids have been detected in surface waters throughout the United States. (Credit: Donald S Hansen, U.S. Geological Survey. Public domain.) This laboratory study demonstrated that exposure to neonicotinoids can slow tadpole behavioral responses, even at environmentally relevant, sublethal concentrations. These findings could indicate that amphibian exposure to clothianidin in the environment could affect a tadpole’s ability to forage, escape predation, and metamorphose before ponds dry. This study adds to the growing body of evidence that there can be sublethal effects of neonicotinoid insecticides on non-target organisms.
This research was funded by the USGS Ecosystems Mission Area; the USGS Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology); the University of Missouri College of Agriculture, Food, and Natural Resources; and the Missouri Cooperative Fish and Wildlife Research Unit, which is jointly sponsored by the Missouri Department of Conservation, the University of Missouri, the U.S. Fish and Wildlife Service, and the Wildlife Management Institute.
- Science
Below are other science projects associated with this research.
Scientists Examined Native Pollinator Exposure Risk to Neonicotinoids in Native Prairie Strips
Neonicotinoids were not detected in native prairie plants placed next to agricultural fields several years after discontinuation of neonicotinoid seed treatment. In addition, neonicotinoid concentrations were lower or absent in soils and runoff at sites with the native prairie strips.Native Bees are Exposed to Neonicotinoids and Other Pesticides
A recent reconnaissance study by the U.S. Geological Survey (USGS) demonstrates the first observed occurrence of pesticides, including neonicotinoid insecticides, in wild-caught native bees. The results indicate that native bees collected in an agricultural landscape are exposed to multiple pesticides including insecticides, fungicides, and herbicides. This reconnaissance study is the first step...First National-Scale Reconnaissance of Neonicotinoid Insecticides in United States Streams
Neonicotinoid insecticides (neonicotinoids) were present in a little more than half of the streams sampled across the United States and Puerto Rico, according to a new U.S. Geological Survey (USGS) study. This is the first national-scale study of the presence of neonicotinoids in urban and agricultural land use settings across the Nation and was completed as part of ongoing USGS investigations of...Neonicotinoid Insecticides Documented in Midwestern U.S. Streams
Three neonicotinoid insecticides (clothianidin, thiamethoxam and imidacloprid) were detected commonly throughout the growing season in water samples collected from nine Midwestern stream sites during the 2013 growing season according to a team of U.S. Geological Survey (USGS) scientists. Clothianidin was detected most frequently (75 percent) and at the highest maximum concentration (257 nanograms... - Publications
Below are publications associated with this research.
Effects of the neonicotinoid insecticide clothianidin on southern leopard frog (Rana sphenocephala) tadpole behavior
Neonicotinoid insecticides are highly water soluble with relatively long half-lives, which allows them to move into and persist in aquatic ecosystems. However, little is known of the impacts of neonicotinoids on non-target vertebrates, especially at sublethal concentrations. We evaluated the effects of the neonicotinoid clothianidin on the behavior of southern leopard frog tadpoles (Rana sphenocep