Nature reports that, in the face of extinction, frogs have a way to adapt to pesticides – a little:
Several species of frogs can quickly switch on genetic resistance to a group of commonly used pesticides. In one case, wood frogs (Lithobates sylvaticus) were able to deploy such defences in just one generation after exposure to contaminated environments, scientists reported last week at a conference of the Ecological Society of America in Baltimore, Maryland.
This is the first-known example of a vertebrate species developing pesticide resistance through a process called phenotypic plasticity, in which the expression of some genes changes in response to environmental pressure. It does not involve changes to the genes themselves, which often take many generations to evolve.
In 2013, [Rick] Relyea [of the Rensselaer Polytechnic Institute] and his team discovered that L. sylvaticus frogs living near agricultural land in northwest Pennsylvania were resistant to the pesticide carbaryl. Laboratory tests revealed that frog embryos and hatchlings living far from farmers’ fields were not pesticide-resistant but could quickly become tolerant when exposed to low levels of the pesticide.
Subsequent research revealed that another species, the grey tree frog (Hyla versicolor), can also switch on resistance to carbaryl in the same speedy way as L.sylvaticus. And frogs that develop resistance to carbaryl also show resistance to another pesticide, malathion. Both pesticides work by inhibiting the enzyme Acetylcholine esterase (AChE), which acts on a neurotransmitter.
“If inducible tolerance occurs more widely in nature, it would alter our perspective on how pesticides affect organisms,” says Relyea.