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.