Lazy to prey and eager to run: Behaviour of a Neotropical land planarian (Platyhelminthes: Geoplanidae) in the presence of its prey and predators

Abstract

We analysed the behaviour of a woodlouse-eating Neotropical planarian, Luteostriata abundans, as a predator and as prey and investigated the planarian's ability to detect prey and predator by environmental cues. The results indicate that the planarian detects but does not follow woodlice chemical trails and cannot track the source of remote chemical and mechanical stimuli. We conclude that this woodlouse-eating planarian is likely to be an ambush predator, patrolling the environment and waiting for prey to come near it. As a prey, the planarian escaped during direct contact with two predators and ignored most non-predators. Contact with secretions of a predator and encounters with its slime tracks rarely triggered anti-predator behaviours. However, a non-predatory species that is phylogenetically closely related to a predator also triggered an escape response after contact with anterior and posterior body ends. It has a similar predator-detection ability along the body and shows anti-predator behaviours toward species that are phylogenetically closely related to its predators. The unexpected lack of anti-predator behaviour during encounters with chemical cues may indicate the need for a tactile stimulus for predator identification.