Diminished Conspecific Odor Recognition in the Rusty Crayfish (Orconectes rusticus) Following a 96-h Exposure to Atrazine.

The presence of agricultural contaminants has been shown to disrupt olfactory-mediated behaviors in aquatic animals. We assessed the effects of atrazine on the ability of reproductively active (form I), male crayfish (Orconectes rusticus) to identify and respond to conspecific chemical signals involved in mating. Male crayfish were exposed to atrazine (80 ppb) and water (control) for 96 h. We analyzed odor localization and locomotor behaviors of herbicide-treated and control male crayfish to two different odor sources: female odor or water (control) delivered from the proximal end of a test arena. Control crayfish spent more time in the proximal region of the test arena and at the odor source. Atrazine-exposed crayfish showed no preference for the proximal region of the test arena and odor source when female odor was delivered. Atrazine exposure did not affect locomotor behaviors. Overall, atrazine-mediated chemosensory deficits have the potential to disrupt mating and affect population size.