Team finds common bioindicator resistant to insecticides

Oct 28, 2013

In a novel study, a University of Oklahoma researcher and collaborators found a common bioindicator, Hyalella azteca, used to test the toxicity of water or sediment was resistant to insecticides used in agricultural areas of central California. The study is the first to demonstrate that the indicator species may adapt to polluted conditions of a habitat and become an entirely unreliable source of information about ecosystem health.

Gary Wellborn, professor of biology in the OU College of Arts and Sciences and director of the Oklahoma Biological Station; Donald P. Weston, University of California, Berkeley; and Helen C. Poyton, University of Massachusetts, Boston; tested cultures in the laboratory and water samples from California lakes, ponds and streams. The Hyalella amphipods are aquatic crustaceans commonly used by scientists and agencies as an indicator species of a healthy, unpolluted environment.

"Our study documented the specific genetic changes that allow the amphipods to survive at 500-times the normal lethal dose of the pesticide," says Wellborn. "The results have far-reaching implications for biomonitoring programs that rely on H. azteca as a bioindicator. H. azteca, a species common across North America, may prove to be an unreliable indicator in other agricultural states where biomonitoring programs use H. azteca as a principal species for monitoring and environmental policy decisions."

Insecticides for agricultural crops are regulated by the Environmental Protection Agency, but runoff during rains can enter a lake, pond or stream and contaminate a non-target species, like H. azteca. The evolution of H. azteca in this study occurred when the mutated and adapted to the widely used pyrethroid insecticides—a principle known as adaptive evolution. As reported in this study, the resistant H. azteca was no longer reliable as a bioindicator when used to test the toxicity of water and sediment.

Explore further: Pesticides contaminate frogs from Californian National Parks

More information: A technical article on this study was published in the October 8, 2013 issue of the Proceedings of the National Academy of Sciences.

add to favorites email to friend print save as pdf

Related Stories

'Velcro' effect in Guianese ants

Jun 28, 2010

In Guiana, symbiosis between Azteca ants and the Cecropia tree (or trumpet tree) is frequent. However, a surprising discovery has been made: one species of ant (Azteca andreae) uses the "Velcro" principle ...

Carbon nanotubes found to be toxic to aquatic animals

Aug 22, 2012

Carbon nanotubes (CNTs) are some of the strongest materials on Earth and are used to strengthen composite materials, such as those used in high-performance tennis rackets. CNTs have potential uses in everything from medicine ...

Pesticides contaminate frogs from Californian National Parks

Jul 26, 2013

Pesticides commonly used in California's Central Valley, one of the world's most productive agricultural regions, have been found in remote frog species miles from farmland. Writing in Environmental Toxicology and Chemistry, resear ...

Recommended for you

Plants with dormant seeds give rise to more species

Apr 18, 2014

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Scientists tether lionfish to Cayman reefs

Apr 18, 2014

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...