Predation on invasive land gastropods by a Neotropical land planarian

Abstract

Studies on the predatory behaviour of land planarians have focused mainly on established invasive species, while the feeding habits of non-invasive planarians are poorly understood. We analyse the predatory behaviour of Obama ladislavii, a land planarian native to southern Brazil that is common in both natural and human-disturbed areas. Observations were performed in the laboratory. Several groups of invertebrates were offered as possible prey and interactions between these invertebrates and planarians were recorded. Obama ladislavii fed on the introduced land gastropods Bradybaena similaris, Helix aspersa and Deroceras laeve, ignoring other invertebrates. Once potential prey were identified, we tested the ability of O. ladislavii to recognize and follow slime trails, and demonstrated the planarian’s ability to follow chemical trails from prey in the environment. The consumption of exotic species indicates a flexible, generalist diet that is consistent with the ability of O. ladislavii to adapt to environments altered by human activities. Thus, this species may become invasive if introduced outside of its original distribution, but it also has the potential to be used in biological control programs for pest management in its native range.