The exposure of a glyphosate-based herbicide, one of the world’s most used substances and suspected of being carcinogenic, is beneficial for toad tadpoles, per a given study. It stimulates the secretion of toxic matter, thus enabling them to escape predators.
Experiments led by a team of researchers in Hungary showed that the animals are exposed to glyphosate “containing quantities of ‘natural toxins’ which are more significant than those produced and stored naturally within their organs to deter predators.” Veronika Bokony, one of the authors of the study explained this to the AFP. The authors of the study, which appeared on Wednesday in the Royal Society’s review Proceedings B, mention that, “Many animals use chemical substances as a means of defence against predators and disease.”
Understanding the effects of chemical pollutants on this means of defence is all the more useful for amphibians, as they are particularly vulnerable owing to the permeability of their skin. Per the researchers, the exposure of common-toad (Bufo bufo) tadpoles to a glyphosate-based herbicide has led to an increase in the quantity of bufadienolides that they secrete. The bufadienolides are the main components of the defensive toxic substance produced by toads.
Bokony stresses, “Although pesticides make toads more toxic, the predator-prey balance and the composition of natural habitats in freshwater, as much as on land, may be altered.” Glyphosate, which is present within the world’s most used pesticides such as Round Up by Monsanto, is classified as a “probable carcinogen” by a UN agency. The European Commission has relaunched the procedure to renew the glyphosate licence within the European Union, having previously extended it to the end of 2017.