Erosion of behavioural plasticity and pace-of-life shifts under multigenerational pharmaceutical pollution

Research Highlight: Aich, U., Polverino, G., Yazdan Parast, F., Melo, G. C., Tan, H., Howells, J., Nosrati, R., & Wong, B. B. M. (2024). Long-term effects of widespread pharmaceutical pollution on trade-offs between behavioural, life history and reproductive traits in fish. Journal of Animal Ecology. . Pharmaceutical pollutants are increasingly common in aquatic ecosystems, and organisms living there are the unintended targets of these compounds, originally designed for humans. However, our understanding of these effects remains limited. In a recent study, Aich et al. (2024) investigated the effects of fluoxetine on a small freshwater fish, the guppy (Poecilia reticulata), with particular emphasis on behaviour. The authors found that, after multigenerational exposure to ecologically relevant concentrations of this compound, there was minimal impact on average behavioural traits at the population level. However, fluoxetine exposure reduced within-individual behavioural plasticity and altered the delicate equilibrium among these traits. These findings could have far-reaching evolutionary implications for how individuals and populations may respond to environmental changes and highlight the need for behavioural ecotoxicology to move beyond population-level effects. This research provides valuable insights into the subtle and multifaceted-yet profound-impacts of pollutants on ecological and evolutionary processes, highlighting the importance of studying behavioural responses at the individual level to predict how populations will respond to our rapidly changing world.