Meeting Abstract
Many aquatic animals use olfactory-based navigation to move relative to prey and predators. Two common navigation strategies are used, depending on the flow in the animal’s environment. To move towards or away from odour sources, either in no flow or laminar flow, chemotaxis can be used (moving up or down a chemical gradient), while in turbulent flow, odour-gated rheotaxis is used (moving up or downstream in the presence of an odour). Moreover, searching-for versus avoidance-of odour sources are distinct goals which need not require a simply inverted navigation strategy (there is only one odour source location, but many locations which could be sufficiently far from an odour source). Few studies have tackled this full complexity in one species. Navigation by the great pond snail, Lymnaea stagnalis, presents an interesting case in that they can experience both kinds of flow environments with both attractive (prey) and aversive (predator) odour sources. In a series of behavioural experiments, we are testing whether the snails can switch between chemotaxis and odour-gated rheotaxis, and how navigation differs relative to prey and predator odour sources. The results indicate that L. stagnalis can use either chemotaxis or odour-gated rheotaxis when moving towards at least some prey odour sources. Navigation relative to predator odour sources is categorically distinct, and seems to primarily involve upwards movement rather than horizontal movement away from the odour source. Other interesting results include diminished navigation success relative to plant prey versus greater success relative to protein-based odour sources and evidence that vision is integrated with odour-based navigation, at least in environments without flow.
