Mussel memory: can bivalves learn to fear parasites?

Fear plays a crucial role in predator-prey interactions and can have cascading impacts on the structure of whole ecosystems. Comparable fear effects have recently been described for hosts and their parasites but our understanding of the underlying mechanisms remains limited by the lack of empirical examples. Here, we experimentally tested if bivalves can potentially 'learn to fear' the infective transmission stages (cercariae) of the trematode , and if experienced mussels change their parasite-avoidance behaviour accordingly.