ATRAZINE EXPOSURE AFFECTS THE ABILITY OF CRAYFISH (ORCONECTES RUSTICUS) TO LOCALIZE A FOOD ODOR SOURCE

Abraham, Noor K., Sana Khan, Gita S. Sabhapathy, Tyler J. Peters, and Rachelle M. Belanger

Environmental pollutants, found in the aquatic ecosystem, have been shown to have an effect on behaviors mediated by the olfactory system, including feeding, mate attraction and other important social behaviors.  We have previously found that high concentrations of atrazine interfere with the ability of male crayfish to receive and/or respond to reproductive female odors. Crayfish are polytrophic meaning that they feed on and become prey for all levels of the aquatic food web as well as being important for the transfer of energy between benthic and terrestrial food webs. Because crayfish are a keystone species, it is important to investigate any factors that may affect their population size. Crayfish are active at night and rely heavily on their sensory appendages (e.g. antennulues, maxillipeds and pereopods) in order to localize food sources. In this experiment, we investigated the effects of atrazine exposure on the chemosensory responses of male and female crayfish to food odors. We exposed crayfish to environmentally relevant, sublethal levels of atrazine (80 ppb) for 96 hours and then examined the behavioral responses of both atrazine-treated and control crayfish to food odor delivered from one end of a test arena. We used Noldus Ethovision to measure odor localization and locomotory behaviors of crayfish in response to food (fish) odor. We found that control crayfish spent more time in the proximal region of the test arena and at the odor source when compared to atrazine-treated crayfish. There was no difference in the walking speed (cm/s), time spent moving and not moving and total distance travelled in the tank. This indicates that the chemosensory abilities of crayfish are impaired after acute atrazine exposure. In the future, we will examine if crayfish are able to recover from the effects of atrazine and how long this recovery takes.