Behavioural Responses of Wood Frog (Lithobates Sylvaticus) Tadpoles to Diluted Bitumen

Abstract

The study of behaviour in ecotoxicology allows for a broader understanding of the effects of pollution in an ecosystem. Amphibians are vulnerable to contaminant exposure, especially during early life stages when they are restricted to a waterbody. Since wood frog (Lithobates sylvaticus) tadpoles are exposed to contamination during diluted bitumen spills, an assessment of the impact of exposure was needed for freshwater systems. As part of the Boreal lake Oil Release Experiment by Additions to Limnocorrals (BOREAL) experiment, diluted bitumen was added to lake mesocosms at the International Institute for Sustainable Development’s Experimental Lake Area near Kenora, Ontario. Water from these mesocosms was transported to separate microcosms in which wood frog (Lithobates sylvaticus) tadpoles were reared from Gosner stage 25. Behavioural assays were conducted every three to four days in a separate arena and video recorded. Space-use, sociality, and activity were quantified across a gradient of exposure to diluted bitumen infused lake water. No relationship between sociality and space use metrics and diluted bitumen concentrations were observed. There was a decrease in activity as diluted bitumen concentration increased, however the relationship between activity and diluted bitumen exposure should be further investigated to determine the physiological basis for this decrease in activity.