Abstract
Pharmaceutical contaminants are becoming increasingly detected in wastewaters and surface waters globally. These xenobiotic compounds are persistent, resist degradation, and accumulate in aquatic systems. Ibuprofen is a widely consumed, over the counter, anti-inflammatory drug that is among the highest detected pharmaceuticals in these waterways. Its’ sublethal behavioral effects on non-target aquatic vertebrates remains poorly studied. I used male Betta splendens as a model organism to study the interaction between ibuprofen and aggressive behavior. I hypothesized that chronic, waterborne exposure to ibuprofen at environmentally relevant concentrations would decrease aggressive behavior in male B. splendens. Thirty fish were randomly assigned to control, low-dose (2 μg/L), and high-dose (20 μg/L) ibuprofen groups, exposed chronically over 21 days. Aggressive behaviors were assessed weekly using a mirror to simulate intruder events, quantifying the average distance, the number of attacks, duration of opercula flaring, duration of a broadside display, and latency to respond to the mirror stimulus. Aggression intensity measures declined over time across all treatment groups, consistent with habituation to the mirror stimulus. No significant main effects of ibuprofen treatment were detected for average distance, attacks, opercula flaring, or broadside displays. However, latency to respond and the initiation of an aggressive display was significantly affected by ibuprofen treatment. Ibuprofen-exposed fish showed delayed behavioral responsiveness relative to control individuals. Thus, chronic exposure selectively disrupted behavioral responsiveness rather than suppressing aggressive behavior outright. Sublethal pharmaceutical contamination can have subtle but ecologically significant effects on aquatic vertebrates.
Advisor
Lynn, Sharon
Department
Biology
Recommended Citation
Peter, Luke B., "The Effects of Chronic Exposure to NSAIDs on the Aggressive Behavior of Betta splendens" (2026). Senior Independent Study Theses. Paper 13468.
https://openworks.wooster.edu/independentstudy/13468
Publication Date
2026
Degree Granted
Bachelor of Arts
Document Type
Senior Independent Study Thesis
© Copyright 2026 Luke B. Peter