PARENT SESSION
Organized Oral Session 8: Contaminants in aquatic systems: Individual effects and community consequences.
Organizer(s): J Kerby and R Relyea
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 510b, Level 5, Palais des congrès de Montréal

Pesticide-induced behavioral shifts differentially alter tadpole survivorship in the presence of a crayfish predator.

Kerby, Jacob^*,1, Sih, Andy¹, ¹ University of California, Davis, CA, USA

ABSTRACT- Pesticide exposure is often correlated with amphibian declines, particularly in California, despite the fact that levels detected in the environment are typically well below lethal concentrations. This study examines the impacts of a sub-lethal level (50 g/L) of the pesticide carbaryl on two species of frogs, the Pacific tree frog (Hyla regilla) and the foothill yellow legged frog (Rana boylii) in the presence of a crayfish predator (Pacifasticus leniusculus). In the absence of pesticide, predation on tadpoles was similar. The presence of pesticide had a significantly larger impact on R. boylii anti-predatory behaviors. In the presence of both pesticide and a predator, R. boylii tadpoles suffered a significantly greater mortality. The differential behavioral responses between tadpole species (increase vs. decrease in refuge use) exposed to sub-lethal levels of pesticides and the resulting differences in survivorship when combined with a predator may provide insight on explaining mechanisms for some amphibian population declines.

Key words: amphibian, predator, pesticide, behavior