Records of Polycladus gayi (Tricladida, Geoplanidae) preying on the invasive slug Limax maximus (Gastropoda, Limacidae) in Chile's temperate forests

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.