If you think you’re in control, think again.

What invisible forces might be guiding your behaviour, your decisions, your most intimate emotions?

Becky Ripley and Emily Knight take a trip into the bizarre nightmare world of the undergrowth, and watch ‘zombie ants’ stumble forward, blindly following the orders of the deadly fungi controlling their brains.

Parasites often get the upper hand of their hosts, manipulating their behaviour in sometimes horrifying ways. But is that true of humans too? Could we be unknowingly subservient to creatures that live inside us?

Do they wish us well, or might they be plotting our downfall?

Featuring entomologist Dr David Hughes from Penn State University, and neuroscientist John Cryan from University College Cork.

Produced and presented by Becky Ripley and Emily Knight.

First broadcast on BBC Radio 4 in June 2019.