Background
- Many species of terrestrial snails show aggregation behaviour - either in their nightly "roosts" or in the sites they use for hibernation or aestivation. This is true of rock-dwelling species, those associated with human habitation or those living on field margins.
- Many snails prefer to rest in tall vegetation. Fennel stalks stand proud, often above the main level of the vegetation and the snails are usually close to the top. It is thought that Theba prefers above-ground sites in South Australia to aestivate so they can remain cool, but this not likely to apply to over-wintering snails in southern France.
- Several reports suggest that released snails tend to favour one or two directions in which to disperse, which would promote their aggregation, at least initially. However, the slime trials of some snails are known to inhibit the movement of members of the same species.
- Snails are known to respond to olfactory clues, most especially in finding food plants.
