Impact of Molinate Exposure on Male Courtship Behavior and Acetylcholinesterase Activity in Zebrafish, Danio rerio

Abstract

Abstract Molinate, a thiocarbamate herbicide, is used to control broad-leaf and grassy weeds. Studies have shown that molinate alters a range of animal behaviors to produce the following symptoms following exposure: lethargy, erratic swimming, and tremors. Fish, in particular, showed variability in sensitivity to molinate. Possible mechanism of action in such observed behavior is alteration in the cholinergic nervous system responsible for messenger transmission in the central nervous system and peripheral nervous system. The current study examined the possible disruption of spawning behavior in zebrafish (Danio rerio) following molinate exposure. Findings indicate that while various forms of spawning behavior were not altered significantly in fish exposed to molinate, a significant difference was observed in the total number of eggs produced; control fish produced approximately twice as many eggs compared to molinate-treated fish. Furthermore, significantly higher levels of acetylcholinesterase activity were observed in male fish, indicating a compensatory mechanism following toxic insult. In conclusion, while molinate does not appear to impact male courtship behavior in zebrafish, the pesticide does appear to alter acetylcholinesterase activity in males, suggesting disruption of the nervous system in males.