Abstract

Terrestrial planarians are important soil predators of a variety of invertebrate groups, including exotic and invasive mollusc species. However, data on prey in natural conditions are scarce. Polycladus gayi is a giant planarian from the forests of southern Chile whose predatory behaviour is poorly known. Here, we report two cases of predation on Limax maximus, an invasive slug recorded within native forests. We suggest that P. gayi displayed two distinct types of predatory behaviour: (1) helicoidal tube formation and (2) surrounding immobilisation. As the reported distributions of the invasive slug and P. gayi are similar, we suggest this predator-prey interaction might be common. Furthermore, depending on the prey type and size, P. gayi might exhibit different types of predatory behaviour. This knowledge reveals little-known aspects of P. gayi ecology, raising new questions about ecological and conservation issues. © Rodrigo M. Barahona-Segovia et al.