The Effects of Nonylphenol on Male Crayfish Aggression in Acute and Chronic Exposures

PURPOSE: Nonylphenol is a compound used in a variety of industrial, domestic, and agricultural products. The compound is classified as an inactive ingredient, therefore has little to no monitoring in the U.S. with a high possibility of exposure occurring via its disposal into the water supply. It acts as an endocrine disruptor by mimicking estrogen, influencing the behavior of organisms like crayfish. Crayfish utilize aggressive behaviors to find food, mates, and establish social hierarchies. Here we examine the effects nonylphenol has on aggression after acute and chronic exposures. We hypothesize that there will be a decrease in the crayfish’s aggressive behaviors as the concentration nonylphenol increases. SUBJECTS: 4 studies were conducted with (n=40) crayfish for each test. METHODS AND MATERIALS: Crayfish were obtained from the Grand River water shed. Crayfish were filtered by carapace length from 2.7cm-3cm for carapace length. The crayfish were stored in individual 1L tanks and were exposed to nonylphenol on week 1 of the 4-week trial. Agonistic behaviors were recorded and scored. ANALYSES: A T test and a one-way ANOVA test were used to calculate statistical significance. RESULTS: For the behavioral assay there was a general decrease in aggressive behavior with an increase in both non-aggressive and submissive behaviors. In some individuals there was a decrease total time of aggressive behavior by over 50% from the pretreatment to week 4. CONCLUSION: The results indicate a decrease in aggressive behavior with the increased doses of nonylphenol. As exposure duration increased there was a decrease in overall aggression