The Effects of a 24-hour Exposure to Carbaryl or Atrazine on the Locomotive Performance of Juvenile Spotted Salamanders (Ambystoma maculatum)

Abstract

Amphibian ecotoxicology research has traditionally focused on chronic aquatic exposure of early life stages. However, multiple studies have shown that the survival of juvenile salamanders, frogs, and toads has the largest impact on population growth. Studies on species within the genus Ambystoma have shown that juvenile salamanders are the most likely of any life stage to disperse to new ponds. Because chemical contaminants are widely used throughout agricultural lands in the U.S. and have been shown to have effects on the central nervous system, it is important to determine any potential role they might have on locomotive performance. Our study sought to determine whether a 24-hour exposure to environmentally relevant concentrations of carbaryl (a neurotoxic insecticide) and atrazine (an herbicide) affected the locomotive performance of juvenile spotted salamanders (Ambystoma maculatum). Exposed salamanders were tested for either speed (max-burst in a U-shaped Plexiglas track) or endurance (time spent running at a constant speed on a treadmill). We found that carbaryl and atrazine treatment did not significantly affect speed or endurance ability. However, we did find that individuals exposed to carbaryl in the speed test experienced significantly increased fatigue throughout the speed trials. In addition, we found that mass to be significantly correlated with speed ability. Overall, our study suggests that a 24-hour exposure to environmentally relevant concentrations of carbaryl and atrazine does not directly significantly affect maximum burst speed or endurance ability in juvenile spotted salamanders.