CRAYFISH (ORCONECTES RUSTICUS) EXPOSED TO ATRAZINE EXHIBIT NEGATIVE CHEMOATTRACTION TO FOOD ODOR

Khan, Sana, Gita Sabhapathy, Juhi Katta, and Rachelle Belanger

The presence of environmental pollutants has been shown to have an effect on olfactory-mediated behaviors in aquatic animals. Previous research in our lab demonstrates that exposure to the herbicide atrazine affects social signaling during reproduction. Crayfish are a keystone species and play an integral role in energy transfer between benthic and terrestrial food webs. Crayfish rely heavily on chemoreceptors located on different sensory appendages (e.g. antennulues, maxillipeds and pereopods) in order to locate food sources. In a previous experiment, we found that sublethal concentrations of atrazine interfere with the ability of male crayfish to receive and/or respond to reproductive female odors. Given this, we examined chemosenory responses of both male and female crayfish to food odors. We exposed crayfish to ecologically relevant, sublethal levels of atrazine (80 ppb) for 96 hours. We analyzed the behavioral reactions of both atrazine-treated and control crayfish to food odor delivered from one end of a test arena. We used Noldus Ethovision® XT to measure odor localization and locomotory behaviors of crayfish in response to food (fish) odor. Crayfish exposed to atrazine spent significantly less time than control individuals in the proximal region of the test arena when food odors were delivered. The exposed crayfish also demonstrated negative chemotaxis when presented with a food odor. After 24 hours of recovery from atrazine exposure, we found that treated crayfish started to increase the amount of time they spent near the food odor source. We conclude that sublethal concentrations of atrazine interfere with the ability of crayfish to find food, and thus may negatively affect their ability to survive in the ecosystems they occupy; however, crayfish may be able to recover from an acute exposure. Future experiments in our lab will examine the time it takes to eliminate atrazine from the body, as well as recovery of chemosensory abilities of crayfish after an acute atrazine exposure.