Amphibians can evolve increased tolerance to pesticides, but the adaptation can make them more susceptible to parasites, according to a team that includes researchers at Rensselaer Polytechnic Institute. The research, led by Binghamton University, showed that wood frogs that evolved increased tolerance to pesticides showed greater susceptibility to a dangerous virus, although they also demonstrated reduced susceptibility to a parasitic worm.“We have only recently begun to understand that amphibians can rapidly evolve tolerance to chemicals like pesticides, which on the surface is good news,” said Rick Relyea, a professor of biological sciences and director of the Darrin Fresh Water Institute at Rensselaer. “But now comes the bad news: with that tolerance there is a tradeoff, which is that they become more susceptible to parasites that, in the case of ranavirus, can wipe out entire amphibian populations.”