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Testing wood frog ecosystems

Late last spring, at the National Wildlife Research Centre on the campus of Carleton University, wood frog tadpoles transformed into adult frogs in 25 repurposed, 300-litre, cattle watering tanks. Shade cloth covered the tanks, both to mimic forest light levels and to keep water in the tanks from heating up.

Once the wood frogs’ tails disappeared, Dr. Stacey Robinson, an ecotoxicologist in Environment and Climate Change Canada’s Science & Technology Branch, brought them into her lab to do behavioural research. She and colleague Vance Trudeau at the University of Ottawa wanted to know if the nervous systems of wood frogs were affected by neonicotinoids (common pesticides used in farming).

Using a standard aquarium lined with moss, water and a hiding place, Dr. Robinson tested each frog’s reaction to a bobbing heron head, a common predator. She wanted to find out how neonicotinoid-exposed wood frogs would react.

Frogs exposed to one of the neonicotinoid chemicals didn’t move when the heron head bobbed towards them, while the control group took evasive action. Frog survival, growth and development were also assessed; minor delays in development were detected with exposure to one of the neonicotinoid chemicals compared to the control group.

“We’re seeing declines in frog populations around the world, and neonicotinoids are widely used in farming, said Dr. Robinson. “We need to do our due diligence to see if this group of pesticides unduly harms non-target animals.”  

Photo: Dr. Stacey Robinson checks on the wood frog microhabitats.


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