Freshwater mussels of the order Unionida are endangered but play a vital role in aquatic ecosystems. Their larvae (glochidia) temporarily parasitize fish, attaching to gills before maturing into free-living adults. Conservation efforts to reintroduce these mussels are generally supported as Unionids are well-known ecosystem engineers. However, public concern arises due to their parasitic nature. Sebastian Rock’s doctoral thesis investigates how two rare European mussel species affect the behaviour of their fish hosts. The results suggest that mussels can influence host movement and habitat choice, possibly expressing an “extended phenotype”—traits of the parasite affecting the host. In our interview, Sebastian let us know more of how his findings can deepen our understanding of mussel-host interactions and inform future conservation strategies.



Sebastian Rock’s doctoral thesis can be downloaded from DiVA: Glochidiosis and behaviour