Neuro-ecotoxicology of a freshwater shredder shrimp, Xiphocaris elongata, exposed to a neonicotinoid insecticide

Marla Valeria Santos-Crespo, Environmental Sciences, Universidad de Puerto Rico, Río Piedras Campus, San Juan, PR; Puerto Rico's Center for Environmental Neuroscience, PRCEN, San Juan, PR

Background/Question/Methods
Thiamethoxam is a neonicotinoid insecticide commonly used in major crops such as rice and cotton. This neurotoxin has been found in surface waters that may contaminate rivers and affect non-target organisms such as decapods. We present changes in behavioral and physical dynamics in the freshwater shredder shrimp, Xiphocaris elongata after exposing them to 200, 400, 600, 800, and 1,000 ug/L of thiamethoxam. Their behavior was assessed using video-monitoring after 15 minutes and 24 hours after exposure and changes in external color were recorded with photographs.
Results/Conclusions
Our preliminary results show that locomotion and residual time in the center of the arena assessed is decreased, which may translate to difficulty in avoiding predation. Therefore, we suggest that thiamethoxam could be potentially toxic to these essential freshwater invertebrates at these levels and more research is needed to understand the further implications of their industrial and global use.