The effects of atrazine on the agonistic behavior of virile crayfish, Orconectes virilis

Abstract

Atrazine is the most commonly used herbicide throughout the United States and its overuse creates problems for aquatic ecosystems. Crayfish are a keystone species in these aquatic ecosystems and the absence of keystone species can alter an entire ecosystem. Therefore, keystone species like crayfish should be protected from substances leaking into their environment that can harm them, such as atrazine. This study looks at the effects of atrazine on the agonistic behavior of O. virilis crayfish. To examine this, crayfish of similar chelae and carapace sizes were introduced to an artificial stream under specific conditions for 24 hours and then the crayfish engaged in a fight. One crayfish would be exposed to atrazine at 200 micrograms per liter for 24 hours and one crayfish would be exposed to normal stream-like conditions. Our results showed no statistical evidence to support our hypothesis that O. virilis exposed to atrazine would be less aggressive compared to crayfish unexposed to atrazine. Regardless of our evidence, there are multiple studies that show the negative effects of atrazine on aquatic organisms and thus, atrazine should not be used as heavily as it has been in the United States.