Science Current Events | Science News |

New Study Is First to Show That Pesticides Can Induce Morphological Changes in Vertebrate Animals, Says Pitt Researcher

April 03, 2012

PITTSBURGH- The world's most popular weed killer, Roundup®, can cause amphibians to change shape, according to research published today in Ecological Applications.

Rick Relyea, University of Pittsburgh professor of biological sciences in the Kenneth P. Dietrich School of Arts and Sciences and director of Pitt's Pymatuning Laboratory of Ecology, demonstrated that sublethal and environmentally relevant concentrations of Roundup® caused two species of amphibians to alter their morphology. According to Relyea, this is the first study to show that a pesticide can induce morphological changes in a vertebrate animal.

Relyea set up large outdoor water tanks that contained many of the components of natural wetlands. Some tanks contained caged predators, which emit chemicals that naturally induce changes in tadpole morphology (such as larger tails to better escape predators). After adding tadpoles to each tank, he exposed them to a range of Roundup® concentrations. After 3 weeks, the tadpoles were removed from the tanks.

"It was not surprising to see that the smell of predators in the water induced larger tadpole tails," says Relyea. "That is a normal, adaptive response. What shocked us was that the Roundup® induced the same changes. Moreover, the combination of predators and Roundup® caused the tail changes to be twice as large." Because tadpoles alter their body shape to match their environment, having a body shape that does not fit the environment can put the animals at a distinct disadvantage.

Predators cause tadpoles to change shape by altering the stress hormones of tadpoles, says Relyea. The similar shape changes when exposed to Roundup® suggest that Roundup® may interfere with the hormones of tadpoles and potentially many other animals.

"This discovery highlights the fact that pesticides, which are important for crop production and human health, can have unintended consequences for species that are not the pesticide's target," says Relyea. "Herbicides are not designed to affect animals, but we are learning that they can have a wide range of surprising effects by altering how hormones work in the bodies of animals. This is important because amphibians not only serve as a barometer of the ecosystem's health, but also as an indicator of potential dangers to other species in the food chain, including humans."

For two decades, Relyea has studied community ecology, evolution, disease ecology, and ecotoxicology. He has authored more than 80 scientific articles and book chapters and has presented research seminars around the world. For more information about his laboratory, visit

University of Pittsburgh

Related Pesticides Current Events and Pesticides News Articles

Researchers identify genes connecting endocrine disruption to genital malformations
University of Florida Health researchers have identified genes that are disrupted by abnormal hormone signaling at crucial points during development, a finding that may lead to a better understanding of how the most common male genital birth defects arise in humans.

'Good' and 'bad' bacteria in the fight against citrus greening disease
New research from the Boyce Thompson Institute (BTI), the USDA Agricultural Research Service and the University of Washington finds that helpful bacteria living inside the insect that transmits the bacterial pathogen associated with citrus greening disease - -an outbreak that is devastating Florida's citrus industry -- may be playing a role in the insect's spread of the pathogen.

Long-term effects of common pesticides on aquatic species
New research indicates that commonly-used insecticide mixtures continue to impact aquatic invertebrate species over multiple weeks, even when the chemicals are no longer detectable in water.

The first human uses of beeswax have been established in Anatolia in 7000 BCE
The current loss of bee populations as a result of pesticides, viruses and parasites has increased awareness about their economic importance and essential role in farming societies.

A new resource for managing crop-damaging greenbugs
Greenbugs (Schizaphis graminum) have been a major vexation for growers of wheat and sorghum for more than half a century, especially in the Great Plains.

Mississippi entomologists report on benefits of neonicotinoid seed treatments on rice
According to researchers from Mississippi State University, rice seeds that are pre-treated with neonicotinoid pesticides yield better than untreated crops and suffer less damage from rice water weevil, the most widely distributed and destructive early-season insect pest of rice in the United States.

Fighting citrus greening with vibrating orange groves
When a male Asian Citrus Psyllid is looking for a mate, he situates himself on a twig, buzzes his wings to send vibrations along adjacent leaves and branches, and listens for a female's response call. If the call comes, he travels in her direction, the abbreviated insect version of courtship ensues, and two to seven weeks later, scores of psyllids nymphs emerge from their eggs, feed on phloem sap, and mature into adults who head out into the world, ravaging untold numbers of citrus trees in the process.

Oil-based pesticides most effective at killing contents of brown widow spider egg sacs
Researchers at the University of California, Riverside might have found a breakthrough in the spider-control field. In a paper published in the Journal of Economic Entomology, the researchers wrote that oil-based pesticides are more effective than water-based pesticides at killing the contents of brown widow spider egg sacs.

Teenage exposure to pesticides may lead to abnormal sperm, new study says
Adolescent exposure to environmental pollutants known as organochlorines may lead to defective sperm, according to a study published today by researchers at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University and co-authors.

Wimps or warriors? Honey bee larvae absorb the social culture of the hive, study finds
Even as larvae, honey bees are tuned in to the social culture of the hive, becoming more or less aggressive depending on who raises them, researchers report in the journal Scientific Reports.
More Pesticides Current Events and Pesticides News Articles

© 2015