Psychoactive pollution suppresses individual differences in fish behaviour

Giovanni Polverino, Jake M. Martin, Michael G. Bertram, Vrishin R. Soman, Hung Tan, Jack A. Brand, Rachel T. Mason, Bob B.M. Wong

Research output: Contribution to journalArticleResearchpeer-review

25 Citations (Scopus)


Environmental contamination by pharmaceuticals is global, substantially altering crucial behaviours in animals and impacting on their reproduction and survival. A key question is whether the consequences of these pollutants extend beyond mean behavioural changes, restraining differences in behaviour between individuals. In a controlled, two-year, multigenerational experiment with independent mesocosm populations, we exposed guppies (Poecilia reticulata) to environmentally realistic levels of the ubiquitous pollutant fluoxetine (Prozac). Fish (unexposed: n = 59, low fluoxetine: n = 57, high fluoxetine: n = 58) were repeatedly assayed on four separate occasions for activity and risk-taking behaviour. Fluoxetine homogenized individuals' activity, with individual variation in populations exposed to even low concentrations falling to less than half that in unexposed populations. To understand the proximate mechanism underlying these changes, we tested the relative contribution of variation within and between individuals to the overall decline in individual variation. We found strong evidence that fluoxetine erodes variation in activity between but not within individuals, revealing the hidden consequences of a ubiquitous contaminant on phenotypic variation in fish - likely to impair adaptive potential to environmental change.

Original languageEnglish
Article number20202294
Number of pages9
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1944
Publication statusPublished - 10 Feb 2021


  • animal personality
  • behavioural plasticity
  • behavioural types
  • ecotoxicology
  • individuality
  • pharmaceuticals

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