Brain teaser: are impacts of pharmaceutical pollution on wildlife mediated by brain size?

Release of novel synthetic chemicals into the environment is amongst the fastest-growing agents of global change. This includes psychoactive pharmaceuticals, which can accumulate in the brain tissue of exposed wildlife.

Despite this, no research to date has considered the potential for one key trait to mediate impacts of pharmaceutical exposure: brain size.

Here, I propose a series of world-first experiments testing whether relative brain size mediates impacts of exposure to psychoactive pharmaceuticals in aquatic wildlife, with major potential implications for contaminated populations.

These experiments will capitalise on established long-term artificial selection lines for large and small brain size in the guppy (Poecilia reticulata), which now have a >15% difference in relative brain mass.

Using the guppy, I will carry out four interrelated work packages investigating the potential for psychoactive pharmaceuticals to induce brain size-dependent effects on a range of key traits and behaviours, including learning and cognition (WP 1), reproductive behaviour (WP 2), and anti-predator responses (WP 3), and will examine physiological mechanisms underpinning these potential effects (WP 4).

By harnessing unique experimental approaches and cutting-edge technologies, this project promises to not only reveal a range of previously unknown impacts of pharmaceutical pollution on wildlife but will also provide critical data to regulators to safeguard our vulnerable aquatic ecosystems.